JP2008123822A - Electrode material, manufacturing method therefor, and nonaqueous lithium secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method of a residual sulfur amount in the active material for a positive electrode material of a lithium secondary battery synthesized using a sulfur compound. <P>SOLUTION: An active material usable for a positive electrode material is synthesized by suspending vanadium oxide, lithium compound, such as lithium sulfide, and contained sulfur organics in water, for heated reflux. Here, residual sulfur which is a subproduct in the active material is controlled by a depressure at depressure condensation during a manufacturing process. By controlling the amount of residual sulfur compound to be less than 1.6 wt.%, by making the pressure to be less than 21.00 kPa, the capacitance keeping rate at 10th cycle with a lithium secondary battery is maintained high. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technology of a lithium secondary battery, and is particularly effective when applied to a non-aqueous lithium secondary battery and a positive electrode material thereof.

  The technology described below has been studied by the present inventors in completing the present invention, and the outline thereof is as follows.

  Conventional non-aqueous lithium secondary batteries use lithium cobaltate, lithium manganate, or lithium nickelate as the positive electrode. The capacity theoretically did not exceed 137 mAh / g, 148 mAh / g, 198 mAh / g and 200 mAh / g per active material.

  Therefore, studies are underway to use a vanadium oxide-based material having a large number of valences and a high capacity potential as a positive electrode material of a lithium secondary battery. However, since the positive electrode material does not include a lithium ion supply source, it is necessary to use a lithium ion supply source for the negative electrode, and its use is limited to a primary battery or a secondary battery with a very low current amount. It was.

  In addition, when crystalline vanadium oxide is used for the positive electrode material, if low-valent vanadium is used to extract a high capacity, the crystal structure collapses due to charge / discharge, resulting in repeated charge / discharge cycles. A decrease in capacity occurred.

  Under such circumstances, in Patent Document 1, an organic sulfur material such as a sulfur-containing conductive polymer is inserted between layers of an insulating layered compound such as vanadium pentoxide, so that the crystal structure of the layered compound is fixed to a certain degree. It has been disclosed that it can be suppressed. By such a method, the capacity characteristics of the layered compound can be maximized.

Further, in such a configuration, an insulating (non-conductive) organic sulfur compound that extends the discharge potential range is also inserted between the layers, so that, for example, a proton of a mercapto group is reduced on the negative electrode to generate hydrogen gas. It is said that high cycle characteristics can be achieved at the same time.
JP 2005-285376 A

  The present inventor has remarkably improved the characteristics of a lithium secondary battery by using vanadium oxide, which is a novel layered crystalline material containing fine crystal grains having a short layer length at a predetermined ratio, as an active material of the positive electrode. Found to improve.

  However, in a layered crystalline material containing such fine crystal grains in a predetermined ratio, a sulfur-containing organic material such as a sulfur-containing organic conductive polymer may be used for the purpose of further improving the characteristics of the lithium secondary battery. Since such a sulfur-containing organic substance is mixed in the production stage, naturally, the produced layered crystalline substance contains a sulfur compound as a by-product.

  It has been found that when such a residual sulfur compound is contained more than necessary, the charge / discharge cycle or capacity is lowered, and further, the cause of the variation in material characteristics is caused. The amount of residual sulfur content halves the effect of the novel layered crystalline material. The present inventor considered that it was necessary to develop a technique for reducing the sulfur residue in the layered crystalline material used as the electrode active material.

  An object of the present invention is to provide a method for controlling the amount of residual sulfur in an electrode material synthesized using a sulfur compound.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  That is, when manufacturing the active material used for electrode material using a sulfur compound, the residual sulfur content in the obtained active material is controlled by adjusting the concentration pressure of the active material solution.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  In the present invention, the residual sulfur that affects the characteristics of the active material used as the electrode material can be removed by appropriately controlling the concentration pressure in the production process.

  In the present invention, since the residual sulfur content in the active material can be controlled by adjusting the concentration pressure in the production process of the active material used as the electrode material, the residual sulfur content in the active material can be easily removed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The present invention is a technique related to the production of an electrode material. In particular, it relates to an active material that can be used as a positive electrode material used in a non-aqueous lithium secondary battery, and is a technique for controlling the residual sulfur content in the active material by using a sulfur-containing organic substance during production. Such residual sulfur content can be easily obtained by controlling the concentration pressure in the concentration step of the active material during production.

