Hollow Silica Spheres Embedded in a Porous Carbon Matrix and Its Superior Performance as the Anode for Lithium-Ion Batteries

Silica (SiO2) is regarded as one of the most promising anode materials for lithium-ion batteries due to the high theoretical specific capacity and extremely low cost. However, the low intrinsic electrical conductivity and the big volume change during charge/discharge cycles result in a poor electrochemical performance. Here, hollow silica spheres embedded in porous carbon (HSS-C) composites are synthesized and investigated as an anode material for lithium-ion batteries. The HSS-C composites demonstrate a high specific capacity of about 910 mA h g(-1) at a rate of 200 mA g(-1) after 150 cycles and exhibit good rate capability. The porous carbon with a large surface area and void space filled both inside and outside of the hollow silica spheres acts as an excellent conductive layer to enhance the overall conductivity of the electrode, shortens the diffusion path length for the transport of lithium ions, and also buffers the volume change accompanied with lithium-ion insertion/extraction processes.