Ultra-stable aqueous zinc-ion battery enabled by highly reversible Zn2+/Na+ co-intercalation chemistry

Rechargeable aqueous zinc-ion batteries (RAZBs) are a promising prospect among next-generation batteries because of their low cost and high safety, but they still suffer from severe electrochemical irreversibility. Herein, we report an ultra-stable RAZB enabled by reversible Zn2+/Na+ co-intercalation chemistry in the vanadium cathode. The additional de-/intercalation of Na+ besides Zn2+ alleviates the collapse of the vanadium-based cathode during cycling and significantly boosts the kinetics and stability of the full battery. We also find that this co-intercalation chemistry is applicable to a wide range of vanadium materials, all of which exhibit significantly enhanced cycle life and rate performance. In particular, the Zn0.3Na0.43V2O5 cathode that is combined with this co-intercalation mechanism retains over 90% of its capacity after 4,000 cycles with a discharge capacity of 209 mAh g−1 at 1 A g−1. The proposed Zn2+/Na+ co-intercalation chemistry provides the grounds for RAZB to reach the next stage in electrochemical performance.