JP2014182885A - Positive electrode material for lithium secondary batteries, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive electrode material for lithium secondary batteries which makes possible to manufacture a lithium secondary battery having high charge and discharge voltages and charge and discharge capacities; and a method for manufacturing such a positive electrode material.SOLUTION: A positive electrode material for lithium secondary batteries is used for a lithium ion secondary battery 100 including a positive electrode 10 capable of occluding and releasing lithium ions, a negative electrode 20 capable of occluding and releasing lithium ions, and an electrolyte 30. The positive electrode material comprises nickel lithium phosphate and nickel phosphide.

Description

  The present invention relates to a positive electrode material for a lithium secondary battery and a manufacturing method thereof, and more particularly to a positive electrode material for a lithium secondary battery containing lithium nickel phosphate and a manufacturing method thereof.

  From the viewpoint of preventing the depletion of limited petroleum resources and the prevention of global warming due to carbon dioxide emissions, electric power is attracting attention as a power source for ships and the like. In such a ship or the like, an onboard motor is driven using electric power stored in a secondary battery such as a lithium secondary battery. And the ship etc. can be navigated by driving the rotary blade etc. which were connected to the motor.

  The secondary battery includes a positive electrode and a negative electrode. The positive electrode and the negative electrode can be manufactured by various methods depending on the type of the secondary battery. For example, a positive electrode in a lithium secondary battery among secondary batteries can be manufactured by applying a positive electrode mixture on the surface of a current collector plate and drying it.

  A positive electrode mixture applicable to the production of a positive electrode of a lithium secondary battery includes a positive electrode active material that occludes and releases lithium ions. Various types of positive electrode active materials are known. Specifically, for example, Patent Document 1 describes lithium iron phosphate as a positive electrode active material.

  However, in the lithium secondary battery using lithium iron phosphate as the positive electrode active material, it is difficult to improve the charge / discharge voltage. Therefore, for example, Non-Patent Document 1 and Non-Patent Document 2 describe lithium nickel phosphate as a positive electrode active material capable of achieving a higher charge / discharge voltage. In this material, it has been confirmed that an oxidation-reduction reaction occurs at 5 V or more.

Japanese Patent Laid-Open No. 9-171827

Journal of Power Sources, pp.389-390, 142 (2005) Nature Materials, pp.147-152, 3 (2004)

  Lithium secondary batteries using lithium nickel phosphate exhibit a particularly high charge / discharge voltage among batteries using various positive electrode active materials. Therefore, a lithium secondary battery using lithium nickel phosphate is a so-called all-solid battery (all-solid-state secondary battery) using a solid electrolyte instead of an organic electrolyte, which is suitable for a higher charge / discharge voltage. Preferably there is.

  However, unlike an all-solid-state battery using a lithium secondary battery using an organic electrolyte, lithium ion diffusion hardly occurs. Therefore, the characteristics of lithium nickel phosphate capable of exhibiting higher charge / discharge voltage characteristics may not be fully utilized.

  Furthermore, the electrical conductivity of olivine-type lithium phosphate metal compounds such as lithium nickel phosphate is usually not so high. Therefore, in order to increase electric conductivity and obtain sufficient charge / discharge capacity, it is preferable to improve the electric conductivity of lithium nickel phosphate.

  From this viewpoint, as a method for improving the electrical conductivity, for example, it is conceivable to coat nickel phosphate lithium particles with an electrically conductive material such as carbon. However, when the nickel phosphate lithium particles are coated with carbon or the like, it may be difficult to exchange lithium ions between the nickel phosphate lithium particles and the outside. That is, as in the case described above, diffusion of lithium ions is less likely to occur, and the characteristics of lithium nickel phosphate may not be fully utilized. In addition, it may be difficult to coat lithium nickel phosphate with an electrically conductive material.

  The present invention has been made in view of such circumstances. This invention makes it a subject to provide the positive electrode material for lithium secondary batteries which can manufacture the lithium secondary battery which has a high charging / discharging voltage and charging / discharging capacity | capacitance, and its manufacturing method.

