Coralloid-like Nanostructured c-nSi/SiOx@Cy Anodes for High Performance Lithium Ion Battery.

Balancing the size of the primary Si unit and void space is considered to be an effective approach for developing high performance silicon-based anode materials and is vital to create a lithium ion battery with high energy density. We herein have demonstrated the facile fabrication of coralloid-like nanostructured silicon composites (c-nSi/SiOx@Cy) via sulfuric acid etching the Al60Si40 alloy, followed by a surface growth carbon layer approach. The HRTEM images of pristine and cycled c-nSi/SiOx@Cy show that abundant nanoscale internal pores and the continuous conductive carbon layer effectively avoid the pulverization and agglomeration of Si units during multiple cycles. It is interesting that the c-nSi/SiOx@C4.0 anode exhibits a high initial Coulombic efficiency of 85.53%, and typical specific capacity of over 850 mAh g-1 after deep 500 cycles at a current density of 1 A g-1. This work offers a facile strategy to create silicon-based anodes consisting of highly dispersed primary nano-Si units.