Method for preparing solid electrolyte and all solid state battery including the same
A method for preparing a solid electrolyte for an all-solid state battery, may include obtaining a slurry by dispersing a first raw material comprising lithium sulfide; and a second raw material selected from the group consisting of silicon sulfide, phosphorus sulfide, germanium sulfide, boron sulfide, and a combination thereof in a solvent; and drying the slurry.
1. A method for preparing a positive electrode for an all-solid state battery, the method comprising:
obtaining a slurry by dispersing a first raw material including lithium sulfide and a second raw material selected from the group consisting of silicon sulfide, phosphorus sulfide, germanium sulfide, boron sulfide, and a combination thereof in a solvent selected from the group consisting of methyl propionate, ethyl propionate, propyl propionate, and a combination thereof;
adding a positive electrode active material to the slurry and mixing the resulting mixture;
obtaining a composite powder comprising a solid electrolyte and a positive electrode active material by drying the slurry;
forming the positive electrode by hot-pressing the composite powder, and
wherein the positive electrode active material is mixed and dried along with the first raw material and the second raw material by a one-pot process.
2. The method of claim 1 , wherein one selected from the group consisting of a conductive material, a binder, and a combination thereof is further added to the slurry and the mixture is mixed.
3. The method of claim 1 , wherein the method does not comprise milling the first raw material, the second raw material, and the positive electrode active material.
4. The method of claim 1 , wherein the positive electrode active material is selected from the group consisting of a lithium metal oxide having a layered structure, a lithium metal oxide having a spinel structure, a lithium metal phosphorus oxide having an olivine structure, and a combination thereof.
5. The method of claim 1 , wherein the drying is carried out at a temperature of about 100° C. to about 200° C. under a vacuum or inert gas atmosphere.
6. The method of claim 2 , wherein the composite powder comprises a positive electrode active material, a solid electrolyte, and a conductive material at a mass ratio of 65 to 80:10 to 25:10 to 20.
7. The method of claim 1 , wherein the hot-pressing is carried out at a temperature of about 100° C. to about 200° C. for about 5 minutes to about 60 minutes.
8. The method of claim 1 , wherein the hot-pressing is carried out under a pressure of about 1 ton to about 10 tons.
9. A method for preparing a positive electrode-electrolyte layer composite for an all-solid state battery, the method comprising:
applying the composite powder of claim 1 in a mold;
applying an electrolyte powder onto the composite powder; and
hot-pressing the composite powder and the electrolyte powder.
10. The method of claim 9 , wherein the electrolyte powder is selected from the group consisting of an oxide-based solid electrolyte powder, a sulfide-based solid electrolyte powder, and a combination thereof.