Microstructure Modulation of Zn Doped VO2(B) Nanorods with Improved Electrochemical Properties towards High Performance Aqueous Batteries

Vanadium dioxide with monoclinic structure is theoretically a promising layered cathode material for aqueous metal-ion batteries due to its excellent specific capacity. However, its poor cycling stability limits its application as an electrode material. In this study, a series of Zn-doped VO2 (V1−xZnxO2) nanorods were successfully fabricated by the technology of one-step hydrothermal synthesis. The XRD result indicated that there was a slight lattice distortion caused by doped Zn2+ with a larger ion radius. The positron lifetime spectrum showed that there were vacancy cluster defects in all the samples. The electrochemical measurement demonstrated the enhancement of the specific capacitance of V1−xZnxO2 electrodes compared with the undoped sample. In addition, the discharge capacitance of the sample remained around 86% after 1000 charge/discharge cycles. This work proves that Zn2+ doping is a valid tactic for the application of nano-VO2(B) in energy storage electrode materials.