High capacity and long-life aqueous zinc-ion battery enabled by improving active sites utilization and protons insertion in polymer cathode

Rechargeable aqueous zinc-ion batteries (AZIBs) using polymer cathode materials generally exhibit excellent cycling stability due to the stable structure of polymer. However, their further development is curbed by relatively low capacity. Herein, we report a graphene/aza-fused π-conjugated microporous polymer composite (G-Aza-CMP) cathode with ultrahigh theoretical capacity (602 mAh g−1) for AZIBs. The introduction of graphene makes the Aza-CMP expose more active sites to coordinate with H+/Zn2+, even boosts the storage of H+ to obtain faster kinetics, and endows the G-Aza-CMP//Zn battery with a redox pseudocapacitance mechanism. Thus, AZIBs using the G-Aza-CMP as cathode exhibit an extraordinary specific capacity of 456 mAh g−1 at 0.05 A g−1, and an outstanding cycling stability with 91.2% capacity retention after 9700 cycles at 10 A g−1. This study provides a new insight into the charge storage mechanism and design of high-capacity polymer cathode materials for AZIBs.