Two-dimensional Mg0.2V2O5·nH2O nanobelts derived from V4C3 MXenes for highly stable aqueous zinc ion batteries

Aqueous zinc ion batteries (ZIBs) are of great concern for their low cost, high safety and eco-friendliness. Vanadium oxides are the underlying cathode materials for ZIBs because of their high theoretical capacity. However, the slow kinetics of multivalent charged Zn2+ in the host structure and unstable structure induce inferior cycling stability and rate performance. Herein, Mg2+ pre-intercalated V2O5·nH2O nanobelts derived from conductive V4C3 MXenes are devised and prepared as cathodes for ZIBs, delivering a high reversible capacity of 346 mAh g−1 at 0.1 A g−1 and preeminent ultra-long cycling stability with capacity retention of 83.7% after 10,000 cycles at 5 A g−1. Using this material as cathode, the soft-packed battery also represents favourable rate and cycling performance. The stable structure originated from pre-intercalated Mg2+ and interlayered water, splendid reversible phase transformation and high pseudocapacitive behavior boost the preeminent cycling stability and rate capacity.