The application relates to the field of energy storage materials and specifically relates to a secondary battery. The secondary battery comprises a cathode pole piece, an anode pole piece, an isolating membrane and an electrolyte, wherein the cathode pole piece contains a high nickel material; the electrolyte comprises electrolyte salt and an organic solvent; the organic solvent contains organic amine and ether. The gas yield of a battery core can be obviously reduced by the electrolyte, so that the storage capacity of the secondary battery under high temperature and high pressure is improved.