All solid state battery and producing method therefor

An all solid state battery comprising a cathode active material layer containing a cathode active material, an anode active material layer containing an anode active material, and a solid electrolyte layer formed between the cathode active material layer and the anode active material layer,

• wherein at least one of the cathode active material layer and the solid electrolyte layer contains a sulfide solid electrolyte material;
• a reaction inhibition portion containing a first lithium ion conductor and a second lithium ion conductor is formed on a surface of the cathode active material;
• the first lithium ion conductor is LiNbO3;
• and
• the second lithium ion conductor is an Li-containing compound provided with a polyanion structural portion having at least one of Ti and Zr.

A method for producing the all solid state battery, the all solid state battery comprises a cathode active material layer containing a cathode active material, an anode active material layer containing an anode active material, and a solid electrolyte layer formed between the cathode active material layer and the anode active material layer, in which at least one of the cathode active material layer and the solid electrolyte layer contains a sulfide solid electrolyte material;

• a reaction inhibition portion containing a first lithium ion conductor and a second lithium ion conductor is formed on a surface of the cathode active material;
• the first lithium ion conductor is LiNbO3;
• and the second lithium ion conductor is an Li-containing compound provided with a polyanion structural portion having at least one of B, Si, P, Ti, Zr, Al, and W;
• wherein the method comprises steps of:
• an inside layer forming step of forming an inside layer by coating and drying one coating liquid of a first precursor coating liquid containing a raw material for the first lithium ion conductor and a second precursor coating liquid containing a raw material for the second lithium ion conductor on the surface of the cathode active material;
• an outside layer forming step of forming an outside layer by coating and drying the other coating liquid of the first precursor coating liquid and the second precursor coating liquid on a surface of the inside layer;
• and
• a heat-treating step of heat-treating the inside layer and the outside layer to form the reaction inhibition portion.