Multi-layer wrapping functionalized silicon via graphene aerogels regenerated from spent graphite anode achieves high efficient lithium storage

The large volume expansion and severe pulverization of silicon nanoparticles (SiNPs) during cycling have significantly hindered its application into lithium-ion batteries (LIBs). Graphene, for its excellent mechanical strength and high conductivity, has been widely applied to alleviate the swelling effect and enhance the ion conductivity of electrode materials. Herein, a facile and low-cost method to wrap Si by graphene aerogels with multiple shells is proposed in this work. Specifically, graphene oxide (GO) is synthesized by an improved Hummers’ method with waste graphite anode as raw material, the surface of SiNPs are modified with an amino group to achieve electrostatic attraction with an abundant carboxyl group on GO. Then a two-step reduction is carried out to synthesize a 3D graphene aerogel structure with uniformly distributed SiNPs, the inner rGO shell enhances the transport of ions on the surface of Si, the outer shell provides excellent confinement against the volume expansion during battery cycling.