High rate capability and long cycling life of graphene-coated silicon composite anodes for lithium ion batteries

With a theoretical specific capacity much higher than that of traditional graphite, silicon (Si) has been considered as a promising anode material for next-generation lithium ion batteries (LIBs). Unfortunately, its practical application has been severely limited by the drawback of drastic volume expansion. In this report, we demonstrate a facile way to prepare binder-free, conductive agent-free silicon/reduced graphene oxide composite (Si/rGO) anode on nickel foam via one-step hydrothermal method followed by a post-annealing process, which delivers extraordinary cyclability and rate performance. The reversible specific capacity of the composite anode retained over 1500 mAh/g at 2 A/g after 2500 cycles and over 600 mAh/g at 4 A/g after 2500 cycles. Especially at a reasonable high current density of 16 A/g, the Si/rGO anode still displayed a specific capacity of 500 mAh/g.