Quantitative Regulation of Interlayer Space of NH V O for Fast and Durable Zn and NH Storage.

Layered vanadium-based oxides are the promising cathode materials for aqueous zinc-ion batteries (AZIBs). Herein, an in situ electrochemical strategy that can effectively regulate the interlayer distance of layered NH V O quantitatively is proposed and a close relationship between the optimal performances with interlayer space is revealed. Specifically, via increasing the cutoff voltage from 1.4, 1.6 to 1.8 V, the interlayer space of NH V O can be well-controlled and enlarged to 10.21, 11.86, and 12.08 Å, respectively, much larger than the pristine one (9.5 Å). Among them, the cathode being charging to 1.6 V (NH V O -C1.6), demonstrates the best Zn storage performances including high capacity of 223 mA h g at 10 A g and long-term stability with capacity retention of 97.5% over 1000 cycles. Such superior performances can be attributed to a good balance among active redox sites, charge transfer kinetics, and crystal structure stability, enabled by careful control of the interlayer space. Moreover, NH V O -C1.6 delivers NH storage performances whose capacity reaches 296 mA h g at 0.1 A g and lifespan lasts over 3000 cycles at 5 A g . This study provides new insights into understand the limitation of interlayer space for ion storage in aqueous media and guides exploration of high-performance cathode materials.