KR101489779B1 - Method of manufacturing fluorine compounds as a cathode material for lithium secondary batteries using solid state reaction and a cathode and a lithium secondary battery comprising the cathode - Google Patents

Abstract

The present invention relates to a method for producing a high purity fluorine compound which can be used as a cathode active material of a lithium secondary battery through one solid phase reaction.
The method according to the present invention comprises heating a precursor mixture comprising at least one selected from the group consisting of a lithium precursor, a metal precursor, a phosphate precursor and an organic compound containing fluorine or an ammonium compound containing fluorine to prepare a fluorine compound of the following formula .
[Chemical Formula]
LiM _x PO ₄ F _y wherein 0 <x? 1, 0 <y? 1, and M is at least one selected from Mn, V, Cr, Ti, Fe, Co, Ni, Nb,

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for producing a fluorine compound for a cathode active material of a lithium secondary battery using a solid-phase reaction, a cathode, and a lithium secondary battery including the cathode, LITHIUM SECONDARY BATTERY COMPRISING THE CATHODE}

The present invention relates to a method for producing a fluorine compound which can be used as a cathode active material of a lithium secondary battery, and more particularly, to a fluorine compound which can be used as a cathode active material of a lithium secondary battery through a solid- It's about how you can.

Since the cathode material is an important factor for determining the characteristics of the lithium ion battery, in order to improve the output and capacity of the lithium ion battery, much research has been conducted to develop a high potential cathode material.

New polyion systems such as boron compounds (LiMBO ₃ ), silicates (Li ₂ MSiO ₄ ), phosphate compounds (Li ₂ MP ₂ O ₇ ) and fluorophosphates (LiMPO ₄ F) have attracted interest from researchers, of 3d metal through electron effects ^{M n + / M (n +} 1) + through the process of oxidation-reduction pair it is due to the large room to increase the open-circuit voltage, in particular, fluorine, such as LiMPO ₄ F, LiMSO ₄ F Studies on compounds have been actively conducted.

As a typical material of the LiMPO ₄ F, the redox potential (V ^{3 +} / V ^{4 +} ) potential is about 4.2 V, the theoretical capacity is 156 mAh / g and the thermal stability is better than the currently used cathode materials LiVPO ₄ F has excellent properties.

However, since fluorine easily evaporates or binds strongly to form an unbroken LiF bond, fluorine compounds are not easy to synthesize. Up to now, fluorine has been used mainly by solvothermal method or ionic liquid method, However, these methods have a problem in that they are very difficult to commercialize because of high production cost.

As a method for solving such a problem, US Pat. No. 6,387,568B1 proposes a method of synthesizing a fluorine compound using a carbon thermal reaction. In this method, VPO ₄ is synthesized first by using carbon oxidation, then synthesized by a two-step reaction of synthesizing VPO ₄ and LiF at a high temperature to synthesize LiVPO ₄ F, and after the high temperature reaction, phase is not formed. Although this method can solve the problems of the conventional synthesis method to a great extent, there is still room for improvement in terms of the process cost due to the synthesis of the two-step reaction, and there is a limitation in synthesizing a high purity fluorine compound.

The present invention has been researched and developed to overcome the problems of the prior art described above, and it is an object of the present invention to provide a fluorine compound capable of synthesizing a fluorine compound of a high purity through a single solid phase reaction, And to provide a method capable of producing the same.

According to an aspect of the present invention, there is provided a method for producing a fluorine compound, which comprises heating a precursor mixture comprising a lithium precursor, a metal precursor, a phosphate precursor, an organic compound containing fluorine or an ammonium compound containing fluorine, The present invention also provides a method for producing a fluorine compound for a cathode material of a lithium secondary battery.

[Chemical Formula]

LiM _x PO ₄ F _y wherein 0 <x? 1, 0 <y? 1, and M is at least one selected from Mn, V, Cr, Ti, Fe, Co, Ni, Nb,

Further, in the production method of the present invention, the lithium precursor may be LiF or Li ₂ CO ₃ .

