Micron silicon-oxide-carbon coated with TiO_x(OH)_y layer as better performance anode for lithium-ion batteries

Micron-silicon based material is a promising anode material for high performance lithium batteries due to its ultra-high specific capacity. However, the volume expansion exceeds 300 % during charging and discharging, resulting in the collapse of the electrode structure and a rapid decline in electrochemical performance. Coating the surface of silicon-based materials with flexible ionic conductors is an effective method to maintain their high capacity and suppress swelling. Here, to further improve the electrochemical performance of silicon-based materials, we have deposited a titanate-type ionic conductor layer on a micron-sized silicon-carbon oxide (SiO_X-C) material to synthesize the SiO_X-C@TiO_x(OH)_y material. The TiO_x(OH)_y layer not only exhibits the elastic properties of a superpolymer to mitigate swelling strain, but also has a fast capacitance effect to improve its rate performance. In addition, the interfacial charge transport of SiO_X-C@TiO_x(OH)_y is enhanced due to the structural diversity of the TiO_x(OH)_y layer. For the above mechanisms, the SiO_X-C@TiO_x(OH)_y has a specific capacity of 278.3 mAh g⁻¹ under high current of 3500 mA g⁻¹. Meanwhile, the SiO_X-C@TiO_x(OH)_y with the capacity retention of 67 % is achieved at 2000 mA g⁻¹ after 100 cycles.