JP7048266B2 - Manufacturing method of positive electrode active material - Google Patents

Description

The present invention relates to a method for producing a fluoride positive electrode active material, and more particularly to a method for producing a fluoride positive electrode active material for a non-aqueous electrolyte secondary battery by gas-treating a metal powder.

Lithium-ion secondary batteries that operate near room temperature are widely used in portable electronic devices, hybrid vehicles, electric vehicles, etc., and are being developed. As a positive electrode active material in a conventional lithium ion secondary battery, a layered oxide positive electrode such as LiCoO ₂ or LiCo _1/3 Ni _1/3 O ₂ called a ternary system has been used. However, in a fully charged state, oxygen is released in an abnormal electronic value state such as Co tetravalent or Ni tetravalent, which causes troubles such as an increase in internal pressure and heat generation in the enclosed space of a battery. rice field.

On the other hand, among the positive electrode active materials, an alkali metal-containing fluoride metal such as Li ₂ TiF ₆ is useful because it does not release oxygen even at high temperature and when fully charged, and has high thermal stability of the battery. A technique for obtaining a 2 wt% fluoride metal by mixing lithium cobaltate, samarium nitrate, and acidic ammonium fluoride and treating them in a gas containing fluorine at 800 ° C. for 5 hours (see, for example, Patent Document 1). Also, in order to synthesize a lithium fluoride metal such as LiTiF ₆ , a technique of reacting a metal material such as TiO ₂ with lithium carbonate (LiCO ₃ ) in a fluoride solution (see, for example, Patent Document 2) has been proposed. There is.

Japanese Unexamined Patent Publication No. 2000-353524 Japanese Unexamined Patent Publication No. 2009-238686

However, in the technique described in Patent Document 1, since fluorine-containing gas such as hydrogen fluoride is used for treatment in a high temperature atmosphere of 800 ° C., fluorine or hydrogen fluoride is applied to a gas contact portion such as a treatment chamber or a pipe. It is necessary to use a material that is resistant to. Therefore, it is not possible to use stainless steel with a resistance to fluorine and hydrogen fluoride of about 200 ° C, and even a highly resistant metal such as Inconel (registered trademark) with high resistance can be practically used at about 600 ° C. Due to the limit, there are not many suitable materials used for the gas contact part such as the treatment chamber, and it is essential to lower the treatment temperature in order to stably obtain the fluoride metal.

Further, in the technique described in Patent Document 2, a large amount of water contained in the hydrofluoric acid solution is mixed in the synthesized fluoride metal. The problem is that the mixed water desorbs from the material as the battery is repeatedly charged and discharged, and reacts with the fluorine compound in the battery material to generate hydrogen fluoride, which causes deterioration of battery life. It has become.

Therefore, an object of the present invention is to provide a method for producing a fluoride positive electrode active material for a lithium ion secondary battery, which can reduce the treatment temperature and obtain a positive electrode active material containing almost no water. ..

In order to achieve the above object, in the method for producing a fluoride positive electrode active material of the present invention, a treated gas is supplied while heating * / arranged in a processing chamber to obtain a fluoride positive electrode active material for a lithium ion secondary battery. It is a manufacturing method, which comprises a heating step of heating a raw material powder composed of at least one of a metal oxide, a metal fluoride and a lithium-containing compound arranged in the treatment chamber, and supplying a hydrogen-containing compound to the treatment chamber. The hydrogen -containing compound comprises a reduction treatment step of reducing the raw material powder and a fluorination treatment step of supplying the fluorine-containing compound to the treatment chamber to perform the fluorination treatment of the raw material powder . The compound is at least one of H ₂ , Si H ₄ , Si ₂ H ₆ , NH ₃ , hydrazine, methyl hydrazine, and dimethyl hydrazine.
The fluorine-containing compound is at least among F ₂ , NF ₃ , HF, BF ₃ , ClF ₃ , CF ₄ , SF ₆ , C ₂ F ₆ , XeF ₂ , PF ₃ , SiF ₄ , CH ₃ F, and CHF ₃ . It is characterized by having one or more types .

