Facile fabrication of a three-dimensional coral-like silicon nanostructure coated with a C/rGO double layer by using the magnesiothermic reduction of silica nanotubes for high-performance lithium-ion battery anodes

Silicon has an ultrahigh theoretical capacity and has been regarded as the best choice for next-generation lithium-ion battery anodes, but it also suffers from dramatic expansion during cycling. Herein, a novel three-dimensional coral-like Si nanostructure coated with C/rGO (CL-Si@C/rGO) was facilely prepared through the high-temperature magnesiothermic reduction of SiO 2 nanotubes , which were then coated with C/rGO. Systematic tests verified the unique coral-like nanostructure, which was formed by the magnesiothermic reduction of several SiO 2 nanotubes at high temperature. The internal voids and outer C/rGO layer of CL-Si@C/rGO could effectively manage the volume expansion phenomenon while enhancing the electrical conductivity of the electrode, respectively. Benefiting from the ability to maintain the electrode integrity and the outer C/rGO layer of this unique nanostructure, the CL-Si@C/rGO composite electrode could maintain a reversible specific discharge capacity of 739.1 mAh g −1 , even at a high current density of 2 A g −1 . Furthermore, this composite electrode exhibited a 0.5% capacity loss from the 3rd to the 100th cycle at a current density of 1 A g −1 . This work provides a simple, economic, and environmentally friendly procedure for the industrial production of high-performance Si-based anodes.