Preparation and characterization of SnO 2-Li 4Ti 5O 12 composite by sol-gel technique

Abstract

SnO 2-Li 4Ti 5O 12 was prepared by sol-gel method using tin tetrachloride, lithium acetate, tetrabutylorthotitanate and aqueous ammonia as starting materials. The composite was characterized by thermogravimertric (TG) analysis and differential thermal analysis (DTA), X-ray diffractometry (XRD) and transmission electron microscopy (TEM) combined with electrochemical tests. The results show that SnO 2-Li 4Ti 5O 12 composite derived by sol-gel technique is a nanocomposite with core-shell structure, and the amorphous Li 4Ti 5O 12 layer with 20–40 nm in thickness is coated on the surface of SnO 2 particles. Electrochemical tests show that SnO 2-Li 4Ti 5O 12 composite delivers a reversible capacity of 688.7 mA·h/g at 0.1 C and 93.4% of that is retained after 60 cycles at 0.2 C. The amorphous Li 4Ti 5O 12 in composite can accommodate the volume change of SnO 2 electrode and prevent the small and active Sn particles from aggregating into larger and inactive Sn clusters during the cycling effectively, and enhance the cycling stability of SnO 2 electrode significantly.