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CN117501472A - Battery cell - Google Patents

Battery cell Download PDF

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Publication number
CN117501472A
CN117501472A CN202280042456.7A CN202280042456A CN117501472A CN 117501472 A CN117501472 A CN 117501472A CN 202280042456 A CN202280042456 A CN 202280042456A CN 117501472 A CN117501472 A CN 117501472A
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CN
China
Prior art keywords
electrode
active material
solid electrolyte
material layer
battery
Prior art date
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Pending
Application number
CN202280042456.7A
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Chinese (zh)
Inventor
大户贵司
大前孝纪
藤本正久
相良晓彦
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Panasonic Intellectual Property Management Co Ltd
Original Assignee
Panasonic Intellectual Property Management Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Priority claimed from PCT/JP2022/023790 external-priority patent/WO2023017673A1/en
Publication of CN117501472A publication Critical patent/CN117501472A/en
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Battery Electrode And Active Subsutance (AREA)

Abstract

The battery of the present disclosure includes a first electrode, a second electrode, and a solid electrolyte layer located between the first electrode and the second electrode, the solid electrolyte layer containing a first solid electrolyte, the first electrode having a base material as a porous body and an active material layer located on a surface of the base material, the active material layer containing an alloy containing Bi and Ni.

Description

Battery cell
Technical Field
The present disclosure relates to a battery.
Background
In recent years, in lithium secondary batteries, which have been actively researched and developed, battery characteristics such as charge/discharge voltage, charge/discharge cycle life characteristics, and storage characteristics are greatly affected by the electrode used. Thus, the electrode active material is improved, whereby the battery characteristics are improved.
For example, lithium secondary batteries using aluminum, silicon, tin, etc. that are electrochemically alloyed with lithium at the time of charging as electrodes have been proposed for a long time. Patent document 1 discloses a lithium secondary battery provided with a negative electrode containing a negative electrode material composed of an alloy having silicon, tin and a transition metal, a positive electrode, and an electrolyte.
Patent document 2 discloses a lithium secondary battery including a negative electrode using a silicon thin film provided on a current collector as an active material, a positive electrode, and an electrolyte.
As the metal alloyed with lithium, bismuth (Bi) is exemplified. Non-patent document 1 discloses a negative electrode produced using Bi powder and containing Bi as a negative electrode active material.
Prior art literature
Patent literature
Patent document 1: japanese patent No. 4898737
Patent document 2: japanese patent No. 3733065
Non-patent literature
Non-patent document 1: synthesis of amorphous polymer negative electrode active material for lithium battery comprising reactant of polyacrylic acid and metal oxide and electrochemical characteristics thereof the substrate is a substrate, and the substrate is a substrate for the electronic battery amorphous substance, polymer, chemical characteristic of the case そ, a substance of the case, a polymer of amorphous substance, a polymer triple university, doctor's paper, 2015
Disclosure of Invention
The present disclosure provides a battery having a structure adapted to improve charge and discharge characteristics.
The battery of the present disclosure is provided with:
a first electrode,
Second electrode, and method for manufacturing the same
A solid electrolyte layer between the first electrode and the second electrode,
the solid electrolyte layer contains a first solid electrolyte,
the first electrode has:
base material as porous body, and method for producing porous body
An active material layer on the surface of the substrate,
The active material layer contains an alloy containing Bi and Ni.
According to the present disclosure, a battery having a structure suitable for improving charge and discharge characteristics may be provided.
Drawings
Fig. 1 is a cross-sectional view schematically showing a structural example of a battery according to an embodiment of the present disclosure.
Fig. 2 is a partially enlarged sectional view schematically showing a structural example of a first electrode in a battery according to an embodiment of the present disclosure.
Fig. 3 is a cross-sectional view schematically showing a modification of the battery according to the embodiment of the present disclosure.
Fig. 4 is a graph showing an example of an X-ray diffraction pattern of an active material layer formed of a BiNi thin film produced on a nickel screen.
Fig. 5 is a graph showing the charge and discharge test results of the test unit of example 1.
Fig. 6 is a graph showing an example of an X-ray diffraction pattern of an active material layer formed of a BiNi thin film produced on porous nickel in example 2.
Fig. 7 is a graph showing the charge and discharge test results of the test unit of example 2.
Fig. 8 is a graph showing an example of an X-ray diffraction pattern of an active material layer formed of a BiNi thin film produced on porous nickel in example 3.
Fig. 9 is a graph showing the charge and discharge test results of the test unit of example 3.
Fig. 10 is a graph showing an example of an X-ray diffraction pattern of an active material layer formed of a BiNi thin film produced on a nickel foil.
Fig. 11 is a graph showing the results of the charge/discharge test of the test unit of reference example 1.
Fig. 12 is a graph showing an example of the X-ray diffraction pattern of the first electrode before, after, and after charging and discharging, for the first electrode used in example 1.
Detailed Description
(insight underlying the present disclosure)
As described in the background section, in the lithium secondary battery, improvement of battery characteristics is achieved by improvement of electrode active materials.
In the case of using lithium metal as the negative electrode active material, a lithium secondary battery having a high energy density per unit weight and unit volume can be obtained. However, in the lithium secondary battery having such a structure, lithium is precipitated in dendrite form during charging. A part of the precipitated lithium metal reacts with the electrolyte, and thus has problems of low charge-discharge efficiency and poor cycle characteristics.
In contrast, it has been proposed to use carbon, particularly graphite, as the negative electrode. In the negative electrode using carbon, charge and discharge are performed by insertion and release of lithium in carbon. In the negative electrode having such a structure, lithium metal does not precipitate in dendrite form in terms of a charge-discharge structure. In addition, in the lithium secondary battery using the negative electrode having such a structure, since the reaction is a topological reaction, the reversibility is very good, and the charge-discharge efficiency is almost 100%. As a result, lithium secondary batteries using negative electrodes using carbon, particularly graphite, have been put into practical use. However, the theoretical capacity density of graphite is 372mAh/g, which is about 1/10 of the theoretical capacity density 3884mAh/g of lithium metal. Therefore, the active material capacity density of the negative electrode using graphite is low. Further, since the actual capacity density of graphite almost reaches the theoretical capacity density, the high capacity has reached a limit in the negative electrode using graphite.
In contrast, lithium secondary batteries using aluminum, silicon, tin, or the like, which is electrochemically alloyed with lithium at the time of charging, as an electrode have been proposed for a long time. The capacity density of metals alloyed with lithium is much greater than that of graphite. In particular, silicon has a high theoretical bulk density. Accordingly, an electrode using aluminum, silicon, tin, or the like alloyed with lithium is expected to be a negative electrode for a battery exhibiting a high capacity, and various secondary batteries using the same as a negative electrode have been proposed (patent document 1).
However, the negative electrode using the metal alloyed with lithium as described above expands when absorbing lithium and contracts when discharging lithium. When such expansion and contraction are repeated during charge and discharge, the alloy itself as the electrode active material is micronized by charge and discharge, and the current collecting characteristics of the negative electrode deteriorate, so that sufficient cycle characteristics are not obtained. In order to improve such drawbacks, the following attempts have been made. For example, there is an attempt to deposit silicon on a collector with a roughened surface by sputtering or vapor deposition, or to deposit tin by electroplating (patent document 2). In this attempt, the active material, i.e., the metal alloyed with lithium, becomes a thin film and is tightly bonded to the current collector, so that even if the negative electrode repeatedly expands and contracts due to the occlusion and release of lithium, the current collector is hardly degraded.
However, as described above, when the active material is formed by sputtering or vapor deposition, the manufacturing cost is high, and it is not practical. It is practical to form the active material by electroplating, which is inexpensive to manufacture, but electroplating of silicon is very difficult. In addition, tin which is easily electroplated lacks discharge flatness, and has a problem that it is difficult to use as an electrode of a battery.
Further, as a metal alloyed with lithium, bismuth (Bi) is exemplified. Bi forms LiBi and Li with lithium (Li) 3 Bi, and the like. Potential and Li of LiBi 3 The potentials of Bi hardly differ from each other. On the other hand, in tin having poor discharge flatness, a compound with lithium is formedThere are a plurality of compounds, and the potentials of the respective compounds greatly differ from each other. That is, bi does not have such a property that the difference in potential between various compounds formed with lithium is large as tin. Therefore, the electrode containing Bi as an active material is excellent in discharge flatness because of flattening of the potential. Therefore, an electrode containing Bi as an active material is considered to be suitable as an electrode of a battery.
However, bi lacks ductility and is difficult to manufacture in the form of a metal plate or foil, and the obtained form is pellets or powder. Therefore, as an electrode containing Bi as an active material, an electrode manufactured by coating Bi powder on a current collector is being studied. However, since an electrode produced using such Bi powder is micronized by repeated charge and discharge, the current collecting characteristics are deteriorated, and thus, sufficient cycle characteristics are not obtained. For example, in non-patent document 1, bi powder is used, and PVdF (polyvinylidene fluoride) or PI (polyimide) is used as a binder to produce an electrode containing Bi as an active material. In non-patent document 1, a battery manufactured using the electrode is charged and discharged. However, the initial charge-discharge curve and cycle characteristics of the fabricated electrode were very poor. Although the measurement was performed at a very low rate equivalent to 0.042IT, the initial charge-discharge efficiency was low, and the cycle degradation was also severe, and thus IT was not practical. Regarding this cycle degradation, non-patent document 1 shows that: it is considered that as the Bi active material expands during Li insertion and contracts during Li release, the active material is miniaturized and cannot form an electron conduction path, resulting in a decrease in capacity.
As described above, the present inventors have paid attention to Bi which is excellent in discharge flatness without having a property of having a large difference in potential from a plurality of compounds formed from Li, and have made intensive studies on a battery capable of improving cycle characteristics. As a result, the present inventors have derived the following new technical ideas: when an alloy containing Bi and Ni is used as an active material, cycle characteristics of the battery are improved.
The present inventors have studied in more detail a battery using an alloy containing Bi and Ni as an active material.