  The present inventor has intensively studied to solve the above problems. As a result, the following findings were found. That is, the gist of the present invention is a lithium secondary comprising a positive electrode capable of inserting and extracting lithium ions, a negative electrode capable of inserting and extracting lithium ions, and a solid electrolyte supported between the positive electrode and the negative electrode. The present invention relates to a positive electrode material for a lithium secondary battery that is used for a battery, and includes lithium nickel phosphate and nickel phosphide.

  Another aspect of the present invention is a lithium battery comprising a positive electrode capable of inserting and extracting lithium ions, a negative electrode capable of inserting and extracting lithium ions, and a solid electrolyte supported between the positive electrode and the negative electrode. A method for producing a positive electrode material for a lithium secondary battery used in an ion secondary battery, comprising: a lithium raw material; an excessive phosphorus raw material than a stoichiometric ratio; and an excessive nickel raw material than a stoichiometric ratio; And a heat treatment to produce at least nickel nickel phosphate and nickel phosphide, and a method for producing a positive electrode material for a lithium secondary battery.

  ADVANTAGE OF THE INVENTION According to this invention, the positive electrode material for lithium secondary batteries which can manufacture the lithium secondary battery which has a high charging / discharging voltage and charging / discharging capacity | capacitance, and its manufacturing method can be provided.

It is sectional drawing of the lithium ion secondary battery which concerns on this embodiment. It is sectional drawing which expands and shows the mode of the positive electrode vicinity of the lithium ion secondary battery which concerns on this embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a mode for carrying out the present invention (the present embodiment) will be described. However, the present embodiment is not limited to the following contents, and may be arbitrarily modified and implemented within a range that does not significantly impair the effects of the present invention. Is possible.

  As long as the positive electrode material for a lithium secondary battery and the manufacturing method thereof according to this embodiment are applied to a lithium secondary battery, the specific configuration of the lithium secondary battery may be any. For example, these can be applied to a so-called “lithium ion secondary battery” using a material other than a metal as a negative electrode, and applied to a “lithium secondary battery” using, for example, metallic lithium or a lithium-aluminum alloy as a negative electrode. You can also

  In addition, the battery manufactured using the positive electrode material for a lithium secondary battery according to the present embodiment may be a lithium secondary battery that uses a non-aqueous electrolyte as an electrolyte, or an all-solid lithium secondary that uses a solid electrolyte. A secondary battery may be used. However, the battery produced using the positive electrode material for a lithium secondary battery according to this embodiment can be used particularly preferably at a high charge / discharge voltage. Considering this point, the positive electrode material for a lithium secondary battery according to the present embodiment is preferably an all-solid-type positive electrode material for a lithium secondary battery (a positive electrode material for an all-solid lithium secondary battery).

  Therefore, as an explanation of the positive electrode material for a lithium secondary battery and the manufacturing method thereof according to the following embodiment, an all solid lithium secondary battery is taken as an example of the lithium secondary battery, and these explanations will be given below. To do. However, as described above, the lithium secondary battery to which the positive electrode material for a lithium secondary battery and the manufacturing method thereof according to the present embodiment can be applied is not limited to the lithium ion secondary battery, and any lithium secondary battery It may be.

[1. Lithium ion secondary battery]
A lithium ion secondary battery 100 according to the present embodiment (hereinafter simply referred to as “secondary battery 100”) is supported between a positive electrode 10, a negative electrode 20, and a positive electrode 10 and a negative electrode 20, as shown in FIG. The solid electrolyte 30 is provided. That is, the secondary battery 100 is an all solid-state lithium ion secondary battery.

[Positive electrode 10]
The positive electrode 10 constituting the secondary battery 100 is capable of inserting and extracting lithium ions. The positive electrode 10 is applied with a positive electrode material containing a positive electrode active material, a solvent, and the like (details will be described later in [2. Manufacturing method of the lithium ion secondary battery 100]) on a current collector plate such as aluminum. Dried. Therefore, the positive electrode 10 includes each component other than the volatile components (such as a solvent) in the positive electrode material.

