Engineering the Proton-Substituted HNaV6O16·4H2O Cathode for the Ultrafast-Charging Zinc Storage

The ultrafast charging property plays a significant role in achieving high-rate performance in a working aqueous battery system. However, the fast charging process usually causes irreversible structure evolution, thereby resulting into a dramatic capacity decay at high current densities. Herein, proton-substituted HNaV6O16·4H2O (HNVO) was fabricated via a facile hydrothermal method and utilized as the cathode of zinc ion batteries. The proton can not only serve as the interlayer pillar to stabilize the layer structure but also improve the utilization of active materials. In addition, the preinserted H+ is also beneficial for accelerating the kinetics of the charge carrier and reducing the electrochemical irreversibility, achieving a high-rate performance. In our case, the Zn/HNVO battery delivers 331.3 mA h g–1 (charged at 10.0 A g–1) and maintains 333.2 mA h g–1 (discharged at 1.0 A g–1) with a high Coulombic efficiency of 100.5%. Importantly, it also delivers an ultralong cycling stability with almost no capacity decay (10 000 cycles at 20 A g–1). This design of the cathode provides a new insight for developing ultrafast-charging aqueous battery systems.