  As an active material that can be used for the positive electrode material of such a non-aqueous lithium secondary battery, a material that includes an oxide of at least one metal element selected from Group V elements and Group VI elements in the periodic table is widely used. Can be mentioned. Examples of the metal oxide include vanadium oxide (vanadium oxide) and niobium oxide. In particular, vanadium pentoxide is preferable.

In such vanadium oxide, for example, V ₂ O ₅ forms one layer by spreading a pentahedral unit having VO ₅ as a unit in a two-dimensional direction by a covalent bond. By laminating these layers, a layered structure is obtained as a whole.

  In the present invention, the layer length of the layered crystalline substance is shortened (miniaturized) by making the layered crystalline substance macroscopically amorphous while maintaining the layered crystal structure. For example, a layered crystal state having a long layer length is divided and a layered crystal state having a short layer length appears.

  Such a state is a structure that cannot be realized if all are in an amorphous state. By stopping the progress of the amorphization halfway, the above state, that is, a layered crystal state having a short layer length can exist.

  Macroscopic amorphization means that the state of the layered crystalline material is such that only a crystal structure with a layer length of 30 nm or less, or such a crystal structure and an amorphous structure, can be observed on the order of nm or less. A coexisting state is confirmed, but when this state is viewed from a macro point of view that can only observe μm order larger than nm, an amorphous structure with randomly arranged crystal structures is observed Say.

  More specifically, as schematically shown in FIG. 1, the layer length L1 of the fine crystal grains does not include 0, and preferably falls within the range of 1 nm or more and 30 nm or less. .

  In the layered crystal state, when the layered crystal is less than 1 nm from the viewpoint of entering and exiting lithium ions between layers, it is difficult to dope and dedope lithium ions, and it is difficult to take out a high capacity. On the other hand, if it exceeds 30 nm, the crystal structure collapses due to charge / discharge, resulting in poor cycle characteristics. Therefore, the layer length does not include 0 and is 30 nm or less, preferably 1 nm or more and 30 nm or less, more preferably 5 nm or more and 25 nm or less.

As a result, the path related to the entry / exit of lithium ions between layers is shortened. By adopting such a configuration, it becomes easy for lithium ions to enter and exit between the vanadium oxide layers, and the discharge capacity, cycle characteristics, and the like are improved.
As shown in FIG. 2, in the state where the layer length L2 is long, it is difficult for lithium ions to enter and exit between the layers as compared with the case where the layer length L1 is short.

  Note that the layered crystal structure of 30 nm or less in which the fine crystal grains of vanadium oxide do not contain 0 may occupy an area ratio of 30% or more in the cross section of the vanadium oxide. When the area ratio is 100%, the amorphous state does not already exist, and only the layered crystal state is obtained. Of course, a layered crystal of 30 nm or less that does not contain 0 is effective even if it is 100%.

  Moreover, lithium ions are doped in metal oxides such as vanadium pentoxide having the above layered crystal structure. The lithium ions are preferably doped at a molar ratio of 0.1 to 6 with respect to the metal oxide. If the doping amount of lithium ions is less than 0.1 in terms of molar ratio, the doping effect is not sufficiently exhibited, and if the doping amount of lithium ions exceeds 6, the metal oxide may be reduced to metal. Therefore, it is not preferable.

  In the present invention, dope means occlusion, support, adsorption or insertion, and means a phenomenon in which lithium ions enter an electrode active material such as a positive electrode.

  Further, the active material contains a sulfur-containing conductive polymer as a sulfur-containing organic substance at the time of production. Such a sulfur-containing conductive polymer has redox activity and contains sulfur. As such a sulfur-containing conductive polymer, a polythiophene compound having a repeating structure of the chemical structural formula (I) shown in FIG. 3 can be used.

  Such a polythiophene compound can be synthesized using a thiophene compound represented by the chemical structural formula (II) in FIG. 4 as a monomer. Preferably, among the thiophene compounds shown in FIG. 4, 3,4-ethylenedioxythiophene, whose structural formula is shown in FIG. 5, is used, and the polythiophene compound shown in FIG. 3 is abbreviated as PEDOT. Oxythiophene) may be synthesized.

  The details are unknown, but when a monomer corresponding to the sulfur-containing conductive polymer is present, this monomer serves as an oxygen inhibitor, the oxygen concentration of the reaction system is kept constant, and the structure of the lithium ion-doped amorphous metal oxide that is produced It is thought to control. However, since the sulfur-containing conductive polymer at the end of the reaction has low performance as an active material, it is considered that the performance of the active material is improved by removing the final product by vacuum concentration or the like.

