Mesoporous Tin-Based Oxide Nanospheres/Reduced Graphene Composites as Advanced Anodes for Lithium-Ion Half/Full Cells...

The large volume variations of tin-based oxides hinder their extensive application in the field of lithium-ion batteries (LIBs). In this study, structure design, hybrid fabrication, and carbon-coating approaches have been simultaneously adopted to address these shortcomings. To this end, uniform mesoporous NiO/SnO₂ @rGO, Ni-Sn oxide@rGO, and SnO₂ @rGO nanosphere composites have been selectively fabricated. Among them, the obtained NiO/SnO₂ @rGO composite exhibited a high capacity of 800 mAh g^-1 at 1000 mA g^-1 after 400 cycles. The electrochemical mechanism of NiO/SnO₂ as an anode for LIBs has been preliminarily investigated by ex situ XRD pattern analysis. Furthermore, an NiO/SnO₂ @rGO-LiCoO₂ lithium-ion full cell showed a high capacity of 467.8 mAh g^-1 at 500 mA g^-1 after 100 cycles. Notably, the NiO/SnO₂ @rGO composite also showed good performance when investigated as an anode for sodium-ion batteries (SIBs). It is believed that the unique mesoporous nanospherical framework, synergistic effects between the various components, and uniform rGO wrapping of NiO/SnO₂ shorten the Li⁺ ion diffusion pathways, maintain sufficient contact between the active material and the electrolyte, mitigate volume changes, and finally improve the electrical conductivity of the electrode.