In particular, the method for producing a fluoride positive electrode active material of the present invention is a method for producing a fluoride positive electrode active material for a lithium ion secondary battery by supplying a processing gas while heating the raw material powder arranged in the processing chamber. A heating step of heating a raw material powder composed of at least one of a metal oxide, a metal fluoride, and a lithium-containing compound arranged in the treatment chamber, and a heating step of supplying the hydrogen-containing compound to the treatment chamber to prepare the raw material powder . A reduction treatment step of performing a reduction treatment, a cooling step of cooling the raw material powder reduced while supplying a hydrogen-containing compound to the treatment chamber to a temperature lower than the temperature of the reduction treatment step, and fluorine in the treatment chamber. The hydrogen-containing compound includes H ₂ , SiH ₄ , Si ₂ H ₆ , NH ₃ , and hydrazine , which comprises a fluoride treatment step of supplying the contained compound and performing a fluoride treatment of the raw material powder cooled after the reduction treatment. , _{Methylhydrazine} , at _least one of dimethylhydrazine, and the fluoride-containing compounds are F2 _{, NF3} , HF , BF3 _, ClF3 _{, CF4} , SF6 _, C2F6 _, XeF2 , It is characterized in that it is at least one of PF ₃ , SiF ₄ , CH ₃ F, and CHF ₃ .

Further, in the method for producing a fluoride positive electrode active material of the present invention, the fluoride positive electrode active material is Li _a M _b PO ₄ F (a and b in the formula are 0 <a ≦ 2.0, 0 <b). ≤1.0, where M indicates at least one of Fe, Mn, Ni, Cu, Ti, Co, Mo, V, and Zn) or Li _c M _{d Fe} (in the formula). c, d, e indicate 0 <c ≦ 3.0, 0 <d ≦ 1.0, 3.0 ≦ e ≦ 6.0, and M is Fe, Mn, Ni, Cu, Ti, Co, It indicates at least one of Mo, V, and Zn.).

Further, the heating step is characterized in that the raw material powder is heated and held at 600 to 750 ° C., and the fluorination treatment step is performed when the raw material powder is heated to 500 to 600 ° C. The reduction treatment step is characterized in that it is carried out until the water concentration in the exhaust gas discharged from the treatment chamber becomes 100 ppm or less.

According to the method for producing a positive electrode active material of the present invention, a fluoride positive electrode active material for a lithium ion secondary battery containing almost no water can be efficiently produced. Further, by performing the reduction treatment step at a high temperature and performing the fluoride treatment step via the cooling step, the reduction treatment can be effectively performed at a high temperature, and the fluoride treatment step can be carried out by contacting gas in a treatment room or the like. The part can be protected from the fluorine-containing compound, and the fluoride positive electrode active material can be produced in a stable state. Furthermore, by monitoring the water concentration in the exhaust gas discharged from the treatment chamber during the reduction treatment step, the reduction treatment step can be performed more reliably, and the fluoride positive electrode active material can be used more efficiently. Can be manufactured.

First, in the present invention, Li _a M _b PO ₄ F (a and b in the formula show 0 <a ≦ 2.0, 0 <b ≦ 1.0, and M is Fe, Mn, Ni, Cu. , Ti, Co, Mo, V, Zn at least one of them (M is the same for each of the following formulas)) or Li _c M _{d Fe} (in the formula). C, d, and e indicate 0 <c ≦ 3.0, 0 <d ≦ 1.0, 3.0 ≦ e ≦ 6.0) as a fluoride positive electrode for a lithium ion secondary battery. An active material, specifically, a metal for producing a fluoride positive electrode active material such as LiCoO ₂ , LiFeF ₃ , and LiFeF ₃ , which is basically a raw material in a processing chamber capable of maintaining a high temperature state. A fluoride positive electrode active material is produced by arranging powder and supplying a specific processing gas while keeping the processing chamber at a specific temperature.

