Intercalation Mechanism of the Ammonium Vanadate (NH4V4O10) 3D Decussate Superstructure as the Cathode for High-Performance Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) are promising candidates for practical energy storage due to their superior energy density, nontoxicity, and environmental friendliness. However, it is still a tremendous quest to seek an outstanding cathode material to reach a splendid rate property as well as stable long-term cycle property. Herein, we present a self-template method to synthesize NH4V4O10 with a decussate structure and the intercalation mechanism via a simple one-step hydrothermal method, which delivers a prominent mass energy density of 332.25 W h kg–1, excellent rate performance, and a stable long-time cycle. Attributing to its specific decussate morphology consisting of vast vertical nanobelts and the intercalation of NH4+ with hydrogen bonding between ammonium ions and vanadium oxide layers as a "pillar" in the V2O5 host, the NH4V4O10 electrode material can effectively prevent structural collapse as well as promote the rate of electronic diffusion in the de(intercalation) process of Zn2+. Importantly, the materials not only deliver 243 and 221.4 mA h g–1 (98.7 and 90% retention of initial discharge capacity of 246 mA h g–1, respectively) in 1480 cycles and 2100 cycles, respectively, at 5 A g–1 but also maintain a specific capacity of 417.35 mA h g–1 at 0.1 A g–1 in the 150th cycle, which delivers a superior property compared with the previously reported metal-intercalated V2O5. Therefore, this work provides the direction to choose and design a novel cathode material with a peculiar morphology and admirable performance for AZIBs and other secondary batteries.