For example, a Bi plating layer is formed by plating Bi on a Ni foil, and heat treatment is performed to cause Ni to be diffused from the Ni foil into the Bi plating layer in a solid phase. Thus, an alloy containing Bi and Ni (for example, biNi) as intermetallic compounds can be synthesized. The alloy containing Bi and Ni is obtained by solid-phase diffusion of Ni from a Ni foil to a Bi plating layer by heat treatment. Thus, the Ni foil that can function as a current collector is firmly bonded to the interface of the BiNi that is an active material, and the degradation of cycle characteristics due to separation at the interface between the current collector and the active material layer caused by expansion and contraction of the active material during charge and discharge of the battery electrode can be improved.
However, the inventors of the present invention have further studied and found that there is room for improvement in charge/discharge characteristics, such as initial efficiency, of the electrode obtained by synthesizing an alloy containing Bi and Ni using a Bi plating layer formed on a Ni foil as described above. The present inventors have studied specifically on the charge/discharge characteristics of an electrode having a structure in which Bi is plated on a Ni foil and heat-treated to synthesize BiNi and an alloy containing Bi and Ni is provided on the Ni foil. Specifically, for using an electrode having a structure in which BiNi is provided on a Ni foil as a Bi-and Ni-alloy-containing electrode as a working electrode, indium-lithium metal as a counter electrode, and Li as a solid electrolyte in an electrolyte layer 3 YBr 4 Cl 2 Is charged and discharged. As a result, the initial charge capacity was 70% or less, the discharge capacity was 60% or less, and the initial efficiency was 79.8% relative to 300mAh/g of the theoretical capacity of BiNi.
The inventors of the present invention have further advanced studies to find the cause of low charge/discharge capacity and initial efficiency of a battery in the case of using an electrode having a structure in which an alloy containing Bi and Ni is provided on a Ni foil as follows.
The reason why the charge-discharge capacity is low and the initial efficiency is also low with respect to the theoretical capacity is considered to be that the Bi and Ni-containing alloy as the active material, for example, the Bi Ni originally has a property of slow in-solid phase diffusion, and the interface amount between the active material layer and the electrolyte is small in the Bi and Ni-containing alloy synthesized by heat treatment from the Bi plating layer on the Ni foil, and thus the resistance at the time of Li ion conduction is large.
As a result of intensive studies, the present inventors have found that, in an electrode containing an alloy containing Bi and Ni as an active material, by forming an alloy containing Bi and Ni on the surface of a porous body as a base material, and forming a layer containing the formed alloy containing Bi and Ni as an active material layer, charge/discharge characteristics can be improved, and completed the present disclosure.
(summary of one mode of the disclosure)
The battery according to claim 1 of the present disclosure includes:
a first electrode,
Second electrode, and method for manufacturing the same
A solid electrolyte layer between the first electrode and the second electrode,
the solid electrolyte layer contains a first solid electrolyte,
the first electrode has:
base material as porous body, and method for producing porous body
An active material layer on the surface of the substrate,
the active material layer contains an alloy containing Bi and Ni.
The area where the active material and the solid electrolyte can contact is larger when the active material layer is formed on the surface of the substrate as a porous body than when the active material layer is formed on the surface of the foil-shaped substrate. Therefore, in the battery according to claim 1, when the same amount of active material is provided on the substrate, the active material layer can be formed thinner than when the active material layer is provided on the foil-shaped substrate. Thus, in the active material layer containing an alloy containing Bi and Ni, the load characteristics due to solid-phase internal diffusion of Li ions are improved, and particularly, the load characteristics at the time of discharge are improved. Therefore, the battery according to embodiment 1 can improve charge/discharge characteristics, for example, initial efficiency. In this way, the battery of embodiment 1 has a structure suitable for improving charge/discharge characteristics.
In embodiment 2 of the present disclosure, for example, the battery according to embodiment 1, the active material layer may contain BiNi.
The battery according to claim 2 can further improve the charge/discharge characteristics.
In the 3 rd aspect of the present disclosure, for example, the battery according to the 2 nd aspect, the active material layer may contain the BiNi as a main component of the active material.
The battery of mode 3 has a higher capacity and improved charge-discharge characteristics.
In the 4 th aspect of the present disclosure, for example, the battery according to the 3 rd aspect, the active material layer may substantially contain only the BiNi as an active material.
The battery of mode 4 has a higher capacity and improved charge-discharge characteristics.
In the 5 th aspect of the present disclosure, for example, the battery according to any one of the 2 nd to 4 th aspects, the BiNi may have a crystal structure in which a space group belongs to C2/m.
The battery of mode 5 has a higher capacity and improved charge-discharge characteristics.
In embodiment 6 of the present disclosure, for example, the battery according to any one of embodiments 1 to 5, the active material layer may contain a material selected from the group consisting of LiBi and Li 3 At least one of Bi.
The battery of mode 6 has a higher capacity and improved charge-discharge characteristics.
In the 7 th aspect of the present disclosure, for example, the battery according to any one of the 1 st to 6 th aspects, the active material layer may not contain an electrolyte.
The battery of mode 7 has a higher capacity and improved charge-discharge characteristics.
In embodiment 8 of the present disclosure, for example, the battery according to any one of embodiment 1 to embodiment 7, the base material may contain Ni.
The battery of mode 8 has a higher capacity and improved charge-discharge characteristics.
In the 9 th aspect of the present disclosure, for example, the battery according to any one of the 1 st to 8 th aspects, the active material layer may be a heat-treated plating layer.
The battery of mode 9 has a higher capacity and improved charge-discharge characteristics.
In a 10 th aspect of the present disclosure, for example, the battery according to any one of the 1 st to 9 th aspects, the first solid electrolyte may contain a first halide solid electrolyte, and the first halide solid electrolyte may contain substantially no sulfur.
The battery of mode 10 has a higher capacity and improved charge-discharge characteristics.
In the 11 th aspect of the present disclosure, for example, the battery according to any one of the 1 st to 10 th aspects, the first solid electrolyte may contain a first sulfide solid electrolyte.
The battery of mode 11 has a higher capacity and improved charge-discharge characteristics.
In a 12 th aspect of the present disclosure, for example, the battery according to any one of the 1 st to 11 th aspects, the first electrode may further include a second solid electrolyte in contact with the active material layer.
In the battery according to claim 12, in the first electrode, the active material layer is located on the surface of the substrate as the porous body, and the solid electrolyte (i.e., the second solid electrolyte) is provided in contact with the active material layer. According to this structure, in the first electrode, the interface area between the active material and the solid electrolyte increases, and therefore the interface resistance between the active material and the solid electrolyte can be reduced. Therefore, the battery of claim 12 has good charge/discharge characteristics. In this way, the battery of claim 12 has a structure suitable for improving charge/discharge characteristics.
In mode 13 of the present disclosure, for example, the battery according to mode 12, the second solid electrolyte may contain a second halide solid electrolyte, and the second halide solid electrolyte may contain substantially no sulfur.
The battery of mode 13 is safer and has improved charge-discharge characteristics.
In the 14 th aspect of the present disclosure, for example, the battery according to the 13 th aspect, the second halide solid electrolyte may also be represented by the following composition formula (1).
Li α M β X γ (1)
Wherein,
alpha, beta and gamma are values greater than 0,
m is at least one selected from the group consisting of metallic elements other than Li and metalloid elements,
x is at least one selected from F, cl, br and I.
The battery of embodiment 14 has further improved charge and discharge characteristics.
In the 15 th aspect of the present disclosure, for example, the battery according to the 14 th aspect, in the composition formula (1), the M may contain Y.
The battery of embodiment 15 has further improved charge and discharge characteristics.
In the 16 th aspect of the present disclosure, for example, the battery according to the 14 th or 15 th aspect, in the composition formula (1), the X may be at least 1 selected from Cl, br, and I.
The battery of mode 16 has further improved charge-discharge characteristics.
In the 17 th aspect of the present disclosure, for example, the battery according to any one of the 14 th to 16 th aspects, the second solid electrolyte may contain a material selected from Li 3 YBr 3 Cl 3 And Li (lithium) 3 YBr 2 Cl 4 At least one of them.
The battery of embodiment 17 has further improved charge and discharge characteristics.
In the 18 th aspect of the present disclosure, for example, the battery according to any one of the 12 th to 17 th aspects, the second solid electrolyte may contain a second solid electrolyte.
The battery of mode 18 has a higher capacity and improved charge-discharge characteristics.
In the 19 th aspect of the present disclosure, for example, the battery according to any one of the 12 th to 18 th aspects, the second solid electrolyte may be contained in the pores of the base material.
In the battery according to claim 19, the second solid electrolyte is contained in the pores of the substrate, that is, the pores of the porous body, in the first electrode. According to this structure, the battery of mode 19 has a higher capacity and improved charge-discharge characteristics.
In a 20 th aspect of the present disclosure, for example, the battery according to any one of the 1 st to 19 th aspects, the first electrode may be a negative electrode, and the second electrode may be a positive electrode.
The battery of mode 20 has a higher capacity and improved charge-discharge characteristics.
(embodiments of the present disclosure)
Embodiments of the present disclosure are described below with reference to the drawings. The following description refers to general or specific examples. The numerical values, compositions, shapes, film thicknesses, electrical characteristics, structures of secondary batteries, and the like shown below are examples, and are not intended to limit the present disclosure.
Fig. 1 is a cross-sectional view schematically showing a structural example of a battery 1000 according to an embodiment of the present disclosure.
The battery 1000 includes a first electrode 101, a second electrode 103, and a solid electrolyte layer 102 between the first electrode 101 and the second electrode 103. Fig. 2 is a partially enlarged sectional view schematically showing a structural example of the first electrode 101 of the battery 1000 according to the embodiment of the present disclosure. As shown in fig. 2, the first electrode 101 has a substrate 105 as a porous body and an active material layer 106 located on the surface of the substrate 105. The active material layer 106 contains an alloy containing Bi and Ni. The active material layer 106 contains, for example, biNi as an alloy containing Bi and Ni.
