JP2013222501A - Positive electrode for all-solid-state lithium secondary battery and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of the positive electrode for an all-solid-state lithium secondary battery in which the charge/discharge capacity has been enhanced.SOLUTION: In the manufacturing method of a positive electrode for an all-solid-state lithium secondary battery, a positive electrode is obtained by mixing and molding a material containing LiS as a positive electrode active material, a carbon material as a conductive material, and LiS-MS(M is selected from P, Si, Ge, B, Al, Ga, and x and y are integers giving a stoichiometric ratio according to the kind of M) as an electrolyte. The LiS is subjected to wet mechanical milling when the material is mixed, or subjected previously to wet mechanical milling before the material is mixed.

Description

  The present invention relates to a positive electrode for an all-solid lithium secondary battery and a method for producing the same. More specifically, the present invention relates to a positive electrode for an all-solid lithium secondary battery having a high charge / discharge capacity and a method for producing the same.

Lithium secondary batteries have high voltage and high capacity, and are therefore widely used as power sources for mobile phones, digital cameras, video cameras, notebook computers, electric vehicles and the like. Generally, lithium secondary batteries in circulation use a liquid electrolyte in which an electrolytic salt is dissolved in a non-aqueous solvent as an electrolyte. Since non-aqueous solvents contain a lot of flammable solvents, it is desired to ensure safety.
In order to ensure safety, an all-solid lithium secondary battery using a so-called solid electrolyte in which an electrolyte is formed from a solid material without using a non-aqueous solvent has been proposed. The positive electrode of this battery contains various components such as a positive electrode active material, a conductive material, and an electrolyte. Among these components, sulfur is attracting attention as a positive electrode active material because of its high theoretical capacity (Japanese Patent Laid-Open No. 2004-95243: Patent Document 1).

By the way, when sulfur is used as the positive electrode active material, it is necessary to use a material containing Li as the negative electrode active material. In a battery using these active materials, the charge / discharge reaction starts from discharge. Therefore, from the viewpoint of further increasing the types of materials that can be used for the negative electrode active material, a positive electrode active material capable of starting a charge / discharge reaction from charging, that is, a positive electrode active material containing Li in advance is desired.
From the above viewpoint, the inventors of the present invention use Li ₂ S having a theoretical capacity of about 1170 mAhg ⁻¹ as the positive electrode active material because sulfur after discharge exists as a mixture with Li in the positive electrode. As a result, the knowledge that charging and discharging are possible was obtained (Abstracts of the 77th Annual Meeting of the Electrochemical Society of Japan p58 (2010): Non-Patent Document 1).

JP 2004-95243 A

Abstracts of the 77th Annual Meeting of the Electrochemical Society p58 (2010)

  Although the positive electrode of the non-patent document can provide a battery having a certain charge / discharge capacity, further improvement of the charge / discharge capacity has been desired.

In Non-Patent Document 1 are denoted by the mixture of Li ₂ S and a conductive material in a dry mechanical milling, the electrolyte was added to the obtained treated product to obtain a mixture, it was subjected the mixture further dry mechanical milling Thereafter, the positive electrode is obtained by molding. The inventors of the present invention have intensively studied the positive electrode manufacturing method in order to further improve the charge / discharge capacity, and as a result, found that the charge / discharge capacity can be improved by subjecting Li ₂ S to wet mechanical milling. It came to. The inventor said that Li ₂ S was able to provide a positive electrode capable of improving the charge / discharge capacity as a result of being subjected to a wet mechanical milling process, thereby reducing the particle size, increasing the contact area with the conductive material and the electrolyte. Etc. are thinking.

Thus, according to the present invention, Li ₂ S as a positive electrode active material, a carbon material as a conductive material, and Li ₂ S—M _x S _y as an electrolyte (M is P, Si, Ge, B, Al, Ga). X and y are integers that give a stoichiometric ratio according to the type of M) and a positive electrode is obtained by mixing and forming a raw material.
The Li ₂ S is subjected to a wet mechanical milling process when the raw materials are mixed, or is subjected to a wet mechanical milling process in advance before mixing the raw materials. A manufacturing method is provided.
Furthermore, according to this invention, the positive electrode for all-solid-state lithium secondary batteries obtained by the said method is provided.

