Stable anode performance of vanadium oxide hydrate semi-microspheres and their graphene based composite microspheres in sodium-ion batteries

Abstract

A simple and versatile method for preparation of new crystalline vanadium oxide hydrate semi-microspheres is developed via a simple hydrothermal route, which are tested as a novel high-energy anode materials for sodium-ion batteries. The enhancement of electrochemical performance for the vanadium oxide hydrate electrode is offered by addition of graphene. The graphene-based vanadium oxide hydrate microsphere composite shows a high discharge capacity of 336.1 mA h g⁻¹ for the second cycle between a 0.05–3.0 V voltage limit at a discharge current density of 10 mA g⁻¹. A reversible capacity of 303.1 mA h g⁻¹ is retained after 20 cycles.