As shown in fig. 1, the battery 1000 of the present embodiment may further include a first current collector 100 in contact with the first electrode 101, for example. The battery 1000 of the present embodiment may further include, for example, a second current collector 104 in contact with the second electrode 103. By providing the first current collector 100 and the second current collector 104, electricity can be taken out of the battery 1000 with high efficiency.
In the battery 1000, in the first electrode 101, an active material layer 106 including an alloy containing Bi and Ni is formed on the surface of a base material 105 as a porous body. For example, as shown in fig. 2, an active material layer 106 is also formed on the inner walls of the pores of the substrate 105. Therefore, in the battery 1000, regarding the area where the active material and the solid electrolyte can contact, the area of the active material layer 106 is larger when the active material layer 106 is formed on the surface of the substrate 105 as a porous body than on the surface of the foil-shaped substrate. Therefore, in the battery 1000, when the same amount of active material is provided on the substrate, the active material layer 106 can be formed thinner than when the active material is provided on the foil-shaped substrate. Thus, in the active material layer 106 including an alloy containing Bi and Ni, the load characteristics due to solid-phase internal diffusion of Li ions, for example, the load characteristics at the time of discharge are improved. Therefore, the battery of the present embodiment can improve charge and discharge characteristics, and particularly can improve initial efficiency. As described above, the battery 1000 of the present embodiment has a structure suitable for improving charge and discharge characteristics.
In the first electrode 101 shown in fig. 2, the active material layer 106 is formed in a thin film on the inner wall of the hole of the substrate 105, and the hole is present in a relatively high porosity state. However, the first electrode 101 is not limited to this structure. The first electrode 101 may be an electrode in which the active material layer 106 substantially fills the pores of the substrate 105 and the porosity is low, for example. Even in the case where the first electrode 101 has such a structure, the boundary between the base material 105 and the active material layer 106 can be clearly confirmed, and it can be said that in the first electrode 101, the base material 105 is a porous body, and the active material layer 106 is formed on the surface of the base material 105. The active material layer 106 may be formed on part of the inner wall of the plurality of holes or on almost all of the inner wall.
A modification of the battery 1000 according to the embodiment of the present disclosure will be described. Fig. 3 is a cross-sectional view schematically showing a modification of the battery according to the embodiment of the present disclosure.
The battery 2000 shown in fig. 3 is different from the battery 1000 in that a second solid electrolyte 107 in contact with the active material layer 106 is further provided, but the structure other than the second solid electrolyte 107 is the same as the battery 1000.
The battery 2000 includes a first electrode 101, a second electrode 103, and a solid electrolyte layer 102 between the first electrode 101 and the second electrode 103. The first electrode 101 has a substrate 105 as a porous body, an active material layer 106 on the surface of the substrate 105, and a second solid electrolyte 107 in contact with the active material layer 106. The active material layer 106 contains an alloy containing Bi and Ni. The active material layer 106 contains, for example, biNi as an alloy containing Bi and Ni.
As shown in fig. 3, the battery 2000 may further include, for example, a first current collector 100 in contact with the first electrode 101, as in the battery 1000 according to the embodiment of the present disclosure. In addition, the battery 2000 may further include, for example, a second current collector 104 in contact with the second electrode 103, similarly to the battery 1000 according to the embodiment of the present disclosure. By providing the first current collector 100 and the second current collector 104, electricity can be taken out of the battery 2000 with high efficiency.
In the battery 2000, in the first electrode 101, an active material layer 106 including an alloy containing Bi and Ni is formed on the surface of a base material 105 as a porous body. For example, as shown in fig. 3, an active material layer 106 is also formed on the inner walls of the pores of the substrate 105. In addition, in the battery 2000, the first electrode 101 also has a second solid electrolyte 107 in contact with the active material layer 106. For example, the second solid electrolyte 107 may also be contained in the pores of the substrate 105. Therefore, in the battery 2000, regarding the area where the active material and the solid electrolyte can contact, the area of the active material layer 106 is larger when the active material layer 106 is formed on the surface of the substrate 105 as a porous body than on the surface of the foil-shaped substrate. Therefore, in the battery 2000, when the same amount of active material is provided on the substrate, the active material layer 106 can be formed thinner than when the active material is provided on the foil-shaped substrate. Thus, in the active material layer 106 including an alloy containing Bi and Ni, the load characteristics due to solid-phase internal diffusion of Li ions, for example, the load characteristics at the time of discharge are improved. Therefore, the battery 2000 of the present embodiment can improve charge and discharge characteristics, and particularly can improve initial efficiency. As described above, the battery 2000 of the present embodiment has a structure suitable for improving charge and discharge characteristics.
In the first electrode 101 shown in fig. 3, the active material layer 106 is formed in a thin film on the inner wall of the hole of the base material 105, and the inner region of the active material layer 106 is almost filled with the second solid electrolyte 107. In this way, the first electrode 101 may be an electrode in which the inside of the hole of the base material 105 is almost filled with the active material layer 106 and the second solid electrolyte 107, and thus the porosity becomes low. Even in the case where the first electrode 101 has such a structure, the boundary between the base material 105 and the active material layer 106 can be clearly confirmed, and it can be said that in the first electrode 101, the base material 105 is a porous body, and the active material layer 106 is formed on the surface of the base material 105. The active material layer 106 may be formed on part of the inner wall of the plurality of holes or on almost all of the inner wall.
The battery 1000 and the battery 2000 are, for example, lithium secondary batteries. In the following, a case where the metal ions stored and released in the active material layer 106 of the first electrode 101 and the second electrode 103 are lithium ions during charge and discharge of the battery 1000 and the battery 2000 will be described as an example.
As described above, the substrate 105 is a porous body. In the present specification, the porous body refers to a structure having a plurality of pores and including open pores in which the pores are open to the outside. Examples of the porous body in the present specification include a mesh (mesh) and a porous structure. The porous structure is a structure made of a porous material having a plurality of pores, and the size of the pores is not particularly limited. Examples of the porous structure include a foam. The porous structure may be a three-dimensional network structure in which pores communicate with each other. In this specification, the term "pore" includes both a clogged active material layer and an unblocked active material layer. That is, a structure in which, for example, an active material layer is blocked inside is also regarded as "pores".
The substrate 105 has conductivity, for example. The base material 105 may be formed of a conductive material such as a metal, or a conductive film made of a conductive material may be provided on the surface of a porous body (for example, foamed resin) made of a nonconductive material such as a resin. The substrate 105 may be, for example, a metal mesh or a porous metal. The substrate 105 may function as a current collector of the first electrode 101. That is, in the case where the first current collector 100 is provided, for example, the first current collector 100 and the base material 105 function as current collectors of the first electrode 101. When the first current collector 100 is not provided, for example, the base material 105 functions as a current collector of the first electrode 101.
The base material 105 may contain Ni, for example. The substrate 105 may be, for example, nickel mesh or porous nickel.
As described above, the active material layer 106 contains, for example, biNi as an alloy containing Bi and Ni. The active material layer 106 may contain BiNi as a main component. Here, "the active material layer 106 contains BiNi as a main component" is defined as "the content ratio of BiNi in the active material layer 106 is 50 mass% or more". The content ratio of BiNi in the active material layer 106 can be determined by, for example, confirming that Bi and Ni are contained in the active material layer 106 by elemental analysis by EDX (energy dispersive X-ray analysis), and calculating the ratio of the contained compounds by Rietveld analysis on the X-ray diffraction result of the active material layer 106.
With the above structure, improved charge and discharge characteristics can be obtained.
The active material layer 106 containing BiNi as a main component may be formed of, for example, biNi formed in a film shape (hereinafter referred to as a "BiNi film").
The active material layer 106 made of a BiNi thin film can be produced by electroplating, for example. A method of manufacturing the first electrode 101 by manufacturing the active material layer 106 by electroplating is as follows, for example.
First, a plated substrate is prepared. As a base material for plating, for example, a porous body which can constitute the base material 105 when the first electrode 101 is formed is used. As the substrate for plating, for example, a metal mesh or a porous metal is used. As the plating base material, for example, nickel mesh or porous nickel may be used. The porous body used as the base material for plating is not particularly limited as long as it can constitute the base material 105 when the first electrode is formed by a process such as plating or pressurizing, and therefore, the structure thereof can be appropriately selected according to the structure of the first electrode 101 as a target. As an example, the porous body used as the base material for plating may have a thickness of, for example, 0.014m 2 /cm 3 Above and 0.036m 2 /cm 3 The specific surface area is as follows.
As an example, nickel mesh was prepared as a base material for plating. Degreasing nickel screen with organic solvent, immersing in acidic solvent for degreasing to make nickel screen surface active And (5) melting. The activated nickel screen is connected to a power source to enable the application of an electrical current. A nickel screen connected to a power supply is immersed in a bismuth plating bath. As the bismuth plating bath, for example, bi-containing plating bath is used 3+ Organic acid bath of ions and organic acids. Then, current is applied to the nickel screen by controlling the current density and the application time, and Bi is plated on the surface of the nickel screen. After the plating, the nickel screen was recovered from the plating bath, and after the mask was removed, it was washed with pure water and dried. By these methods, a Bi plating layer was formed on the surface of the nickel screen. The bismuth plating bath used for producing the Bi plating layer is not particularly limited, and may be appropriately selected from known bismuth plating baths capable of depositing a Bi simple substance film. In the bismuth plating bath, as the organic acid bath, an organic sulfonic acid bath, a gluconic acid and ethylenediamine tetraacetic acid (EDTA) bath, or a citric acid and EDTA bath may be used. In addition, a sulfuric acid bath, for example, can be used as the bismuth plating bath. In addition, additives may be added to the bismuth plating bath.
Even when porous nickel is used as a base material for plating, for example, a Bi plating layer can be produced in the same manner as described above.
