SECONDARY BATTERY

摘要

The purpose of the present invention is to provide a high-performance secondary battery with superior flame resistance and cycle characteristics. An embodiment of the present invention is a secondary battery having electrode elements with a positive electrode and negative electrode disposed in opposition to each other, an electrolyte, and an outer package that encases the electrode elements and electrolyte. The secondary battery is characterized by this negative electrode having a negative electrode active material comprising a metal (a) that can be alloyed with lithium, a metal oxide (b) that can store and release lithium ions, and a carbon material (c) that can store and release lithium ions being bound to a negative electrode collector by a negative electrode binding agent. The secondary battery is further characterized by the electrolyte containing a supporting salt and an electrolyte medium. The electrolyte medium contains at least one phosphate ester compound selected from phosphite esters, phosphonate esters, and bisphosphonate esters.