Nano-Si/graphite/N-doped biocarbon hybrid anode material for high-performance lithium-ion batteries

Abstract

Improving the cycle life of silicon-based anodes is extremely important to the development of Li-ion batteries. Nano-silicon / graphite / Nitrogen-doped carbon composites are prepared as hybrid anode material in this work. The nano-silicon particles are distributed in the graphite framework, which improves the electrical conductivity of the composite. The amorphous nitrogen-doped carbon layer of the composite could be a buffer structure for the volume change of Si while providing a fast transport channel for lithium ions and further enhancing the electrical conductivity of the composites. The specific capacity of the composite electrode is 656.5 mAh g-1 at 500 mA g-1. The capacity retention rate is 91% after 100 cycles. The composite electrode could deliver a specific capacity of 497.3 mAh g-1 after 200 cycles even at a large current density of 1A g-1.