The metal powder as a raw material is at least one kind of a metal oxide, a metal fluoride and a lithium-containing compound, and the metal oxide and the metal fluoride are not particularly limited, but for example, Li _2- . _x M _x PO ₄ (in the formula, x is 0 ≦ x ≦ 2.0), LiM _y O ₂ (in the formula, y is 0 ≦ y ≦ 1.0), MF ₃ , MF ₂ , MO ₂ , MO, M ₂ O ₃ can be used. Specifically, Li ₂ CoPO ₄ , Li ₂ NiPO ₄ , LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiFeO ₂ , CoF ₂ , CoF ₃ , NiF ₂ , NiF ₃ , MnF ₂ , MnF ₃ , MnF ₄ , FeF ₂ . , FeF ₃ , CoO, Co ₂ O ₃ , Co ₃ O ₄ , NiO, TiO ₂ , Fe ₂ O ₃ , FeO and the like. These metal oxides and metal fluorides can be used alone or in a mixed state of a plurality of types. Further, as the lithium-containing compound, for example, LiF, Li ₂ CO ₃ , LiOH, Li ₂ O, Li H and the like can be used alone or in combination of two or more.

The heating step can be performed by providing a heating means such as a heater in the processing chamber or heating the processing gas supplied to the processing chamber. The heating temperature varies depending on conditions such as the type of the raw material metal powder used and the type of the processing gas used, but usually the temperature of the raw material metal powder in the reduction treatment step following the heating step is 750 ° C. or lower, preferably 600 to 750. I try to heat it to ℃.

The treatment gas used in the reduction treatment step in which the raw metal powder is held in the range of 600 to 750 ° C. is a gas composed of a hydrogen-containing compound containing hydrogen alone capable of reducing the metal powder, or hydrogen. A mixed gas of the contained compound and the inert gas can be used. The hydrogen-containing compound varies depending on the conditions such as the raw metal powder used and the heating temperature, but usually H ₂ , SiH ₄ , Si ₂ H ₆ , NH ₃ , hydrazine, methylhydrazine, and dimethylhydrazine can be used. , These hydrogen-containing compounds can be used alone or in a mixed state of a plurality of types.

The fluorination treatment step is performed at a temperature similar to that of the reduction treatment step, preferably lower than the temperature of the reduction treatment step, and usually, after the reduction treatment step is completed, a hydrogen-containing compound is placed in the treatment chamber. A cooling step is performed to cool the reduced metal powder to a temperature lower than the temperature of the reduction treatment step, and the fluoride treatment step is started in a state where the reduced metal powder is at 600 ° C. or lower, preferably 500 to 600 ° C. Is desirable. In the cooling step, the operation of the heater or the like may be temporarily stopped, the temperature may be lowered to a preset temperature, and then the temperature may be maintained.

The fluorine-containing compound containing fluorine alone used in the fluoride treatment step is not particularly limited, and is, for example, F ₂ , NF ₃ , HF, BF ₃ , ClF ₃ , CF ₄ , SF ₆ , C ₂ . F ₆ , XeF ₂ , PF ₃ , SiF ₄ , CH ₃ F, CHF ₃ , and the like can be used, and these can be used alone or in a state where a plurality of types are mixed.

It is also possible to supply the hydrogen-containing compound or the fluorine-containing compound to the treatment chamber in an activated state by using plasma, microwave, ultraviolet rays, a catalyst or the like.

As described above, by performing the reduction treatment step at a high temperature, for example, 750 ° C., the reduction treatment of the metal powder by the hydrogen-containing compound can be efficiently performed, and the water content contained in the metal powder can be effectively removed. Further, since ordinary metal materials have resistance to hydrogen-containing compounds, even if they are carried out at a high temperature of 750 ° C., the gas contact portion such as a treatment chamber is hardly corroded or deteriorated. ..

On the other hand, in the fluorination treatment step, by performing the metal material in the treatment chamber at a temperature lower than that in the reduction treatment step, for example, 600 ° C., the gas contact portion of the treatment chamber or the like is less likely to be corroded by fluorine or a fluorine-containing compound. In particular, by using the above-mentioned Inconel (registered trademark), the gas contact portion is hardly corroded or deteriorated, and the fluorination treatment step can be stably performed for a long period of time.

Further, it is desirable to continuously perform the reduction treatment step and the fluorination treatment step in one treatment chamber, but it is appropriate to form a treatment chamber for the reduction treatment step and a treatment chamber for the fluorination treatment step separately. It can also be formed so as to transfer the metal powder from the processing chamber for the reduction treatment step to the treatment chamber for the fluorination treatment step by the transport means.

