Porous Silicon-Carbon Composite Li-ion Anode Materials toward Practical Applications

Emerging application of Li-ion batteries for electric vehicles requires LIBs with higher energy density. Developing new anode materials with high specific capacity is an effective way to increase the energy density of LIBs. Due to its high theoretical capacity (3579 mAh/g) and abundance, silicon has been regarded as one of most promising alternatives to the currently-used graphite anode. However, there is a major barrier to the practical application Si: its large volume change during charge/discharge causes to severe pulverization of Si particles and degradation of Si electrodes, leading to poor cycling stability. Extensive efforts have been devoted to improving the cyclability of Si-based anodes with encouraging results, including development of various Si nanostructures/nanocomposites, novel binders and electrolyte additives.

In this talk, I will present development of micro-sized porous Si-C composite composed of interconnected Si nanoscale building blocks and carbon conductive network. The effect of Si nanoscale building blocks (size and doping composition) and carbon coating are studied on the electrochemical performance. We also engineered to produce graphene enabled dual conductive network on the micro-sized porous Si-C composite for high areal capacity electrodes toward practical application. New interpenetrated polymer gel binder for the Si anode materials will be also studied for improving efficiency and cycling stability of Si anodes. High temperature electrochemical performance of the Si anode material and related safety issues will be also discussed and correlated with the surface properties of Si materials.