TWI481102B - Protected active metal electrode and device with the electrode - Google Patents

Description

Protected active metal electrode and component having the same

The present invention relates to the structure of an active metal electrode, and more particularly to a protected active metal electrode and an element having the same.

Improving storage capacity is one of the current research and development priorities for secondary batteries. Lithium-ion battery cells can have the highest energy density by using lithium ion intercalation/extraction materials respectively in the positive and negative electrodes of the lithium ion battery, but the lithium ion battery is limited by the limited capacitance of the positive and negative materials. The highest energy density that can be achieved is limited by the material bottleneck and cannot be lifted upwards, so electrode material development with high capacitance is urgently needed.

Among many materials, the use of active metals such as lithium, sodium, magnesium, calcium, aluminum, etc. as active materials for batteries can have the advantages of light weight and high capacitance, especially lithium metal itself and alloying with lithium. Materials such as tantalum, tin, aluminum, etc. can achieve high capacitance. However, materials that are alloyed with lithium are accompanied by inevitable volume expansion in the reaction with lithium, during the reverse charging and discharging process. The active material is broken and detached, resulting in poor cycle life. Among the active metals, For example, lithium metal itself has a capacitance of up to 3862 mAh/g, but its activity is extremely high, not only sensitive to water vapor and air, but also lithium metal reacts with substances in the electrolyte during charge and discharge. The gradual loss of activity and the reduction in the available capacity, other active metals such as sodium, magnesium, calcium, and aluminum are also affected by the external reactive substances and affect their capacitance. On the other hand, for example, the lithium metal surface will produce dendritic lithium deposition after repeated charging and discharging, and the lithium deposition on the surface hides the safety concerns of piercing the isolation film to short-circuit the element. Therefore, if a conductive protective layer can be plated on the surface of the active metal electrode, the capacitance of the component should be effectively improved and the life of the cycle can be improved.

At present, there is a single layer structure or a multilayer structure as a protective layer on the surface of the active metal electrode. If the surface protective layer is a single-layer structure designer, the active electrode cannot be effectively degraded when used in the element. However, if the surface protective layer is a multilayer structure designer, there is a problem of compatibility and electrical conductivity. In the prior art, if the multilayer structure contains an ion-conducting ceramic, an ion-conductive salt, an organic compound, a polymer, or the like, there is a problem that the electron-conducting ability is unfavorable. If the multilayer structure contains a metal that can be alloyed with ions, it is easy to cause volume expansion during the alloying process with the ions, resulting in the electrode layers not being able to maintain a stable compatible structure and affecting the service life, and even the protective layer material is broken. Cracked situation.

The protected active metal electrode of the present invention comprises an active metal substrate and a protective layer on the surface of the active metal substrate. This protective layer includes at least a metal thin film on the surface of the active metal substrate and a conductive film coated on the surface of the metal thin film. The material of the metal thin film is titanium, vanadium, chromium, zirconium, hafnium, molybdenum, niobium, tantalum or tungsten; the material of the electroconductive thin film is selected from the group consisting of a metal nitride including a metal thin film, a metal carbide of a metal thin film, and the like. Drilling carbon film (DLC) and one of its combinations.

Yet another protected lithium metal electrode of the present invention comprises a lithium metal substrate and a protective layer on the surface of the lithium metal substrate. The protective layer includes at least a metal thin film coated on the surface of the lithium metal substrate and a conductive thin film coated on the surface of the metal thin film. The material of the metal thin film is titanium, vanadium, chromium, zirconium, hafnium, molybdenum, niobium, tantalum or tungsten; the material of the electroconductive thin film is selected from the group consisting of a metal nitride including a metal thin film, a metal carbide of a metal thin film, and the like. Drilling carbon film (DLC) and one of its combinations.

Another element of the present invention having a protected active metal electrode includes a positive electrode, an active metal negative electrode, and an electrolyte in contact with the positive electrode and the active metal negative electrode to provide a conductive metal ion for conduction. The active metal negative electrode is the above-mentioned protected active metal electrode.

Based on the above, the present invention forms a protective layer composed of a specific metal thin film and a conductive thin film on the surface of the active metal, so that the disadvantage that the recyclable life of the electrochemical element using the active metal as the negative electrode is too low can be solved. Moreover, when the active metal electrode is applied to the externally reactive material, it can have better resistance without causing loss of activity, so when applied to the component, it does not react with the components contained in the electrolyte. Affecting its electrochemical recyclability, it can also effectively avoid charging and discharging Deterioration of lithium metal due to surface type changes during electrical cycling.

In order to make the above-described features of the present invention more comprehensible, the following detailed description of the embodiments will be described in detail below.

100‧‧‧Active metal substrate

100a, 104a‧‧‧ surface

102‧‧‧Protective layer

104‧‧‧Metal film

106, 300, 302‧‧‧ conductive film

200, 400‧‧‧ positive

202, 402‧‧‧active metal anode

204, 404‧‧‧ electrolyte

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing a protected active metal electrode in accordance with a first embodiment of the present invention.

2 is a schematic cross-sectional view of an element having a protected active metal electrode in accordance with a second embodiment of the present invention.

3 is a cross-sectional view showing still another protected active metal electrode in accordance with a third embodiment of the present invention.

4 is a cross-sectional view showing another element having a protected active metal electrode in accordance with a fourth embodiment of the present invention.

Fig. 5 is a graph showing the relationship between the number of cycles and the capacitance of Experimental Example 3.

Figure 6A is a SEM photograph of Control Element 1 after 20 cycles of Experimental Example 3.

