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

Nonstoichiometric SiOx-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 SiOx nanocomposites without sacrificing their capacity and cycle performance. We suggest that the TiO2 coating layer could significantly improve the thermal reliability of the SiOx nanocomposites. Even though the TiO2 phase introduced is less active, TiO2-coated nonstoichiometric SiOx nanocomposites showed electrochemical performance comparable with that of bare nonstoichiometric SiOx 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.