V<sub>2</sub>O<sub>3</sub>@C Microspheres as the High-Performance Cathode Materials for Advanced Aqueous Zinc-Ion Storage
Deqiang Wang, Wenhao Liang, Xuedong He, Yun Yang, Shun Wang, Jun Li, Jichang Wang, Huile Jin
Abstract
Vanadium oxides attract increasing research interests for constructing the cathode of aqueous zinc-ion batteries (ZIBs) because of high theoretical capacity, but the low intrinsic conductivity and unstable phase changes during the charge/discharge process pose great challenges for their adoption. In this work, V 2 O 3 @C microspheres were developed to achieve enhanced conductivity and improved stability of phase changes. Compounding vanadium oxides and conductive carbon through the in-situ carbonization led to significant improvement of the cathode materials. ZIBs prepared with V 2 O 3 @C cathodes produce a specific capacity of 420 mA h g –1 at 0.2 A g –1 . A reversible capacity of 132 mA h g –1 was achieved at 21.0 A g –1 . After 2000 cycles, the electrode could still deliver a capacity of 202 mA h g –1 at the current of 5.0 A g –1 . Besides, the energy density of batteries constructed with the thus-prepared electrodes was about 294 W h kg –1 at 148 W kg –1 power. The in-situ compounding of V 2 O 3 and carbon resulted in a microstructure that facilitated the stable phase transformation of Zn x V 2 O 5– a · n H 2 O (ZnVOH), which provided more Zn 2+ storage activity than the original phase before electrochemical activation. Moreover, the in-situ compositing strategy presents a simple route to the development of ZIB cathodes with promising performance.