KR20180115130A - A method for producing a sulfide-based solid electrolyte powder, a method for producing an electrode composite layer and a solid electrolyte layer including a solid electrolyte powder, and solid state battery including the same - Google Patents

Abstract

The present invention relates to a method for manufacturing sulfide-based solid electrolyte powder, a solid electrolyte layer including solid electrolyte powder, a method for manufacturing an electrode composite layer, and a solid battery including the same. The method for manufacturing sulfide-based solid electrolyte powder comprises the steps of: manufacturing a sulfide-based amorphous solid electrolyte by firstly milling a solid electrolyte raw material composed of lithium sulfide (Li_2S), a sulfur compound, and a lithium compound; forming amorphous solid electrolyte powder by differentiating the sulfide-based amorphous solid electrolyte through secondary milling; and obtaining crystalline or glass crystalline solid electrolyte powder by drying and heat-treating the amorphous solid electrolyte powder. Accordingly, a sulfide composed of fine powder having a size of several nm or several μm can be obtained through a plurality of grinding processes having different sizes of grinding balls. The size of sulfide can be decreased to reduce the use of binders and pores between sulfides. In addition, a solvent removal step is minimized through a non-solvent coating with no use of a solvent or a low solvent coating with a minimized solvent of 5 wt% or less. It is possible to prevent a problem in which ion conductivity is greatly reduced due to agglomeration of a binder.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for producing a sulfide-based solid electrolyte powder, a solid electrolyte layer including a solid electrolyte powder, a method for producing an electrode composite layer, layer and a solid electrolyte layer including a solid electrolyte powder, and a solid state battery including the same}

The present invention relates to a method for producing a sulfide-based solid electrolyte powder, a solid electrolyte layer comprising a solid electrolyte powder, a method for producing an electrode composite layer, and an all-solid-state cell including the same. More particularly, , A method of producing a sulfide-based solid electrolyte powder capable of obtaining a sulfide composed of fine powders of several nm or several 탆 in size and capable of decreasing the size of sulfide and decreasing the voids between sulfides, and a solid electrolyte powder A solid electrolyte layer, an electrode composite layer production method, and an all-solid-state cell including the same.

The secondary battery has been mainly applied to a small-sized field such as a mobile device or a notebook computer. However, recently, the application of the secondary battery has been expanding into a medium- and large-sized field, and an energy storage system (ESS) And the like are being expanded to fields requiring high energy and high output. Unlike a small-sized and medium-sized secondary battery, operating environments such as temperature and impact are not only severe but also require a large number of batteries. Therefore, it is necessary to ensure safety with good performance and reasonable prices. Most commercialized secondary batteries use an organic liquid electrolyte in which a lithium salt is dissolved in an organic solvent, which poses a potential risk of ignition and explosion including leakage.

Accordingly, all-solid-state batteries have been developed in recent years. Batteries using non-combustible inorganic or polymeric solid electrolytes as compared with lithium secondary batteries using conventional combustible organic liquid electrolytes And has a high thermal stability. The precharge cell generally has a laminated structure of a negative electrode collector layer, a negative electrode electrode composite layer or a lithium metal, a solid electrolyte layer, a positive electrode electrode composite layer and a positive electrode collector layer. Examples of suitable processes for mass production of such prior solid-state batteries include 'Slurry, a method for producing a solid electrolyte layer, a method for producing an electrode active material layer, and a method for manufacturing an all-solid battery', Korean Registered Patent No. 10-1506833 A technique of the same slurry application method is being developed. In the case of a glass and a lithium battery made of solid electrolyte particles, another prior art 'Korean Patent Registration No. 10-1707351', a technique of performing a step of contacting and reacting a raw material containing lithium sulfide and another sulfide in a solvent It is known.

However, in such a conventional technique, since the sulfide is pulverized by using the single grinding apparatus, it takes a long time to obtain the raw material particles, and it is difficult to obtain a fine powder having a size of several nm or several 탆. In addition, when the solid electrolyte layer and the electrode composite layer are produced by a conventional method, the sulfide and the binder are mixed with the solvent and then coated on the substrate. In this case, the solvent evaporation step must be separately performed, There is a problem in that the ion conductivity of the solid electrolyte layer is significantly lowered due to such a complex cause.

