Binder-free K0.44V2O5 nanowires@carbon cloth cathodes with fast electrochemical kinetics for high-performance aqueous zinc metal batteries

Potassium vanadate (K0.44V2O5, KVO) exhibiting high electrochemical activity in Zn2+-containing aqueous electrolytes are promising cathode materials for aqueous zinc metal batteries (AZMBs). However, the conventional electrodes with non-conductive and electrochemically inert binders limit the electrochemical kinetics of KVO in the electrodes. Herein, binder-free KVO nanowires@carbon cloth (CC) cathodes, KVO nanowires chemically deposited onto the CC current collector without the use of polymer binder, are proposed for AZMBs. The pseudocapacitive contribution at 1 mV s−1 is improved from 49 % for conventional electrodes employing PVDF binder to 82 % for the as-fabricated KVO@CC binder-free electrodes, implying the promoted electrochemical kinetics. As result, the binder-free KVO@CC electrode demonstrates a high specific capacity of 391 mAh g−1 at 0.1 A g−1 and a stable cycle of 3100 cycles a 5 A g−1 with a capacity retention of 89.5 %. In contrast, the conventional binder-containing KVO electrodes are only 234 mAh g−1 and 53.8 %, respectively, under the same conditions. These results demonstrate that the optimization at the electrode level, i.e., the binder-free strategy, is feasible for designing high-performance AZMBs.