  In the present embodiment, the positive electrode 10 contains lithium nickel phosphate and nickel phosphide. Here, the lithium nickel phosphate normally functions as a positive electrode active material. By including lithium nickel phosphate in the positive electrode 10, the charge / discharge voltage of the secondary battery 100 can be increased. In addition, in the case of an all-solid lithium secondary battery, the positive electrode 10 includes, in addition to lithium nickel phosphate and nickel phosphide, usually a binder resin such as polyvinylidene fluoride, a conductive aid such as acetylene black and carbon black, etc. A solid electrolyte is also included.

  The positive electrode active material contained in the positive electrode 10 includes any positive electrode active material such as lithium iron phosphate, lithium manganese phosphate, and lithium cobaltate in addition to lithium nickel phosphide that normally functions as the positive electrode active material. Also good. In addition, the positive electrode active material may be coated with an electrically conductive material such as a carbon material as long as the effects of the present invention are not significantly impaired.

  The nickel phosphide contained in the positive electrode 10 is used for improving the electrical conductivity of a positive electrode active material such as lithium nickel phosphate contained in the positive electrode 10. The electrical conductivity of lithium nickel phosphate is usually not very high. Thus, by making nickel phosphide coexist in the positive electrode 10 containing lithium nickel phosphate, the electrical conductivity of the lithium nickel phosphate can be particularly enhanced. Thereby, the charge / discharge capacity of the secondary battery 100 having the positive electrode 10 can be increased.

The nickel phosphide includes several compounds such as a compound represented by the composition formula NiP ₃ and a compound represented by the composition formula Ni ₃ P. The positive electrode material used for producing the positive electrode 10 constituting the secondary battery 100 may contain any nickel phosphide, and above all, includes the nickel phosphide represented by the composition formula NiP _3. It is preferable. Thereby, although details will be described later, it can be easily prepared together with lithium nickel phosphate preparation.

  The amount of lithium nickel phosphate and nickel phosphide contained in the positive electrode 10 is not particularly limited. However, it is preferable that the content of nickel phosphide is large from the viewpoint that the electrical conductivity of the lithium nickel phosphate can be increased and the charge / discharge capacity of the secondary battery 100 can be increased. Specifically, when the content of nickel phosphide is measured (calculated) using, for example, a powder X-ray diffractometer using CuKα rays, 110/201 of 25.9 ± 0.5 ° of lithium nickel phosphate. The 110 diffractive peak intensity ratio of 16.0 ± 0.5 ° of the nickel phosphide with respect to the diffraction peak is preferably 0.002 or more, and particularly preferably 0.006 or more. By setting it as this range, the charge / discharge capacity of the secondary battery 100 can be particularly increased. As the powder X-ray diffractometer, RINT2000 manufactured by Rigaku Corporation can be used, for example.

  In calculating the diffraction peak intensity ratio, a sample corresponding to a so-called background that does not contain nickel phosphide is prepared and analyzed, so that the diffraction peak intensity ratio attributable to nickel phosphide (ie, nickel phosphide) is calculated. The diffraction peak intensity ratio) can be calculated.

  FIG. 2 is an enlarged view showing the vicinity of the positive electrode 10 constituting the secondary battery 100. In FIG. 2, only lithium nickel phosphate and nickel phosphide are shown for simplification of illustration.

  As shown in FIG. 2, the positive electrode 10 is formed by fixing lithium nickel phosphate 2, nickel phosphide 3 and the like on the surface of the positive electrode plate 1 with a binder resin (not shown in FIG. 2). That is, it can be said that the individual nickel lithium phosphates 2 are electrically joined by the nickel phosphide 3. Thus, the electrical conductivity of the lithium nickel phosphide 2 can be improved by further fixing the nickel phosphide 3 to the positive electrode 10 to which the nickel lithium phosphate 2 is fixed.

