Graphene nanoribbon and nanostructured SnO₂ composite anodes for lithium ion batteries

A composite made from graphene nanoribbons (GNRs) and tin oxide (SnO ₂) nanoparticles (NPs) is synthesized and used as the anode material for lithium ion batteries (LIBs). The conductive GNRs, prepared using sodium/potassium unzipping of multiwall carbon nanotubes, can boost the lithium storage performance of SnO₂ NPs. The composite, as an anode material for LIBs, exhibits reversible capacities of over 1520 and 1130 mAh/g for the first discharge and charge, respectively, which is more than the theoretical capacity of SnO₂. The reversible capacity retains ∼825 mAh/g at a current density of 100 mA/g with a Coulombic efficiency of 98% after 50 cycles. Further, the composite shows good power performance with a reversible capacity of ∼580 mAh/g at the current density of 2 A/g. The high capacity, good power performance and retention can be attributed to uniformly distributed SnO ₂ NPs along the high-aspect-ratio GNRs. The GNRs act as conductive additives that buffer the volume changes of SnO₂ during cycling. This work provides a starting point for exploring the composites made from GNRs and other transition metal oxides for lithium storage applications.