ADVANTAGE OF THE INVENTION According to this invention, the positive electrode for all-solid-state lithium secondary batteries which has high charge / discharge capacity, and its manufacturing method can be provided.
In addition, when the wet mechanical milling process is performed at a temperature at the time of the process and is performed in the presence of a solvent inert to Li ₂ S, the all-solid lithium secondary battery having a higher charge / discharge capacity is used. A method for producing a positive electrode can be provided.
Furthermore, when a wet mechanical milling process is performed in presence of toluene, the manufacturing method of the positive electrode for all-solid-state lithium secondary batteries which has higher charge / discharge capacity can be provided.

Further, when the wet mechanical milling process is performed under the conditions of 50 to 300 revolutions / minute, 0.1 to 10 hours, and 1 to 100 kWh / 1 kg of Li ₂ S using a planetary ball mill, higher charge / discharge A method for producing a positive electrode for an all-solid lithium secondary battery having a capacity can be provided.
Li ₂ S, carbon materials and electrolytes, 100: 10-200: 10 to 500 when mixed in a ratio (weight ratio), a method for manufacturing a positive electrode for all-solid lithium secondary battery having a higher charge-discharge capacity Can be provided.
Li ₂ S-M _x S _y is, Li ₂ S and M _x S _y and 50: 50-90: 10 when having a ratio (molar ratio), all-solid lithium secondary battery having a higher charge-discharge capacity A method for producing a positive electrode for an automobile is provided.

_{2 is} a scanning electron micrograph of Li ₂ S of Example 1 and Comparative Example 1. FIG. It is a graph which shows the relationship between the cell potential and charge / discharge capacity of Example 1 and Comparative Examples 1 and 2. It is a graph which shows the relationship between the cell potential of Example 2, and discharge capacity. It is a graph which shows the relationship between the current density of Example 2, and discharge capacity. 6 is a graph showing the relationship between the utilization rate of the positive electrode active material of Example 5 and the cell potential.

The positive electrode for an all-solid lithium secondary battery is a composite formed body including Li ₂ S as a positive electrode active material, a carbon material as a conductive material, and Li ₂ S-M _x S _y as an electrolyte.
(Li ₂ S)
Li ₂ S that can be used in the present invention is not particularly limited, and commercially available products can be used. Li ₂ S is preferably used as high as possible. For example, it is preferable to use Li ₂ S having a purity of 99% or more. Furthermore, the shape of the Li ₂ S is not particularly limited, granular, include various shapes such as massive.
Li ₂ S is subjected to a wet mechanical milling process. This treatment may be performed in advance before mixing with the conductive material and the electrolyte, or may be performed at the time of mixing with the conductive material and the electrolyte. Furthermore, in any one of the method of mixing Li ₂ S and a conductive material and then mixing with the electrolyte, or mixing Li ₂ S and the electrolyte, and then mixing with the conductive material, Li ₂ S and the conductive material or electrolyte Li ₂ S may be subjected to a wet mechanical milling process by performing a wet mechanical milling process.

The wet mechanical milling process is performed in the presence of a solvent. The solvent is preferably a liquid at the temperature during the treatment (for example, 10 to 50 ° C.) and inert to Li ₂ S. Examples of the solvent include aromatic hydrocarbons such as toluene, xylene, decalin, and tetrahydronaphthalene, saturated hydrocarbons such as hexane, pentane, ethyl hexane, heptane, decane, and cyclohexane, and unsaturated carbons such as hexene, heptene, and cyclohexene. Hydrogen etc. are mentioned. Of these, aromatic hydrocarbons are more preferred, and toluene is even more preferred.
The amount of the solvent used, for example, with respect to Li ₂ S100 parts, may be in the range of 10 to 100 parts by weight.

It is preferable to remove the solvent after the wet mechanical milling treatment. The removal of the solvent may be performed at any stage as long as no solvent is finally present in the positive electrode. For example, it may be performed immediately after the wet mechanical milling treatment, may be performed after mixing with the conductive material and / or the electrolyte, or may be performed after forming the positive electrode.
The wet mechanical milling process is not particularly limited to a processing apparatus and processing conditions as long as desired charge / discharge characteristics can be obtained.

As a processing apparatus, a ball mill can be used normally. A ball mill is preferable because large mechanical energy can be obtained. Among the ball mills, the planetary ball mill is preferable because the pot automatically rotates and the base plate revolves and high impact energy can be efficiently generated.
The processing conditions can be appropriately set according to the processing apparatus to be used. For example, when using a ball mill, the higher the rotational speed and / or the longer the processing time, the more uniformly the raw material mixture can be mixed. Specifically, when a planetary ball mill is used, conditions of 50 to 500 revolutions / minute, 0.1 to 10 hours, and 1 to 100 kWh / 1 kg of Li ₂ S are exemplified. More preferable processing conditions include 150 to 300 revolutions / minute, 0.5 to 2 hours, and 6 to 50 kWh / 1 kg of Li ₂ S.

