Nanocrystalline silicon embedded in an alloy matrix as an anode material for high energy density lithium-ion batteries

The development of electrode materials with high capacity and good cycling stability is a challenging prerequisite for improving the energy density of lithium-ion batteries. In this work, we synthesize silicon nanoparticles embedded in the inactive Al4Cu9, AlFe and TiFeSi2 matrix phases, as an anode material. The silicon alloy material exhibits good high rate performance and delivers a high initial discharge capacity of 1459.3 mAh g−1 with capacity retention of 85.7% after 200 cycles at a current density of 300 mA g−1. The superior cycling performance of the silicon alloy compared to that of micro-sized pure silicon can be attributed to the unique structure of the alloy material. Here, the nano-sized silicon particles reduce the ionic diffusion path length and minimize volume expansion during lithiation, while the inactive matrix phases accommodate volume changes during repeated cycling and provide a continuous electronic conduction pathway to the silicon nanoparticles.