| CPC H01M 4/364 (2013.01) [H01M 4/131 (2013.01); H01M 4/133 (2013.01); H01M 4/136 (2013.01); H01M 4/366 (2013.01); H01M 4/525 (2013.01); H01M 4/582 (2013.01); H01M 4/5825 (2013.01); H01M 4/587 (2013.01); H01M 2004/021 (2013.01); H01M 2004/028 (2013.01)] | 14 Claims | 

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               1. A positive electrode active material composition comprising a first positive electrode active material and a second positive electrode active material, wherein 
            the first positive electrode active material comprises a core and a coating layer covering the core; the coating layer comprises one or more of pyrophosphate, phosphate, and carbon; and the core comprises a compound LiaAbMnfB1-fP1-dRdO4-nDn, wherein 
                A comprises one or more elements of Zn, Al, Na, K, Mg, Nb, Mo, and W; 
                B comprises one or more elements of Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge; 
                R comprises one or more elements of B (boron), S, Si, and N; 
                D comprises one or more elements of S, F, Cl, and Br; 
                a is 0.9 to 1.1; b is 0 to 0.1; f is 0.1 to 0.999; d is 0 to 0.11; and n is 0 to 0.1; 
                the second positive electrode active material comprises a compound LiNixCoyM1-x-yO2, wherein M comprises one or more elements of Al, Mn, Mg, Nb, Ti, and Ba; 0.5≤x≤0.69; and 0<y<0.31; 
                and 
                0.018m+0.003f≤z≤0.02m+0.02f is satisfied, 
                wherein 
                m represents a mass percentage of the first positive electrode active material in the positive electrode active material composition; and 
                z represents a ratio of a coating layer thickness to a particle size Dv50 of the first positive electrode active material. 
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