Tin nanoparticles encapsulated in hollow TiO2 spheres as high performance anode materials for Li-ion batteries.

摘要

Tin, an anode material with a high capacity for lithium-ion batteries, has poor cyclic performance because of the high volume expansion upon lithiation. Based on a literature review of the applications of lithium-ion batteries and current research progress of the tin-based anode materials for lithium-ion batteries, we developed a method to synthesize hollow TiO2 spheres with tin nanoparticles anchored on the inner surface of the TiO2 shell. Such a unique tin/TiO2 composite alleviates the volume change of tin--based anode materials in charge-discharge processes. SnCl 2˙2H2O (Tin (II) chloride dihydrate) and titanium (IV) isopropoxide (TIPT) were used as the Sn source and the Ti source, respectively, while CaCO3 was used as a template to fabricate the TiO2 hollow shell. A variety of modern material testing methods (XRD, SEM, XPS, Raman, BET, etc.) and electrochemical measurements such as galvanostatic charge-discharge and cyclic voltammetry (CV) testing were employed to systematically study effects of various synthesis parameters on the structure and battery performance of the as-prepared materials. We also discussed the key factors influencing the cycle performance of the composite electrode material and the related mechanism.