Cathode active material for all-solid-state battery comprising coating layer including ternary oxide and method of manufacturing same

A method of manufacturing a cathode active material for an all-solid-state battery, the method comprising:

• preparing a mixture comprising an active-material particle precursor, a lithium (Li) precursor, a niobium (Nb) precursor, and at least one element selected from the group consisting of a vanadium (V) precursor, a zirconium (Zr) precursor and combinations thereof;
• stirring the mixture;
• and
• calcining the mixture after the stirring,
• wherein the cathode active material comprises active material particles and a coating layer covering at least a portion of a surface of the active material particles and comprising lithium (Li), niobium (Nb), and at least one element selected from a group consisting of vanadium (V), zirconium (Zr) and combinations thereof.