That is, by performing the reduction treatment step in a _high temperature state, the redox reaction between hydrogen and the like and oxygen atoms and the like is facilitated, and the raw material can be brought into a state close to that of a monoatomic metal. The reactivity of the compound can be enhanced, and the fluorine treatment can be performed at a low temperature. By combining the reduction treatment step of supplying such a hydrogen-containing compound and the fluoride treatment step of supplying the fluorine-containing compound. , The reaction efficiency with the fluoride positive electrode active material is improved, and the temperature of the fluoride treatment step can be lowered.

Further, since the manufacturing process is in a completely dry environment without using a hydrofluoric acid solution, it is possible to obtain a fluoride positive electrode active material containing significantly less water than the synthesis method using a hydrofluoric acid solution. Further, by continuing the reduction treatment step until the water concentration in the exhaust gas discharged from the treatment chamber becomes 100 ppm or less, preferably 50 ppm or less, more preferably 10 ppm or less, hydrogen and oxygen are released in the reduction treatment step. By surely removing the water generated by the reaction and confirming the water concentration in the exhaust gas, the progress and completion time of the reduction reaction can be grasped, and the necessary and sufficient reduction treatment can be performed. ..

The metal powder to be placed in the treatment chamber is preferably 1 g or more per unit volume (L) in the treatment chamber volume, and if it is less than 1 g, the treatment amount is small, so that not only the productivity is lowered but also the exhaust gas is contained. It may be difficult to detect the water concentration of the gas. Further, the supply amount of the hydrogen-containing compound is preferably 100 sccm or less per gram (g) of the raw metal powder amount, and if it exceeds 100 sccm, the water content in the exhaust gas is too diluted, which makes measurement difficult. Sometimes. For example, when the processing chamber volume is 10 L, the raw metal powder is preferably 10 g or more, and when the raw metal powder is 10 g, the supply amount of the hydrogen-containing compound is preferably 1000 sccm or less. Further, it is desirable to carry out each gas treatment in a state where the pressure in the treatment chamber is controlled to 1 kPa or more, preferably 100 kPa or more, and the pressure may be changed in each step.

The supply of each treatment gas to the treatment chamber is not particularly limited, and the supply of the hydrogen-containing compound and the supply of the fluorine-containing compound may be repeated, and the hydrogen-containing compound, the fluorine-containing compound, and the inert gas may be supplied in each step. Each may be mixed and then supplied to the processing chamber. Further, the case where two or more types are mixed and introduced is not particularly limited, but as a mixing method, for example, a method of supplying a mixed gas filled in a container to the processing chamber, or an upstream side of the processing chamber. A method of premixing two or more types of gas and supplying them to the processing chamber, a method of individually supplying each gas type and mixing them in the processing chamber, and the like can be appropriately selected. As the inert gas, N ₂ , He, Ar, Ne, Xe, Kr can be used.

Example 1
A manufacturing experiment of LiCoF ₃ was carried out. First, a sufficiently mixed mixture of CoO powder and LiF powder is used as a raw material metal powder and installed in a processing chamber, and a heating step is performed with nitrogen flowing in the processing chamber to bring the metal powder to 750 ° C. Heated. At 750 ° C., H ₂ as a hydrogen-containing compound was supplied and heat-treated for 240 minutes to carry out a reduction treatment step. After the reduction treatment step was completed, a cooling step of cooling the metal powder to 600 ° C. was performed while the supply of H ₂ was continued. While the temperature was maintained at 600 ° C., the supply of H ₂ was stopped, a gas containing 20% of F ₂ in N ₂ was supplied as a fluorine-containing compound, and heat treatment was performed for 240 minutes to perform a fluoride treatment step. The pressure in the processing chamber in each step was controlled to 100 kPa (hereinafter, the same applies). When the XRD measurement of the sample was carried out after the completion of the fluorination treatment step, the component peaks of CoF ₂ and LiF disappeared, and the component peak of LiCoF ₃ was confirmed.

