Graphene caging silicon nanoparticles anchored on graphene sheets for high performance Li-ion batteries

Abstract

Silicon is regarded as the best choice for the new emergence of lithium-ion battery anode materials owing to its high theoretical capacity and safety, but it also faces great challenges in practical applications, namely structural instability, solid electrolyte interphase film rupture and capacity attenuation caused by volume expansion. Here we report the graphene caging Si nanoparticles anchored on graphene sheets by simple coating and calcination. The interspace between the silicon nanoparticles and the graphene cage affords volume expansion sufficient space. The graphene affords two parts in this material simultaneously, one of which is forming a flexible shell of silicon nanoparticles that can relieve internal stress and improve the adaptability to the expansion of silicon in different directions, the second is building an interlinked network matrix to increase conductivity. Nano‑silicon is under the dual protection of graphene cage and graphene sheets interlinked network, this interesting structure also significantly enhances the electrochemical performance of the silicon nanoparticles. The prepared electrode material exhibits excellent cycle performance with an excellent capacity of 1616.1 mAh g−1 after 100 cycles at a high current density of 1 A g−1.