Positive electrode including first and second lithium compounds and lithium battery using same

A positive electrode having a surface on which a positive electrode active material composition including a positive electrode active material is formed, the positive electrode comprising:

• a solid solution having an open-circuit voltage less than 3 V with respect to lithium metal;
• and
• a lithium compound having an open-circuit voltage of 3 V or greater with respect to lithium metal, wherein:
• the solid solution is represented by Formula 1 below:
• xLizM1-yM′yO2-(1−x)LiaM″bMocO3, Formula 1
• M is at least one of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), and copper (Cu);
• M′ is at least one of magnesium (Mg), aluminum (Al), zinc (Zn), zirconium (Zr), gallium (Ga), and germanium (Ge);
• M″ is at least one of aluminum (Al), gallium (Ga), germanium (Ge), magnesium (Mg), niobium (Nb), zinc (Zn), cadmium (Cd), titanium (Ti), cobalt (Co), nickel (Ni), potassium (K), sodium (Na), calcium (Ca), silicon (Si), iron (Fe), copper (Cu), tin (Sn), vanadium (V), boron (B), phosphorus (P), selenium (Se), bismuth (Bi), arsenic (As), zirconium (Zr), manganese (Mn), chromium (Cr), strontium (Sr), vanadium (V), scandium (Sc), yttrium (Y), and a rare-earth element;
• x, y and z satisfy 0<x<0.5, 0≦y<0.5, and 0.7<z<1.3 respectively;
• and
• a, b and c satisfy 0.1≦a≦2.3, 0≦b≦0.3, and 0.7≦c≦1.1, respectively, wherein the LizM1-yM′yO2 of the solid solution represented by Formula 1 is different from the lithium compound, and wherein the solid solution and the lithium compound form a mixture, the mixture including about 1 to about 40 weight percent of the solid solution and about 60 to about 99 weight percent of the lithium compound, based on a total weight of the solid solution and the lithium compound in the mixture.