Example 2
The same production experiment of LiCoF ₃ as in Example 1 was carried out using lithium cobalt oxide (LiCoO ₂ ) as a raw material metal powder. The heating step, the reduction treatment step, and the fluorine treatment step were performed under the same conditions as in Example 1. When the XRD measurement of the sample was carried out after the completion of the fluorination treatment step, the component peak of LiCoO ₂ disappeared and the component peak of LiCoF ₃ was confirmed.

Comparative Example 1
A sufficiently mixed mixture of LiCoO ₂ powder and acidic ammonium fluoride (NH _4F · HF) powder was installed in the treatment chamber. The metal powder was heated to 800 ° C. with nitrogen flowing through the treatment chamber. At 800 ° C., a gas containing 20% of F ₂ in N ₂ was supplied as a fluorine-containing compound, and heat treatment was performed for 240 minutes. When the XRD measurement of the treated sample was carried out, the component peak of LiCoF ₃ was not detected, and LiCoO ₂ remained.

Comparative Example 2
A sufficiently mixed mixture of CoO powder and LiF powder was installed in the treatment chamber. The metal powder was heated to 600 ° C. with nitrogen flowing through the treatment chamber. A gas containing 20% of F ₂ in N ₂ was supplied as a fluorine-containing compound at 600 ° C., and heat treatment was performed for 240 minutes. When the XRD measurement of the treated sample was carried out, the peak component of LiCoF ₃ was not detected, and the component peak of LiCoO and the component peak of LiF were detected.

The results of Examples 1 and 2 and Comparative Examples 1 and 2 are summarized in Table 1.

As shown in Table 1, the production of LiCoF ₃ could be confirmed in Examples 1 and 2, but LiCoF ₃ could not be detected in both Comparative Examples 1 and 2. In particular, Comparative Example 1 was not produced even under high temperature conditions of 800 ° C. As a factor for this, the reaction energy due to F ₂ is insufficient at 800 ° C. or lower, indicating that it is difficult to produce a fluoride positive electrode active material only by the step of supplying the fluorine-containing compound.

On the other hand, in Examples 1 and 2, the Co produced by supplying hydrogen to perform the reduction treatment step and performing the reduction treatment of CoO and LiCoO ₂ is the fluoride that supplies the contained LiF and F ₂ . Since it has the effect of accelerating the fluorination reaction in the treatment step, it is possible to carry out the fluorination treatment step of supplying the fluorine-containing compound at a low temperature. Therefore, it can be seen that when LiCoF ₃ is produced by gas treatment, the temperature of the fluoride treatment step can be lowered by introducing a reduction treatment step of supplying a hydrogen-containing compound before the fluoride treatment step.

Example 3
A manufacturing experiment of LiFeF ₃ was carried out. A sufficiently mixed mixture of Fe ₂ O ₃ powder and LiF powder was placed in the treatment chamber, and a heating step was performed with nitrogen flowing through the treatment chamber to heat the metal powder to 750 ° C. At 750 ° C., H ₂ as a hydrogen-containing compound was supplied and heat-treated for 240 minutes to carry out a reduction treatment step. After the reduction treatment step was completed, a cooling step of cooling the metal powder to 600 ° C. was performed while the supply of H ₂ was continued. While the temperature was maintained at 600 ° C., the supply of H ₂ was stopped, a gas containing 20% of F ₂ in N ₂ was supplied as a fluorine-containing compound, and heat treatment was performed for 240 minutes to perform a fluoride treatment step. When the XRD measurement of the sample was carried out after the completion of the fluorination treatment step, the component peaks of Fe ₂ O ₃ and LiF disappeared, and the component peak of LiFeF ₃ was confirmed.

Example 4
The same production experiment of LiFeF ₃ as in Example 3 was carried out using the powder of LiFeO ₂ . The heating step, the reduction treatment step, and the fluorine treatment step were performed under the same conditions as in Example 3. When the XRD measurement of the sample was carried out after the completion of the fluorination treatment step, the component peak of LiFeO ₂ disappeared and the component peak of LiFeF ₃ was confirmed.