  In the active material of the positive electrode material for a non-aqueous lithium secondary battery to which the manufacturing technology of the present invention is applied, the X-ray diffraction pattern of the metal oxide contained in the metal oxide has a diffraction angle in the range of 2θ = 5 to 15 °. Has a peak.

  The active material thus obtained is mixed with a binder such as polyvinylidene fluoride (PDVF), preferably with conductive particles, to form a positive electrode material, which is coated on a conductive substrate to produce a positive electrode. be able to. The layer of the positive electrode material for a non-aqueous lithium secondary battery is preferably formed to a thickness of, for example, 10 to 100 μm.

  The conductive particles include conductive carbon (conductive carbon such as ketjen black), copper, iron, silver, nickel, palladium, gold, platinum, indium, tungsten, and other metals, indium oxide, tin oxide. And the like, and the like. Such conductive particles are preferably contained in a proportion of 1 to 30% of the weight of the metal oxide.

  Furthermore, a conductive substrate that exhibits conductivity at least on the surface in contact with the positive electrode material is used as the base (current collector) that supports the positive electrode material layer. Such a substrate can be formed of a conductive material such as metal, conductive metal oxide, or conductive carbon. In particular, it is preferable to form with copper, gold | metal | money, aluminum, those alloys, or conductive carbon. Alternatively, the base may have a configuration in which a base body formed of a non-conductive material is covered with a conductive material.

  An active material that can be used as a positive electrode material of such a non-aqueous lithium secondary battery is manufactured through a manufacturing process as shown in the flowchart of FIG.

  That is, as shown in FIG. 6, in step S100, an active material for the positive electrode material of the non-aqueous lithium secondary battery is synthesized. This synthesis is performed by mixing the required materials with water and refluxing for a predetermined time.

  The active material suspension for the positive electrode material thus synthesized is concentrated in step S200. At the time of such concentration, concentration under reduced pressure is performed, and the residual sulfur content of the active material for the positive electrode material produced thereafter is controlled by appropriately adjusting the pressure at which the pressure is reduced. The present inventor has found that the residual sulfur content of the active material for the positive electrode material to be produced differs depending on how to adjust the reduced pressure in step S200.

  As will be described in detail in Examples described later, if it is less than 21.00 kPa, the residual sulfur content in the active material of the electrode material that can be used as the positive electrode material can be adjusted to less than 1.6 wt%. More preferably, it may be less than 19.00 kPa, and the residual sulfur content can be reliably removed to be controlled to 1.4 wt% or less.

  The lower limit may be 0.01 kPa or more. At 21.00 kPa or more, the sulfur content is substantially difficult to remove, and when it is less than 0.01 kPa, it is difficult to set the actual pressure. That is, it is generally preferably 0.01 kPa or more and less than 21.00 kPa.

  Thereafter, in step S300, vacuum drying and solidification are performed. The drying temperature may be 30 ° C. or more and less than 250 ° C. If it is less than 30 degreeC, it cannot be dried substantially. Further, at 250 ° C. or higher, the crystal structure changes. After solidification, the positive electrode material powder may be produced by pulverizing to a predetermined particle size by a ball mill or the like in step S400, and performing sieving and classification in step S500.

  By forming a positive electrode using such an active material, a non-aqueous lithium secondary battery can be configured. The non-aqueous lithium secondary battery includes the positive electrode, the negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode.

  In the non-aqueous lithium secondary battery having such a configuration, the negative electrode can be formed of a commonly used lithium-based material. Such lithium-based materials include lithium-based metal materials such as metallic lithium and lithium alloys (for example, Li-Al alloys), intermetallic compound materials of metals such as tin and silicon and lithium metals, and lithium such as lithium nitride. Examples thereof include carbon materials that can be doped or dedoped with a compound or lithium ion.

As electrolytes, lithium salts such as CF ₃ SO ₃ Li, C ₄ F ₉ SO ₈ Li, (CF ₃ SO ₂ ) ₂ NLi, (CF ₃ SO ₂ ) ₃ CLi, LiBF ₄ , LiPF ₆ , LiClO _4, etc. Can be used. The solvent that dissolves the electrolyte is a non-aqueous solvent.

