Secondary battery comprising positive electrode plate and non-aqueous electrolyte solution

A secondary battery, comprising a positive electrode plate and a non-aqueous electrolyte solution, wherein

• the positive electrode plate comprises a positive electrode active material, the positive electrode active material comprises an inner core and a shell cladding the inner core, and
• the inner core comprises Li1+xMn1−yAyP1−zRzO4, wherein x=−0.100-0.100, y=0.001-0.500, z=0.001-0.100, A is selected from one or more elements in a group consisting of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb and Ge, and optionally one or more elements in a group consisting of Fe, Ti, V, Ni, Co and Mg, and R is selected from one or more elements in a group consisting of B, Si, N and S;
• the shell comprises a first cladding layer cladding the inner core, and a second cladding layer cladding the first cladding layer, wherein
• the first cladding layer comprises pyrophosphate MP2O7 and phosphate XPO4, wherein M and X are each independently selected from one or more elements in a group consisting of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb and Al,
• and the second cladding layer comprises carbon;
• the non-aqueous electrolyte solution comprises a first additive, and the first additive comprises one or more compounds in a group consisting of a compound shown in Formula 1, a compound shown in Formula 2 and a compound shown in Formula 3:
• R1 and R2 each independently represent any one of F, C1-C6 fluoroalkyl, C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl and C6-C10 aryl, and at least one of R1 and R2 represents any one of F or C1-C6 fluoroalkyl;
• R3 and R4 each independently represent any one of F, C1-C6 fluoroalkyl, C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl and C2-C6 alkynyl, and at least one of R3 and R4 represents any one of F or C1-C6 fluoroalkyl;
• R5 and R6 each independently represent any one of F, C1-C6 fluoroalkyl, C1-C6 alkyl, C1-C6 alkoxy, C2-C6 alkenyl, C2-C6 alkynyl, carbonyl, O—, ═O, —−BF3 and —O—BF3;
• M in each chemical formula each independently represents one of alkali metals and alkaline-earth metals;
• and
• n is 0, 1 or 2.