In the case where nickel foil, nickel mesh and porous nickel are used as the plating base, the plating quality of Bi produced by the above method is shown in table 1. When a nickel foil is used as a base material for plating, the nickel foil is pre-degreased with an organic solvent, and then one surface is masked and immersed in an acidic solvent to thereby degrease and activate the surface of the nickel foil. Then, the nickel foil was immersed in a bismuth plating bath, and Bi was plated on the surface of the nickel foil to which no mask was applied.
TABLE 1
Then, the nickel net and the Bi plating layer formed on the nickel net are heated. By this heat treatment, ni is diffused from the nickel mesh as a base material into the Bi-plated solid phase, and an active material layer composed of a BiNi thin film can be produced. Here, the active material layer formed of a BiNi thin film can be produced by performing a heat treatment at a temperature of 250 ℃ or higher for 30 minutes or more and less than 100 hours in a non-oxidizing atmosphere on a sample in which Bi is plated on the nickel mesh, and performing solid-phase internal diffusion of Ni from the nickel mesh into the Bi plating layer.
The sample obtained by plating Bi on the nickel mesh was subjected to heat treatment at 400 ℃ for 60 hours in an argon atmosphere, to thereby prepare an active material layer composed of a BiNi thin film.
The active material layer formed of the BiNi thin film produced on the nickel screen was also subjected to surface structural analysis by surface X-ray diffraction measurement.
Fig. 4 is a graph showing an example of an X-ray diffraction pattern of an active material layer formed of a BiNi thin film produced on a nickel screen. The X-ray diffraction pattern was obtained from the surface of the active material layer, that is, the thickness direction of the active material layer, using an X-ray diffraction apparatus (manufactured by RIGAKU, miNi Flex) at a wavelength And->Is measured by a theta-2 theta method using Cu-K alpha rays as X-rays. From the X-ray diffraction pattern shown in FIG. 4, the phase of BiNi belonging to C2/m as a space group of crystal structure and Ni contained in the nickel mesh and active material layer as a base material was determined.
For BiNi formed when a porous body such as porous nickel is used as a base material, biNi having a space group of C2/m can be synthesized by electroplating and heat treatment in the same manner. That is, in the battery 1000 of the present embodiment, the active material layer 106 containing BiNi included in the first electrode 101 may be, for example, a heat-treated plating layer produced as described above. In the battery 1000 of the present embodiment, biNi contained in the active material layer 106 of the first electrode 101 has a crystal structure in which the space group is C2/m, for example.
In the case of manufacturing the first electrode 101 in the battery 2000, that is, the first electrode 101 having a structure in which the second solid electrolyte 107 is provided, as described above, after the active material layer 106 containing BiNi is formed on the surface of the substrate 105, the second solid electrolyte 107 is formed in contact with the active material layer 106. The second solid electrolyte 107 is not particularly limited as long as it is formed so as to be in contact with the active material layer 106. For example, the second solid electrolyte 107 may be formed by a liquid phase method. The second solid electrolyte 107 may be formed by filling, for example, a powder-like solid electrolyte in an inner region of the active material layer 106 formed in a thin film on the inner wall of the hole of the base material 105. In the case where the second solid electrolyte 107 is formed by a liquid phase method, for example, a solution in which a raw material of the second solid electrolyte 107 is dispersed or dissolved in a solvent is prepared, the substrate 105 on which the active material layer 106 is formed is immersed in the solution, and then the solvent is removed, whereby the second solid electrolyte 107 is formed. The heat treatment may be performed after the solvent is removed.
Hereinafter, each structure of the battery 1000 and the battery 2000 according to the present embodiment will be described in more detail, taking a case where the first electrode 101 is a negative electrode and the second electrode 103 is a positive electrode as an example. Hereinafter, the battery 1000 and the battery 2000 according to the present embodiment will be simply referred to as the battery according to the present embodiment.
[ first electrode ]
As described above, the first electrode 101 has the substrate 105 as a porous body and the active material layer 106 located on the surface of the substrate 105. The second solid electrolyte 107 may also be provided in contact with the active material layer 106. The constitution of the base material 105, the active material layer 106, and the second solid electrolyte 107 is described above and in more detail below.
For example, the first electrode 101 functions as a negative electrode. Accordingly, the active material layer 106 contains a negative electrode active material having a property of occluding and releasing lithium ions. The active material layer 106 contains an alloy containing Bi and Ni, and the alloy containing Bi and Ni functions as a negative electrode active material. The active material layer 106 contains, for example, biNi as an active material. The BiNi in the active material layer 106 has a crystal structure in which space groups belong to C2/m, for example.
Bi is a metal element alloyed with lithium. On the other hand, since Ni does not alloy with lithium, it is presumed that Ni-containing alloy is active on the negative electrode when lithium atoms accompanying charge and discharge are released and intercalated The load of the crystal structure of the substance is reduced, and the reduction of the capacity maintenance rate of the battery is suppressed. When BiNi functions as a negative electrode active material, bi forms an alloy with lithium during charging, thereby occluding lithium. That is, in the active material layer 106, a lithium bismuth alloy is generated when the battery of the present embodiment is charged. The lithium bismuth alloy produced contains, for example, a material selected from the group consisting of LiBi and Li 3 At least one of Bi. That is, when the battery of the present embodiment is charged, the active material layer 106 contains, for example, a material selected from the group consisting of LiBi and Li 3 At least one of Bi. When the battery of this embodiment is discharged, lithium is released from the lithium bismuth alloy, and the lithium bismuth alloy is restored to BiNi.
The BiNi as the negative electrode active material reacts, for example, as follows during charge and discharge of the battery of the present embodiment. Further, the following reaction is exemplified in that the lithium bismuth alloy formed at the time of charging is Li 3 Examples of Bi.
Charging: biNi+3Li++3e －－ →Li 3 Bi+Ni
Discharging: li (Li) 3 Bi+Ni→BiNi+3Li++3e －－
The active material layer 106 may contain substantially only BiNi as an active material. In this case, the battery of the present embodiment can have an increased capacity and improved cycle characteristics. The phrase "the active material layer 106 contains substantially only BiNi as an active material" means that, for example, the active material contained in the active material layer 106 contains 1 mass% or less of active materials other than BiNi. The active material layer 106 may contain only BiNi as an active material.
The active material layer 106 may not contain an electrolyte. For example, the active material layer 106 may be a layer made of BiNi and/or a lithium bismuth alloy and nickel that are generated during charging. The electrolyte referred to herein is a liquid or solid electrolyte having lithium ion conductivity.
The active material layer 106 may be disposed in direct contact with the surface of the substrate 105. In the case where the battery of the present embodiment includes the first current collector 100, the base material 105 may be disposed in contact with the first current collector 100.
The active material layer 106 may be thin film-shaped.
The active material layer 106 may be a heat-treated plating layer. The active material layer 106 may be a heat-treated plating layer provided in direct contact with the surface of the substrate 105. That is, as described above, the active material layer 106 may be a layer formed by heat-treating a Bi plating layer formed on the surface of the Ni-containing substrate 105.
If the active material layer 106 is a heat-treated plating layer provided in direct contact with the surface of the substrate 105, the active material layer 106 is firmly and tightly bonded to the substrate 105. This can further suppress deterioration of the current collecting characteristics of the first electrode 101 caused when the active material layer 106 repeatedly expands and contracts. Therefore, the charge/discharge characteristics of the battery of the present embodiment are further improved. Further, if the active material layer 106 is a heat-treated plating layer, the active material layer 106 contains Bi alloyed with lithium at a high density, and thus further higher capacity can be achieved.
The active material layer 106 may contain a material other than an alloy containing Bi and Ni.
The active material layer 106 may further contain a conductive material.
Examples of the conductive material include carbon materials, metals, inorganic compounds, and conductive polymers. Examples of the carbon material include graphite, acetylene black, carbon black, ketjen black, carbon whiskers, needle coke, and carbon fibers. Examples of the graphite include natural graphite and artificial graphite. Examples of the natural graphite include bulk graphite and flake graphite. Examples of the metal include copper, nickel, aluminum, silver, and gold. Examples of the inorganic compound include tungsten carbide, titanium carbide, tantalum carbide, molybdenum carbide, titanium boride and titanium nitride. These materials may be used alone or in combination of two or more.
The active material layer 106 may further contain a binder.
Examples of the binder include fluorine-containing resins, thermoplastic resins, ethylene propylene diene monomer rubber (EPDM) rubber, sulfonated EPDM rubber, and Natural Butyl Rubber (NBR). Examples of the fluorine-containing resin include Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluororubber. Examples of the thermoplastic resin include polypropylene and polyethylene. These materials may be used alone or in combination of two or more.
The thickness of the active material layer 106 is not particularly limited, and may be, for example, 0.1 μm or more and 100 μm or less.
The material of the substrate 105 is, for example, an elemental metal or an alloy. More specifically, the metal may be an elemental metal or an alloy containing at least one selected from copper, chromium, nickel, titanium, platinum, gold, aluminum, tungsten, iron, and molybdenum. The substrate 105 may also be stainless steel.
The substrate 105 may also contain nickel (Ni).
The structure of the substrate 105 is as described above. The substrate 105 may also be considered as a current collector or part of a current collector of the first electrode 101.
The second solid electrolyte 107 may also include a second halide solid electrolyte. The second halide solid electrolyte is substantially free of sulfur.
In the present specification, the halide solid electrolyte means a solid electrolyte containing a halogen element. The halide solid electrolyte may contain not only a halogen element but also oxygen. The halide solid electrolyte does not contain sulfur (S).
The second halide solid electrolyte is composed of Li, M, and X, M contains at least one selected from the group consisting of a metal element other than Li and a metalloid element, and X may be at least one selected from the group consisting of F, cl, br, and I.
The second solid electrolyte 107 may be made substantially of Li, M, and X. The phrase "the second solid electrolyte 107 is substantially composed of Li, M, and X" means that the ratio (i.e., mole fraction) of the total mass of Li, M, and X to the total mass of all elements constituting the second solid electrolyte 107 in the second solid electrolyte 107 is 90% or more. As an example, the ratio (i.e., mole fraction) may be 95% or more. The second solid electrolyte may also be composed of only Li, M, and X.