  Further, the lithium nickel phosphate 2 is not completely covered with the nickel phosphide 3. Therefore, the diffusion of lithium ions from nickel lithium phosphide 2 is difficult to be inhibited, and the decrease in charge / discharge capacity can be suppressed.

[Negative electrode 20]
The negative electrode 20 constituting the secondary battery 100 is capable of inserting and extracting lithium ions, like the positive electrode 10. The negative electrode 20 can have any configuration. For example, the negative electrode 20 includes a binder resin, a solvent, a conductive auxiliary agent, and the like similar to those of the carbon element such as carbon powder or a metal element-containing alloy positive electrode 10 such as a lithium-containing alloy with respect to a current collector plate of copper or aluminum. The negative electrode material can be applied and dried.

[Solid electrolyte 30]
The solid electrolyte 30 constituting the secondary battery 100 mediates exchange of lithium ions and the like between the positive electrode 10 and the negative electrode 20. Type of solid electrolyte 30 is not particularly limited, for _example, can be used _{Li 10 GeP 2 S 12, La} 0.5 Li 0.5 TiO 3 or the like. One of these may be used alone, or two or more of these may be used in combination.

[2. Method for manufacturing lithium ion secondary battery 100]
Next, a method for manufacturing the above-described lithium ion secondary battery 100 (hereinafter simply referred to as “method for manufacturing the secondary battery 100”) will be described. The secondary battery 100 can be manufactured by manufacturing the positive electrode 10 and the negative electrode 20 and supporting the solid electrolyte 30 therebetween.

  In the manufacturing method of the secondary battery 100 of the present embodiment, the positive electrode 10 is manufactured by using a lithium raw material, an excessive phosphorus raw material than the stoichiometric ratio, an excessive nickel raw material than the stoichiometric ratio, Is mixed and heat-treated to at least include a step of producing at least nickel nickel phosphate and nickel phosphide (nickel phosphide producing step).

Regarding “stoichiometric ratio”, in lithium nickel phosphate (LiNiPO ₄ ), phosphorus, nickel, and lithium are all contained in an amount of 1 mol. Therefore, “excess amount than the stoichiometric ratio” means that, for example, in the case of a phosphorus raw material, the amount of phosphorus element is more than 1 mole per mole of lithium element.

  The positive electrode 10 is produced using nickel nickel phosphate and nickel phosphide obtained through the nickel phosphide generation step. Specifically, the positive electrode 10 is manufactured by mixing these, a solvent, a binder resin, a conductive additive, and the like, and applying and drying the mixture on a current collector plate.

  In the nickel phosphide production step, any material may be used as the lithium raw material as long as it is a material containing lithium. For example, lithium carbonate or lithium hydroxide can be used. A plurality of lithium raw materials may be used in combination. Among these, lithium hydroxide is preferably used from the viewpoint that nitrogen oxides are not generated even when heat treatment is performed in an oxidizing atmosphere.

  As the phosphorus raw material, any material may be used as long as it is a material containing phosphorus. For example, ammonium hydrogen phosphate, phosphoric acid, pyrophosphoric acid and the like can be used. A plurality of phosphorus raw materials may be used in combination.

  Furthermore, any material may be used as the nickel raw material as long as the material contains nickel. For example, nickel hydroxide, nickel oxide, nickel oxalate, or the like can be used. A plurality of nickel raw materials may be used in combination.

  A compound containing both phosphorus and nickel may also be used. Specifically, for example, nickel pyrophosphate is used, and in this case, nickel pyrophosphate corresponds to a phosphorus raw material and a nickel raw material. Other compounds containing both phosphorus and lithium (corresponding to phosphorus raw material and lithium raw material), compounds containing both nickel and lithium (corresponding to nickel raw material and lithium raw material), and compounds containing all of phosphorus, lithium and nickel (Corresponding to phosphorus raw material, lithium raw material and nickel raw material) or the like may be used as appropriate.