Fig. 6B is a SEM photograph of the element one after the 20th cycle of the experimental example 3.

Fig. 7 is an impedance spectrum of the control element one and the element one after the 20th cycle of the experimental example 3.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing a protected active metal electrode in accordance with a first embodiment of the present invention.

Referring to FIG. 1, the protected active metal electrode of the present embodiment includes an active metal substrate 100 and a protective layer 102 on its surface 100a. The active metal substrate 100 may include lithium, sodium, magnesium, calcium, aluminum, or a combination thereof, and lithium may be used in terms of high capacity and weight. The protective layer 102 includes at least a metal thin film 104 coated on the surface 100a of the active metal substrate 100 and a conductive film 106 coated on the surface 104a of the metal thin film 104. The thickness of the metal thin film 104 is, for example, between 10 nm and 100 nm. The thickness of the conductive film 106 is, for example, between 10 nm and 1000 nm; preferably between 50 nm and 1000 nm. The metal thin film 104 is a metal that does not react with the active metal substrate 100, and may be titanium, vanadium, chromium, zirconium, hafnium, molybdenum, niobium, tantalum or tungsten; high stability, good corrosion resistance, low impedance For other characteristics, titanium, chromium, ruthenium or osmium may be used. The material of the electroconductive thin film 106 is one selected from the group consisting of a metal nitride including the metal thin film 104, a metal carbide of the metal thin film 104, and a combination thereof because the metal nitride or the metal carbide has good electrical conductivity. In this embodiment, the resistivity of the conductive film 106 is, for example, 10 ^-5 Ω. Cm~10 ² Ω. Between cm; preferably 10 ^-5 Ω. Cm~10 ⁰ Ω. Between cm; more preferably 10 ^-5 Ω. Cm~10 ^-2 Ω. Between cm. If the material of the metal film 104 is titanium, chromium, tantalum or niobium, the material of the conductive film 106 may be TiN _x , CrN _x , NbN _x or TaN _x , or TiC _x , CrC _x , NbC _x or TaC _x , where x =0.01~1.0; preferably between x=0.1~1.0; more preferably between x=0.3~1.0. In addition, if the active metal substrate 100 is lithium, when the conductive film 106 is a metal nitride, the thickness of the metal film 104 can be appropriately adjusted to ensure that nitrogen does not affect the active metal substrate 100.

In the first embodiment, the conductive film 106 may also be a diamond-like carbon film (DLC), which is, for example, a tetrahedral amorphous carbon (ta-C) structure, and has a sp ³ ratio of >40%. If the active metal substrate 100 is lithium, since the diamond-like carbon film does not affect the active metal substrate 100, there is a large margin for the thickness of the metal film 104. Moreover, this embodiment can use a Cathodic Arc deposited thin film technique to grow a film having low resistivity and high adhesion characteristics under high vacuum.

2 is a schematic cross-sectional view of an element having a protected active metal electrode in accordance with a second embodiment of the present invention.

Referring to FIG. 2, the element of the present embodiment includes a positive electrode 200, an active metal negative electrode 202, and an electrolyte 204 that is in contact with the positive electrode 200 and the active metal negative electrode 202 to provide a conductive metal ion for conduction. The active metal negative electrode 202 herein is, for example, the protected active metal electrode of FIG. 1, including the active metal substrate 100 and the metal thin film 104 stacked on the surface 100a thereof and the conductive film 106 stacked on the surface 104a thereof. The positive electrode 200 is not particularly limited but may be selected from materials including sulfur-containing substances, metal oxides, carbon materials, and combinations thereof. The aforementioned sulfur-containing substance is, for example, a substance selected from the group consisting of sulfur, metal sulfide, organic sulfur, and combinations thereof. The aforementioned metal oxide is, for example, a lithium-containing metal oxide or a lithium-free metal oxide. The lithium-containing oxide is, for example, selected from the group consisting of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt oxide, lithium cobalt manganese oxide, lithium nickel cobalt manganese oxide. , lithium iron oxide, lithium cobalt phosphorus oxide, lithium nickel phosphorus oxide, lithium iron phosphorus oxide, lithium Manganese phosphorus oxide, lithium cobalt manganese phosphorus oxide, lithium nickel cobalt phosphorus oxide, lithium iron cobalt phosphorus oxide, lithium iron nickel phosphorus oxide, lithium iron manganese phosphorus oxide, lithium iron oxide, lithium iron boron oxidation , lithium titanium oxide, lithium cobalt titanium oxide, lithium manganese titanium oxide, lithium iron titanium oxide, lithium titanium phosphorus oxide, lithium vanadium oxide, lithium vanadium phosphorus oxide, and combinations thereof. The lithium-free oxide is, for example, selected from the group consisting of vanadium oxide, manganese oxide, tungsten oxide, titanium oxide, chromium oxide, iron oxide, cobalt oxide, nickel oxide, antimony oxide, molybdenum. Oxide, tin oxide, sodium vanadium oxide, sodium manganese oxide, sodium titanium oxide, sodium chromium oxide, sodium iron oxide, sodium cobalt oxide, sodium nickel manganese oxide, sodium nickel cobalt oxide, sodium Cobalt manganese oxide, sodium nickel cobalt manganese oxide, sodium cobalt phosphorus oxide, sodium nickel phosphorus oxide, sodium iron phosphorus oxide, sodium manganese phosphorus oxide, sodium iron manganese phosphorus oxide, sodium vanadium phosphorus oxide, sodium Titanium phosphorus oxides, and oxides in combinations thereof. The foregoing carbon material is, for example, a material selected from the group consisting of activated carbon, carbon black, graphite, carbon fiber, carbon nanotube, mesoporous carbon, graphene, and combinations thereof. The foregoing electrolyte 204 is not particularly limited but may be a solid electrolyte, a molten salt, an ionic liquid, a colloidal electrolyte, or an electrolytic solution. The electrolyte includes active metal ions selected from the group consisting of lithium ions, sodium ions, magnesium ions, calcium ions, aluminum ions, and combinations thereof. For example, the foregoing electrolyte 204 may be a solid electrolyte containing lithium ions, a molten salt containing lithium ions, an ionic liquid containing lithium ions, a colloidal electrolyte containing lithium ions, an electrolyte containing lithium ions, and a solid containing sodium ions. Electrolyte, molten salt containing sodium ion, ionic liquid containing sodium ion, colloidal electrolyte containing sodium ion, electrolyte containing sodium ion, solid electrolyte containing magnesium ion, molten salt containing magnesium ion, ion containing magnesium ion Liquid, colloidal electrolyte containing magnesium ions, electrolyte containing magnesium ions, solid with calcium ions Electrolyte, molten salt containing calcium ions, ionic liquid containing calcium ions, colloidal electrolyte containing calcium ions, electrolyte containing calcium ions, solid electrolyte containing aluminum ions, molten salt containing aluminum ions, aluminum-containing ions Ionic liquid, colloidal electrolyte containing aluminum ions, or electrolyte containing aluminum ions.

