A sandwich nanocomposite composed of commercially available SnO and reduced graphene oxide as advanced anode materials for sodium-ion full batteries

Abstract

In the past years, sodium-ion batteries (SIBs) have attracted much attention due to their potential application in large-scale energy storage. However, for now, it is difficult for anode materials to achieve further practical application. In this work, we designed a sandwich structure in which SnO nanoparticles were entrapped between the layers of reduced graphene oxide (SnO/rGO) via freeze drying. The unique structure can not only offer a 3D carbon network but also relieve volume expansion during discharge/charge processes. When used as an anode material for SIBs, the material exhibits excellent rate capability and stable cycling performance. It can be found that a reversible capacity of 132.3 mA h g⁻¹ can be obtained even at a current density of 5 A g⁻¹. In addition, SnO/rGO shows a charge capacity of 109.5 mA h g⁻¹ with a capacity retention of 70.62% after 1200 cycles at 4 A g⁻¹. When assembled with Na₃V₂(PO₄)₂O₂F (NVPOF) as the cathode, the sodium-ion full cells also display high rate performance, suggesting a reversible capacity of 65.7 mA h g⁻¹ at 20C and an energy density of 138.95 W h kg⁻¹ at −0.1C. The unique structure provides a simple and facile method to achieve high electrochemical performance which is beneficial for developing commercial anode materials for SIBs.