A Deep‐Cycle Aqueous Zinc‐Ion Battery Containing an Oxygen‐Deficient Vanadium Oxide Cathode

, 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.