  Examples of non-aqueous solvents include chain carbonates, cyclic carbonates, cyclic esters, nitrile compounds, acid anhydrides, amide compounds, phosphate compounds, amine compounds, and the like. Furthermore, specific examples of the non-aqueous solvent include ethylene carbonate, diethyl carbonate (DEC), propylene carbonate, dimethoxyethane, γ-butyrolactone, n-methylpyrrolidinone, N, N′-dimethylacetamide, acetonitrile, or propylene carbonate. A mixture of dimethoxyethane, a mixture of sulfolane and tetrahydrofuran, and the like.

  The electrolyte layer interposed between the positive electrode and the negative electrode may be a solution of the electrolyte in a non-aqueous solvent or a polymer gel (polymer gel electrolyte) containing the electrolyte solution.

  An example of such a lithium secondary battery is a configuration as shown in FIG. That is, in the nonaqueous lithium secondary battery 10, the positive electrode 1 and the negative electrode 2 are opposed to each other through the electrolyte layer 3. The positive electrode 1 is composed of a positive electrode active material 1a having a predetermined amount of a layered crystal structure and a base 1b that functions as a current collector. As shown in FIG. 7, a layer of the positive electrode active material 1a is provided on the surface of the base 1b.

  Similarly, the negative electrode 2 includes a negative electrode active material 2a and a base 2b as a current collector, and a layer of the negative electrode active material 2a is provided on the surface of the base 2b. The positive electrode 1 and the negative electrode 2 are opposed to each other with the electrolyte layer 3 interposed therebetween.

  Hereinafter, the present invention for controlling the amount of residual sulfur in an active material of an electrode material that can be used as a positive electrode material to be produced by adjusting the reduced pressure during concentration under reduced pressure will be described based on Examples.

(Example 1)
In this example, vanadium pentoxide (V ₂ O ₅ ), for example, was used as the oxide. That is, 2.0 g of vanadium pentoxide, 0.3 g of a half molar amount of lithium sulfide (Li ₂ S), and 0.6 g of 3,4-ethylenedioxythiophene (EDOT) with respect to vanadium pentoxide, Suspend in 50 ml. The suspension was heated to reflux with stirring for 12 hours, and the solution was concentrated under reduced pressure at 75 ° C. and a pressure of 10.67 kPa to obtain a black solid. The active material was vacuum dried at 100 ° C.

  After vacuum drying, X-ray diffraction of the active material was performed. As a result, as shown in FIG. 8A, a peak was observed in the vicinity of 2θ = 10 °. It was confirmed that the active material of Example 1 was an amorphous material. ICP analysis confirmed that lithium ions were incorporated into the amorphized product.

  When the obtained active material was observed with a transmission electron microscope, it was confirmed that 99% of fine crystal grains having a layer length of 5 nm or more and 25 nm or less were obtained.

  When the active material is vacuum-dried at 250 ° C. for 12 hours, as shown in FIG. 8B, the active material shows a peak different from that of the active material, and the layer length is more than 30 nm. confirmed. Therefore, the production of the active material used in the electrode material according to the present invention including decompression as described above must be performed at a temperature of less than 250 ° C. FIG. 8B also shows a peak of lithium vanadate for reference.

  The amount of residual sulfur in the active material was measured by elemental analysis. The measurement result was 0.2 wt% as shown in FIG.

  The positive electrode material powder made of such an active material was pulverized and subsequently classified by sieving. A positive electrode material powder of 70 wt%, conductive carbon black of 20 wt%, and polyvinylidene fluoride (PVDF) of 10 wt% were mixed and slurried using N-methylpyrrolidone (NMP) as a solvent. The slurry was coated on an Al foil used as a conductive substrate (current collector) by a doctor blade method to produce a positive electrode.

A lithium secondary battery was assembled using such a positive electrode, using 1M LiBF ₄ dissolved in a mixed solvent of EC: DEC = 1: 3 as an electrolyte, and using metallic lithium for the negative electrode.

  Charging / discharging evaluation was performed at 0.1 C discharge. The result of the discharge test is shown in FIG. The initial capacity was 392 mAh / g per active material, and the capacity retention rate after 10 cycles was 94%.

(Example 2)
In the present example, the active material was manufactured in the same manner as in Example 1 except that the vacuum concentration pressure was 13.33 kPa in step S200 shown in FIG. As a result of elemental analysis, the active material contained 0.6 wt% sulfur as shown in FIG.

