NEGATIVE ELECTRODE ACTIVE MATERIAL, METHOD FOR PRODUCING THE NEGATIVE ELECTRODE ACTIVE MATERIAL, AND LITHIUM ION SECONDARY BATTERY USING THE NEGATIVE ELECTRODE ACTIVE MATERIAL

摘要

Disclosed is a negative electrode active material which has a high capacity and good cycle properties. The negative electrode active material comprises nanosized carbon particles and nanosized tin dioxide particles that are carried on the nanosized carbon particles in a high-dispersion state. This negative electrode active material has a high discharge capacity because of the reversible progress of a conversion reaction of tin dioxide (SnO2+4Li++4e-?2Li2O+Sn) therein. In a charge-discharge cycle test within a voltage range of 0-2 V vs. an Li/Li+ electrode, the aforesaid negative electrode active material shows a discharge capacity retention ratio of about 90% even after repeating the charge-discharge cycles 500 times under rate 1C conditions, which indicates very good cycle properties. Thus, the aforesaid negative electrode active material can be appropriately used in a lithium ion secondary battery and a hybrid capacitor.