Korea Intellectual Property Office Registration No. 10-1506833 Korea Patent Office Registration No. 10-1460113 Korea Patent Office Registration No. 10-1707351 Korean Patent Application Publication No. 10-2014-0073400

Accordingly, it is an object of the present invention to provide a method for producing a sintered body, which comprises obtaining a sintered body composed of fine powders of several nm or several 탆 in size through a plurality of pulverizing processes having different sizes of the pulverizing balls and reducing the size of sulphides, A solid electrolyte layer containing a solid electrolyte powder, a method for producing an electrode composite layer, and an all solid battery including the solid electrolyte layer.

In addition, a solvent-free coating that does not use a solvent or a low-solvent coating that minimizes the solvent to 5 wt% or less minimizes the solvent removal step, thereby preventing the ion conductivity from being significantly lowered A solid electrolyte layer including a solid electrolyte powder, a method for producing an electrode composite layer, and a pre-solid battery including the solid electrolyte layer.

The above object can be accomplished by a process for preparing a sulfide amorphous solid electrolyte by first milling an amorphous solid electrolyte raw material composed of lithium sulfide (Li ₂ S), a sulfur compound, and a lithium compound; Forming an amorphous solid electrolyte powder by pulverizing the sulfide-based amorphous solid electrolyte through secondary milling; And then drying and heat-treating the amorphous solid electrolyte powder to obtain a crystalline or free crystalline solid electrolyte powder.

Here, the sulfide-based solid electrolyte powder is manufactured using a continuous milling apparatus including a primary milling unit and a secondary milling unit, and the sulfide-based solid electrolyte and the solvent, which have been subjected to the primary milling in the primary milling unit, It is preferable to carry out the second milling immediately after the solvent and the dispersant are further injected into the second milling portion.

Also, the primary milling may be performed by milling zirconia balls having a particle size of 1 to 10 mm for 5 to 40 hours to obtain a sulfide-based amorphous solid electrolyte having an average particle size of 3 to 10 μm, It is preferable to obtain an ultrafine amorphous solid electrolyte powder having an average particle size of 0.01 to 3 占 퐉 through milling of the sulfide based amorphous solid electrolyte using zirconia balls having a particle size of 0.1 to 1 mm.

The sulfur compound is a mixture of elements selected from the group consisting of phosphorus (P), silicon (Si), germanium (Ge), aluminum (Al), boron (B) It is preferable that the compound is a mixture of elements selected from the group consisting of chlorine (Cl), bromine (Br), iodine (I) and a mixture thereof as a halogen group element in lithium (Li).

The above object can be accomplished by a process for preparing a sulfide amorphous solid electrolyte by first milling an amorphous solid electrolyte raw material composed of lithium sulfide (Li ₂ S), a sulfur compound, and a lithium compound; Forming an amorphous solid electrolyte powder by pulverizing the sulfide-based amorphous solid electrolyte through secondary milling; A method for producing a solid electrolyte layer, an electrode composite layer, and a solid electrolyte layer comprising the solid electrolyte powder, which comprises mixing a binder in the amorphous solid electrolyte powder solution, followed by drying and heat treatment to prepare a crystalline or glass crystalline powder-binder complex .

Also, the present invention relates to a method for producing a sulfide-based amorphous solid electrolyte, which comprises: preparing a sulfide-based amorphous solid electrolyte by first milling an amorphous solid electrolyte raw material composed of lithium sulfide (Li ₂ S), a sulfur compound, and a lithium compound; Forming an amorphous solid electrolyte powder by pulverizing the sulfide-based amorphous solid electrolyte through secondary milling; Mixing the amorphous solid electrolyte powder solution with a binder, followed by drying and heat treatment to produce a crystalline or glassy crystalline powder-binder complex; Wherein the powder-binder composite is applied to a collector by solvent-free solventless coating or a low-solvent coating using 50 wt% or less of solvent to form a solid electrolyte layer or an electrode composite layer A solid electrolyte layer containing a solid electrolyte powder, and a method for producing an electrode composite layer.