In the production method of the present invention, carbon may be produced during the production of the fluorine compound.

Further, in the production method of the present invention, the precursor mixture may contain 10 to 200% of the sum of the weight of the lithium precursor, the metal precursor and the phosphate precursor in the fluorine-containing organic compound or fluorine-containing ammonium compound .

Further, in the production method of the present invention, the precursor mixture may contain 10 to 200% of the sum of the weight of the lithium precursor, the metal precursor and the phosphate precursor in the fluorine-containing organic compound or fluorine-containing ammonium compound .

Further, in the production method of the present invention, the fluorine-containing organic compound may be polytetrafluoroethylene (PTFE) or polyfluorinated vinylidene (PVDF).

Further, in the production method of the present invention, the fluorine-containing ammonium compound may be ammonium fluoride (NH ₄ F).

Further, in the production method of the present invention, the heating temperature of the precursor mixture may be 500 to 750 ° C.

In the method of the present invention, the metal precursor may be at least one selected from the group consisting of V ₂ O ₅ , Fe ₂ O ₃ , Fe ₃ O ₄ , MnO ₂ , Mn ₂ O ₃ , TiO ₂ , Ti ₂ O ₃ , Cr ₂ O ₃ , CrO _3, may be _{CoO, Nb 2 O 5, Mo} 2 O 3, Co 3 O 4, CrO ₃ or.

Further, in the production method of the present invention, the fluorine compound may be LiVPO ₄ F, LiV ₀ . ₉ Mn _{0 .1} PO ₄ F, or LiV _{0. 9} Fe _0.1 PO ₄ F.

The present invention also provides a positive electrode comprising a fluorine compound for a positive electrode material, a binder and a conductive powder produced by the above-described production method of the present invention.

The present invention also provides a lithium secondary battery comprising the positive electrode.

According to the present invention, LiF, V ₂ O _5, and NH ₄ H ₂ PO _4, which are precursors used in the synthesis of LiVPO ₄ F in the prior art, are used. In addition, A high purity LiVPO ₄ F can be produced through one solid phase reaction by further containing fluorine-containing organic compound or fluorine-containing ammonium compound serving as loss-providing fluorine in the precursor.

As a result, fluorine compounds having excellent properties can be mass-produced at a low cost, and the present invention is expected to contribute to the commercialization of a lithium secondary battery containing a fluorine compound.

1 is an XRD pattern of LiVPO ₄ F prepared according to Example 1 of the present invention.
2 is an XRD pattern of LiVPO ₄ F prepared according to Example 2 of the present invention.
3 is an XRD pattern of LiVPO ₄ F prepared according to Example 3 of the present invention.
4 is an XRD pattern of LiVPO ₄ F prepared according to Example 4 of the present invention.
5 is a graph showing the results of evaluating electrochemical behavior of LiVPO ₄ F prepared according to Example 2 of the present invention.

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

It should also be understood that the terms or words used in the present specification and claims should not be construed in a conventional and dictionary sense and that the inventors may properly define the concept of the term to best describe its invention And should be construed in accordance with the principles and meanings and concepts consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely preferred embodiments of the present invention and do not represent all the technical ideas of the present invention, so that various equivalents And the scope of the present invention is not limited to the following embodiments.

When a fluorine compound such as LiMPO ₄ F is synthesized through a solid phase reaction capable of mass production at a low cost, LiF is not easily decomposed due to a large binding force of LiF used as a precursor, and F generated by decomposition of LiF is easily And thus it is difficult to produce a fluorine compound of high purity due to the loss of fluorine.

As a result of research and development to solve these problems, the present inventors have found that, in the synthesis of a fluorine compound such as LiMPO ₄ F, in addition to LiF, a metal precursor and a phosphate precursor as precursors, It has been found that when a solid phase reaction is carried out by adding an extra fluorine source that can compensate for the loss of fluorine in the process, a high purity fluorine compound can be obtained even by a single reaction process, leading to the present invention .

