Preparation and characterization of SnO2-Li4Ti5O12
composite by sol-gel technique
composite by sol-gel technique
(1. College of Biology and Environmental Sciences, Jishou University, Jishou 416000, China;
2. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China)
2. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China)
Abstract: SnO2-Li4Ti5O12 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 SnO2-Li4Ti5O12 composite derived by sol-gel technique is a nanocomposite with core-shell structure, and the amorphous Li4Ti5O12 layer with 20−40 nm in thickness is coated on the surface of SnO2 particles. Electrochemical tests show that SnO2-Li4Ti5O12 composite delivers a reversible capacity of 688.7 mA∙h/g at 0.1C and 93.4% of that is retained after 60 cycles at 0.2C. The amorphous Li4Ti5O12 in composite can accommodate the volume change of SnO2 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 SnO2 electrode significantly.
Key words: SnO2; Li4Ti5O12; composite; sol-gel method; lithium ion batteries