Figure 3 is a cross-sectional view showing still another protected active metal electrode in accordance with a third embodiment of the present invention, wherein the same reference numerals are used to denote the same members as the first embodiment.

In FIG. 3, in addition to the active metal substrate 100 and the metal film 104 shown in FIG. 1, the conductive film 106 on the surface 104a of the metal film 104 is composed of a first conductive film 300 and a second conductive film 302, wherein The second conductive film 302 is a diamond-like carbon film (DLC) having a thickness of, for example, 10 nm to 1000 nm. The first conductive film 300 may be a metal nitride or a carbide of the metal film 104. For example, the metal film 104 is titanium, chromium, tantalum or niobium. The material of the first conductive film 300 may be TiN _x or CrN. _x , NbN _x , TaN _x , TiC _x , CrC _x , NbC _x or TaC _x , 0.01 < x < 1.0. In addition, since the second conductive film 302 is a diamond-like carbon film, the material of the first conductive film 300 is preferably a metal carbide of the metal film 104.

4 is a cross-sectional view showing another element having a protected active metal electrode in accordance with a fourth embodiment of the present invention.

Referring to FIG. 4, the element of the present embodiment includes a positive electrode 400, an active metal negative electrode 402, and an electrolyte 404 that is in contact with the positive electrode 400 and the active metal negative electrode 402 to provide a conductive metal ion for conduction. The active metal anode 402 herein is, for example, the protected active metal electrode of FIG. 3, including the active metal substrate 100 and stacked thereon. The metal film 104 of the surface 100a has a conductive film 106 composed of a first conductive film 300 and a second conductive film 302, wherein the second conductive film 302 is a diamond-like carbon film (DLC) having a thickness of, for example, 10 nm. Between 1000nm. The positive electrode 400 is not particularly limited but may be selected from materials including sulfur-containing substances, metal oxides, carbon materials, and combinations thereof. The aforementioned sulfur-containing substance is, for example, a substance selected from the group consisting of sulfur, metal sulfide, organic sulfur, and combinations thereof. The aforementioned metal oxide is, for example, a lithium-containing metal oxide or a lithium-free metal oxide. The lithium-containing oxide is, for example, selected from the group consisting of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt oxide, lithium cobalt manganese oxide, lithium nickel cobalt manganese oxide. , lithium iron oxide, lithium cobalt phosphorus oxide, lithium nickel phosphorus oxide, lithium iron phosphorus oxide, lithium manganese phosphorus oxide, lithium cobalt manganese phosphorus oxide, lithium nickel cobalt phosphorus oxide, lithium iron cobalt phosphorus oxidation , lithium iron nickel phosphorus oxide, lithium iron manganese phosphorus oxide, lithium iron lanthanum oxide, lithium iron boron oxide, lithium titanium oxide, lithium cobalt titanium oxide, lithium manganese titanium oxide, lithium iron titanium oxide , lithium titanium phosphorus oxide, lithium vanadium oxide, lithium vanadium phosphorus oxide, and combinations thereof. The lithium-free oxide is, for example, selected from the group consisting of vanadium oxide, manganese oxide, tungsten oxide, titanium oxide, chromium oxide, iron oxide, cobalt oxide, nickel oxide, antimony oxide, molybdenum. Oxide, tin oxide, sodium vanadium oxide, sodium manganese oxide, sodium titanium oxide, sodium chromium oxide, sodium iron oxide, sodium cobalt oxide, sodium nickel manganese oxide, sodium nickel cobalt oxide, sodium Cobalt manganese oxide, sodium nickel cobalt manganese oxide, sodium cobalt phosphorus oxide, sodium nickel phosphorus oxide, sodium iron phosphorus oxide, sodium manganese phosphorus oxide, sodium iron manganese phosphorus oxide, sodium vanadium phosphorus oxide, sodium Titanium phosphorus oxides, and oxides in combinations thereof. The foregoing carbon material is, for example, selected from the group consisting of activated carbon, carbon black, graphite, carbon fiber, carbon nanotubes. Materials in tubes, mesoporous carbon, graphene, and combinations thereof. The foregoing electrolyte 404 is not particularly limited but may be a solid electrolyte, a molten salt, an ionic liquid, a colloidal electrolyte, or an electrolytic solution. The electrolyte includes active metal ions selected from the group consisting of lithium ions, sodium ions, magnesium ions, calcium ions, aluminum ions, and combinations thereof. For example, the foregoing electrolyte 404 may be a solid electrolyte containing lithium ions, a molten salt containing lithium ions, an ionic liquid containing lithium ions, a colloidal electrolyte containing lithium ions, an electrolyte containing lithium ions, and a solid containing sodium ions. Electrolyte, molten salt containing sodium ion, ionic liquid containing sodium ion, colloidal electrolyte containing sodium ion, electrolyte containing sodium ion, solid electrolyte containing magnesium ion, molten salt containing magnesium ion, ion containing magnesium ion Liquid, colloidal electrolyte containing magnesium ions, electrolyte containing magnesium ions, solid electrolyte containing calcium ions, molten salt containing calcium ions, ionic liquid containing calcium ions, colloidal electrolyte containing calcium ions, calcium-containing ions An electrolyte, a solid electrolyte containing aluminum ions, a molten salt containing aluminum ions, an ionic liquid containing aluminum ions, a colloidal electrolyte containing aluminum ions, or an electrolyte containing aluminum ions.

