US Patent 9219274 Secondary battery

A secondary battery having high capacity and satisfactory high-temperature cycle characteristics is provided. A secondary battery according to the exemplary embodiment has an electrode element in which a positive electrode and a negative electrode are arranged so as to face each other, an electrolytic solution and an outer package packaging the electrode element and the electrolytic solution, wherein the negative electrode is formed by binding a negative electrode active material containing at least one of a metal (a) capable of forming an alloy with lithium and a metal oxide (b) capable of absorbing and releasing lithium ions, to a negative electrode collector, with a polyimide or a polyamide-imide serving as a negative electrode binder; and the electrolytic solution contains a phosphazene compound.