The second halide solid electrolyte may be a material represented by the following composition formula (1), for example.
Li α M β X γ (1)
Wherein α, β and γ are values greater than 0, M is at least one selected from the group consisting of metallic elements other than Li and metalloid elements, and X is at least one selected from the group consisting of F, cl, br and I.
The "metalloid elements" are B, si, ge, as, sb and Te.
The "metal element" is all elements contained in groups 1 to 12 of the periodic table except hydrogen, and all elements contained in groups 13 to 16 except B, si, ge, as, sb, te, C, N, P, O, S and Se. That is, the group of elements is capable of becoming a cation when forming an inorganic compound with a halogen element.
In order to improve the ion conductivity, M may contain at least one element selected from the group consisting of a group 1 element, a group 2 element, a group 3 element, a group 4 element, and a lanthanoid element.
Examples of group 1 elements are Na, K, rb or Cs. Examples of group 2 elements are Mg, ca, sr or Ba. Examples of group 3 elements are Sc or Y. Examples of group 4 elements are Ti, zr or Hf. An example of a lanthanide is La, ce, pr, nd, sm, eu, gd, tb, dy, ho, er, tm, yb or Lu.
In order to improve ion conductivity, M may contain a group 5 element, a group 12 element, a group 13 element, or a group 14 element.
Examples of group 5 elements are Nb or Ta. An example of a group 12 element is Zn. Examples of group 13 elements are Al, ga, in. An example of a group 14 element is Sn.
In order to further improve the ion conductivity, M may contain at least one element selected from Na, K, mg, ca, sr, ba, sc, Y, zr, hf, la, ce, pr, nd, sm, eu, gd, tb, dy, ho, er, tm, yb and Lu.
In order to further improve the ion conductivity, M may contain at least one element selected from Mg, ca, sr, Y, sm, gd, dy and Hf.
In order to further improve ion conductivity, M may contain Y.
In order to further improve the ion conductivity, X may contain at least one selected from Br, cl, and I.
X may also contain Br, cl and I in order to further increase ionic conductivity.
In the composition formula (1), M may contain Y, and X may contain Cl and Br. The second halide solid electrolyte may also be, for example, one selected from Li 3 YBr 3 Cl 3 And Li (lithium) 3 YBr 2 Cl 4 At least one of them. That is, the second solid electrolyte 107 may contain Li 3 YBr 3 Cl 3 And Li (lithium) 3 YBr 2 Cl 4 At least one of them.
As the second halide solid electrolyte, for example, li may also be used 3 (Ca,Y,Gd)X 6 、Li 2 MgX 4 、Li 2 FeX 4 、Li(Al,Ga,In)X 4 、Li 3 (Al,Ga,In)X 6 LiI, etc. Wherein, in these solid electrolytes, the element X is at least one selected from F, cl, br, and I. In the present disclosure, when an element In the formula is expressed as "(Al, ga, in)", the expression means at least 1 element selected from the group of elements In parentheses. That is, "(Al, ga, in)" is synonymous with "at least one selected from Al, ga, and In". As are other elements.
Another example of a second halide solid electrolyte is a solid electrolyte made of Li a Me b Y c X 6 A compound represented by the formula (I). Wherein a+mb+3c=6 and c are satisfied>0.Me is at least one selected from the group consisting of metal elements other than Li and Y and metalloid elements. m represents the valence of Me. The "metalloid element" and the "metal element" are as described above.
In order to increase the ionic conductivity of the second halide solid electrolyte material, me may be at least one selected from Mg, ca, sr, ba, zn, sc, al, ga, bi, zr, hf, ti, sn, ta and Nb. The halide solid electrolyte may also be Li 3 YCl 6 、Li 3 YBr 6 Or Li (lithium) 3 YBr p Cl 6-p . Furthermore, p satisfies 0<p<6。
The second solid electrolyte 107 may also contain a second sulfide solid electrolyte.
Herein, the sulfide solid electrolyte refers to a solid electrolyte containing sulfur (S). The sulfide solid electrolyte may contain not only sulfur but also a halogen element.
As the second sulfide solid electrolyte, li, for example, can be used 2 S-P 2 S 5 、Li 2 S-SiS 2 、Li 2 S-B 2 S 3 、Li 2 S-GeS 2 、Li 3.25 Ge 0.25 P 0.75 S 4 Or Li (lithium) 10 GeP 2 S 12 Etc.
The second solid electrolyte 107 may also include an oxide solid electrolyte, a polymer solid electrolyte, or a complex hydride solid electrolyte.
The thickness of the first electrode 101 may be 10 μm or more and 2000 μm or less. That is, the entire thickness of the substrate 105 as a porous body having the active material layer 106 provided on the surface thereof may be 10 μm or more and 2000 μm or less. By having such a thickness of the first electrode 101, the battery can operate at a high output.
[ first collector ]
In the battery of the present embodiment, the first current collector 100 may or may not be provided. The first current collector 100 is provided in contact with the first electrode 101, for example. The first current collector 100 is provided in contact with the substrate 105 of the first electrode 101, for example. By providing the first current collector 100, electricity can be taken out from the battery of the present embodiment with high efficiency.
The material of the first current collector 100 is, for example, elemental metal or alloy. More specifically, the metal may be an elemental metal or an alloy containing at least one selected from copper, chromium, nickel, titanium, platinum, gold, aluminum, tungsten, iron, and molybdenum. The first current collector 100 may be stainless steel.
The first current collector 100 may also contain nickel (Ni).
The first current collector 100 may be plate-shaped or foil-shaped. The first current collector 100 may be a metal foil from the viewpoint of ensuring high conductivity. The thickness of the first current collector 100 may be, for example, 5 μm or more and 20 μm or less.
The first current collector 100 may be a laminated film.
[ solid electrolyte layer ]
As the first solid electrolyte contained in the solid electrolyte layer 102, a halide solid electrolyte (i.e., a first halide solid electrolyte), a sulfide solid electrolyte (i.e., a first sulfide solid electrolyte), an oxide solid electrolyte, a polymer solid electrolyte, or a complex hydride solid electrolyte may also be used.
The first solid electrolyte may also include a first halide solid electrolyte. Examples of the first halide solid electrolyte are the same as those of the second halide solid electrolyte described above.
The first solid electrolyte may also include a first sulfide solid electrolyte. Examples of the first sulfide solid electrolyte are the same as those of the second sulfide solid electrolyte described above.
As the oxide solid electrolyte, for example, liTi can be used 2 (PO 4 ) 3 NASICON type solid electrolyte represented by element substitution body thereof, (LaLi) TiO 3 Perovskite-based solid electrolyte comprising Li 14 ZnGe 4 O 16 、Li 4 SiO 4 、LiGeO 4 Lisicon type solid electrolyte represented by element substitution body thereof, and lithium ion secondary battery 7 La 3 Zr 2 O 12 Garnet-type solid electrolyte represented by element substitution body thereof, and lithium ion secondary battery 3 PO 4 And N-substituted body thereof, and LiBO 2 And Li (lithium) 3 BO 3 Based on the equal Li-B-O compound, li is added 2 SO 4 、Li 2 CO 3 Glass or glass ceramic, etc.
As the polymer solid electrolyte, for example, a polymer compound and a compound of lithium salt can be used. The polymer compound may have an ethylene oxide structure. The polymer compound having an ethylene oxide structure can contain a plurality of lithium salts. Therefore, the ion conductivity can be further improved. As lithium salt, liPF can be used 6 、LiBF 4 、LiSbF 6 、LiAsF 6 、LiSO 3 CF 3 、LiN(SO 2 CF 3 ) 2 、LiN(SO 2 C 2 F 5 ) 2 、LiN(SO 2 CF 3 )(SO 2 C 4 F 9 ) And LiC (SO) 2 CF 3 ) 3 Etc. One lithium salt selected from the exemplified lithium salts may be used alone. Alternatively, a mixture of 2 or more lithium salts selected from the exemplified lithium salts may be used.
As the complex hydride solid electrolyte, liBH, for example, can be used 4 -LiI、LiBH 4 -P 2 S 5 Etc.
The solid electrolyte layer 102 may be substantially composed of only a halide solid electrolyte. In the present specification, "substantially … composition" means that impurities having a content of less than 0.1% are allowed to be contained. The solid electrolyte layer 102 may be composed of only a halide solid electrolyte.
With the above configuration, the ion conductivity of the solid electrolyte layer 102 can be improved. This can reduce the decrease in energy density of the battery.
The solid electrolyte layer 102 may further contain a binder. As the binder, the same material as that which can be used for the active material layer 106 can be used.
The solid electrolyte layer 102 may have a thickness of 1 μm or more and 500 μm or less. In the case where the solid electrolyte layer 102 has a thickness of 1 μm or more, the first electrode 101 and the second electrode 103 become less likely to be short-circuited. In the case where the solid electrolyte layer 102 has a thickness of 500 μm or less, the battery can operate at a high output.
The shape of the solid electrolyte is not particularly limited. In the case where the solid electrolyte is a powder material, the solid electrolyte may have a needle shape, a spherical shape, an elliptic spherical shape, or the like, for example. For example, the solid electrolyte may be in the form of particles.
For example, in the case where the solid electrolyte is in the form of particles (e.g., spheres), the median diameter of the solid electrolyte may be 100 μm or less, or may be 10 μm or less.
In the present disclosure, "median diameter" refers to a particle diameter at which the cumulative volume in the volume-based particle size distribution is equal to 50%. The volume-based particle size distribution is measured by, for example, a laser diffraction type measuring device or an image analyzing device.
The solid electrolyte contained in the solid electrolyte layer 102 can be produced by the following method.
The raw material powder is prepared in such a manner as to have a target composition. Examples of raw material powders are oxides, hydroxides, halides or oxyhalides.
For example, in the target composition Li 3 YBr 4 Cl 2 In the case of LiBr, YCl and YBr at 3:0.66: a molar ratio of about 0.33. The raw meal may be mixed in a pre-adjusted molar ratio to counteract compositional variations that may occur during the synthesis process.