The amount of lithium raw material, phosphorus raw material, and nickel raw material used is not particularly limited. However, in the present embodiment, in the composition ratio of lithium nickel phosphate (LiNiPO ₄ ), the amount used of the phosphorus raw material and the nickel raw material is an amount that exceeds the amount of the lithium raw material used as described above. Shall. That is, the lithium nickel phosphate includes 1 mol of lithium element, 1 mol of nickel element, and 1 mol of phosphorus element. Therefore, for example, for a lithium raw material containing 1 mol of lithium element, a phosphorus raw material containing 1.1 mol of phosphorus element and a nickel raw material containing 1.1 mol of nickel element can be used in combination. Further, for example, 1.1 mol of phosphorus element and 1.1 mol of nickel element may be used in combination with respect to a lithium raw material containing 1 mol of lithium element.

  After mixing a lithium raw material, a phosphorus raw material, and a nickel raw material with the said usage-amount, in addition to nickel lithium phosphate, nickel phosphide can be produced | generated by heat-processing with respect to a mixture. That is, normally, the raw materials (lithium raw material, phosphorus raw material and nickel raw material) are charged according to the stoichiometric ratio, and the heat treatment is performed. In this embodiment, however, the phosphorus raw material and nickel raw material are intentionally excessive in the stoichiometric ratio. It is prepared to become. Thus, nickel phosphide can be produced by changing the amount of the raw material used from the stoichiometric ratio. Thereby, the electrical conductivity of lithium nickel phosphate can be easily improved.

  The conditions during the heat treatment are not particularly limited. For example, heat treatment can be performed by calcining at 300 ° C. to 500 ° C. for 2 hours to 12 hours and then firing at 600 ° C. to 800 ° C. for 2 hours to 12 hours. However, from the viewpoint of more reliably obtaining a mixture of nickel phosphide and nickel phosphide, it is preferable to perform the main calcination at a temperature of 600 ° C. or higher and 700 ° C. or lower. Moreover, it is not necessary to perform temporary baking as needed.

  The atmosphere during the heat treatment is not particularly limited, and may be any atmosphere such as an oxidizing atmosphere (for example, in the air) or an inert atmosphere (for example, in nitrogen gas or argon gas). However, it is preferable to perform the heat treatment in an oxidizing atmosphere from the viewpoint that the heat treatment tank can be downsized and can be easily heat treated. In addition, by performing heat treatment in an oxidizing atmosphere, for example, carbon atoms in the raw material can be discharged to the outside as carbon monoxide or carbon dioxide, and the generation and residue of impurities in the product after the heat treatment is suppressed. be able to. Thereby, the improvement of electrical conductivity is further promoted.

  After the heat treatment, the mixture of the obtained lithium nickel phosphide and nickel phosphide is added with the material constituting the positive electrode 10 in addition to the solvent, applied to the current collector plate and dried, whereby the positive electrode 10 Can be made.

  On the other hand, the method for producing the negative electrode 20 is not particularly limited, and the negative electrode 20 can be produced by appropriately mixing the materials constituting the negative electrode 20 with a solvent, applying the mixture to a current collector plate, and drying. And the secondary battery 100 can be produced by carrying the solid electrolyte 30 between the positive electrode 10 and the negative electrode 20 which were obtained.

  Hereinafter, the present invention will be described in more detail with reference to examples.

[Example 1]
Lithium monohydrate (LiOH _· H 2 O) 8.46g hydroxide as lithium source, a phosphorus raw material and pyrophosphate nickel as nickel material _{(Ni 2 P 2 O 7 ·} 6H 2 O) 41.53g Mix well. The obtained mixture was calcined in air at 500 ° C. for 6 hours and pulverized, followed by firing at 700 ° C. for 6 hours. As a result, lithium nickel phosphate and nickel phosphide (NiP _{3 in} this example) were produced, and a mixture containing lithium nickel phosphate and nickel phosphide was obtained.

