Engineering High-Performance SiO x Anode Materials with a Titanium Oxynitride Coating for Lithium-Ion Batteries

Micron-sized silicon oxide (SiO x ) has been regarded as a promising anode material for new-generation lithium-ion batteries due to its high capacity and low cost. However, the distinct volume expansion during the repeated (de)­lithiation process and poor conductivity can lead to structural collapse of the electrode and capacity fading. In this study, SiO x anode materials coated with TiO0.6N0.4 layers are fabricated by a facile solvothermal and thermal reduction technique. The TiO0.6N0.4 layers are homogeneously dispersed on SiO x particles and form an intimate contact. The TiO0.6N0.4 layers can enhance the conductivity and suppress volume expansion of the SiO x anode, which facilitate ion/electron transport and maintain the integrity of the overall electrode structure. The as-prepared SiO x -TiON-200 composites demonstrate a high reversible capacity of 854 mAh g–1 at 0.5 A g–1 with a mass loading of 2.0 mg cm–2 after 250 cycles. This surface modification technique could be extended to other anodes with low conductivity and large volume expansion for lithium-ion batteries.