Lithium secondary battery-use active matter

摘要

A lithium secondary battery-use active matter containing a material capable of electrochemically desorbing and inserting Li, and having a metallic iron grade in the material of less than 5 ppm; and a lithium secondary battery having this active matter. An iron grade in the material of less than 5 ppm can keep a capacity maintaining factor within a high-value range after specified cycles to improve the performance of a lithium secondary battery.