In the case of the powder-binder complex for a solid electrolyte layer, the crystalline or crystalline solid electrolyte powder and the binder may be used. In the case of the powder-binder complex for an electrode composite layer, the cathode active material or the anode active material, Crystalline or free crystalline solid electrolyte powder, the binder and the conductive material.

The step of forming the solid electrolyte layer and the electrode composite layer may include a step of coating the current collector with the solvent-free solvent-free powder-binder complex for the electrode composite layer or a low-solvent using 5 wt% It is preferable to form an electrode composite layer having a high structural density by pressing and dry-coating and pressing the solid-electrolyte layer powder-binder complex for the solid electrolyte layer on the electrode composite layer to form a solid electrolyte layer having a high structural density, The powder-binder complex is preferably mixed so as to have a crystalline or crystalline glass solid electrolyte powder: binder = 80 to 99: 1 to 20 weight ratio.

It is preferable that the step of forming the solid electrolyte layer or the electrode composite layer is performed simultaneously with the heat treatment at 140 to 200 ° C.

The above object is also achieved by a method of manufacturing a semiconductor device, comprising: a current collector; A negative electrode composite layer formed on the current collector through a dry coating and comprising an ultrafine sulfide-based crystalline material having a diameter of 0.01 to 3 탆 or a crystalline solid electrolyte powder, a binder, a conductive material, and an active material, A composite layer; And a solid electrolyte layer laminated on the upper surface of the electrode composite layer through a solventless or low solvent coating and comprising a 0.01 to 3 탆 diameter ultrafine sulfide crystalline or crystalline solid electrolyte powder and a binder, The positive electrode composite layer, the solid electrolyte layer, the negative electrode composite layer, or the lithium metal-current collector.

According to the structure of the present invention described above, it is possible to obtain a sulfide composed of fine powders of several nm or several micrometers in size through a plurality of grinding processes with different sizes of the grinding balls, and the size of the sulfide decreases, And the use of the binder.

In addition, it is possible to minimize the solvent removal step by minimizing the solvent-free coating or the solvent to 5% by weight or less, thereby preventing the problem that the ion conductivity is greatly lowered due to the lump of the binder or the like Can be obtained.

FIG. 1 is a flowchart of a method for producing a solid electrolyte powder according to an embodiment of the present invention,
2 is a conceptual diagram of a continuous apparatus,
3 is a flowchart of a method for producing a solid electrolyte layer and an electrode composite layer,
4 is an SEM photograph of the LPSI powder after the first milling,
5 is an SEM photograph of the LPSI powder after the second milling,
Figure 6 is a PSA analysis graph of LPSI-based powders through primary milling and secondary milling,
7 is a graph showing the results of AC impedance of the LPSI-based powder through the primary milling and the secondary milling,
Figure 8 is a graph comparing the resistance to ionic conductivity of the solid electrolyte layer through dry coating and wet coating,
9 is a scanning electron micrograph of the surface of the wet-coated solid electrolyte layer before and after pressing,
10 is a scanning electron micrograph of the surface of the dry coated solid electrolyte layer after compression.

Hereinafter, a method for manufacturing a sulfide-based solid electrolyte powder, a solid electrolyte layer including a solid electrolyte powder, a method for producing an electrode composite layer, and a pre-solid battery including the same will be described in detail with reference to the drawings.

A high-voltage battery of the present invention comprises a current collector, a superfine sulfide-based crystalline material or a glass crystalline solid electrolyte powder formed on the current collector through a dry coating and having a diameter of 0.01 to 3 탆, a binder, a conductive material and an active material A cathode composite layer (or lithium metal) and a positive electrode composite layer; and an ultra-fine sulfide-based crystalline solid electrolyte powder and binder which are laminated on the electrode composite layer through a dry coating and have a diameter of 0.01 to 3 탆 And is laminated with a current collector-positive electrode composite layer-solid electrolyte layer-negative electrode composite layer-current collector.