(Carbon material)
The carbon material is not particularly limited, and is used as a conductive material in the field of secondary batteries such as carbon black such as acetylene black, Denka black, Ketjen black, carbon nanotube, natural graphite, artificial graphite, and vapor growth carbon fiber (VGCF). The material used is mentioned.
The amount of the carbon material is preferably 10 to 200 parts by weight with respect to 100 parts by weight of Li ₂ S. When the amount is less than 10 parts by weight, a sufficient charge / discharge capacity may not be obtained due to a decrease in the amount of electrons that can move to the positive electrode. When the amount is more than 200 parts by weight, the amount of Li ₂ S and Li ₂ S-M _x S _y occupying the positive electrode is relatively small, and the charge / discharge efficiency may be lowered. A more preferable amount of the carbon material is in the range of 50 to 100 parts by weight.

(Electrolytes)
The positive electrode, the electrolyte comprises _{Li 2 S-M x S y} .
In M _x S _y that is a sulfide, M is selected from P, Si, Ge, B, Al, and Ga, and x and y are integers that give a stoichiometric ratio depending on the type of M. The six elements that can be used as M can have various valences, and x and y can be set according to the valences. For example, P can be trivalent and pentavalent, Si can be tetravalent, Ge can be divalent and tetravalent, B can be trivalent, Al can be trivalent, and Ga can be trivalent. Specific examples of M _x S _y include P ₂ S ₅ , SiS ₂ , GeS ₂ , B ₂ S ₃ , Al ₂ S ₃ , Ga ₂ S _{3 and the} like. These specific M _x S _y may be used alone or in combination of two or more. Of these, P ₂ S ₅ is particularly preferred.
Furthermore, the molar ratio of Li ₂ S to M _x S _y is preferably 50:50 to 90:10, more preferably 67:33 to 80:20, and 70:30 to 80:20. More preferably.

The electrolyte, in addition to _{Li 2 S-M x S y} , LiI, may include other electrolytes such as Li ₃ PO _4.
The amount of Li ₂ S-M _x S _y, relative to Li ₂ S100 parts by weight, preferably 10 to 500 parts by weight. When the amount is less than 10 parts by weight, a sufficient charge / discharge capacity may not be obtained due to a decrease in the amount of lithium ions that can move to the positive electrode. When the amount is more than 500 parts by weight, the amount of Li ₂ S and the carbon material occupying the positive electrode is relatively reduced, and the charge / discharge efficiency may be lowered. More preferable amount of Li ₂ S-M _x S _y is in the range of 50 to 200 parts by weight.

(Other ingredients)
In addition to Li ₂ S, the carbon material, and Li ₂ S-M _x S _y , components that are usually used in all-solid lithium secondary batteries may be included. Examples thereof include active materials such as LiCoO ₂ and LiMn ₂ O ₄ . These active materials may be provided with a film of a metal sulfide selected from Ni, Mn, Fe, and Co on the surface. Examples of the method for forming a film include a method in which an active material is immersed in a film precursor solution and then heat-treated, and a method in which a film precursor solution is sprayed on the active material and then heat-treated.
Further, a binder may be included. Examples of the binder include polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl acetate, polymethyl methacrylate, and polyethylene.

(Raw material mixing and molding process)
The mixing of raw materials is not particularly limited as long as a desired charge / discharge capacity can be obtained. For example, mixing in a mortar, mechanical milling treatment and the like can be mentioned. Among these, the mechanical milling process which can obtain a larger charge / discharge capacity is preferable. The mechanical milling process may be dry or wet. In particular,
(1) Method of subjecting mixture of Li ₂ S, conductive material and electrolyte to wet mechanical milling treatment (2) After subjecting Li ₂ S to wet mechanical milling treatment, the mixture of Li ₂ S, conductive material and electrolyte is wet or Method of subjecting to dry mechanical milling (3) After subjecting Li ₂ S to wet mechanical milling, a mixture of Li ₂ S and a conductive material is subjected to wet or dry mechanical milling, and Li ₂ S, conductive material and Method of subjecting electrolyte mixture to wet or dry mechanical milling treatment (4) Li ₂ S is subjected to wet mechanical milling treatment, and then the mixture of Li ₂ S and electrolyte is subjected to wet or dry mechanical milling treatment to obtain Li ₂ And a method of subjecting a mixture of S, a conductive material and an electrolyte to a wet or dry mechanical milling process.

