Si/graphene composite as high-performance anode materials for Li-ion batteries

Diatomite, treated by low temperature magnesiothermic reduction as the Si source, was used to synthesize the porous Si/graphene (Si/G) composite. Graphene deposited on the surface of porous Si by a chemical vapor deposition (CVD) process not only buffered the volume effect, but also optimized the electrical conductivity. The obtained Si/G composites exhibited superior reversible capacity of about 1173.6 mAh·g−1 and the current density of 100 mA·g−1 with an excellent capacity retention in the following circulations. Moreover, the composite possesses an excellent rate performance even at high current density. The results suggested that the successful composite of porous Si and graphene could effectively improve the electrochemical performance of Si-based materials and it also offered a new way for the application of diatomite.