Several experiments are listed below to confirm the effects of the above-described embodiments of the present invention.

Production Example 1 : Lithium metal electrode for metal lithium/titanium/titanium carbide/dye-like film

Coating process: DC arc ion plating consists of a negatively charged cathode target and a positively charged anode arc starter using low voltage (~20V) and current from tens of amps to one hundred amps. The plasma generated by the cathodic arc spot rapidly diffuses into the vacuum chamber for coating. The cathode target comprises a pure graphite carbon target and a titanium metal target to produce a diamond-like film (DLC) and a titanium carbide film, and the deposition temperature of the deposited film is about 50 ° C ~ 100 ° C, and the process pressure is about 10 ^-4 Pa ~ 1Pa, the gas that is introduced is argon or methane gas.

The titanium metal film, the titanium carbide layer and the diamond-like film structure are sequentially coated on the lithium metal substrate by the above coating process, as shown in FIG. The thickness of the drill film in the structure is about 530 nm, the thickness of the titanium carbide film is between 50 nm and 180 nm, and the thickness of the titanium metal film is between 10 nm and 95 nm.

The resistivity of the protective layer (titanium/titanium carbide/dye-like film) was measured to be 8×10 ^-4 Ω. Cm. The analysis of the compositional structure is based on XPS to identify its carbon bond pattern. According to the energy spectrum analysis of XPS, the binding energy of such a drill film with CO, sp ³ and sp ² is 286.4, 284.9 and 284.2 eV, respectively. The sp ³ ratio was calculated to be 42%.

Production Example 2 : Lithium metal electrode for metal lithium/titanium/titanium nitride

As in the case of the first example, but using titanium as a target, the gas introduced is replaced with nitrogen gas by methane gas, and a titanium metal film and a titanium nitride (TiN _x ) film are sequentially coated on the lithium metal substrate, such as The structure of Figure 1. The thickness of the titanium nitride (TiN _x ) film in the structure is between 50 nm and 500 nm, and the thickness of the titanium metal film is between 25 nm and 95 nm.

The resistivity of the protective layer (Ti/TiN _x ) is measured to be about 9.9×10 ^-5 Ω. Cm. The analysis of the compositional structure is based on XPS to identify its bond pattern of titanium and nitrogen. From the energy spectrum analysis of XPS, the binding energy of Ti 2p _3/2 of titanium nitride (TiN _x ) film is quite close to the value of TiN material (454.8 eV) at 454.9 eV. The position of the N 1s binding energy is 397.2 eV, which is the energy spectrum position of the nitride. The binding energy of Ti and N energy spectrum can be compared with each other, and the grown film is a TiN _0.98 film formed by bonding Ti and N to each other.

Production Example 3 : Lithium metal electrode for metal lithium/titanium/titanium carbide

As in the case of the first example, titanium metal was used as a target, and a titanium metal film and a titanium carbide (TiC _x ) film were sequentially coated on the lithium metal substrate, as shown in FIG. The thickness of the titanium carbide film in the structure is between 50 nm and 500 nm, and the thickness of the metal titanium film is between 25 nm and 95 nm.

The resistivity of the protective layer (titanium/titanium carbide) was measured to be 1.5×10 ^-4 Ω. Cm. The analysis of the compositional structure is based on XPS to identify its carbon-titanium bonding pattern. From the energy spectrum analysis of XPS, the Ti 2p3/2 binding energy of the titanium carbide film is 454.6 eV. The position of the C 1s binding energy is 281.8 eV, which is the energy spectrum position of the carbide. The Ti and C energy spectrum binding can be compared with each other. The grown film is a film in which Ti and C are bonded to each other to form TiC _0.95 .

Production Example 4 : Lithium metal electrode for metal lithium/titanium/titanium nitride

As in the second embodiment, the nitrogen flow rate was controlled to sequentially coat the titanium metal film and the titanium nitride (TiN _x ) film on the lithium metal substrate, as shown in FIG. The composition of titanium nitride (TiN _x ) in the structure is 0.01<x<1.0, and the thickness is between 100 nm and 180 nm, and the rest is the same as in Production Example 2. The resistivity of the protective layer (Ti/TiN _x ) is estimated to be about 6.1×10 ^-5 Ω. Cm. From the energy spectrum analysis of XPS, the grown film is a titanium nitride (TiN _x ) film formed by bonding Ti and N to each other.