The mechanical milling process is not particularly limited to a processing apparatus and processing conditions as long as desired charge / discharge characteristics can be obtained.
The processing apparatus can be used the apparatus described in wet mechanical milling of Li ₂ S.
As for the processing conditions, a planetary ball mill is used, and in the case of a dry type, the rotational speed is 50 to 600 rotations / minute, the processing time is 0.1 to 10 hours, and the conditions are 1 to 100 kWh / processing target 1 kg. More preferable processing conditions include a rotation speed of 200 to 500 rotations / minute, a processing time of 1 to 5 hours, and 6 to 50 kWh / kg of a processing target. In the case of a wet type, conditions of a rotation speed of 50 to 500 rotations / minute, a processing time of 0.1 to 10 hours, and 1 kg of raw material mixture of 1 to 100 kWh can be mentioned. More preferable processing conditions include a rotational speed of 150 to 300 rotations / minute, a processing time of 0.5 to 2 hours, and 6 to 50 kWh / kg of processing target.
The mixed raw material can be made into a pellet-like positive electrode (molded body) by, for example, press molding. Here, the positive electrode may be formed on a current collector made of a metal plate such as aluminum or copper.

(All-solid lithium secondary battery)
The all solid lithium secondary battery includes a positive electrode, an electrolyte layer, and a negative electrode. The all-solid lithium secondary battery can be obtained, for example, by laminating a positive electrode, an electrolyte layer, and a negative electrode and pressing them.
(1) Electrolyte layer It does not specifically limit to the electrolyte which comprises an electrolyte layer, All the electrolytes normally used for an all-solid-state lithium secondary battery can be used. For example, the electrolyte illustrated in description of the said positive electrode is mentioned. Incidentally, in the electrolyte layer, the proportion of the Li ₂ S-M _x S _y is preferably 90 wt% or more, and more preferably the total amount. The thickness of the electrolyte layer is preferably 5 to 500 μm, and more preferably 20 to 100 μm. The electrolyte layer can be obtained as a pellet by, for example, pressing the electrolyte.

(2) Negative electrode A negative electrode is not specifically limited, Any negative electrode normally used for an all-solid lithium secondary battery can be used. The negative electrode may be composed only of the negative electrode active material, and may be mixed with a binder, a conductive material, an electrolyte, and the like.
Since the present invention uses a Li ₂ S as the positive electrode active material, usable negative electrode active material that does not contain Li. Examples of such a negative electrode active material include metals such as In and Sn, alloys thereof, various transition metal oxides such as graphite and SnO. It is also possible to use a negative electrode active material containing Li, such as Li or Li _4/3 Ti _5/3 O ₄ .

Examples of the binder include polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl acetate, polymethyl methacrylate, and polyethylene.
Examples of the conductive material include natural graphite, artificial graphite, acetylene black, vapor grown carbon fiber (VGCF), and the like.
Examples of the electrolyte include an electrolyte used for an electrolyte layer.
The negative electrode can be obtained as a pellet by, for example, mixing a negative electrode active material and optionally a binder, a conductive material, an electrolyte, and the like, and pressing the obtained mixture. Moreover, when using the metal sheet (foil) which consists of a metal or its alloy as a negative electrode active material, can be used as it is.
The negative electrode may be formed on a current collector such as aluminum or copper.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
Example 1
1 g of Li ₂ S (manufactured by Idemitsu Kosan Co., Ltd .: purity 99.9% or more, average particle size 100 μm) was subjected to wet mechanical milling treatment. Pulverisete P-7 manufactured by Fritsch, which is a planetary ball mill equipped with a pot and a ball, was used as the processing apparatus. The pots and balls were made of zirconium oxide, and 160 balls with a diameter of 5 mm were used in a 45 ml pot. As a solvent, 50 parts by weight of toluene was used with respect to 100 parts by weight of Li ₂ S. The treatment conditions were room temperature (about 25 ° C.), 230 rotations / minute, 10 hours, and about 30 kWh / 1 kg of Li ₂ S.
After the treatment, toluene was removed by subjecting Li ₂ S to a vacuum drying treatment at 160 ° C. for 24 hours. A scanning electron micrograph of the obtained Li ₂ S is shown in FIG.
Next, 0.5 g of Li ₂ S after the drying treatment and 0.5 g of acetylene black (Denka Black: average particle diameter 35 nm: hereinafter also referred to as AB) manufactured by Denki Kagaku Kogyo Co., Ltd. are subjected to dry mechanical milling treatment. did. The above-mentioned apparatus was used as the processing apparatus, and the processing conditions were room temperature (about 25 ° C.), 510 rotations / minute, 5 hours, and about 50 kWh / 1 kg.

