A facile fabrication of micro/nano-sized silicon/carbon composite with a honeycomb structure as high-stability anodes for lithium-ion batteries

Silicon based anodes for lithium ion batteries have attracted great interests because of a high theoretical capacity of 4200 mAh g(-1). To achieve high performance and low cost silicon anodes by overcoming their inherent drawbacks, a facile route was carried out to successfully encapsulate the micro/nano-sized silicon particles into a nitrogen-enriched porous carbon matrix using CaCO3 as the structural template, polyacrylonitrile (PAN) as the carbon and nitrogen source. The resultant porous composite (Si/PC) exhibits dramatically enhanced cycling stability and excellent rate performance, about 830 mAh g(-1) can be achieved after discharged/charged at 200 mA g(-1) for 200 cycles with a high retention of 81.5% based on the second reversible capacity, furthermore, 230 mAh g(-1) can still be maintained even at a high current density of up to 3200 mA g(-1). The enhanced performance is ascribed to the unique porous structure that can accommodate the volume variation of silicon during the lithiation/delithiation process, and the increased conductivity due to the enriched nitrogen species in the carbon network.

Automated summary

By encapsulating silicon particles into a nitrogen-enriched porous carbon matrix, a silicon/carbon composite was created with enhanced cycling stability and rate performance. The porous structure accommodates volume changes in silicon, while the enriched nitrogen species improve the conductivity of the carbon network.