Lithium niobate and method for producing the same

A method for producing an all-solid-state battery,

• the method comprising:
• preparing a solution containing niobium ions and lithium ions,
• drying the solution to obtain a lithium niobate precursor, and
• obtaining a lithium niobate by heating the lithium niobate precursor at a temperature of from 250° C. to 300° C. for a heating time of more than 0 minute and 10 minutes or less, and
• wherein an A/B ratio value of the lithium niobate between a first peak intensity value A at a diffraction angle (2θ) of 23.7°±0.5° and a second peak intensity value B at a diffraction angle (2θ) of 53.2°±0.5°, is 1.96 or more and 2.54 or less, and the peak intensities are observed by X-ray diffraction (XRD) measurement using CuKα radiation;
• wherein the all-solid-state battery comprises a cathode comprising a cathode layer, an anode comprising an anode layer, and a solid electrolyte layer disposed between the cathode layer and the anode layer;
• wherein the cathode layer contains composite active material particles;
• wherein the composite active material particles are composed of cathode active material particles and a covering layer;
• wherein the covering layer contains the lithium niobate and covering at least part of the surface of the cathode active material particles;
• wherein the solid electrolyte layer contains a sulfide-based solid electrolyte;
• and
• wherein the sulfide-based solid electrolyte contains 10LiI-15LiBr-37.5Li3PS4 as a raw material composition.