As shown in FIGS. 1 and 2, the sulfide-based solid electrolyte powder is firstly milled with a solid electrolyte raw material to prepare a sulfide-based amorphous solid electrolyte (S1).

The amorphous solid amorphous solid electrolyte is produced through a solid electrolyte raw material composed of lithium sulfide (Li ₂ S), a sulfur compound, and a lithium compound, and is a crystalline solid or an amorphous solid electrolyte . Here, the sulfur compound means a mixture of elements selected from the group consisting of phosphorus (P), silicon (Si), germanium (Ge), aluminum (Al), boron (B) The compound means that lithium (Li) is mixed with an element selected from the group consisting of chlorine (Cl), bromine (Br), iodine (I) and a mixture thereof as a halogen group element.

The prepared lithium sulfide, sulfur compound and lithium compound are added to the first milling part together with the solvent and uniformly mixed through an attrition mill or a ball mill to prepare a sulfide amorphous solid electrolyte. In the case of a ball mill, a mixing process is performed using a zirconia ball having a particle size of 1 to 10 mm. The primary milling is performed for 5 to 40 hours to obtain a sulfide-based amorphous solid electrolyte having an average particle size of 3 to 10 mu m.

The preferred sulfide amorphous solid electrolyte is preferably a solid electrolyte having a composition of LPSX (Li _x P _y S _z X, X = Cl, Br, I, for example Li ₇ P ₂ S ₈ I, Li ₆ PS ₅ Cl) But is not limited thereto. There arises a problem that the grain size becomes large during the crystallization process in which the sulfide-based solid electrolyte is made into crystalline or crystalline free of amorphous substance through the first milling, drying and heat treatment, so that it takes a long time to grind at the subsequent stage, It is difficult to obtain particles having a small particle size, and in particular, there is a problem in that the crystallinity is destroyed in the pulverization process and the ion conductivity is lowered. On the other hand, since the amorphous amorphous solid electrolyte has a lower strength than crystalline or free crystalline, it has a merit that the time for pulverization is shortened.

The amorphous sulfide amorphous solid electrolyte is pulverized by secondary milling to form an amorphous solid electrolyte powder (S2).

The sulfide amorphous solid electrolytic electrolyte mixed in step S1 is subjected to secondary milling through an induction mill or a ball mill and the secondary milling is performed to reduce the grain size of the amorphous sulfide amorphous solid electrolyte. Here, when the step is performed through the ball mill, milling is performed using a zirconia ball of 0.1 to 1 mm which is smaller than the step of S1. At this time, the amorphous solid electrolyte powder is an ultrafine amorphous solid electrolyte powder having a diameter of 0.01 to 3 탆.

This secondary milling is performed not by performing secondary milling again after recovering the sulfide amorphous solid electrolyte formed from the primary milling but by performing the first and second milling operations by one operation of the apparatus using the continuous apparatus do. That is, instead of collecting the first milled amorphous sulfide amorphous solid electrolyte and then injecting it into another device, the first milled amorphous solid amorphous solid electrolyte is subjected to secondary milling .

In the first milling part, the first milled amorphous amorphous solid electrolyte and the solvent are put into the second milling part as it is, and then the second milling is performed immediately after the solvent and the dispersing agent are further injected. If the primary milling and the secondary milling are performed using the continuous apparatus as described above, it is not necessary to add the solvent for the secondary milling after obtaining the sulfide amorphous solid electrolyte with the solvent removed after the primary milling, The amorphous solid electrolyte can be removed from the device, dried, and then the amorphous solid electrolyte can be introduced into the device again.

The amorphous solid electrolyte powder is dried and heat-treated to obtain a crystalline or free crystalline solid electrolyte powder (S3).

After the solvent present in the ultrafine amorphous solid electrolyte powder solution, which has been completed to the second milling, is removed by drying, the amorphous solid electrolyte powder is crystallized into crystalline or free crystalline by heating the amorphous solid electrolyte powder to produce ultrafine crystalline or free crystalline solid electrolyte powder . When the temperature is lower than 140 ° C., the solid electrolyte is not crystallized properly. If the temperature exceeds 200 ° C., a separate equipment for heat treatment at a higher temperature is required. There is a drawback that it increases. In some cases, drying and heat treatment may be carried out simultaneously at 140 to 200 캜.