  The content of nickel phosphide in the obtained mixture was measured. Specifically, the nickel phosphide with respect to the 25.9 ± 0.5 ° 110/201 diffraction peak of lithium nickel phosphate using a powder X-ray diffractometer (RINT2000 manufactured by Rigaku Corporation) using CuKα rays. The 110 diffraction peak intensity ratio of 16.0 ± 0.5 ° was calculated. As a result, it was found that the calculated diffraction peak intensity ratio was 0.021. In addition, the larger the diffraction peak intensity ratio, the greater the content of nickel phosphide.

Moreover, electrical conductivity was measured about the obtained mixture. The measurement was performed by a four-terminal method using a chemical impedance meter 3532-80 (manufactured by Hioki Electric Co., Ltd.) as a measuring device and a pressure of 100 MPa. As a result, the electric conductivity was 1.7 × 10 ⁻⁶ S / cm (= 170 × 10 ⁻⁸ S / cm).

[Example 2]
A mixture containing lithium nickel phosphate and nickel phosphide was obtained in the same manner as in Example 1 except that the preliminary firing was not performed.

With respect to the obtained mixture, the diffraction peak intensity ratio was calculated in the same manner as in Example 1. As a result, the calculated diffraction peak intensity ratio was 0.043. Moreover, when the electrical conductivity was measured about the obtained mixture like Example 1, it was 1.5 * 10 < ^-6 > S / cm (= 150 * 10 < ^-8 > S / cm).

Example 3
A mixture containing lithium nickel phosphate and nickel phosphide was obtained in the same manner as in Example 1 except that the preliminary calcination was not performed and the temperature during the main calcination was changed to 800 ° C.

For the obtained mixture, the diffraction peak intensity ratio was calculated in the same manner as in Example 1. As a result, the calculated diffraction peak intensity ratio was 0.017. Moreover, when the electrical conductivity of the obtained mixture was measured in the same manner as in Example 1, it was 1.7 × 10 ⁻⁷ S / cm (= 17 × 10 ⁻⁸ S / cm).

[Comparative Example 1]
1.65 g of lithium hydroxide monohydrate (LiOH.H 2 O) as a lithium raw material, 3.83 g of nickel hydroxide (Ni (OH) ₂ ) as a nickel raw material, ammonium dihydrogen phosphate (NH ₄ H ₂ PO) as a phosphorus raw material ₄ ) After pulverizing and mixing 4.52 g in a mortar, it was calcined in the atmosphere at 350 ° C. for 6 hours. Then, after pulverizing with a mortar, main baking was performed at 700 ° C. for 6 hours to prepare lithium nickel phosphate.

For the obtained mixture, the diffraction peak intensity ratio was calculated in the same manner as in Example 1. As a result, the calculated diffraction peak intensity ratio was 0.015. Moreover, when the electrical conductivity of the obtained mixture was measured in the same manner as in Example 1, it was 3.4 × 10 ⁻⁸ S / cm).

〔Consideration〕
The results of Examples 1 to 3 and Comparative Example 1 are shown in Table 1 below.

As shown in Table 1, the diffraction peak intensity ratio was also calculated in Comparative Example 1 that did not contain nickel phosphide. This diffraction peak intensity ratio is considered to be background. Then, the value of the comparative example 1 was subtracted from each value of Examples 1-3, and the evaluation result which considered this background is shown in Table 2. That is, the diffraction peak intensity ratio shown in Table 2 is the diffraction peak intensity ratio due to nickel phosphide.

  As shown in Table 2, the electrical conductivity was improved by including lithium nickel phosphate (Examples 1 to 3). That is, when nickel phosphide is included (for example, the diffraction peak intensity ratio is 0.002 or more), the electrical conductivity is improved. In particular, when the diffraction peak intensity ratio of nickel phosphide is 0.006 or more, the electrical conductivity is improved to about 45 to 50 times compared to the case where nickel phosphide is not included (Comparative Example 1). (Example 1 and Example 2).