Production Example 5 : Lithium metal electrode for metal lithium/titanium/titanium carbide

As in the case of the third example, the methane flow rate was controlled to sequentially coat the titanium metal film and the titanium carbide (TiC _x ) film on the lithium metal substrate, as shown in FIG. The composition of titanium carbide (TiC _x ) in the structure is 0.01<x<1.0, and the thickness is between 100 nm and 180 nm, and the rest is the same as in the second production example. The resistivity of the protective layer (Ti/TiC _x ) is measured to be about 1.8×10 ^-4 Ω. Cm. From the energy spectrum analysis of XPS, the grown film is a titanium carbide (TiC _x ) film formed by bonding Ti and C to each other.

Production Example 6 : Lithium metal electrode for metal lithium/chromium/chromium nitride

As in the case of the first example, but using chromium metal as the target, the gas introduced replaces the methane gas with nitrogen, and sequentially chrome metal film and chromium nitride (CrN _x ) film are coated on the lithium metal substrate, such as The structure of Figure 1. The composition of chromium nitride (CrN _x ) in the structure is 0.01 < x < 1.0. The thickness of the chromium nitride film is between 50 nm and 500 nm, and the thickness of the chromium metal film is between 25 nm and 95 nm.

The resistivity of the protective layer (Cr/CrN _x ) is estimated to be about 1.4×10 ^-4 Ω. Cm. The analysis of the compositional structure is based on XPS to identify its bond pattern of chromium and nitrogen. From the energy spectrum analysis of XPS, the binding energy of Cr 2p3/2 of the chromium nitride film is 574.9 eV. The position of the N 1s binding energy is 397.1 eV, which is the energy spectrum position of the nitride. The binding energy of Cr and N energy spectrum can be compared with each other, and the grown film is a CrN _0.85 film formed by bonding Cr and N to each other.

Production Example 7 : Lithium metal electrode for metal lithium/chromium/chromium carbide

As in the case of the first example, a chromium metal was used as a target, and a chromium metal film and a chromium carbide (CrC _x ) film were sequentially coated on the lithium metal substrate, as shown in FIG. The composition of chromium carbide (CrC _x ) in the structure is 0.01 < x < 1.0. The thickness of the chromium carbide film is between 50 nm and 500 nm, and the thickness of the chromium metal film is between 25 nm and 100 nm.

The resistivity of the protective layer (Cr/CrC _x ) is estimated to be about 7.8×10 ^-4 Ω. Cm. From the energy spectrum analysis of XPS, the binding energy of Cr 2p3/2 of the chromium nitride film is 574.7 eV. The position of the C 1s binding energy is 283.0 eV, which is the energy spectrum position of the carbide. The binding energy of Cr and C energy spectrum can be compared with each other, and the grown film is a CrC _0.37 film formed by bonding Cr and C to each other.

Production Example 8 : Lithium metal electrode for metal lithium/germanium/tantalum nitride

As in the case of the first example, but using a base metal as a target, the introduced gas replaces the methane gas with nitrogen, and the tantalum metal film and the tantalum nitride (NbN _x ) film are sequentially coated on the lithium metal substrate, such as The structure of Figure 1. The composition of chromium nitride (NbN _x ) in the structure is 0.01 < x < 1.0. The thickness of the tantalum nitride film is between 50 nm and 500 nm, and the thickness of the tantalum metal film is between 25 nm and 95 nm.

The resistivity of the protective layer (Nb/NbN _x ) is estimated to be about 4.8×10 ^-5 Ω. Cm. The analysis of the compositional structure is based on XPS to identify the bond pattern of bismuth and nitrogen. From the energy spectrum analysis of XPS, the grown film is a tantalum nitride (NbN _x ) film formed by bonding Nb and N to each other.

Production Example 9 : Lithium Metal Electrode for Metal Lithium/Yttrium/Carbide

As in the case of the first example, but using a base metal as a target, a tantalum metal film and a niobium carbide (NbC _x ) film are sequentially coated on the lithium metal substrate, as shown in FIG. The composition of chromium nitride (NbC _x ) in the structure is 0.01 < x < 1.0. The thickness of the tantalum carbide film is between 50 nm and 500 nm, and the thickness of the tantalum metal film is between 25 nm and 95 nm.

The analysis of the compositional structure is based on XPS to identify the bonding pattern of carbon and yttrium. From the energy spectrum analysis of XPS, the grown film is a niobium carbide (NbC _x ) film formed by bonding Nb and C to each other.

Production Example 10 : Lithium metal electrode for metal lithium/germanium/tantalum nitride

As in the case of the first example, but using a base metal as a target, the introduced gas replaces the methane gas with nitrogen, and the tantalum metal film and tantalum nitride (TaN _x ) film are sequentially coated on the lithium metal substrate, such as The structure of Figure 1. The composition of chromium nitride (TaN _x ) in the structure is 0.01 < x < 1.0. The thickness of the tantalum nitride film is between 50 nm and 500 nm, and the thickness of the tantalum metal film is between 25 nm and 95 nm.

The resistivity of the protective layer (Ta/TaN _x ) was measured to be about 2.7 × 10 ^-4 Ω. Cm. The analysis of the compositional structure is based on XPS to identify the bond pattern of bismuth and nitrogen. From the energy spectrum analysis of XPS, the grown film is a tantalum nitride (TaN _x ) film formed by bonding Ta and N to each other.

