Superior sodium storage of novel VO2 nano-microspheres encapsulated into crumpled reduced graphene oxide

Abstract

To uniformly encapsulate electrode materials with reduced graphene oxide (rGO) has been a considerable challenge due to the lack of appropriate synthetic methods and/or effective reaction systems. In this study, we present a one-step rapid and scalable solvothermal approach to achieve a crumpled reduced graphene oxide encapsulated VO₂ material. As a demonstration of this promising configuration, for the first time, we systematically studied its Na⁺ storage behavior in the voltage range of 3.0 to 0.01 V (versus Na/Na⁺). It turned out that the as-prepared anode material exhibits high reversible capacities of 383 mA h g⁻¹ at 0.1 A g⁻¹ and 214 mA h g⁻¹ at 4 A g⁻¹, and can stably operate for as long as 2000 cycles at 4 A g⁻¹ with a capacity fade of 0.013% per cycle, resulting from the improved electronic conductivity, structural stability, and electrode wettability. Furthermore, the formation mechanism and structural features of the desired crumpled reduced graphene oxide encapsulated VO₂ material are discreetly expounded. More interestingly, a chain of cogent evidence is provided by coating on various electrode materials to confirm the scalability of this facile and rapid solvothermal synthesis method, which would open up a novel avenue to create more fascinating graphene-based functional materials for the multitudinous application domain.