High voltage positive electrode active material including lithium manganese-based oxide and method for producing the same

A positive electrode active material comprising:

• lithium-rich lithium manganese-based oxide, in a form of a particle, and
• a lithium ion conductive glass-ceramic solid electrolyte layer formed on a surface of the particle,
• wherein the lithium manganese-based oxide has a composition of the following chemical formula (1),
• Li1−xMyMn1−x−yO2−zQz (1)
• wherein, 0<x≤0.2, 0<y≤0.2, and 0≤z≤0.5;
• M is at least one element selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Ga, In, Ru, Zn, Zr, Nb, Sn, Mo, Sr, Sb, W, Ti and Bi;
• and
• Q is at least one element selected from the group consisting of P, N, F, S and Cl, and
• wherein the lithium ion conductive glass-ceramic solid electrolyte layer comprises thio-LISICON(thio-lithium super ionic conductor), or
• the thio-LISICON and at least one of LISICON(lithium super ionic conductor), Li2S—SiS2—Li4SiO4, or Li2S—SiS2—P2S5—Lil, and
• wherein the thio-LISICON is a material represented by Li1+x+y(Al, Ga)x(Ti, Ge)2−xSiyP3−yS12, wherein, 0≤x≤1, and 0≤y≤1, and the LISICON is a material represented by Li1+x+y(Al, Ga)x(Ti, Ge)2−xSiyP3−yO12, wherein, 0≤x≤1, and 0≤y≤1.