  Using the positive electrode material powder made of such an active material, a positive electrode was produced in the same manner as in Example 1 and subjected to charge / discharge evaluation. The result of the discharge test is shown in FIG. Similar to Example 1, the initial capacity was 385 mAh / g per active material, and the capacity retention rate after 10 cycles was 90%.

(Example 3)
In this example, the positive electrode material was manufactured in the same manner as in Example 1 except that the vacuum concentration pressure in step S200 shown in FIG. As shown in FIG. 9, the active material contained 0.8 wt% sulfur as a result of elemental analysis.

  Using this positive electrode, a positive electrode was produced in the same manner as in Example 1, and subjected to charge / discharge evaluation. The result of the discharge test is shown in FIG. The initial capacity was 382 mAh / g per active material, and the capacity retention rate after 10 cycles was 91%.

Example 4
In this example, the active material for the positive electrode material was manufactured in the same manner as in Example 1 except that the vacuum concentration pressure in step S200 shown in FIG. 6 was 18.67 kPa. As shown in FIG. 9, the active material contained 1.4 wt% sulfur as a result of elemental analysis.

  Using the positive electrode material powder composed of such an active material, a positive electrode was produced in the same manner as in Example 1 and subjected to charge / discharge evaluation. The result of the discharge test is shown in FIG. The initial capacity was 388 mAh / g per active material, and the capacity retention rate after 10 cycles was 87%.

(Example 5)
In this example, when the active material for the positive electrode material was synthesized, the lithium sulfide used in Example 1 was changed to lithium hydroxide. The rest is the same as in the first embodiment. The vacuum concentration pressure in step S200 of the manufacturing flow shown in FIG. 6 was set to 10.67 kPa. As shown in FIG. 9, the active material contained 0.9 wt% sulfur as a result of elemental analysis.

  A positive electrode was produced in the same manner as in Example 1 using the positive electrode material powder made of such an active material, and charge / discharge evaluation was performed. The result of the discharge test is shown in FIG. The initial capacity was 386 mAh / g per active material, and the capacity retention rate after 10 cycles was 91%.

(Example 6)
In this example, the positive electrode material was manufactured in the same manner as in Example 1 except that the vacuum concentration pressure in step S200 of the manufacturing flow shown in FIG. As shown in FIG. 9, the active material contained 1.0 wt% sulfur as a result of elemental analysis.

  A positive electrode was produced in the same manner as in Example 1 using the positive electrode material powder made of such an active material, and charge / discharge evaluation was performed. The result of the discharge test is shown in FIG. The initial capacity was 380 mAh / g per active material, and the capacity retention rate after 10 cycles was 94%.

(Comparative Example 1)
In Comparative Example 1, a positive electrode active material was produced in the same manner as in Example 1 except that the vacuum concentration pressure in Step S200 shown in FIG. 6 was 21.33 kPa. As a result of elemental analysis, the active material contained 1.6 wt% sulfur as shown in FIG.

  Using the positive electrode material powder made of such an active material, a positive electrode was produced in the same manner as in Example 1, and charge / discharge evaluation was performed. The result of the discharge test is shown in FIG. The initial capacity was 354 mAh / g per active material, which was lower than that of Example 1. The capacity continued to decrease according to the number of cycles, and good cycle characteristics as in Example 1 were not obtained. The capacity retention rate after 10 cycles was 82%.

(Comparative Example 2)
In Comparative Example 2, an active material was produced in the same manner as in Example 1 except that the vacuum concentration pressure in Step S200 shown in FIG. 6 was 24.00 kPa. As a result of elemental analysis, the active material contained 1.9 wt% sulfur as shown in FIG.

  Using the positive electrode material powder composed of such an active material, a positive electrode was produced in the same manner as in Example 1, and charge / discharge evaluation was performed. The result of the discharge test is shown in FIG. The initial capacity was 366 mAh / g per active material, which was lower than that in Example 1. The capacity continued to decrease according to the number of cycles, and good cycle characteristics as in Example 1 were not obtained. The capacity retention rate after 10 cycles was 77%.

  From Examples 1 to 6 and Comparative Examples 1 and 2, as shown in FIG. 9, if the pressure during vacuum concentration is less than 21.33 kPa, the residual sulfur content of the positive electrode material is adjusted to less than 1.6 wt%. It was confirmed that More preferably, if it is 18.67 kPa or less, the residual sulfur content can be reliably set to 1.4 wt% or less.