Production Example 11 : Lithium Metal Electrode for Metal Lithium/钽/Carbide

As a way of forming an example, but using tantalum as a target, a lithium metal on a substrate sequentially coated with a thin metal film of tantalum, niobium carbide (TaC _x) film, a structure of FIG. The composition of tantalum carbide (TaC _x ) in the structure is 0.01 < x < 1.0. The thickness of the tantalum carbide film is between 50 nm and 500 nm, and the thickness of the tantalum metal film is between 25 nm and 95 nm.

The analysis of the compositional structure is based on XPS to identify the bonding pattern of carbon and yttrium. From the energy spectrum analysis of XPS, the grown film is a tantalum carbide (TaC _x ) film formed by bonding Ta and C to each other.

Production comparison example 1

No protection is given to the surface of the lithium metal substrate.

Production comparison example 2

Only the lithium nitride film is coated on the surface of the lithium metal substrate. The lithium nitride film is formed by introducing a mixed gas (nitrogen gas and argon gas) of 2.8 × 10 ^-1 Pa to 3 Pa into the vacuum chamber at a process temperature of 50 ° C to 70 ° C and a substrate bias of about 400 V. 150V, process time 5 minutes to 20 minutes.

Experimental example one

In the production example 4, the lithium metal electrode of Comparative Example 1 and Comparative Example 2 was prepared as a negative electrode material, and lithium cobalt oxide was used as a positive electrode and a binder was mixed and coated on the aluminum foil as a positive electrode, and the electrolyte was composed of a lithium ion-containing electrolyte. Element 1, control element one and control element two, as shown in the element structure of FIG.

The above three components were tested to obtain the following table 1.

Zp: positive electrode impedance; Ze: electrolyte impedance; Zn: negative electrode impedance.

As can be seen from Table 1, the use of conventional non-conductive lithium nitride to protect the lithium electrode method will result in a significant increase in impedance. The component of the present invention, in terms of impedance, can have a lower impedance performance than the unprotected lithium electrode.

Experimental example 2

The initial capacitance of the component 1 and the control component 1 of the experimental example 1 was measured and recorded together with the total impedance thereof in the following Table 2.

Further, the element one and the control element were combined in the same manner as in Experimental Example 1, except that the lithium negative electrode was subjected to the following deterioration test before the composition.

Deterioration test: Various lithium electrodes were exposed to an atmosphere of 25 ° C and 70% RH for 3 minutes.

Then, the initial capacitance and the total impedance of the element 1 and the control element 1 of the lithium negative electrode having the deterioration test were measured, and the results are also shown in Table 2 below.

As can be seen from Table 2, the total resistance of the unprotected lithium electrode was greatly increased after the deterioration test, and the active capacitance was remarkably lowered. The design of the protected lithium metal electrode of the fourth example was used as the negative electrode, and even after the deterioration test, the impedance increase range was much lower than that of the unprotected lithium electrode, and the active capacitance loss range was small.

Experimental example three

In the same manner as in Experimental Example 1, component one, control element one and control element two were combined, and then 20 charge-discharge cycles were performed. The relationship between the number of cycles and the capacitance is shown in Fig. 5, and the electricity after the first and 20 cycles. The capacity results are reported in Table 3 below.

Experimental example four

The lithium metal electrode of the second example is used as a negative electrode material, and is oxidized by lithium cobalt. The positive electrode and the binder are mixed and coated on the aluminum foil as the positive electrode, and the electrolyte containing the lithium ion is composed of the component 2, as shown in the element structure of FIG. 2, and then the charge and discharge cycle is performed 20 times, and the electricity after the first time and 20 cycles The capacity results are reported in Table 3 below.

Experimental example five

The lithium metal electrode of the third example is used as the negative electrode material, and the lithium cobalt oxide is used as the positive electrode and the binder is mixed and coated on the aluminum foil as the positive electrode, and the electrolyte containing the lithium ion is composed of the component three, as shown in the component structure of FIG. The charge and discharge cycle was performed 20 times, and the results of the capacitance after the first and 20 cycles are described in Table 3 below.

Experimental example six

The lithium metal electrode of the fifth example is used as the negative electrode material, and the lithium cobalt oxide is used as the positive electrode and the binder is mixed and coated on the aluminum foil as the positive electrode, and the electrolyte containing the lithium ion is composed of the component four, as shown in the component structure of FIG. The charge and discharge cycle was performed 20 times, and the results of the capacitance after the first and 20 cycles are described in Table 3 below.

Experimental example seven

The lithium metal electrode of the sixth example is used as the negative electrode material, and the lithium cobalt oxide is used as the positive electrode and the binder is mixed and coated on the aluminum foil as the positive electrode, and the electrolyte containing the lithium ion is composed of the component five, as shown in the component structure of FIG. The charge and discharge cycle was performed 20 times, and the results of the capacitance after the first and 20 cycles are described in Table 3 below.

Experimental example eight

The lithium metal electrode of the seventh example is used as a negative electrode material, and the lithium cobalt oxide is used as a positive electrode and a binder is mixed and coated on the aluminum foil as a positive electrode, and the electrolyte containing lithium ions is composed of a component six, as shown in the component structure of FIG. Perform 20 charge and discharge cycles The cycle, the capacitance results after the first and 20 cycles are described in Table 3 below.

Experimental example nine

The lithium metal electrode of the eighth example is used as a negative electrode material, and lithium cobalt oxide is used as a positive electrode and a binder is mixed and coated on the aluminum foil as a positive electrode, and the electrolyte containing lithium ions is composed of a component seven, as shown in the component structure of FIG. The charge and discharge cycle was performed 20 times, and the results of the capacitance after the first and 20 cycles are described in Table 3 below.