The raw material powders are reacted with each other in a mechanochemical manner (that is, by mechanochemical means) in a mixing device such as a planetary ball mill to obtain a reactant. The reactants may also be calcined in vacuo or in an inert atmosphere. Alternatively, the mixture of raw material powders may be baked in vacuum or in an inert atmosphere to obtain the reactant. For example, the firing is desirably performed at 100℃or more and 300℃or less for 1 hour or more. In order to suppress the composition change during firing, it is desirable that the raw material powder is fired in a closed vessel such as a quartz tube.
By these methods, a solid electrolyte of the solid electrolyte layer 102 is obtained.
[ second electrode ]
The second electrode 103 functions as a positive electrode, for example. The second electrode 103 contains a material capable of occluding and releasing metal ions such as lithium ions. The material is, for example, a positive electrode active material.
The second electrode 103 contains a positive electrode active material. In the case where the battery of the present embodiment includes the second current collector 104, the second electrode 103 is disposed between the second current collector 104 and the solid electrolyte layer 102, for example.
The second electrode 103 may be disposed on the surface of the second current collector 104 so as to be in direct contact with the second current collector 104.
As the positive electrode active material, for example, a lithium-containing transition metal oxide, transition metal fluoride, polyanion material, fluorinated polyanion material, transition metal sulfide, transition metal oxysulfide or oversulfide may be usedTransition metal oxynitrides, and the like. Examples of the lithium-containing transition metal oxide include LiNi 1-x-y Co x Al y O 2 ((x+y)<1)、LiNi 1-x-y Co x Mn y O 2 ((x+y)<1) Or LiCoO 2 Etc. In particular, when a lithium-containing transition metal oxide is used as the positive electrode active material, the manufacturing cost of the electrode can be reduced, and the average discharge voltage of the battery can be increased. For example, the positive electrode active material may contain Li (Ni, co, mn) O 2 。
The second electrode 103 may also contain a solid electrolyte. As the solid electrolyte, a solid electrolyte exemplified as a material constituting the solid electrolyte layer 102 may be used.
The positive electrode active material may have a median diameter of 0.1 μm or more and 100 μm or less. When the positive electrode active material has a median diameter of 0.1 μm or more, the positive electrode active material and the solid electrolyte can be well dispersed. This improves the charge/discharge characteristics of the battery. When the positive electrode active material has a median diameter of 100 μm or less, the lithium diffusion rate increases. Thus, the battery can operate at a high output.
The positive electrode active material may have a larger median diameter than the solid electrolyte. Thus, the positive electrode active material and the solid electrolyte can be well dispersed.
From the viewpoint of energy density and output of the battery, the ratio of the volume of the positive electrode active material to the total of the volume of the positive electrode active material and the volume of the solid electrolyte in the second electrode 103 may be 0.30 or more and 0.95 or less.
In order to prevent the solid electrolyte from reacting with the positive electrode active material, a coating layer may be formed on the surface of the positive electrode active material. This can suppress the reaction overvoltage of the battery from rising. Examples of the covering material contained in the covering layer are sulfide solid electrolyte, oxide solid electrolyte or halide solid electrolyte.
The thickness of the second electrode 103 may be 10 μm or more and 500 μm or less. When the thickness of the second electrode 103 is 10 μm or more, a sufficient energy density of the battery can be ensured. In the case where the thickness of the second electrode 103 is 500 μm or less, the battery can operate at a high output.
The second electrode 103 may also contain a conductive material for the purpose of improving electron conductivity.
The second electrode 103 may also contain a binder.
As the conductive material and the binder, the same material as that which can be used for the active material layer 106 can be used.
The second electrode 103 may contain a nonaqueous electrolytic solution, a gel electrolyte, or an ionic liquid for the purpose of facilitating transfer of lithium ions and improving the output characteristics of the battery.
The nonaqueous electrolytic solution contains a nonaqueous solvent and a lithium salt dissolved in the nonaqueous solvent. Examples of nonaqueous solvents are cyclic carbonate solvents, chain carbonate solvents, cyclic ether solvents, chain ether solvents, cyclic ester solvents, chain ester solvents or fluorosolvents. Examples of cyclic carbonate solvents are ethylene carbonate, propylene carbonate or butylene carbonate. Examples of chain carbonate solvents are dimethyl carbonate, methylethyl carbonate or diethyl carbonate. Examples of cyclic ether solvents are tetrahydrofuran, 1, 4-di- An alkane or a 1, 3-dioxolane. Examples of chain ether solvents are 1, 2-dimethoxyethane or 1, 2-diethoxyethane. An example of a cyclic ester solvent is gamma-butyrolactone. An example of a chain ester solvent is methyl acetate. Examples of fluorosolvents are fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, methylethyl fluorocarbonate or dimethylene fluorocarbonate. The non-aqueous solvent selected from 1 of them may be used alone. Alternatively, a mixture of 2 or more nonaqueous solvents selected from them may be used.
An example of a lithium salt is LiPF 6 、LiBF 4 、LiSbF 6 、LiAsF 6 、LiSO 3 CF 3 、LiN(SO 2 CF 3 ) 2 、LiN(SO 2 C 2 F 5 ) 2 、LiN(SO 2 CF 3 )(SO 2 C 4 F 9 ) Or LiC (SO) 2 CF 3 ) 3 . 1 kind of lithium salt selected from them may be used alone. Alternatively, a mixture of 2 or more lithium salts selected from them may be used. The concentration of the lithium salt is, for example, in the range of 0.5 mol/liter or more and 2 mol/liter or less.
As the gel electrolyte, a polymer material impregnated with a nonaqueous electrolytic solution can be used. Examples of polymeric materials are polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate or polymers with ethylene oxide linkages.
Examples of cations contained in the ionic liquid are:
(i) Tetraalkylammonium or tetraalkylammoniumAliphatic chain quaternary salts of the same;
(ii) Pyrrolidine compoundsClass, morpholine- >Class I, imidazoline->Class, tetrahydropyrimidine->Class, piperazine->Class or piperidine->Aliphatic cyclic ammonium such as a class; or alternatively
(iii) Pyridine compoundClass or imidazole->Nitrogen-containing heterocyclic aromatic cations such as the like.
Examples of anions contained in ionic liquids are PF 6 －－ 、BF 4 －－ 、SbF 6 －－ 、AsF 6 －－ 、SO 3 CF 3 －－ 、N(SO 2 CF 3 ) 2 －－ 、N(SO 2 C 2 F 5 ) 2 －－ 、N(SO 2 CF 3 )(SO 2 C 4 F 9 ) －－ Or C (SO) 2 CF 3 ) 3 －－。
The ionic liquid may also contain lithium salts.
In the above, the configuration example in which the first electrode 101 is a negative electrode and the second electrode 103 is a positive electrode has been described, but the first electrode 101 may be a positive electrode and the second electrode 103 may be a negative electrode.
In the case where the first electrode 101 is a positive electrode and the second electrode 103 is a negative electrode, the active material layer 106 is a positive electrode active material layer. That is, bi contained in the active material layer 106 functions as a positive electrode active material. In this case, the second electrode 103 serving as the negative electrode is made of lithium metal, for example.
[ second collector ]
In the battery of the present embodiment, the second current collector 104 may or may not be provided. The second current collector 104 is provided in contact with the second electrode 103, for example. By providing the second current collector 104, electricity can be taken out from the battery of the present embodiment with high efficiency.
The material of the second current collector 104 is, for example, an elemental metal or an alloy. More specifically, the metal may be an elemental metal or an alloy containing at least one selected from copper, chromium, nickel, titanium, platinum, gold, aluminum, tungsten, iron, and molybdenum. The second current collector 104 may also be stainless steel.
The second current collector 104 may contain nickel (Ni).
The second current collector 104 may be plate-shaped or foil-shaped. The second current collector 104 may be a metal foil from the viewpoint of ensuring high conductivity. The thickness of the second current collector 104 may be, for example, 5 μm or more and 20 μm or less.
The second current collector 104 may be a laminated film.
The battery of the present embodiment has a basic structure including the first electrode 101, the solid electrolyte layer 102, and the second electrode 103, and is sealed in a sealed container so that the air and moisture do not mix. The shape of the battery of the present embodiment may be coin type, cylinder type, square type, sheet type, button type, flat type, laminated type, or the like.
Examples
Hereinafter, the details of the present disclosure are disclosed using examples and reference examples. The following examples are merely examples, and the present disclosure is not limited to the following examples.
Example 1
< preparation of first electrode >
As a pretreatment, nickel mesh (10 cm. Times.10 cm, thickness: 50 μm, ni-318200 made by Kagaku コ Co., ltd.) was pre-degreased with an organic solvent, and then, the nickel mesh was degreased by immersing in an acidic solvent, thereby activating the surface of the nickel mesh. Bi is used in 1.0mol/L methanesulfonic acid 3+ Bismuth methanesulfonate was added as a soluble bismuth salt so that the ion concentration became 0.18mol/L, to prepare a plating bath. The activated nickel screen is connected to a power source to enable the application of an electric current and then immersed in a plating bath. Then, by controlling the current density to 2A/dm 2 Bi was plated on the surface of the nickel net to a thickness of about 5 μm. After the plating, the nickel screen was recovered from the acid bath, and then washed with pure water and dried. The quality of the Bi plating layer produced on the nickel screen is shown in table 1.
Then, the Bi-plated nickel mesh was subjected to heat treatment at 400℃for 60 hours in an electric furnace set to an argon atmosphere. After the heat treatment, formation of BiNi was confirmed by X-ray diffraction, and then the resultant was punched out to have a size of 0.92cm, thereby obtaining a first electrode. That is, the first electrode of example 1 has a structure in which an active material layer 106 made of BiNi is provided on a substrate 105 made of nickel mesh. The surface X-ray diffraction measurement was performed on the active material layer 106 formed of BiNi. Fig. 4 is a graph showing an example of an X-ray diffraction pattern of an active material layer formed of a BiNi thin film produced on a nickel screen.
