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.

Automated summary

This study demonstrates the synthesis of NH4V4O10 with a decussate structure using a self-template method, which shows remarkable mass energy density, excellent rate performance, and stable cyclic stability. The NH4V4O10 material can effectively prevent structural collapse and enhance electronic diffusion rate, exhibiting superior cycling performance compared to previous reports.