VSe2/FeSe2 nanocubes synthesized by template method for high-performance aqueous ammonium ion batteries

Aqueous ammonium ion batteries have attracted wide attention due to their advantages of low cost, high safety and environmental friendliness. However, the low energy density limits its large-scale commercial application. In this work, a novel positive electrode material VSe2/FeSe2 for aqueous ammonium ion batteries was prepared by using KVFe PBAs NCs as a precursor. The as-synthesized VSe2/FeSe2 electrode exhibits excellent rate capability and stability at ultra-high current density. In 1 M (NH4)2SO4 electrolyte, the maximum charge/discharge capacity of the battery reached 227.1 mAh·g−1 at 1 A·g−1 current density, while the specific capacity retention rate of the battery reached 81.22% after 2000 cycles at 2 A·g−1. The excellent rate capability with a specific capacity of 109.7 mAh·g−1 at 5 A·g−1. This work provides some valuable ideas for the development of efficient electrode materials for aqueous ammonium ion batteries. •The VSe2/FeSe2 electrode exhibited excellent rate capability and stability at ultra-high current density.•Uniform nanocube morphology.•By selenizing the KVFe PBAs precursor, the voltage window was effectively widened.