SECONDARY BATTERY AND PREPARATION METHOD THEREFOR

Provided is a secondary battery, comprising a positive electrode, an electrolytic solution, a negative electrode and a diaphragm, wherein the positive electrode comprises a positive electrode current collector, and a positive electrode active material layer arranged on the positive electrode current collector; the positive electrode active material layer comprises a positive electrode active material, and the positive electrode active material comprises a material into which potassium salt anions can be embedded; the electrolytic solution comprises potassium salt and a non-aqueous solvent; and the negative electrode comprises a metal foil, and the metal foil serves as a negative electrode current collector and a negative electrode active material at the same time. An electrolytic solution of the secondary battery takes potassium salt as an electrolyte, thereby solving the problem of limited lithium resource reserves in lithium secondary batteries commonly used at present, reducing the cost of the secondary ba