CPC H01M 4/366 (2013.01) [H01M 4/505 (2013.01); H01M 4/5825 (2013.01); H01M 4/587 (2013.01); H01M 4/602 (2013.01); H01M 2004/028 (2013.01); H01M 2220/20 (2013.01)] | 24 Claims |
1. A positive electrode active material having a core-shell structure, comprising a core and a shell cladding the core,
wherein the core has a chemical formula of Li1+xMn1-yAyP1-zRzO4, in which x is any value in a range of −0.100 to 0.100, y is any value in a range of 0.001 to 0.500, z is any value in the range of 0.001 to 0.100, A comprises Fe, V, and Co, and R is S;
the values of x, y, and z satisfy that an entire core is electrically neutral; and
the shell comprises a first cladding layer cladding the core, a second cladding layer cladding the first cladding layer, a third cladding layer cladding the second cladding layer and a fourth cladding layer cladding the third cladding layer,
wherein the first cladding layer comprises crystalline pyrophosphates LiaMP2O7 and/or Mb(P2O7)c, 0≤a≤2, 1≤b≤4, 1≤c≤6, in which the values of a, b and c satisfy that the crystalline pyrophosphate LiaMP2O7 or Mb(P2O7)c is electrically neutral, and in which each M in the crystalline pyrophosphates LiaMP2O7 and/or Mb(P2O7)c comprises Fe;
the second cladding layer comprises crystalline phosphate XPO4, X comprises Li and Fe;
the third cladding layer is carbon; and
the fourth cladding layer comprises a polymer comprising a polysaccharide.
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