Experimental example ten

The lithium metal electrode of the production example 9 is used as a negative electrode material, and lithium cobalt oxide is used as a positive electrode and a binder is mixed and coated on the aluminum foil as a positive electrode, and an electrolyte containing lithium ions is composed of an element eight, as shown in the component structure of FIG. The charge and discharge cycle was performed 20 times, and the results of the capacitance after the first and 20 cycles are described in Table 3 below.

Experimental example eleven

The lithium metal electrode of the tenth example is used as a negative electrode material, and lithium cobalt oxide is used as a positive electrode and a binder is mixed and coated on the aluminum foil as a positive electrode, and an electrolyte containing lithium ions is composed of a component nine, as shown in the component structure of FIG. The charge and discharge cycle was performed 20 times, and the results of the capacitance after the first and 20 cycles are described in Table 3 below.

Experimental example twelve

The lithium metal electrode of the eleventh example is used as the negative electrode material, and the lithium cobalt oxide is used as the positive electrode and the binder is mixed and coated on the aluminum foil as the positive electrode, and the electrolyte containing the lithium ion is composed of the component ten, as shown in the component structure of FIG. Then, the charge and discharge cycle was performed 20 times, and the results of the capacitance after the first and 20 cycles are described in Table 3 below.

As can be seen from Table 3, the component of the present invention has a higher capacitance performance.

Then, the surface of the lithium negative electrode of the control element 1 and the element 1 after 20 cycles was observed by SEM, and the results are shown in Fig. 6A and Fig. 6B. Fig. 6A is an unprotected lithium electrode, the surface of which apparently produces regional uneven pits and dendritic deposits (please refer to the portion enclosed by the dotted line), which may have a piercing separator Safety concerns for shorting components. On the other hand, Fig. 6B shows the surface of the lithium electrode of the element 1 of the present invention, which is fragmented but exhibits a relatively flat pattern without dendritic deposition.

The total impedance performance of the control element one and the element one after 20 cycles was measured and shown in Fig. 7. -Z" is the imaginary part of the impedance spectrum, and Z' is the impedance map The real part of the spectrum. As can be seen from Figure 7, the elements of the present invention can have a lower total impedance performance after 20 cycles.

Experimental example thirteen

Lithium metal electrodes of Production Example 1, Production Example 4, Production Example 8, Production Example 7, Production Example 3, and Comparative Example 1 were used as negative electrode materials, and sulfur/carbon composite materials, a promoter and a binder were used for the aluminum foil. As the positive electrode, the electrolyte containing lithium ions is composed of element eleven, component twelve, component thirteen, component fourteen, component fifteen and comparison component three. These components are as shown in the component structure of FIG.

The initial capacitance of the above six elements was tested, and the charge and discharge cycles were further performed 10 times. The results of the capacitance after the first and 10 cycles are described in Table 4 below.

As can be seen from Table 4, the elements 11 to 15 of the present invention have high capacitance performance as compared with the unprotected lithium electrode.

In summary, the present invention forms a surface of a lithium metal with a specific metal film and The conductive film constitutes a protective layer, so that a lower impedance performance than the unprotected lithium electrode can be obtained, and the adhesion of the protective layer is improved. Moreover, when the lithium metal electrode of the present invention is applied to an element, not only the high electric capacity can be maintained but also reacts with the components contained in the electrolyte to affect its electrochemical recyclability, and the lithium during the charge and discharge cycle can be effectively avoided. Deterioration of metal due to surface pattern changes.

It is known from the above that the lithium metal substrate is an embodiment that the protective layer structure of the present invention not only has low impedance characteristics but also avoids deterioration of the lithium electrode compared to the conventional protective layer design, so that the element is maintained relatively stable. High capacity. The protective layer design concept of the present invention can also be applied to an active metal protective layer such as sodium, magnesium, calcium or aluminum.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Active metal substrate

100a, 104a‧‧‧ surface

102‧‧‧Protective layer

104‧‧‧Metal film

106‧‧‧Electrical film

Claims (24)

