A High-Capacity Ammonium Vanadate Cathode for Zinc-Ion Battery

Given the advantages of being abundant in resources, environmental benign and highly safe, rechargeable zinc-ion batteries (ZIBs) enter the global spotlight for their potential utilization in large-scale energy storage. Despite their preliminary success, zinc-ion storage that is able to deliver capacity > 400 mAh g^-1 remains a great challenge. Here, we demonstrate the viability of NH₄V₄O₁₀ (NVO) as high-capacity cathode that breaks through the bottleneck of ZIBs in limited capacity. The first-principles calculations reveal that layered NVO is a good host to provide fast Zn²⁺ ions diffusion channel along its [010] direction in the interlayer space. On the other hand, to further enhance Zn²⁺ ion intercalation kinetics and long-term cycling stability, a three-dimensional (3D) flower-like architecture that is self-assembled by NVO nanobelts (3D-NVO) is rationally designed and fabricated through a microwave-assisted hydrothermal method. As a result, such 3D-NVO cathode possesses high capacity (485 mAh g^-1) and superior long-term cycling performance (3000 times) at 10 A g^-1 (~ 50 s to full discharge/charge). Additionally, based on the excellent 3D-NVO cathode, a quasi-solid-state ZIB with capacity of 378 mAh g^-1 is developed.