< preparation of solid electrolyte >
In an argon atmosphere (hereinafter referred to as "dry argon atmosphere") having a dew point of-60 ℃ or lower, liBr: YCl 3 ：YBr 3 =3: 2/3:1/3 molar ratio of LiBr, YCl were prepared 3 And YBa 3 As raw material powder. These raw material powders were pulverized and mixed in a mortar to obtain a mixed powder. Then, the obtained mixture of raw material powders was fired at 500 ℃ for 3 hours in a dry argon atmosphere using an electric furnace to obtain a fired product. The obtained fired product was pulverized with a pestle in a mortar. Thus, a material having Li 3 YBr 4 Cl 2 A solid electrolyte of the composition of (a).
< production of test cell >
The obtained first electrode was used as a working electrode in an insulating outer tube having an inner diameter of 9.4mm, and a solid electrolyte Li was laminated on the working electrode 3 YBr 4 Cl 2 (80 mg) and then an indium-lithium alloy (molar ratio In: li=1:1) (200 mg) was laminated as a counter electrode to obtain a laminate. Indium-lithium alloys are made by crimping small pieces of lithium foil onto indium foil, causing lithium to diffuse into the indium. A pressure of 360MPa was applied to the laminate to form a working electrode, a solid electrolyte layer and a counter electrode. In the laminate, the thickness of the first electrode as a working electrode was 65 μm, the thickness of the solid electrolyte layer was 400 μm, and the thickness of the counter electrode was 15 μm.
Next, current collectors made of stainless steel are mounted on the working electrode and the counter electrode, and current collecting leads are mounted on the current collectors.
Finally, the inside of the insulating outer cylinder is blocked from the outside air atmosphere by using an insulating collar, and the inside of the cylinder is sealed.
By the above-described process, a test cell of example 1 was obtained, which uses an electrode (i.e., a first electrode) obtained by forming an active material layer composed of BiNi on a nickel mesh as a working electrode and a lithium-indium alloy as a counter electrode. The test cell manufactured here is a monopolar test cell using a working electrode and a counter electrode, and is used to test the performance of one electrode in a secondary battery. Specifically, the working electrode is an electrode to be tested, and the counter electrode is an appropriate active material in an amount sufficient to supply the working electrode for reaction. Since the present test unit is a unit for testing the performance of the negative electrode as the first electrode, a large excess of lithium-indium alloy is used as the counter electrode as is commonly used. The negative electrode subjected to performance test using such a test cell can be used as a secondary battery by, for example, combining the negative electrode with the positive electrode active material described in the above embodiment, for example, a positive electrode containing a Li-containing transition metal oxide or the like.
< charge and discharge test >
The charge and discharge test of the test unit thus produced was performed under the following conditions. The Bi theoretical capacity is set to 384mAh/g according to the Bi quality of the electroplating, and the electroplating is charged at a constant current value of 0.5IT based on the Bi standard until-0.42V (0.2V vs Li) + Li), then discharge up to 1.38V (2.0V vs Li + /Li). The charge and discharge test of the test unit was performed in a constant temperature bath at 25 ℃. Fig. 5 is a graph showing the charge and discharge test results of the test unit of example 1. The initial charge capacity was 272.7mAh/g in terms of BiNi active material (theoretical capacity 300 mAh/g). The subsequent discharge capacity was 227.1mAh/g, and the initial efficiency was 83.3%. In addition, the initial charge capacity and the initial discharge capacity were 90.9% and 75.7% of the theoretical capacity, respectively.
Example 2
< preparation of first electrode >
As a pretreatment, porous nickel (10 cm. Times.10 cm, thickness: 1.6mm, NI-318161 made by Kagaku コ, inc.) was pre-degreased with an organic solvent, and then, the porous nickel was degreased by immersing it in an acidic solvent, thereby activating the surface of the porous nickel. Bi is used in 1.0mol/L methanesulfonic acid 3+ Bismuth methanesulfonate was added as a soluble bismuth salt so that the ion concentration became 0.18mol/L, to prepare a plating bath. The activated porous nickel is connected to a power source to apply a current, and then Which is immersed in the plating bath. Then, by controlling the current density to 2A/dm 2 Bi was plated on the surface of the porous nickel to a thickness of about 1 μm. After the plating, porous nickel was recovered from the acidic bath, and then washed with pure water and dried. The coating quality of Bi produced on porous nickel is shown in table 1.
Then, the Bi-plated porous nickel was subjected to heat treatment at 400℃for 60 hours in an electric furnace in an argon atmosphere. After the heat treatment, formation of BiNi was confirmed by X-ray diffraction, and then the resultant was punched out to have a size of 0.92cm, thereby obtaining a first electrode. That is, the first electrode of example 2 has a structure in which an active material layer 106 made of BiNi is provided on a substrate 105 made of porous nickel. The surface X-ray diffraction measurement was performed on the active material layer 106 formed of BiNi. Fig. 6 is a graph showing an example of an X-ray diffraction pattern of an active material layer formed of a BiNi thin film produced on porous nickel.
< preparation of solid electrolyte >
Li was produced in the same manner as in example 1 3 YBr 4 Cl 2 A solid electrolyte of the composition of (a).
< production of test cell >
As the first electrode, the first electrode of example 2 having a structure in which an active material layer 106 made of BiNi was provided on a substrate 105 made of porous nickel was used. Except for this point, the test unit of example 2 was obtained in the same manner as the test unit of example 1. The thickness of the first electrode as a working electrode was 400. Mu.m, the thickness of the solid electrolyte layer was 400. Mu.m, and the thickness of the counter electrode was 15. Mu.m.
< charge and discharge test >
The charge and discharge test of the test unit of example 2 was performed under the same conditions as in example 1. Fig. 7 is a graph showing the charge and discharge test results of the test unit of example 2. The initial charge capacity was 300.0mAh/g in terms of BiNi active material (theoretical capacity 300 mAh/g). The discharge capacity after that was 249.7mAh/g, and the initial efficiency was 83.2%. In addition, the initial charge capacity and the initial discharge capacity were 100.0% and 83.2% of the theoretical capacity, respectively.
Example 3
< preparation of first electrode >
As a pretreatment, porous nickel (10 cm. Times.10 cm, thickness: 1.6mm, NI-318161 made by Kagaku コ, inc.) was pre-degreased with an organic solvent, and then, the porous nickel was degreased by immersing it in an acidic solvent, thereby activating the surface of the porous nickel. Bi is used in 1.0mol/L methanesulfonic acid 3+ Bismuth methanesulfonate was added as a soluble bismuth salt so that the ion concentration became 0.18mol/L, to prepare a plating bath. The activated porous nickel is connected to a power source to enable application of an electric current, and then immersed in a plating bath. Then, by controlling the current density to 2A/dm 2 Bi was plated on the surface of the porous nickel to a thickness of about 1 μm. After the plating, porous nickel was recovered from the acidic bath, and then washed with pure water and dried.
Then, the Bi-plated porous nickel was subjected to heat treatment at 400℃for 60 hours in an electric furnace in an argon atmosphere.
Then, after Li is added 3 YBr 2 Cl 4 The porous nickel was dissolved and dispersed in a 10 mass% solution of acetonitrile, and the solution was impregnated with the heat-treated porous nickel under a pressure of 0.5 gas for 5 minutes. After drying the solution at 80 ℃, a heat treatment was performed at 400 ℃ for 1 hour in an argon atmosphere.
The porous nickel thus obtained was punched out to a size of 0.92cm to obtain a first electrode. That is, the first electrode of example 1 has an active material layer made of BiNi and Li provided on a substrate made of porous nickel 3 YBr 2 Cl 4 And the second solid electrolyte is structured. Fig. 8 is a graph showing an example of an X-ray diffraction pattern of an active material layer formed of a BiNi thin film produced on porous nickel.
< preparation of solid electrolyte >
In an argon atmosphere (hereinafter referred to as "dry argon atmosphere") having a dew point of-60 ℃ or lower, liBr: YCl 3 ：YBr 3 =3: 2/3:1/3 molar ratio of LiBr,YCl 3 And YBa 3 As raw material powder. These raw material powders were pulverized and mixed in a mortar to obtain a mixed powder. Then, the obtained mixture of raw material powders was fired at 500 ℃ for 3 hours in a dry argon atmosphere using an electric furnace to obtain a fired product. The obtained fired product was pulverized with a pestle in a mortar. Thus, a material having Li 3 YBr 4 Cl 2 A solid electrolyte of the composition of (a).
< production of test cell >
The obtained first electrode was used as a working electrode in an insulating outer tube having an inner diameter of 9.4mm, and a solid electrolyte Li was laminated on the working electrode 3 YBr 4 Cl 2 (80 mg) and then an indium-lithium alloy (molar ratio In: li=1:1) (200 mg) was laminated as a counter electrode to obtain a laminate. Indium-lithium alloys are made by crimping small pieces of lithium foil onto indium foil, causing lithium to diffuse into the indium. A pressure of 360MPa was applied to the laminate to form a working electrode, a solid electrolyte layer and a counter electrode. In the laminate, the thickness of the first electrode as a working electrode was 600 μm, the thickness of the solid electrolyte layer was 400 μm, and the thickness of the counter electrode was 15 μm.
Next, current collectors made of stainless steel are mounted on the working electrode and the counter electrode, and current collecting leads are mounted on the current collectors.
Finally, the inside of the insulating outer cylinder is blocked from the outside air atmosphere by using an insulating collar, and the inside of the cylinder is sealed.
By the above-mentioned treatments, a test cell of example 3 was obtained, which was obtained by forming an active material layer composed of BiNi and Li on porous nickel 3 YBr 4 Cl 2 The electrode (i.e., the first electrode) obtained by constituting the second solid electrolyte was used as a working electrode, and the lithium-indium alloy was used as a counter electrode. The test cell manufactured here is a monopolar test cell using a working electrode and a counter electrode, and is used to test the performance of one electrode in a secondary battery. Specifically, the working electrode is an electrode to be tested, and the counter electrode is an appropriate active material in an amount sufficient to supply the working electrode for reaction. The book is provided with Since the test unit is a unit for testing the performance of the negative electrode as the first electrode, a large excess of lithium-indium alloy is used as the counter electrode as is commonly used. The negative electrode subjected to performance test using such a test cell can be used as a secondary battery by, for example, combining the negative electrode with the positive electrode active material described in the above embodiment, for example, a positive electrode containing a Li-containing transition metal oxide or the like.