A protected lithium metal electrode comprising: a lithium metal substrate; and a protective layer on a surface of the lithium metal substrate, wherein the protective layer comprises: a metal film coated on the surface of the lithium metal substrate The material of the metal film is titanium, vanadium, chromium, zirconium, hafnium, molybdenum, niobium, tantalum or tungsten; and a conductive film coated on the surface of the metal film, wherein the material of the conductive film is selected from the group consisting of One of a metal nitride of a metal thin film, a metal carbide of the metal thin film, a diamond-like carbon thin film (DLC), and a combination thereof. The protected lithium metal electrode according to claim 1, wherein the metal thin film has a thickness of between 10 nm and 100 nm. The protected lithium metal electrode according to claim 1, wherein the conductive film has a resistivity of 10 ^-5 Ω. Cm~10 ² Ω. Between cm. The protected lithium metal electrode according to claim 1, wherein the conductive film has a thickness of between 10 nm and 1000 nm. The protected lithium metal electrode according to claim 1, wherein the carbon-like film is a tetrahedral amorphous carbon (ta-C) structure, and the sp ³ ratio is >40%. The protected lithium metal electrode according to claim 1, wherein the material of the conductive film comprises TiN _x , CrN _x , NbN _x or TaN _x , and 0.01 < x < 1.0. The protected lithium metal electrode according to claim 1, wherein the material of the conductive film comprises TiC _x , CrC _x , NbC _x or TaC _x , and 0.01 < x < 1.0. An element having a protected active metal electrode comprising: a positive electrode having electrochemical activity; an active metal negative electrode comprising: an active metal substrate; and a protective layer on a surface of the active metal substrate, wherein the protective layer comprises: a metal film coated on the active metal The surface of the substrate, wherein the metal film is made of titanium, vanadium, chromium, zirconium, hafnium, molybdenum, niobium, tantalum or tungsten; and a conductive film coated on the surface of the metal film, wherein the material of the conductive film Is one selected from the group consisting of a metal nitride including the metal thin film, a metal carbide of the metal thin film, a diamond-like carbon thin film (DLC), and a combination thereof; and an electrolyte in contact with the positive electrode and the active metal negative electrode, To provide active metal ions for conduction. An element having a protected active metal electrode according to claim 8 wherein the thickness of the metal thin film of the active metal negative electrode is between 10 nm and 100 nm. An element having a protected active metal electrode according to claim 8 wherein the conductive film of the active metal negative electrode has a resistivity of 10 ^-5 Ω. Cm~10 ² Ω. Between cm. An element having a protected active metal electrode according to claim 8, wherein the conductive film of the active metal negative electrode has a thickness of between 10 nm and 1000 nm. An element having a protected active metal electrode as described in claim 8 wherein the diamond-like carbon film is a tetrahedral amorphous carbon (ta-C) structure and has a sp ³ ratio of >40%. An element having a protected active metal electrode according to claim 8, wherein the material of the conductive film of the active metal negative electrode comprises TiN _x , CrN _x , NbN _x or TaN _x , and 0.01<x<1.0 . An element having a protected active metal electrode according to claim 8, wherein the material of the conductive film of the active metal negative electrode comprises TiC _x , CrC _x , NbC _x or TaC _x , and 0.01<x<1.0 . An element having a protected active metal electrode as described in claim 8 wherein the positive electrode is selected from the group consisting of sulfur-containing materials, metal oxides, carbon materials, and combinations thereof. An element having a protected active metal electrode as described in claim 15 wherein the sulfur-containing material is selected from the group consisting of sulfur, metal sulfides, organic sulfur, and combinations thereof. An element having a protected active metal electrode according to claim 15, wherein the carbon material is selected from the group consisting of activated carbon, carbon black, graphite, carbon fiber, carbon nanotube, mesoporous carbon, graphene, And the materials in their combination. An element having a protected active metal electrode as described in claim 15 wherein the metal oxide comprises a lithium-containing metal oxide or a lithium-free metal oxide. An element having a protected active metal electrode according to claim 18, wherein the lithium-containing oxide is selected from the group consisting of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide. , lithium nickel cobalt oxide, lithium cobalt manganese oxide , lithium nickel cobalt manganese oxide, lithium iron oxide, lithium cobalt phosphorus oxide, lithium nickel phosphorus oxide, lithium iron phosphorus oxide, lithium manganese phosphorus oxide, lithium cobalt manganese phosphorus oxide, lithium nickel cobalt phosphorus oxidation , lithium iron cobalt phosphorus oxide, lithium iron nickel phosphorus oxide, lithium iron manganese phosphorus oxide, lithium iron lanthanum oxide, lithium iron boron oxide, lithium titanium oxide, lithium cobalt titanium oxide, lithium manganese titanium oxide An oxide in lithium iron titanium oxide, lithium titanium phosphorus oxide, lithium vanadium oxide, lithium vanadium phosphorus oxide, and combinations thereof; the lithium-free oxide is selected from the group consisting of vanadium oxide, manganese oxide , tungsten oxide, titanium oxide, chromium oxide, iron oxide, cobalt oxide, nickel oxide, cerium oxide, molybdenum oxide, tin oxide, sodium vanadium oxide, sodium manganese oxide, sodium titanium Oxide, sodium chromium oxide, sodium iron oxide, sodium cobalt oxide, sodium nickel manganese oxide, sodium nickel cobalt oxide, sodium cobalt manganese oxide, sodium nickel cobalt manganese oxide, sodium cobalt phosphorus oxide, sodium Nickel phosphorus oxide, sodium iron phosphorus oxide, sodium manganese phosphorus oxide, sodium iron manganese phosphorus oxide, sodium vanadium phosphorus oxide, sodium Phosphorus oxide, oxides and combinations thereof. An element having a protected active metal electrode as described in claim 8 wherein the electrolyte is a solid electrolyte, a molten salt, an ionic liquid, a colloidal electrolyte, or an electrolyte. An element having a protected active metal electrode as described in claim 20, wherein the electrolyte comprises an active metal ion selected from the group consisting of lithium ion, sodium ion, magnesium ion, calcium ion, aluminum ion, and combinations thereof. An element having a protected active metal electrode as described in claim 8 wherein the active metal substrate comprises a lithium, sodium, magnesium, calcium, aluminum metal substrate, or a combination thereof. A protected active metal electrode comprising: an active metal substrate; and a protective layer on a surface of the active metal substrate, wherein the protective layer comprises: a metal film coated on the surface of the active metal substrate The material of the metal film is titanium, vanadium, chromium, zirconium, hafnium, molybdenum, niobium, tantalum or tungsten; and a conductive film coated on the surface of the metal film, wherein the material of the conductive film is selected from the group consisting of One of a metal nitride of a metal thin film, a metal carbide of the metal thin film, a diamond-like carbon thin film (DLC), and a combination thereof. The protected active metal electrode of claim 23, wherein the active metal substrate comprises a lithium, sodium, magnesium, calcium, aluminum metal substrate, or a combination thereof.