A facile strategy to unlock the high capacity of vanadium-based cathode for aqueous zinc-ion batteries

High-capacity cathode materials are highly important for aqueous zinc-ion batteries (ZIBs). However, the capacity output of cathode materials still remains far from their theoretical values. Herein, we report a facile strategy by integrating a small amount of multi-wall carbon nanotube (MWCNT) into (NH4)(2)V6O16 vanadium-based ammonium hexavanadate (NVO) that greatly improves the capacity for zinc-ion storage. Specifically, the NVO/MWCNT composite cathode presents a high specific capacity of 462.8 mAh g(-1) at 0.5 A g(-1) and 120.2 mAh g(-1) at 5 A g(-1) with excellent cyclic stability of 92.6% capacity retention after 1000 cycles. Additionally, the structural evolution of cathode material and zinc-ion storage mechanism are further analyzed with a series of voltage-dependent spectroscopic investigation. The performance improvement of NVO/MWCNT cathode is ascribed to the enlargement of interfacial area of NVO nanorods with the electrolyte and promotion of electron transfer within NVO cathode. This work gives a new approach for development of cathode material of ZIBs.