As described above, a crystalline or crystalline free-crystalline solid electrolyte having an ultrafine diameter of 0.01 to 3 탆 can be obtained by a continuous apparatus through steps S1 to S3 without an operator having to perform a separate work process.

It is generally known that when the binder is mixed, the ion conductivity of the solid electrolyte layer and the electrode composite layer is greatly lowered. To solve this problem, the solid electrolyte layer and the electrode composite layer are manufactured through the following steps to prevent the ion conductivity of the solid electrolyte layer and the electrode composite layer from being lowered.

As shown in FIG. 3, the binder is mixed with the amorphous solid electrolyte powder solution without performing step S3 after steps S1 to S2, followed by drying and heat treatment to form a powder-binder complex (S4).

A binder is mixed with a solvent in which an amorphous solid electrolyte powder having an ultrafine size is dispersed, and the mixture is dried and heat-treated to form a powder-binder complex. The formed powder-binder is formed around the ultra-fine amorphous solid electrolyte powder such that the binder surrounds the amorphous solid electrolyte powder. The amorphous solid electrolyte powder and the binder are uniformly dispersed, and the binder is dispersed in an ultra- Lt; / RTI >

At this time, it is preferable to mix the amorphous solid electrolyte powder: binder = 80 to 99: 1 to 20 by weight. When the amount of the powder increases in the weight ratio, the amount of the binder is decreased to form a solid electrolyte layer, And when the amount of the binder increases, the ionic conductivity may not be sufficiently exhibited due to an increase in the amorphous solid electrolyte-binder interface which interferes with ion conduction.

In the case of the powder-binder complex constituting the solid electrolyte layer, in the case of the powder-binder complex comprising the amorphous solid electrolyte powder and the binder and forming the electrode composite layer, the cathode active material or the anode active material, the amorphous solid electrolyte powder And a conductive material may be added to the binder. Here, the cathode active material or the anode active material may be an active material used in a conventional secondary battery, or may be any surface-treated active material to reduce chemical reactivity with a sulfide-based solid electrolyte.

The binder may be a polyamide-imide (PAI), a polyimide (PI), a polyamide (PA), a polyamic acid, a polyethylene oxide (PEO) polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), nitrile-butadiene rubber (NBR) , Butadiene rubber (PS-NBR), poly (methacrylate) nitrile-butadiene rubber (PMMA-NBR), and mixtures thereof. carbon black, carbon nanotube, carbon fiber, graphene, graphite, carbon black, acetylene black, ketjen black, KR), super P, metal nanowires, and mixtures thereof. The.

The powder-binder complex is solvated or low-solvent coated to form a solid electrolyte layer and an electrode composite layer (S5).

The powder-binder complex for the electrode composite layer is coated on the upper part of the current collector by using a solventless or low-solvent coating, that is, a solvent is not used or a solvent is used in an amount of 5% by weight or less, To form an electrode composite layer having a high structural density, and a solid-electrolyte layer having a high structural integrity is formed by coating and bonding a powder-binder complex for a solid electrolyte layer on the upper part of the electrode composite layer with no solvent or low solvent. At this time, it is preferable to carry out the heat treatment at the same time as the pressing so as to induce the bonding of the binder together with the densification and crystallization of the amorphous solid electrolyte. The heat treatment temperature is preferably 140 to 200 ° C. If the temperature is lower than 140 ° C., the solid electrolyte layer and the electrode composite layer having a high ionic conductivity can not be formed. If the temperature is higher than 200 ° C., the binder may be decomposed or deteriorated have.

In some cases, wet coating using a powder-binder slurry, which is not solvent-free or low-solvent coating, may be performed, but when performing wet coating using a powder-binder slurry containing a large amount of solvent in an amount exceeding 5 wt% Since the solvent evaporates during the process, pores are formed in the place where the solvent is present. Therefore, it is difficult to obtain a solid electrolyte layer and an electrode composite layer having high structural densities due to pores. Therefore, in the present invention, it is more preferable to form a solid electrolyte layer and an electrode composite layer using a solventless or low-solvent coating. As a low-solvent coating, an extrusion-type printing process can be applied.

