Self-Healing Lamellar Structure Boosts Highly Stable Zinc-Storage Property of Bilayered Vanadium Oxides.

Rechargeable aqueous zinc-ion batteries have been considered one of the promising alternative energy-storage systems to lithium ion-batteries owing to their low cost and high safety. However, there is lack of long-life positive materials, which severely restricts the development of zinc-ion batteries. The strong interactions present between the intercalated multivalent cations and host materials inevitably cause structural distortions and create large migration barriers for the diffusion of cations, resulting in poor cycling stability and limited rate performance. Here, we report the application of bilayered ammonium vanadium oxide (NHVO) as the cathode material for zinc-ion batteries. A self-healing lamellar structure, which combines a macroscopically reversible morphological transformation and a microscopically adjustable interlayer spacing to accommodate the strong interactions, is observed upon insertion and release of cations. This stable architecture enables a specific capacity of 147 mA h g at a current density of 200 mA g (voltage window: 1.7-0.8 V vs Zn/Zn) and a capacity retention of more than 70.3% over 5000 cycles (5000 mA g). Our finding provides a new alternative for zinc-ion batteries and inspiration for how to further develop advanced positive electrodes by employing materials with flexible microarchitectures.