The method for synthesizing a fluorine compound according to the present invention comprises heating a precursor comprising LiF, a metal precursor, a phosphate precursor, and an organic compound containing fluorine or an ammonium compound containing fluorine to produce a fluorine compound of the following formula .

[Chemical Formula]

LiM _x PO ₄ F _y wherein 0 <x? 1, 0 <y? 1, and M is at least one selected from Mn, V, Cr, Ti, Fe, Co, Ni, Nb,

The metal precursor provides a metallic component to the composition of the above formula and can be any material capable of synthesizing the material through heating with a material including Mn, V, Cr, Ti, Fe, Co, Ni, Nb and Mo . For example, metal oxides, metal nitrides, metal oxynitrides, and the like can be used.

The phosphoric acid precursor provides a phosphoric acid salt component to the composition of the formula, and any of the compounds can be used as long as the compound can be synthesized through heating. For example, NH ₄ H ₂ PO _{4 ,} (NH ₄ ) ₂ HPO ₄ Etc. may be used.

The fluorine-containing organic compound is a compound containing carbon and hydrogen. Any compound that is easily decomposed at a solid-phase reaction temperature to provide fluorine while remaining decomposed without being involved in the synthesis reaction can be used have. For example, polytetrafluoroethylene (PTFE), polyfluorinated vinylidene (PVDF), or the like can be used.

Since the fluorine-containing ammonium compound is easily decomposed at a solid-state reaction temperature to provide fluorine, the remaining fluorine-containing ammonium compound is easily removed without participating in the synthesis reaction, and thus can be preferably used as an extra fluorine-containing component .

The amount of the excess added organic compound or ammonium compound plays an important role in the production of a high purity fluorine compound. The amount of the organic compound or ammonium compound to be added is 10 to 200 parts by weight based on the weight of the lithium precursor, metal precursor and phosphate precursor such as LiF and Li ₂ CO _3. If the amount of the ammonium compound to be added is less than 10% by weight, the amount of fluorine to be added is insufficient and the possibility of generating an impurity phase is high. If the amount of the ammonium compound is more than 200% by weight, , And it is more preferable to maintain the range of 10 to 30% by weight.

The precursor may be prepared by a pretreatment process including a mixing process of a raw material, a drying process, and a pelletizing process.

In the mixing process of the raw materials, LiF, a metal precursor, a phosphate precursor, a fluorine-containing organic compound, or a fluorine-containing ammonium compound may be added to a solvent such as acetone and then mixed using a ball mill. The time of the ball mill is preferably from 1 hour to 24 hours. When the time is less than 1 hour, the ball mill is not sufficient for dissolving, crushing or mixing the precursor. If the time exceeds 24 hours, the mixing effect is saturated, This is economically disadvantageous. In the present invention, a solvent such as acetone or water is used as the solvent, but any material can be used without limitation as long as the precursor is properly mixed and does not affect the subsequent process. Also, if the prepared precursor can produce a homogeneous mixture without performing ball milling, it can also be performed by a simple stirring process.

The drying step is a step of removing the solvent by heating the mixed precursor through a mixing process to a predetermined temperature. In the drying process, it is preferable to use a device such as a hot plate to heat the mixture containing the solvent to 50 to 100 ° C. If the drying time is less than 50 ° C, the drying time becomes too long, This is because a phase can be formed.

The pelletization process is performed so that gas components decomposed in a subsequent synthesis process can be easily discharged and synthesis is facilitated, and a known pelletization apparatus is used to make pellets.

The heating temperature for the solid-phase reaction is preferably 500 ° C to 750 ° C. When the temperature is less than 500 ° C, the synthesis is difficult to occur. When the temperature exceeds 750 ° C, an impurity phase is likely to be formed. The heating temperature of the solid phase reaction is more preferably 700 to 750 占 폚.

