Secondary battery, and battery module, battery pack, and electrical device comprising the same

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

• the positive electrode plate comprises a positive electrode active material having a core-shell structure, said positive electrode active material comprising a core and a shell covering the core,
• said core has a chemical formula of Li1+xMn1-yAyP1-zRzO4, in which
• x is any value in the range of from −0.100 to 0.100,
• y is any value in the range of from 0.001 to 0.500,
• z is any value in the range of from 0.001 to 0.100,
• A is one or more element(s) selected from the group consisting of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge, and optionally is one or more element(s) selected from the group consisting of Fe, Ti, V, Ni, Co, and Mg,
• R is one or more element(s) selected from the group consisting of B, Si, N, and S, and optionally is one or more element(s) selected from the group consisting of B, Si, N and S, and
• x, y and z satisfy the condition that the core as a whole is electrically neutral;
• said shell comprises a first coating layer covering said core, a second coating layer covering said first coating layer, and a third coating layer covering said second coating layer, wherein
• said first coating layer comprises a crystalline pyrophosphate LiaMP2O7 and/or Mb(P2O7)c, in which
• 0≤a≤2, 1≤b≤4, 1≤c≤6, and a, b and c satisfy the condition that the crystalline pyrophosphate LiaMP2O7 or Mb(P2O7)c is electrically neutral,
• M, at each occurrence in said crystalline pyrophosphate LiaMP2O7 and Mb(P2O7)c, each independently is one or more element(s) selected from the group consisting of Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb and Al,
• said second coating layer comprises crystalline phosphate XPO4, in which X is one or more element(s) selected from the group consisting of Li, Fe, Ni, Mg, Co, Cu, Zn, Ti, Ag, Zr, Nb and Al;
• and
• said third coating layer is carbon;
• and
• said non-aqueous electrolytic solution comprises a first additive including one or more of the compounds shown in formulae 1-A to 1-D,
• in which
• R1 represents a hydrogen atom or at least one selected from the group consisting of hydroxyl, C1-C18 monovalent alkyl, C1-C18 monovalent alkoxy, C2-C18 monovalent alkoxy alkyl, C3-C18 monovalent cycloalkyl, C2-C18 monovalent heterocyclic alkyl, C6-C18 monovalent aryl, C7-C18 monovalent aryl alkyl, C7-C18 monovalent alkylaryl, C6-C18 monovalent aryloxy, C7-C18 monovalent aryloxy alkyl, C12-C18 monovalent aryl ether group, C2-C18 monovalent heteroaryl, C3-C18 monovalent heteroaryl alkyl, C3-C18 monovalent alkyl heteroaryl, and C1-C18 monovalent silyl;
• R2 to R21 each independently represent a hydrogen atom or at least one selected from the group consisting of C1-C18 monovalent alkyl, C2-C18 monovalent alkoxyalkyl, C3-C18 monovalent cycloalkyl, C2-C18 monovalent oxocycloalkyl, C6-C18 monovalent aryl, C7-C18 monovalent aryl alkyl, C7-C18 monovalent alkylaryl, C7-C18 monovalent aryloxyalkyl, C12-C18 monovalent aryl ether group, C2-C18 monovalent heteroaryl, C3-C18 monovalent heteroaryl alkyl, C3-C18 monovalent alkyl heteroaryl, and C1-C18 monovalent silyl, and when R2 and R3 both are hydrogen atoms, R1 is not hydroxyl;
• optionally, R2 and R3 can further bond with each other to form a ring structure, R4 and R5 can further bond with each other to form a ring structure, R6 and R7 can further bond with each other to form a ring structure, R8 and R9 can further bond with each other to form a ring structure, R10 and R11 can further bond with each other to form a ring structure, R12 and R13 can further bond with each other to form a ring structure, R14 and R15 can further bond with each other to form a ring structure, R16 and R17 can further bond with each other to form a ring structure, R18 and Rig can further bond with each other to form a ring structure, and R20 and R21 can further bond with each other to form a ring structure;
• L1 represents an oxygen atom or at least one selected from the group consisting of C1-C18 divalent alkyl, C1-C18 oxodialkyl, C6-C18 divalent cycloalkyl, C6-C18 divalent oxo cycloalkyl, C6-C18 divalent aryl, C7-C18 divalent arylalkyl, C7-C18 divalent alkyl aryl, C6-C18 divalent aryloxy, C7-C18 divalent aryloxyalkyl, C12-C18 divalent aryl ether group, C2-C18 divalent heteroaryl, C3-C18 divalent heteroaryl alkyl, and C3-C18 divalent alkyl heteroaryl;
• L2 represents at least one selected from the group consisting of C1-C18 trivalent alkyl, C1-C18 oxo trivalent alkyl, C6-C18 trivalent cycloalkyl, C6-C18 trivalent oxocycloalkyl, C6-C18 trivalent aryl, C7-C18 trivalent arylalkyl, C7-C18 trivalent alkylaryl, C6-C18 trivalent aryloxy, C7-C18 trivalent aryloxyalkyl, C12-C18 trivalent aryl ether group, C3-C18 trivalent heteroaryl, C3-C18 trivalent heteroaryl alkyl, and C3-C18 trivalent alkyl heteroaryl;
• and
• L3 represents at least one selected from the group consisting of C1-C18 tetravalent alkyl, C1-C18 oxo tetravalent alkyl, C6-C18 tetravalent cycloalkyl, C6-C18 tetravalent oxo cycloalkyl, C6-C18 tetravalent aryl, C7-C18 tetravalent arylalkyl, C7-C18 tetravalent alkylaryl, C7-C18 tetravalent aryloxyalkyl, C12-C18 tetravalent aryl ether group, C4-C18 tetravalent heteroaryl, C4-C18 tetravalent heteroaryl, and C4-C18 tetravalent alkyl heteroaryl.