Hereinafter, embodiments of the present invention will be described in more detail.

≪ Example 1 >

First, Li ₂ S, P ₂ S ₅ , a sulfur compound, and LiI powder, a lithium compound, were mixed in a molar ratio of Li ₂ S: P ₂ S ₅ : LiI = 3: 1: 1 for synthesis of a LPSI- And 8 g of heptane as a solvent were placed in a ball mill reaction vessel and subjected to a first wet mechanical milling at 500 rpm together with 53 g of zirconia balls of 5 mm to disperse the amorphous solid electrolyte powder through a homogenization process To obtain a heptane solution. At this time, in order to prevent the excessive rise of the temperature of the reaction vessel, the operation is repeated for 30 to 30 minutes and then the operation is repeated for 5 to 80 times.

The heptane solution in which the amorphous solid electrolyte powder was dispersed was extracted and put back into a reaction vessel filled with 40 g of zirconia balls having a diameter of 1 mm. Then, 1 g of butyl ether was added as a low boiling point dispersing agent, Secondary wet mechanical milling was performed. At this time, in order to prevent the excessive rise of the temperature of the reaction vessel, the operation is repeated for 30 to 30 minutes and then the operation is repeated for 5 to 80 times.

Fig. 4 shows the shape of the LPSI-based powder observed by a scanning microscope after primary milling through Example 1, and Fig. 5 is an SEM photograph showing the shape of the LPSI-based powder after the secondary milling. The particle size analyzer (PSA) analysis of FIG. 6 shows that the average grain size after the first mechanical milling was about 5.2 μm and the average grain size after the second mechanical milling was about 2.7 μm. These particle sizes can be controlled by adjusting the size and operating time of the zirconia balls used.

Fig. 7 is a graph showing the results of measurement of the crystallinity of the disc-shaped pellets obtained by applying 0.13 g of the crystalline powder obtained by heat-treating the primary and secondary wet mechanical-milled amorphous solid electrolyte powders at 160 캜 into a mold having a diameter of 14 mm, Fig. 5 shows the results of AC impedance measurement of a symmetric cell with electrodes as electrodes. The resistance of the cell is manifested by a combination of various resistance elements, in particular, intrinsic resistance of the solid electrolyte, interfacial resistance between the solid electrolyte powder, and electrode-solid electrolyte particle resistance.

In the case of the LPSI free crystalline solid electrolyte, the smaller the particle size, the lower the ionic conductivity of the crystalline phase, the better the ionic conductivity, and the lower the interfacial interface resistance and the electrode - electrolyte interface resistance, the better the ion conductivity of the cell. In FIG. 7, the ionic conductivity can be obtained by taking the reciprocal of the value of the intersection of the X-axis and the graph. In Example 1, the ionic conductivity after the first wet mechanical milling is 4.0 × 10 ^-4 S / cm, After milling, it was improved to 9.4 × 10 ^-4 S / cm.

≪ Example 2 >

First, Li ₂ S, P ₂ S _{5 as a} sulfur compound, and LiI powder as a lithium compound were mixed in a molar ratio of Li ₂ S: P ₂ S ₅ : LiI = 3: 1: 1 2 g of the precursor and 8 g of heptane as a solvent were put in a ball mill reaction vessel and subjected to a first wet mechanical milling with a 5 mm zirconia ball (53 g) at 500 rpm, followed by a homogenization process A heptane solution in which the amorphous solid electrolyte powder is dispersed is obtained. At this time, in order to prevent the excessive rise of the temperature of the reaction vessel, the operation is repeated for 30 to 30 minutes and then the operation is repeated for 5 to 80 times.