  In addition, if the pressure during vacuum concentration is adjusted to less than 19.00 kPa and the residual sulfur content is set to 1.4 wt% or less, the initial discharge amount is set to 380 mAh / g or more, and the capacity at the 10th cycle of the discharge cycle. The maintenance rate can be 90% or more.

  However, if the pressure during vacuum concentration is adjusted to 21.00 kPa or more and the residual sulfur content exceeds 1.6 wt%, the initial discharge capacity is 350 to 360 mAh / g, and the capacity maintenance rate after 10 cycles is 82, It decreases to 77%.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments and examples. However, the present invention is not limited to the above-described embodiments and examples, and does not depart from the spirit of the invention. It goes without saying that various changes can be made.

  The present invention can be effectively used particularly in the field of positive electrode materials for lithium secondary batteries.

It is explanatory drawing which showed typically the layered crystal structure with a short layer length of this invention. It is explanatory drawing which showed typically the layered crystal structure with a long layer length different from this invention. It is explanatory drawing which showed an example of the polymer structure of the sulfur containing organic substance which can be used for the synthesis | combination of the positive electrode material to which this invention is applied. It is explanatory drawing which showed an example of the monomer used with the polymer of the sulfur containing organic substance used by the synthesis | combination of the positive electrode material to which this invention is applied with the chemical structure. It is explanatory drawing which showed the chemical structural formula of 3, 4- ethylene dioxythiophene used with the polymer of the sulfur containing organic substance used by the synthesis | combination of the positive electrode material to which this invention is applied. It is a flowchart which shows the manufacturing method of this invention. 1 is a cross-sectional view showing a schematic configuration of a non-aqueous lithium secondary battery to which the present invention can be applied. (A) is explanatory drawing which shows the result of the X-ray crystal diffraction of the positive electrode material of this invention, (b) is the result of the X-ray crystal diffraction at the time of vacuum-drying at 250 degreeC, and lithium vanadate. It is explanatory drawing which shows a peak. It is explanatory drawing which shows the result which compared and contrasted the residual sulfur content and the effect of the positive electrode material in the Example of this invention with the case shown in a comparative example.

Explanation of symbols

10 Nonaqueous lithium secondary battery 1 Positive electrode 1a Positive electrode active material 1b Base (current collector)
2 Negative electrode 2a Negative electrode active material 2b Substrate (current collector)
3 Electrolyte layer
L1 layer length
L2 layer length

Claims (11)

A method for producing an electrode material using a sulfur-containing organic substance and vanadium oxide as an active material,
A method for producing an electrode material, wherein a residual sulfur content in an active material is controlled by a concentration pressure in the production of the active material. In the manufacturing method of the electrode material of Claim 1,
The method for producing an electrode material, wherein the concentration pressure is 0.01 kPa or more and less than 21.00 kPa. In the manufacturing method of the electrode material of any one of Claim 1 or 2,
The method for producing an electrode material, wherein the residual sulfur content is less than 1.6% by weight. In the manufacturing method of the electrode material of any one of Claims 1-3,
The method for producing an electrode material, wherein the vanadium oxide is dried at 30 ° C. or higher and lower than 250 ° C. In the manufacturing method of the electrode material of any one of Claims 1-4,
The method for producing an electrode material, wherein the vanadium oxide is mixed with a lithium compound with water at a production stage and doped with lithium ions. An electrode material that can be used as a positive electrode active material having a vanadium oxide doped with lithium ions in a lithium secondary battery,
The electrode material, wherein a sulfur content in the electrode material is less than 1.6% by weight. The electrode material according to claim 6,
The vanadium oxide has fine crystal grains having a layer length of 30 nm or less and not containing 0. The electrode material according to claim 6 or 7,
An electrode material, wherein the vanadium oxide has an amorphous state and a layered crystal state mixed therein. The electrode material according to claim 7 or 8,
The electrode material characterized in that the fine crystal grains have an area ratio of 30% or more and 100% or less observed in a cross section of the vanadium oxide. The electrode material according to any one of claims 7 to 9,
The layered crystal state is an electrode material characterized in that the layer length of the fine crystal grains exceeds 30 nm at a temperature of 250 ° C. or higher. The positive electrode having a vanadium oxide doped with lithium ions is a non-aqueous lithium secondary battery facing the negative electrode through a non-aqueous electrolyte,
The non-aqueous lithium secondary battery, wherein the positive electrode is provided with the vanadium oxide having a sulfur content of less than 1.6% by weight.

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