POSITIVE ACTIVE MATERIAL FOR ALL SOLID SECONDARY BATTERY, AND ALL SOLID SECONDARY BATTERY INCLUDING THE SAME

A positive active material for an all-solid secondary battery, an all-solid secondary battery including the same, and a method of manufacturing the positive active material for an all-solid secondary battery, the positive active material including a secondary particle including a plurality of primary particles; and a buffer layer on a surface of the secondary particle; wherein the secondary particle includes a nickel lithium transition metal oxide represented by Formula 1, the buffer layer includes a copper compound represented by Formula 2, LiNiMOA LiCuX.