The heating time of the solid-phase reaction is preferably 1 to 2 hours. If the heating time is less than 1 hour, the synthesis reaction is not sufficient. If the heating time is more than 2 hours, it is economically disadvantageous and the impurity phase can be synthesized Because.

[Example 1]

In Example 1 of the present invention, LiVPO ₄ F was synthesized in the following manner.

First, as a precursor for the solid phase reaction, LiF powder (having a purity of 98.5% or more), V ₂ O ₅ powder (Sigma Aldrich, purity 98%) and NH ₄ H ₂ PO ₄ PTFE (Sigma Aldrich, about 1 mu m in particle diameter) was used as an additional fluorine source in the following manner.

LiF + 0.5 V ₂ O ₅ + NH ₄ H ₂ PO ₄ + 15 wt% PTFE

(Here, the amount of PTFE is being other precursor _{(LiF, V 2 O 3,} NH 4 H 2 PO 4) 15% by weight of an agreement)

Specifically, the weight of each material prepared is 1.054 g of LiF, 3.7118 g of V ₂ O _5, 4.6584 g of NH ₄ H ₂ PO ₄ , and 1.4136 g of PTFE.

The thus prepared precursor was put into an acetone solvent, followed by ball milling for about 12 hours to dissolve the PTFE, and the agglomerated powder in the precursor was disintegrated to prepare a uniformly mixed mixture. Zirconia balls having diameters of 3.5 mm and 10 mm were used for the ball milling.

After mixing the powders through ball milling, the mixture was dried in air at a temperature of 85 ° C using a hot plate, and the dried mixture was pelletized using a disc mold.

The thus prepared pellets were charged into an alumina crucible and heated to 700 DEG C under an argon gas atmosphere (flow rate of 0.5 mL per minute). At this time, the heating rate was 3.8 占 폚 / min and the heating time at 700 占 폚 was 1 hour so that the solid phase reaction was caused. After heating, it was allowed to cool naturally at room temperature.

The powder obtained through the above method was analyzed using XRD, and Fig. 1 shows the result. As shown in FIG. 1, the powder obtained according to Example 1 of the present invention exhibited an XRD pattern of LiVPO ₄ F.

[Example 2]

In Example 2 of the present invention, LiVPO ₄ F was synthesized by the following method.

First, as a precursor for the solid-phase reaction, LiF powder (having a purity of 98.5% or more), V ₂ O ₅ powder (Sigma Aldrich, purity 98%) and NH ₄ H ₂ PO ₄ As an additional fluorine source, PTFE (Sigma Aldrich, about 1 탆 in particle size) was prepared as follows.

LiF + 0.5V ₂ O ₅ + NH ₄ H ₂ PO ₄ + 25 wt% PTFE

(Here, the amount of PTFE is being other precursor _{(LiF, V 2 O 3,} NH 4 H 2 PO 4) 25% by weight of an agreement)

Specifically, the weight of each material prepared is 1.054 g of LiF, 3.7118 g of V ₂ O _5, 4.6584 g of NH ₄ H ₂ PO ₄ , and 2.3560 g of PTFE. The subsequent synthetic process the LiVPO ₄ F was prepared in the same way as in Example 1. That is, the synthesis was carried out in the same manner as in Example 1, except that the amount of PTFE added was 10% by weight more than in Example 1.

Fig. 2 shows XRD analysis results of the material synthesized according to Example 2. Fig. 2, it was confirmed that the material synthesized according to Example 2 was also LiVPO ₄ F.

[Example 3]

In Example 3 of the present invention, LiVPO ₄ F was synthesized in the following manner.

First, as a precursor for the solid-phase reaction, LiF powder (having a purity of 98.5% or more), V ₂ O ₅ powder (Sigma Aldrich, purity 98%) and NH ₄ H ₂ PO ₄ NH ₄ F (Sigma Aldrich, purity 98%) as an additional fluorine source was prepared as follows.

