Method of producing cathode slurry, cathode and all-solid-state battery, and cathode and all-solid-state battery

Abstract

In conventional arts, it is impossible to form a good solid-solid interface in cathode mixture layers of all-solid-state batteries, which significantly deteriorates resistance of the all-solid-state battery after the charge/discharge cycle, which is problematic. A cathode slurry is produced by a method including: a first step of dispersing a conductive additive constituted of carbon in a solvent to obtain a first slurry; a second step of dispersing a sulfide solid electrolyte in the first slurry to obtain a second slurry; and a third step of dispersing a cathode active material in the second slurry to obtain a third slurry, to be used to form a cathode mixture layer. This may suppress agglomeration of the cathode active material as using the conductive additive as a core, and may lower the proportion of agglomerate present in the cathode mixture layer. As a result, a good solid-solid interface may be formed in the cathode mixture layer of the all-solid-state battery, and the resistance increase of the all-solid-state battery after the charge/discharge cycle may be suppressed.

1 . A method of producing a cathode slurry, the method comprising:
 a first step of dispersing a conductive additive constituted of carbon in a solvent to obtain a first slurry;   a second step of dispersing a sulfide solid electrolyte in the first slurry to obtain a second slurry; and   a third step of dispersing a cathode active material in the second slurry to obtain a third slurry.   
     
     
         2 . The method according to  claim 1 , wherein the solvent contains a binder before the conductive additive is dispersed in the solvent. 
     
     
         3 . The method according to  claim 1 , wherein the cathode active material is a lithium-containing transition metal oxide. 
     
     
         4 . The method according to  claim 1 , wherein the conductive additive is at least one selected from a vapor grown carbon fiber, acetylene black, and furnace black. 
     
     
         5 . A method of producing a cathode, the method comprising:
 obtaining a cathode slurry by the method according to  claim 1 ; and   obtaining a cathode mixture layer by using the cathode slurry.   
     
     
         6 . The method according to  claim 5 , wherein
 a surface of a cathode current collector is coated with the cathode slurry to be dried, to form the cathode mixture layer over the surface of the cathode current collector.   
     
     
         7 . A method of producing an all-solid-state battery, the method comprising:
 obtaining a cathode by the method according to  claim 5 ;   obtaining an anode: and   obtaining a solid electrolyte layer.   
     
     
         8 .- 12 . (canceled)