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

Abstract

A secondary battery includes a positive electrode sheet having a positive electrode active material and a non-aqueous electrolyte. The positive electrode active material includes a central core material and a modification layer disposed on a surface of the central core material. The modification layer including an orthophosphate with a molecular formula Aa+x[PO4]3−y, where A denotes one or more of Li, Na, K, Rb, Cs, Mg, Ca, Ba, Ni, Fe, Co, Ti, Al, Cr, V, Nb, and W, 1≤a≤6, and ax=3y. The non-aqueous electrolyte includes a fluorinated phosphate with a molecular formula Bb+m[PO1+cF3-c]c−n, where B denotes one or more of Li, Na, K, Rb, Cs, Mg, Ca, and Ba, 1≤b≤2, c denotes 1 or 2, and bm=cn.

Dependencies are inferred from the claim text.