珪素酸化物粒子及びその製造方法、ならびにリチウムイオン二次電池及び電気化学キャパシタ

摘要

Silicon oxide particles each comprising an inner portion having an iron content of 10-1,000 ppm and an outer portion having an iron content of up to 30 ppm are suitable as negative electrode active material in nonaqueous electrolyte secondary batteries. Using a negative electrode comprising the silicon oxide particles as active material, a lithium ion secondary battery or electrochemical capacitor having a high capacity and improved cycle performance can be constructed.