The heptane solution in which the amorphous solid electrolyte powder was dispersed was extracted and put back into a reaction vessel filled with 40 g of zirconia balls having a diameter of 1 mm. Then, 1 g of butyl ether was added as a low boiling point dispersing agent, Secondary wet mechanical milling was performed. At this time, in order to prevent the excessive rise of the temperature of the reaction vessel, the operation is repeated for 30 to 30 minutes and then the operation is repeated for 5 to 80 times.

(PEP-MNB) (poly-ethylene-co-propylene-co-5-methylene-2-norbornene) was added to the secondary milling solution so that the ratio of the solid electrolyte and the binder was solid electrolyte: binder = 80 to 99: ) Were mixed to prepare a composite of ultrafine glassy powder and binder, and then a solid electrolyte layer was prepared by a dry coating method and heat-treated at 160 ° C.

FIG. 8 is a graph showing the results of analysis of the symmetric cell resistance of the dry-coated solid electrolyte layer and the solid electrolyte layer prepared by wet slurry coating of the powder prepared by the primary ball mill in Example 1. FIG. Here, the slurry coating was a solid electrolyte layer obtained by coating and drying a slurry obtained by redispersing the powder prepared in Example 1 in heptane in which the binder was dissolved, and the weight ratio of the solid electrolyte powder and the binder was the same as in Example 2 Respectively. The dry-coated solid electrolyte layer exhibits an ion conductivity of 4.7 × 10 ^-4 S / cm, which is 10 times higher than that of the wet-coated solid electrolyte of 3.6 × 10 ^-5 S / cm. This is because, in the case of the wet-coated solid electrolyte layer, the resistance increases due to the particles of the binder and the electrode surface coating, and the inter-particle interface resistance caused by the volatilized porous structure of the solvent greatly increases the resistance. FIG. 9 shows that the intergranular interface appears prominently on the surface image of the wet-coated solid electrolyte layer before and after the compression. On the other hand, the solid electrolyte layer of FIG. 10 manufactured by the method of the second embodiment shows almost no interface between particles after the compression, and the ion conductivity is improved.

In the case of the present invention, the amorphous solid electrolyte is pulverized and pulverized by several pulverizing processes to form sulfides of fine powders of several nm or several micrometers in size Can be obtained. Thus, the size of the sulfide can be reduced and the voids between the sulfides can be reduced. In addition, in the case of the present invention, the solvent removal step is minimized through solvent-free solventless coating or a low-solvent coating using 5 wt% or less of solvent, so that the interface is almost eliminated after compression and the solid electrolyte layer and the electrode composite layer An effect of improving the ionic conductivity can be obtained.

Claims (11)