LiF + 0.5 V ₂ O ₅ + NH ₄ H ₂ PO ₄ + 8 NH ₄ F

(Here, the addition amount of NH ₄ F is about 128% of the total weight of the other precursors (LiF, V ₂ O ₃ , and NH ₄ H ₂ PO ₄ )

Specifically, the weight of each material prepared is 1.054 g of LiF, 3.7118 g of V ₂ O _5, 4.6584 g of NH ₄ H ₂ PO ₄ , and 12.094 g of NH ₄ F. The subsequent synthetic process the LiVPO ₄ F was prepared in the same way as in Example 1. That is, the synthesis was carried out in the same manner as in Example 1, except that NH ₄ F was added as an additional fluorine source.

Fig. 3 shows the XRD analysis results of the material synthesized according to Example 3. Fig. From FIG. 3, it was confirmed that the material synthesized in accordance with Example 3 was also LiVPO ₄ F.

[Example 4]

In Example 4 of the present invention, LiVPO ₄ F was synthesized in the following manner.

First, as a precursor for the solid-phase reaction, LiF powder (having a purity of 98.5% or more), V ₂ O ₅ powder (Sigma Aldrich, purity 98%) and NH ₄ H ₂ PO ₄ PVDF as an additional fluorine source was prepared as follows.

LiF + 0.5V ₂ O ₅ + NH ₄ H ₂ PO ₄ + 25 wt% PVDF

(Here, the amount of the PVDF was being other precursor _{(LiF, V 2 O 3,} NH 4 H 2 PO 4) 25% by weight of an agreement)

Specifically, the weight of each material prepared is 1.054 g of LiF, 3.7118 g of V ₂ O _5, 4.6584 g of NH ₄ H ₂ PO _{4 and} 2.3560 g of PVDF.

The thus prepared precursor was put into an acetone solvent, followed by ball milling for about 12 hours to dissolve the PTFE, and the agglomerated powder in the precursor was disintegrated to prepare a uniformly mixed mixture. Zirconia balls having diameters of 3.5 mm and 10 mm were used for the ball milling.

After mixing the powders through ball milling, the mixture was dried in air at a temperature of 85 ° C using a hot plate, and the dried mixture was pelletized using a disc mold.

The thus prepared pellets were charged into an alumina crucible and heated to 550 DEG C under an argon gas atmosphere (0.5 mL flow rate per minute). At this time, the heating rate was 3.8 ° C / min and the heating time at 550 ° C was 1 hour, so that the solid phase reaction was caused. After heating, it was allowed to cool naturally at room temperature.

The powder obtained through the above method was analyzed using XRD, and Fig. 4 shows the results. As shown in FIG. 4, the powder obtained according to Example 4 of the present invention exhibited an XRD pattern of LiVPO ₄ F.

[Example 5]

In Example 5 of the present invention, LiVPO ₄ F was synthesized in the following manner.

First, as a precursor for the solid phase reaction, LiF powder (having a purity of 98.5% or more), V ₂ O ₅ powder (Sigma Aldrich, purity 98%) and NH ₄ H ₂ PO ₄ PTFE (Sigma Aldrich, about 1 mu m in particle diameter) was used as an additional fluorine source in the following manner.

LiF + 0.5 V ₂ O ₅ + NH ₄ H ₂ PO ₄ + 15 wt% PTFE

(Here, the amount of PTFE is being other precursor _{(LiF, V 2 O 3,} NH 4 H 2 PO 4) 15% by weight of an agreement)

Specifically, the weight of each material prepared is 1.054 g of LiF, 3.7118 g of V ₂ O _5, 4.6584 g of NH ₄ H ₂ PO ₄ , and 1.4136 g of PTFE.

The thus prepared precursor was put in a water solvent and then subjected to ball milling for about 12 hours to prepare a uniformly mixed mixture while the aggregated powder in the precursor was disintegrated. Zirconia balls having diameters of 3.5 mm and 10 mm were used for the ball milling.

After mixing the powders through ball milling, the mixture was dried in air at a temperature of 85 ° C using a hot plate, and the dried mixture was pelletized using a disc mold.