Furthermore, Li ₂ S and acetylene black after dry mechanical milling treatment and 80Li ₂ S-20P ₂ S ₅ (hereinafter also referred to as SE. 80 and 20 are molar ratio: average particle diameter 5 μm) are subjected to dry mechanical milling treatment. (Li ₂ S: AB: SE = 25: 25: 50 (weight ratio)). The above-mentioned apparatus was used as a processing apparatus, and the processing conditions were room temperature (about 25 ° C.), 370 revolutions / minute, 1 hour, and about 40 kWh / 1 kg.

The SE used was synthesized by the following method.
Li ₂ S (Idemitsu Kosan Co., Ltd .: purity 99.9% or higher) and P ₂ S ₅ (Aldrich purity 99%) were charged into a planetary ball mill at a molar ratio of 80:20. After the addition, SE was obtained by dry mechanical milling. As the planetary ball mill, Pulverisette P-7 manufactured by Fritsch was used, and the pot and balls were made of zirconium oxide, and a mill containing 500 balls having a diameter of 4 mm in a 45 ml pot was used. The dry mechanical milling process was performed for 10 hours in a dry nitrogen glove box at a rotation speed of 510 rpm, room temperature. This synthesis method is described in Akitoshi Hayashi et al. , Journal of Non-Crystalline Solids 356 (2010) 2670-2673.

10 mg of a composite of Li ₂ S, AB and SE after treatment was pressed (pressure 370 MPa / cm ² ) to obtain a pellet (positive electrode) having a diameter of 10 mm and a thickness of about 0.1 mm.
By pressing 80 mg of a solid electrolyte composed of Li ₂ S—P ₂ S ₅ (a molar ratio of Li ₂ S to P ₂ S ₅ of 80:20) (pressure 370 MPa / cm ² ), the diameter is 10 mm and the thickness is about 0. A 1 mm pellet (electrolyte layer) was obtained.
For the negative electrode, an indium foil having a thickness of 0.1 mm was used.
The positive electrode, electrolyte layer, and negative electrode were laminated, sandwiched between stainless steel current collectors, and pressed (pressure 250 MPa / cm ² ) to obtain an all-solid lithium secondary battery.

FIG. 2 shows the relationship between the cell potential and the charge / discharge capacity when the obtained secondary battery (cell) is repeatedly charged and discharged at 25 ° C. and a current density of 0.064 mA / cm ² . In FIG. 2, the left vertical axis indicates the potential with respect to the Li—In counter electrode, and the right vertical axis indicates the potential with respect to the Li reference electrode (potential difference between Li and Li—In, plotted considering 0.62 V). In FIG. 2, the curve indicated by “wet-milled” shows the relationship diagram of the first embodiment. It can be seen from FIG. 2 that a reversible capacity of about 860 mAhg ⁻¹ is obtained.

Comparative Example 1
An all solid lithium secondary battery was obtained in the same manner as in Example 1 except that Li ₂ S was subjected to dry mechanical milling. The treatment conditions were room temperature (about 25 ° C.), 510 rotations / minute, 20 hours, and about 50 kWh / 1 kg.
Scanning electron micrographs of Li ₂ S after 2 hours, 20 hours and 50 hours after the dry mechanical milling treatment are shown in FIGS.
FIG. 2 shows the relationship between the cell potential and the charge / discharge capacity when the obtained secondary battery is repeatedly charged and discharged at 25 ° C. and a current density of 0.064 mA / cm ² . In FIG. 2, the curve indicated by “dry-milled” shows the relationship diagram of Comparative Example 1. It can be seen from FIG. 2 that a reversible capacity of about 800 mAhg ⁻¹ is obtained.

Comparative Example 2
An all solid lithium secondary battery was obtained in the same manner as in Example 1 except that Li ₂ S was not subjected to wet mechanical milling.
FIG. 2 shows the relationship between the cell potential and the charge / discharge capacity for each number of cycles when the obtained secondary battery is repeatedly charged and discharged at 25 ° C. and a current density of 0.064 mA / cm ² . In FIG. 2, the curve indicated by “non-milled” shows the relationship diagram of Comparative Example 2. It can be seen from FIG. 2 that a reversible capacity of about 680 mAhg ⁻¹ is obtained.