  Thus, it was found that the electrical conductivity can be improved by including nickel phosphide. In particular, the electrical conductivity can be drastically improved by setting the diffraction peak intensity ratio of nickel phosphide that can be calculated using, for example, a powder X-ray diffractometer using CuKα rays to 0.006 or more. I understood.

Also in Example 3, the electrical conductivity increased to about 5 times despite the relatively small value of the diffraction peak intensity ratio. However, the electrical conductivity of Example 3 was lower than the electrical conductivity of Example 1 or Example 2. This is considered to be due to the fact that the main firing temperature in Example 3 is slightly high at 800 ° C., which causes sintering with a crystal phase such as lithium phosphate, and a large amount of lithium nickel phosphate is generated. If Shimese specific chemistry _briefly, the _{Li 3 PO 4 + NiP 3 +} O 2 → LiNiPO 4. And as a result, it is thought that electrical conductivity became lower than Example 1 or Example 2.

  As shown in Examples 1 to 3, nickel phosphide can be easily generated by heat treatment with an excessive amount of a phosphorus raw material and a nickel raw material. That is, it is possible to easily generate nickel phosphide by changing the amount of these raw materials used, thereby improving the electrical conductivity. In particular, since the electric conductivity can be improved without separately using a metal such as niobium or molybdenum, limited resources can be effectively used.

  Further, since the electrical conductivity can be improved without coating with lithium nickel phosphate, diffusion of lithium ions due to coating can be suppressed. Therefore, the high electrical conductivity of lithium nickel phosphate, which is the positive electrode active material, and the high diffusibility of lithium ions can both be achieved. As a result, the charge / discharge capacity of the lithium ion secondary battery can be increased.

  Further, the positive electrode prepared in this example contains lithium nickel phosphate, and a lithium ion secondary battery including this positive electrode exhibits high charge / discharge voltage characteristics. Therefore, if a positive electrode material containing lithium nickel phosphate and nickel phosphide is used, a lithium ion secondary battery having both a high charge / discharge voltage and a charge / discharge capacity can be produced.

1 Current collector plate 2 Lithium nickel phosphate 3 Nickel phosphide 4 Cathode material 10 Cathode

Claims (7)

A positive electrode material for a lithium secondary battery used in a lithium secondary battery comprising a positive electrode capable of inserting and extracting lithium ions, a negative electrode capable of inserting and extracting lithium ions, and an electrolyte,
A positive electrode material for a lithium secondary battery, comprising lithium nickel phosphate and nickel phosphide. The positive electrode material for a lithium secondary battery according to claim 1, wherein the nickel phosphide is NiP ₃ .   16.0 ± 0.5 ° 110 of the nickel phosphide relative to the 25.9 ± 0.5 ° 110/201 diffraction peak of lithium nickel phosphate calculated by a powder X-ray diffractometer using CuKα. The positive electrode material for a lithium secondary battery according to claim 1 or 2, wherein a diffraction peak intensity ratio is 0.002 or more.   The positive electrode material for a lithium secondary battery according to any one of claims 1 to 3, wherein the positive electrode material is an all-solid-type positive electrode material for a lithium secondary battery. A method for producing a positive electrode material for a lithium secondary battery used in a lithium ion secondary battery comprising a positive electrode capable of inserting and extracting lithium ions, a negative electrode capable of inserting and extracting lithium ions, and an electrolyte,
At least lithium lithium phosphate and nickel phosphide are produced by mixing and heat-treating lithium raw material, an excessive amount of phosphorus raw material than the stoichiometric ratio, and an excessive amount of nickel raw material beyond the stoichiometric ratio. The manufacturing method of the positive electrode material for lithium secondary batteries characterized by including the process to make.   The method of manufacturing a positive electrode material for a lithium secondary battery according to claim 5, wherein the heat treatment is performed in an oxidizing atmosphere.   The method for producing a positive electrode material for a lithium secondary battery according to claim 5, wherein the positive electrode material for a lithium secondary battery is an all-solid-type positive electrode material for a lithium secondary battery.

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