The thus prepared pellets were charged into an alumina crucible and heated to 700 DEG C under an argon gas atmosphere (flow rate of 0.5 mL per minute). At this time, the heating rate was 3.8 占 폚 / min and the heating time at 700 占 폚 was 1 hour so that the solid phase reaction was caused. After heating, it was allowed to cool naturally at room temperature.

[Example 6]

In Example 6 of the present invention, LiVPO ₄ F was synthesized in the following manner.

First, as a precursor for the solid phase reaction, LiF powder (having a purity of 98.5% or more), V ₂ O ₅ powder (Sigma Aldrich, purity 98%) and NH ₄ H ₂ PO ₄ PTFE (Sigma Aldrich, about 1 mu m in particle diameter) was used as an additional fluorine source in the following manner.

LiF + 0.5 V ₂ O ₅ + NH ₄ H ₂ PO ₄ + 15 wt% PTFE + 20 wt% excess carbon

(Here, the amount of PTFE is being other precursor _{(LiF, V 2 O 3,} NH 4 H 2 PO 4) 15% by weight of an agreement)

Specifically, the weight of each material prepared is 1.054 g of LiF, 3.7118 g of V ₂ O _5, 4.6584 g of NH ₄ H ₂ PO _4, 1.4136 g of PTFE and 2.3560 g of super P.

The thus prepared precursor was put into an acetone solvent, followed by ball milling for about 12 hours to dissolve the PTFE, and the agglomerated powder in the precursor was disintegrated to prepare a uniformly mixed mixture. Zirconia balls having diameters of 3.5 mm and 10 mm were used for the ball milling.

After mixing the powders through ball milling, the mixture was dried in air at a temperature of 85 ° C using a hot plate, and the dried mixture was pelletized using a disc mold.

The thus prepared pellets were charged into an alumina crucible and heated to 700 DEG C under an argon gas atmosphere (flow rate of 0.5 mL per minute). At this time, the heating rate was 3.8 占 폚 / min and the heating time at 700 占 폚 was 1 hour so that the solid phase reaction was caused. After heating, it was allowed to cool naturally at room temperature.

When using this method, no additional carbon is added to the electrode when making the electrode.

Charging / discharging characteristics evaluation result

5 shows the results of evaluating charge and discharge characteristics of LiVPO ₄ F prepared according to Example 1 of the present invention.

In order to evaluate the electrochemical behavior, an electrode was formed using the LiVPO ₄ F material prepared according to Example 1 of the present invention to conduct an electrochemical test.

80 wt% of active material LiVPO ₄ F prepared according to Example 1 of the present invention, 15 wt% of super P as a carbon powder and 5 wt% of PTFE as a binder were put into a mortar and mixed well for 20 to 30 minutes, After repeating the pushing process, a 2 to 5 mg anode was prepared by punching with 8 mm punch, which was performed in an argon atmosphere glove box.

The cell was assembled by using the anode thus prepared. In the cell assembly, the wellcos 2400 was cut to about 13 mm. The electrolyte was 1M LiPF ₆ in an organic solvent of EC / DMC (1: 1 weight ratio) Lithium metal was used.

The electrochemical behavior of the thus prepared cell was measured at room temperature. The measurement equipment was a maccor series 4000, and the measurement was started from 3V to 4.5V and the current was measured by adding the C / 5 rate size. As a result, as shown in FIG. 5, the battery using the active material prepared according to Example 1 of the present invention exhibited a performance of about 80% of the theoretical capacity.