Comparative Example 3
A sufficiently mixed mixture of Fe ₂ O ₃ powder and Li F powder was placed in the processing chamber, and in a state of being heated to 600 ° C., a gas containing 20% of F ₂ was supplied into N ₂ and heated for 240 minutes. Processing was performed. When the XRD measurement of the sample after the treatment was carried out, the component peak of LiFeF ₃ was not detected, and Fe ₂ O ₃ and LiF remained.

The results of Examples 3 and 4 and Comparative Example 3 are summarized in Table 2.

From the results shown in Table 2, the production of LiFe ₃ could be confirmed in Examples 3 and 4, but LiFeF ₃ was not detected in Comparative Example 3. This indicates that, as in Examples 1 and 2, the reduction treatment step causes a reduction reaction of Fe ₂ O ₃ and LiFeO ₂ , and the step of supplying F ₂ has the effect of promoting the fluorination reaction. .. Therefore, it can be seen that when LiFeF ₃ is produced by gas treatment, the temperature of the fluoride treatment step can be lowered by introducing a reduction treatment step of supplying a hydrogen-containing compound before the fluoride treatment step.

Example 5
A production experiment of LiFeF ₃ was carried out, and the water content was measured. A sufficiently mixed mixture of Fe ₂ O ₃ powder and LiF powder was placed in the treatment chamber, and a heating step was performed with nitrogen flowing through the treatment chamber to heat the metal powder to 750 ° C. At 750 ° C., H ₂ as a hydrogen-containing compound was supplied and heat-treated for 240 minutes to carry out a reduction treatment step. At this time, the water concentration in the exhaust gas discharged from the treatment chamber was analyzed using FT-IR, and it was confirmed that the water concentration after 240 minutes was 10 ppm or less. After the reduction treatment step was completed, a cooling step of cooling the metal powder to 600 ° C. was performed while the supply of H ₂ was continued. While the temperature was maintained at 600 ° C., the supply of H ₂ was stopped, a gas containing 20% of F ₂ in N ₂ was supplied as a fluorine-containing compound, and heat treatment was performed for 240 minutes to perform a fluoride treatment step. When the XRD measurement of the sample was carried out after the completion of the fluorination treatment step, the component peaks of Fe ₂ O ₃ and LiF disappeared, and the component peak of LiFeF ₃ was confirmed. Further, the water content in the obtained LiFeF ₃ was measured by temperature-temperature desorption gas mass spectrometry (TDS-MS) and found to be 14.5 μg per 1 g of LiFeF ₃ .

Comparative Example 4
FeCl ₃ and lithium carbonate (LiCO ₃ ) were dissolved in a 50% hydrofluoric acid solution and reacted. After completion of the reaction, the mixture was washed with an organic solvent and then vacuum dried to produce LiFeF ₃ . When TDS-MS was carried out to measure the water content in the obtained LiFeF ₃ , it was 1089 μg per 1 g of LiFeF ₃ .

Comparative Example 5
In Example 5, the reduction treatment step was not sufficiently performed, and the process was completed in 20 minutes. The water concentration in the exhaust gas at this time was 300 ppm or more. Other than this, each step was performed under the same conditions as in Example 5. When the XRD measurement of the sample was carried out after the completion of the fluorination treatment step, the component peaks of Fe ₂ O ₃ , LiF and LiFeF ₃ were confirmed, respectively. Further, the water content in the obtained sample was measured by temperature-temperature desorption gas mass spectrometry (TDS-MS) and found to be 30.5 μg per 1 g of the sample.

The results of Example 5 and Comparative Examples 4 and 5 are summarized in Table 3.

From the results in Table 3, it can be seen that the water content of Example 5 subjected to the gas treatment is significantly smaller than that of Comparative Example 4 using the hydrofluoric acid solution. That is, regarding the amount of water, it is shown that the amount of water taken in is small because it was produced in a dry environment in Example 5. On the other hand, in Comparative Example 4, a large amount of water in the hydrofluoric acid solution was taken in during the synthesis process. From this, it can be seen that the fluoride positive electrode active material having a low water content, which adversely affects the battery life, can be produced by producing in a dry environment by gas treatment. Further, in the comparison between Example 5 and Comparative Example 5, since both were produced in a dry environment, the water content was low. However, from the results of the XRD peak intensity ratio, while LiFeF ₃ was produced in Comparative Example 5, a large amount of unreacted Fe ₂ O ₃ and LiF remained. This indicates that the reduction treatment step of Comparative Example 5 is insufficient, and the reduction treatment step is completed when the water concentration in the exhaust gas is 300 ppm or more, so that the reduction reaction is insufficient. Therefore, by monitoring the water concentration in the exhaust gas during the reduction treatment step, it is possible to grasp the progress state of the reduction reaction.

