▎ 摘　　要

Graphene or graphene based composites are widely used in various fields. Reducing graphene oxide is a simple and common method to prepare graphene for energy storage fields such as Li-ion batteries. However, thermal reduction needs a high temperature under vacuum or inert gas conditions and chemical reduction needs hazardous reducing agents. Accordingly, we report an electrochemical method to reduce graphene oxide in Li-ion batteries. By this method, we could assemble graphene oxide based composite electrodes into cells and directly reduce the graphene oxide in situ. Compared to the conventional method to reduce graphene oxide, our work is simple and effective. In particular, when the reduced graphene oxide is used in Li-ion batteries, our method could greatly simplify the electrode fabrication process.