< charge and discharge test >
The charge and discharge test of the test unit thus produced was performed under the following conditions. The Bi theoretical capacity is set to 384mAh/g according to the Bi quality of the electroplating, and the electroplating is charged at a constant current value of 0.5IT based on the Bi standard until-0.42V (0.2V vs Li) + Li), then discharge up to 1.38V (2.0V vs Li + Li) is then charged up to-0.42V (0.2V vs Li + /Li). The charge and discharge test of the test unit was performed in a constant temperature bath at 25 ℃. Fig. 9 is a graph showing the charge and discharge test results of the test unit of example 1. The initial charge capacity was 300.2mAh/g in terms of BiNi active material (theoretical capacity 300 mAh/g). The discharge capacity and the charge capacity after the above were about 271.5 mAh/g.
Reference example 1
< preparation of first electrode >
As pretreatment, a nickel foil (10 cm×10cm, thickness: 10 μm) was pre-degreased with an organic solvent, and then one surface was masked and immersed in an acidic solvent to degrease the foil, thereby activating the surface of the nickel foil. Bi is used in 1.0mol/L methanesulfonic acid 3+ Bismuth methanesulfonate was added as a soluble bismuth salt so that the ion concentration became 0.18mol/L, to prepare a plating bath. The activated nickel screen is connected to a power source to enable the application of an electric current and then immersed in a plating bath. Then, by controlling the current density to 2A/dm 2 Bi was plated on the surface of the nickel foil without the mask to a thickness of about 5 μm. After the plating, the nickel foil was recovered from the acid bath, and after the mask was removed, it was washed with pure water and dried. Then, the Bi-plated nickel foil was subjected to heat treatment at 400℃for 60 hours in an electric furnace in an argon atmosphere. After heat treatment, the Bi plating layer on the nickel foil is subjected to surface X-ray diffraction measurementAnd (5) setting. Fig. 10 is a graph showing an example of an X-ray diffraction pattern of an active material layer formed of a BiNi thin film produced on a nickel foil.
< preparation of solid electrolyte >
Li was produced in the same manner as in example 1 3 YBr 4 Cl 2 A solid electrolyte of the composition of (a).
< production of test cell >
As the first electrode, the first electrode of reference example 1 having a structure in which an active material layer 106 made of BiNi was provided on a substrate 105 made of nickel foil was used. Except for this point, the test unit of reference example 1 was obtained in the same manner as the test unit of example 1. The thickness of the first electrode as a working electrode was 1.5 μm, the thickness of the solid electrolyte layer was 500 μm, and the thickness of the counter electrode was 15 μm.
< charge and discharge test >
The charge and discharge test of the test unit of example 2 was performed under the same conditions as in example 1. Fig. 7 is a graph showing the charge and discharge test results of the test unit of example 2. The initial charge capacity was 203.9mAh/g in terms of BiNi active material (theoretical capacity 300 mAh/g). The discharge capacity after that was 162.8mAh/g, and the initial efficiency was 79.8%. In addition, the initial charge capacity and the initial discharge capacity were 68.0% and 54.3% of the theoretical capacity, respectively.
The charge and discharge test results of the BiNi electrode (reference example 1) obtained by plating Bi on a nickel foil and synthesizing it by heat treatment, the BiNi electrode (example 1) obtained by plating Bi on a nickel net and synthesizing it by heat treatment, the BiNi electrode (example 2) obtained by plating Bi on a porous nickel and synthesizing it by heat treatment, and the BiNi electrode (example 3) obtained by plating Bi on a porous nickel and synthesizing it by heat treatment and then providing a second solid electrolyte are shown in table 2.
TABLE 2
As is clear from table 2, by using the nickel mesh of example 1 and the porous meshes of examples 2 and 3 as the base material of the porous body, the initial efficiency of the electrode using BiNi as the active material was improved, and the load characteristics were also improved.
From the above results, it was found that the initial efficiency of the electrode using BiNi as an active material was significantly improved and the load characteristics were also significantly improved by using the porous material as a base material. That is, it was confirmed that the battery of the present disclosure provided with the first electrode including: a substrate as a porous body, and an active material layer which is located on the surface of the substrate and contains BiNi. In the present example, a halide solid electrolyte Li was used 3 YBr 4 Cl 2 However, similar effects can be expected even with other solid electrolytes in general.
In addition, as is clear from comparison of example 3 with example 2, as shown in example 3, the charge/discharge characteristics of the battery were further improved by using an electrode provided with the second solid electrolyte in contact with the active material layer located on the surface of the porous body substrate. In example 3 of the present application, a halide solid electrolyte Li was used as the second solid electrolyte 3 YBr 4 Cl 2 However, similar effects can be expected even with other solid electrolytes in general.
Further, the first electrode manufactured in example 1 was subjected to surface X-ray diffraction measurement using cu—kα rays, and the substance present in the first electrode in a charged state was confirmed. The test cell used in this case was different from the test cell of example 1 in that an electrolyte was used. Specifically, the first electrode produced in example 1 was used as a working electrode, li metal was used as a counter electrode, and LiPF was used 6 A solution obtained by dissolving vinylene carbonate at a concentration of 1.0 mol/L was used as an electrolyte. The Li metal used as the working electrode is doubly covered with a microporous separator (a case 3401, of the company, asahi chemical). The charge and discharge of the test unit were carried out at 0.6mA (0.15 mA/cm 2 ) Charging is carried out up to 0V and discharging is carried out up to 2V. X-ray diffraction pattern enablesBy using an X-ray diffraction apparatus (manufactured by RIGAKU, miNi Flex) using a wavelengthAnd->The Cu-K alpha ray of (C) was measured by the theta-2 theta method as X-ray. Fig. 12 is a graph showing an example of the X-ray diffraction pattern of the first electrode before, after, and after the first electrode was charged and discharged in example 1. Based on the obtained X-ray diffraction pattern, biNi and Ni can be identified before charging, and compounds derived from the active material and the base material can be identified, respectively. After charging, can be identified as LiBi, li 3 Bi and Ni. That is, it was found that LiBi and Li were generated after charging 3 Bi. Further, biNi and Ni can be identified after discharge. Further, although the substances present in the first electrode after charging were confirmed in the test cell using the electrolyte, it was considered that even in the case of the battery of example 1 in which the electrolyte layer used a solid electrolyte, the first electrode after charging was formed to be selected from the group consisting of LiBi and Li 3 At least one of Bi.
Industrial applicability
The battery of the present disclosure may be used as, for example, an all-solid lithium secondary battery or the like.
Description of the reference numerals
1000. Battery cell
2000. Battery cell
100. First current collector
101. First electrode
102. Solid electrolyte layer
103. Second electrode
104. Second current collector
105. Substrate material
106. Active material layer
107. Second solid electrolyte

Claims (20)

1. A battery is provided with:
a first electrode,
Second electrode, and method for manufacturing the same
A solid electrolyte layer between the first electrode and the second electrode, the solid electrolyte layer containing a first solid electrolyte,
the first electrode has:
base material as porous body, and method for producing porous body
An active material layer on the surface of the substrate,
the active material layer contains an alloy containing Bi and Ni.
2. The battery according to claim 1,
the active material layer contains BiNi.
3. The battery according to claim 2,
the active material layer contains the BiNi as a main component of an active material.
4. A battery according to claim 3,
the active material layer contains substantially only the BiNi as an active material.
5. The battery according to claim 2,
The BiNi has a crystal structure with space group belonging to C2/m.
6. The battery according to claim 1,
the active material layer contains an active material selected from LiBi and Li 3 At least one of Bi.
7. The battery according to claim 1,
the active material layer does not contain an electrolyte.
8. The battery according to claim 1,
the substrate contains Ni.
9. The battery according to claim 1,
the active material layer is a heat-treated plating layer.
10. The battery according to claim 1,
the first solid electrolyte contains a first halide solid electrolyte,
the first halide solid electrolyte is substantially free of sulfur.
11. The battery according to claim 1,
the first solid electrolyte contains a first sulfide solid electrolyte.
12. The battery according to claim 1,
the first electrode also has a second solid electrolyte in contact with the active material layer.
13. The battery according to claim 12,
the second solid electrolyte contains a second halide solid electrolyte,
the second halide solid electrolyte is substantially free of sulfur.
14. The battery according to claim 13,
the second halide solid electrolyte is represented by the following composition formula (1),
Li α M β X γ (1)
Wherein,
alpha, beta and gamma are values greater than 0,
m is at least one selected from the group consisting of metallic elements other than Li and metalloid elements,
x is at least one selected from F, cl, br and I.
15. The battery according to claim 14,
in the composition formula (1), the M contains Y.
16. The battery according to claim 14,
in the composition formula (1), the X is at least 1 selected from Cl, br and I.
17. The battery according to claim 14,
the second solid electrolyte contains a material selected from Li 3 YBr 3 Cl 3 And Li (lithium) 3 YBr 2 Cl 4 At least one of them.
18. The battery according to claim 12,
the second solid electrolyte contains a second sulfide solid electrolyte.
19. The battery according to claim 12,
the second solid electrolyte is contained in the pores of the substrate.
20. The battery according to claim 1,
the first electrode is a negative electrode and,
the second electrode is a positive electrode.
CN202280042456.7A 2021-08-10 2022-06-14 Battery cell Pending CN117501472A (en)

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JP2021-130969 2021-08-10
JP2021-130968 2021-08-10
JP2022069727 2022-04-20
JP2022-069727 2022-04-20
PCT/JP2022/023790 WO2023017673A1 (en) 2021-08-10 2022-06-14 Battery

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