Extraction of oxygen anions from vanadium oxide making deeply cyclable aqueous zinc ion battery

Rechargeable aqueous zinc-ion batteries are attractive because of their inherent safety, low cost, and high energy density. However, viable cathode materials (such as vanadium oxides) suffer from strong Coulombic ion-lattice interactions with divalent Zn(2+) , thereby limiting stability when cycled at a high charge/discharge depth with high capacity. A synthetic strategy is reported for an oxygen-deficient vanadium oxide cathode in which facilitated Zn(2+) reaction kinetic enhance capacity and Zn(2+) pathways for high reversibility. The benefits for the robust cathode are evident in its performance metrics; the aqueous Zn battery shows an unprecedented stability over 200 cycles with a high specific capacity of approximately 400 mAh g(-1) , achieving 95 % utilization of its theoretical capacity, and a long cycle life up to 2 000 cycles at a high cathode utilization efficiency of 67 %. This work opens up a new avenue for synthesis of novel cathode materials with an oxygen-deficient structure for use in advanced batteries.