In the method for producing a sulfide-based solid electrolyte powder,
A process for producing a sulfide-based amorphous solid electrolyte, comprising: preparing a sulfide-based amorphous solid electrolyte by first milling an amorphous solid electrolyte raw material composed of lithium sulfide (Li ₂ S), a sulfur compound, and a lithium compound;
Forming an amorphous solid electrolyte powder by pulverizing the sulfide-based amorphous solid electrolyte through secondary milling;
And drying and heat-treating the amorphous solid electrolyte powder to obtain a crystalline or free crystalline solid electrolyte powder. The method according to claim 1,
The above-described sulfide-based solid electrolyte powder is produced by using a continuous milling apparatus including a primary milling unit and a secondary milling unit,
Wherein the sulfide-based solid electrolyte and the solvent, which have been subjected to the primary milling in the primary milling unit, are directly introduced into the secondary milling unit, and the secondary milling is performed immediately after the solvent and the dispersing agent are further injected. Based solid electrolyte powder. The method according to claim 1,
The primary milling is performed by milling zirconia balls having a particle size of 1 to 10 mm for 5 to 40 hours to obtain a sulfide-based amorphous solid electrolyte having an average particle size of 3 to 10 μm,
Wherein the secondary milling is performed by milling a sulfide-based amorphous solid electrolyte using zirconia balls having a grain size of 0.1 to 1 mm to obtain an ultrafine amorphous solid electrolyte powder having an average grain size of 0.01 to 3 占 퐉 A method for producing an electrolytic powder. The method according to claim 1,
The sulfur compound is a mixture of elements selected from the group consisting of phosphorus (P), silicon (Si), germanium (Ge), aluminum (Al), boron (B)
The method for producing a sulfide-based solid electrolyte powder according to claim 1, wherein the lithium compound is a mixture of lithium (Li) and an element selected from the group consisting of chlorine (Cl), bromine (Br), iodine (I) . A solid electrolyte layer comprising a solid electrolyte powder, and a method for producing an electrode composite layer,
A process for producing a sulfide-based amorphous solid electrolyte, comprising: preparing a sulfide-based amorphous solid electrolyte by first milling an amorphous solid electrolyte raw material composed of lithium sulfide (Li ₂ S), a sulfur compound, and a lithium compound;
Forming an amorphous solid electrolyte powder by pulverizing the sulfide-based amorphous solid electrolyte through secondary milling;
A method for producing a solid electrolyte layer, an electrode composite layer, and a solid electrolyte layer comprising the solid electrolyte powder, which comprises mixing a binder in the amorphous solid electrolyte powder solution, followed by drying and heat treatment to prepare a crystalline or glass crystalline powder-binder complex . A solid electrolyte layer comprising a solid electrolyte powder, and a method for producing an electrode composite layer,
A process for producing a sulfide-based amorphous solid electrolyte, comprising: preparing a sulfide-based amorphous solid electrolyte by first milling an amorphous solid electrolyte raw material composed of lithium sulfide (Li ₂ S), a sulfur compound, and a lithium compound;
Forming an amorphous solid electrolyte powder by pulverizing the sulfide-based amorphous solid electrolyte through secondary milling;
Mixing the amorphous solid electrolyte powder solution with a binder, followed by drying and heat treatment to produce a crystalline or glassy crystalline powder-binder complex;
Wherein the powder-binder composite is applied to a collector by solvent-free solventless coating or a low-solvent coating using 50 wt% or less of solvent to form a solid electrolyte layer or an electrode composite layer A solid electrolyte layer comprising the solid electrolyte powder, and a method for producing the electrode composite layer. The method according to any one of claims 5 and 6,
The powder-binder composite may comprise
In the case of a powder-binder complex for a solid electrolyte layer, the crystalline or free crystalline solid electrolyte powder and the binder,
Wherein the solid electrolyte layer comprises a solid electrolyte powder comprising a positive electrode active material or a negative electrode active material, a crystalline or crystalline solid electrolyte powder, a binder and a conductive material in the case of a powder-binder complex for an electrode composite layer, Way. 8. The method of claim 7,
Wherein the step of forming the solid electrolyte layer and the electrode composite layer comprises:
Binder composite for a electrode composite layer is coated with a solvent-free solvent or a low-solvent using a solvent in an amount of 5% by weight or less and then pressed to form an electrode composite layer having a high structural integrity, Wherein the solid electrolyte layer having a high structural integrity is formed by dry-coating and pressing a powder-binder complex for a solid electrolyte layer on the upper surface of the electrode composite layer. The method according to any one of claims 5 and 6,
Wherein the powdery-binder complex is mixed with a crystalline or crystalline solid crystalline solid electrolyte powder and binder in a weight ratio of 80: 99: 1 to 20: 1. The method according to any one of claims 5 and 6,
Wherein the step of forming the solid electrolyte layer or the electrode composite layer comprises:
Wherein the heat treatment is carried out simultaneously at 140 to 200 캜. In all solid state batteries,
The whole house;
A negative electrode composite layer formed on the current collector through a dry coating and comprising an ultrafine sulfide-based crystalline material having a diameter of 0.01 to 3 탆 or a crystalline solid electrolyte powder, a binder, a conductive material, and an active material, A composite layer;
And a solid electrolyte layer laminated on the upper surface of the electrode composite layer through a solventless or low solvent coating and comprising a 0.01 to 3 탆 diameter ultrafine sulfide crystalline or crystalline solid electrolyte powder and a binder,
Wherein the current collector, the positive electrode composite layer, the solid electrolyte layer, the negative electrode composite layer, or the lithium metal and the current collector are laminated.

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