Catalytic Growth of Graphitic Carbon‐Coated Silicon as High‐Performance Anodes for Lithium Storage

Abstract

Although silicon is considered as one of the most promising anode materials in next‐generation lithium‐ion batteries, large volumetric expansion during cycling hampers its practical application. The fabrication of silicon/carbon composites is an effective way to improve electrical conductivity and inhibit electroactive material delaminating from the current collector. Herein, a graphitic carbon‐coated porous silicon nanospheres (p‐SiNSs@C) composite is prepared through a chemical vapor deposition (CVD) technique by using the magnesiothermic reduction by‐product MgO as a template and catalyst. With the template of in situ generation of MgO, the p‐SiNSs@C material is obtained in a very short time. Due to the graphitic carbon shell and porous structure inside the silicon nanospheres, the obtained p‐SiNSs@C, with 8 min carbon growing time (p‐SiNSs@C‐2), deliver a high initial reversible capacity of 2220 mAh g−1 at 0.1 A g−1 and respectable rate capability. Furthermore, the p‐SiNSs@C‐2//LiCoO2 Li‐ion full cell displays a high energy density of ≈409 Wh kg−1 and good cycling performance. The high performance of the p‐SiNSs@C‐2 composite can be attributed to the synergistic effect of nanoscale‐sized Si, porous structure, and stable carbon shell.