Claims (14)

A process for producing a fluorine compound for a cathode material of a lithium secondary battery, which produces a compound represented by the following formula through one solid phase synthesis reaction,
Characterized in that the solid-phase synthesis reaction is performed by heating a precursor mixture comprising at least one selected from the group consisting of a lithium precursor, a metal precursor, a phosphate precursor, and an organic compound containing fluorine or an ammonium compound containing fluorine. (Method for producing fluorine compound for cathode material).
[Chemical Formula]
LiM _x PO ₄ F _y wherein 0 <x? 1, 0 <y? 1, and M is at least one selected from Mn, V, Cr, Ti, Fe, Co, Ni, Nb, A process for producing a fluorine compound for a cathode material of a lithium secondary battery, which produces a compound represented by the following formula through one solid phase synthesis reaction,
Wherein the solid phase synthesis reaction is carried out by heating a precursor mixture comprising at least one selected from LiF, a metal precursor, a phosphate precursor and an organic compound containing fluorine or an ammonium compound containing fluorine. A method for producing a fluorine compound.
[Chemical Formula]
LiM _x PO ₄ F _y wherein 0 <x? 1, 0 <y? 1, and M is at least one selected from Mn, V, Cr, Ti, Fe, Co, Ni, Nb, A process for producing a fluorine compound for a cathode material of a lithium secondary battery, which produces a compound represented by the following formula through one solid phase synthesis reaction,
Wherein the solid-phase synthesis reaction is performed by heating a precursor mixture comprising at least one selected from Li ₂ CO ₃ , a metal precursor, a phosphate precursor, an organic compound containing fluorine, and an ammonium compound containing fluorine. Of the fluorine compound for a cathode material.
[Chemical Formula]
LiM _x PO ₄ F _y wherein 0 <x? 1, 0 <y? 1, and M is at least one selected from Mn, V, Cr, Ti, Fe, Co, Ni, Nb, 4. The method according to any one of claims 1 to 3,
Wherein carbon is produced during the production of the fluorine compound. The method according to claim 1,
Wherein the fluorine-containing organic compound or the fluorine-containing ammonium compound is contained in the precursor mixture in an amount of 10 to 200% based on the total weight of the lithium precursor, the metal precursor, and the phosphate precursor. &Lt; / RTI &gt; 3. The method of claim 2,
Wherein the fluorine-containing organic compound or fluorine-containing ammonium compound is contained in the precursor mixture in an amount of 10 to 200% based on the total weight of LiF, the metal precursor, and the phosphate precursor. &Lt; / RTI &gt; The method of claim 3,
Wherein the precursor mixture contains the fluorine-containing organic compound or the fluorine-containing ammonium compound in an amount of 10 to 200% based on the total weight of Li ₂ CO ₃ , the metal precursor and the phosphate precursor. A method for producing a fluorine compound for recycling. 4. The method according to any one of claims 1 to 3,
Wherein the fluorine-containing organic compound is polytetrafluoroethylene (PTFE) or polyfluorinated vinylidene (PVDF). 2. A method for producing a fluorine compound for a cathode material for a lithium secondary battery, 4. The method according to any one of claims 1 to 3,
Wherein the fluorine-containing ammonium compound is ammonium fluoride (NH ₄ F). The method for producing a fluorine compound for a cathode material of a lithium secondary battery according to claim ₁ , wherein the fluorine-containing ammonium compound is ammonium fluoride (NH ₄ F). 4. The method according to any one of claims 1 to 3,
Wherein the precursor mixture has a heating temperature of 500 to 750 DEG C. 5. The method for producing a fluorine compound for a cathode material of a lithium secondary battery according to claim 1, 4. The method according to any one of claims 1 to 3,
The metal precursor may include V ₂ O ₅ And the amount of the fluorine compound to be used for producing the fluorine compound for the cathode material of the lithium secondary battery is less than the amount of the fluorine compound. 4. The method according to any one of claims 1 to 3,
The fluorine compound is LiVPO ₄ F, LiV ₀ . ₉ Mn _{0 .1} PO ₄ F, or LiV _{0. 9} Fe _{0 .1} PO ₄ F The method of producing a positive electrode of a lithium secondary battery re-dissolve the fluorine compound, characterized in that. A positive electrode comprising a fluorine compound for a cathode material produced by the method according to any one of claims 1 to 3, a binder and a conductive powder. A lithium secondary battery comprising the positive electrode according to claim 13.

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