TiO2-coated Nonstoichiometric SiOx Nanosphere for High Capacity Anode Material for Lithium Ion Batteries

Abstract

Nonstoichiometric SiO x -based nanocomposites have gained considerable attention as promising anode materials for lithium-ion batteries because of their high capacity and relatively good cycle performance. However, their commercial use is still limited by some technical problems such as poor thermal reliability, dimensional stability, and safety. Herein we show that surface modification with TiO2 can effectively improve the thermal reliability of SiO x nanocomposites without sacrificing their capacity and cycle performance. We suggest that the TiO2 coating layer could significantly improve the thermal reliability of the SiO x nanocomposites. Even though the TiO2 phase introduced is less active, TiO2-coated nonstoichiometric SiO x nanocomposites showed electrochemical performance comparable with that of bare nonstoichiometric SiO x nanocomposite. We believe that the surface modification approach proposed herein will open up a new route toward high capacity Si-based anode materials for lithium-ion batteries.