(Consideration of results of Example 1 and Comparative Examples 1 and 2)
It can be seen from FIG. 2 that the charge / discharge capacity can be increased by subjecting Li ₂ S to wet mechanical milling (about 7% UP compared to Comparative Example 1 and about 26% UP compared to Comparative Example 2). The inventors have considered that this is because the particle size of Li ₂ S can be reduced by wet mechanical milling treatment and the aggregate of Li ₂ S can be reduced. Specifically, FIG. 1B shows that the particle size (about 10 μm) of Li ₂ S after 2 hours of dry mechanical milling is extremely large. In FIG. 1 (c), after 20 hours of dry mechanical milling treatment, the particle size of Li ₂ S is reduced, but aggregates are observed (portion surrounded by a dotted line in the figure). This agglomerate is observed even after 50 hours of dry mechanical milling treatment, as shown in FIG. In contrast, as shown in FIG. 1 (a), after 10 hours of wet mechanical milling treatment, the particle size of Li ₂ S is as small as about 3 μm, which is reduced by about 70%, and aggregates are observed. Absent. This is considered to be because a larger number of Li ion and electron conduction paths can be secured by reducing the particle size of Li ₂ S and preventing aggregation.

Example 2
The battery obtained in Example 1 was charged at a current density of 0.064 mA / cm ² at 25 ° C., and current densities of 0.13 mA / cm ² , 1.3 mA / cm ² and 6.4 mA / cm ² were obtained. FIG. 3 shows the relationship between the cell potential and the discharge capacity when discharged in FIG. 4, and FIG. 4 shows the relationship between the current density and the discharge capacity. Further, the relationship between the current density and the discharge capacity when the battery obtained in Comparative Example 2 was discharged at the above current density is also shown in FIG.
3 and 4 that the reversible capacity can be improved even at a high rate.

Example 3
Replacing Li ₂ S with S (manufactured by Aldrich: purity 99.998%) and using a positive electrode for the negative electrode and a 0.1 mm thick Li-In alloy foil (Li: In = 50: 50 (molar ratio)) for the negative electrode Except that, an all solid lithium secondary battery was obtained in the same manner as in Example 1.
The relationship between the utilization rate of the S active material and the cell potential in the obtained battery is shown in FIG. 5 (current density is set to 0.064 mA / cm ² ). In addition, the relationship between the utilization rate of the Li ₂ S active material and the cell potential of the battery of Example 1 is also shown in FIG. 5 (current density is set to 0.013 mA / cm ² ).
From FIG. 5, it can be seen that the battery using Li ₂ S as the positive electrode active material has a utilization rate of the positive electrode active material substantially the same as the battery using S as the positive electrode active material.

Claims (7)

Li ₂ S as the positive electrode active material, carbon material as the conductive material, and Li ₂ S-M _x S _y as the electrolyte (M is selected from P, Si, Ge, B, Al, Ga, x and y Is an integer that gives a stoichiometric ratio depending on the type of M) and a positive electrode is obtained by mixing and forming
The Li ₂ S is subjected to a wet mechanical milling process when the raw materials are mixed, or is subjected to a wet mechanical milling process in advance before mixing the raw materials. Production method. _2. The production of a positive electrode for an all-solid-state lithium secondary battery according to claim 1, wherein the wet mechanical milling treatment is performed in the presence of a solvent that is liquid at the temperature at the time of the treatment and inert to the Li ₂ S. Method. The manufacturing method of the positive electrode for all-solid-state lithium secondary batteries of Claim 1 or 2 with which the said wet mechanical milling process is performed in presence of toluene. The wet-type mechanical milling process is performed using a planetary ball mill under conditions of 50 to 300 revolutions / minute, 0.1 to 10 hours, and 1 to 100 kWh / 1 kg of Li ₂ S. The manufacturing method of the positive electrode for all-solid-state lithium secondary batteries as described in any one. 5. The all-solid-state lithium secondary battery according to claim 1, wherein the Li ₂ S, the carbon material, and the electrolyte are mixed at a ratio of 100: 10 to 200: 10 to 500 (weight ratio). A method for producing a positive electrode. The Li ₂ S-M _x S _y has a Li ₂ S and _{M x S y 50: 50~90:} 10 according to any one of claims 1 to 5 comprising a ratio (molar ratio) total A method for producing a positive electrode for a solid lithium secondary battery. The positive electrode for all-solid-state lithium secondary batteries obtained by the method of any one of Claims 1-6.