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 TiO_0.6N_0.4 layers are fabricated by a facile solvothermal and thermal reduction technique. The TiO_0.6N_0.4 layers are homogeneously dispersed on SiO_x particles and form an intimate contact. The TiO_0.6N_0.4 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.