Synthesis of high volumetric capacity graphene oxide-supported tellurantimony Na- and Li-ion battery anodes by hydrogen peroxide sol gel processing

High-charge-capacity sodium-ion battery anodes made of Sb₂Te₃@reduced graphene oxide are reported for the first time. Uniform nano-coating of graphene oxide is carried out from common sol of peroxotellurate and peroxoantimonate under room temperature processing. Reduction by hydrazine under glycerol reflux yields Sb₂Te₃@reduced graphene oxide. The electrodes exhibit exceptionally high volumetric charge capacity, above 2300 mAh cm⁻³ at 100 mA g⁻¹ current density, showing very good rate capabilities and retaining 60% of this capacity even at 2000 mA g⁻¹. A comparison of sodiation and lithiation shows that lithiation exhibits better volumetric charge capacity, but surprisingly only marginally better relative rate capability retention at 2000 mA g⁻¹. Tellurium-based electrodes are attractive due to the high volumetric charge capacity of Te, its very high electric conductivity, and the low relative expansion upon lithiation/sodiation.