Claims (6)

A method for producing a fluoride positive electrode active material for a lithium ion secondary battery by supplying a treatment gas while heating a raw material powder placed in the treatment chamber, wherein the metal oxide or metal fluoride placed in the treatment chamber is produced. A heating step of heating a raw material powder composed of at least one kind of a lithium-containing compound, a reduction treatment step of supplying a hydrogen-containing compound to the treatment chamber to perform a reduction treatment of the raw material powder , and a fluorine-containing treatment chamber. It includes a fluoride treatment step of supplying a compound and performing a fluoride treatment of the raw material powder which has been reduced.
The hydrogen-containing compound is at least one of H ₂ , SiH ₄ , Si ₂ H ₆ , NH ₃ , hydrazine, methylhydrazine, and dimethylhydrazine.
The fluorine-containing compound is at least among F ₂ , NF ₃ , HF, BF ₃ , ClF ₃ , CF ₄ , SF ₆ , C ₂ F ₆ , XeF ₂ , PF ₃ , SiF ₄ , CH ₃ F, and CHF ₃ . A method for producing a fluoride positive electrode active material, which is characterized by having one or more types . A method for producing a fluoride positive electrode active material for a lithium ion secondary battery by supplying a treatment gas while heating a raw material powder placed in the treatment chamber, wherein the metal oxide or metal fluoride placed in the treatment chamber is produced. A heating step of heating a raw material powder composed of at least one kind of a lithium-containing compound, a reduction treatment step of supplying a hydrogen-containing compound to the treatment chamber to perform a reduction treatment of the raw material powder , and a hydrogen-containing treatment chamber. A cooling step of cooling the raw material powder reduced while supplying the compound to a temperature lower than the temperature of the reduction treatment step, and the raw material powder of supplying the fluorine-containing compound to the treatment chamber and cooling after the reduction treatment. Including the fluorination treatment step of performing the fluorination treatment of
The hydrogen-containing compound is at least one of H ₂ , SiH ₄ , Si ₂ H ₆ , NH ₃ , hydrazine, methylhydrazine, and dimethylhydrazine.
The fluorine-containing compound is at least among F ₂ , NF ₃ , HF, BF ₃ , ClF ₃ , CF ₄ , SF ₆ , C ₂ F ₆ , XeF ₂ , PF ₃ , SiF ₄ , CH ₃ F, and CHF ₃ . A method for producing a fluoride positive electrode active material, which is characterized by having one or more types . The fluoride positive electrode active material is Li _a M _b PO ₄ F (a and b in the formula show 0 <a ≦ 2.0, 0 <b ≦ 1.0, and M is Fe, Mn, Ni). , Cu, Ti, Co, Mo, V, Zn.) Or Li _c M _{d Fe} (c, d, e in the formula is 0 <c ≦ 3.0, 0 <d ≦ 1.0, 3.0 ≦ e ≦ 6.0, and M indicates at least one of Fe, Mn, Ni, Cu, Ti, Co, Mo, V, and Zn. ). The method for producing a fluoride positive electrode active material according to claim 1 or 2. The method for producing a fluoride positive electrode active material according to any one of claims 1 to 3 , wherein the heating step heats and holds the raw material powder at 600 to 750 ° C. The method for producing a fluoride positive electrode active material according to any one of claims 1 to 4 , wherein the fluoride treatment step is performed when the raw material powder is at 500 to 600 ° C. The fluoride positive electrode active material according to any one of claims 1 to 5 , wherein the reduction treatment step is carried out until the water concentration in the exhaust gas discharged from the treatment chamber becomes 100 ppm or less. Method.