Facile hydrothermal synthesis and electrochemical properties of (NH4)2V10O25·8H2O nanobelts for high-performance aqueous zinc ion batteries

Abstract Aqueous rechargeable Zn-ion batteries (ARZIBs) are highly desirable for grid-scale applications because of their high safety, low cost, sustainability, and environmental friendliness. However, the lack of suitable cathode materials possessing satisfactory cycle performance and energy density limits their wide applications. In this work, (NH4)2V10O25·8H2O nanobelts, the ammonium ion, and water expanded VO skeletons, are synthesized by a facile hydrothermal synthesis and reported as a cathode material in ARZIBs. The Zn//(NH4)2V10O25·8H2O nanobelts battery achieves capacities as high as 417, 366, 322, 268 and 209 mA h g−1 at 0.1, 0.2, 0.5, 1.0 and 2.0 A g−1 respectively, showing high rate capacity. In addition, the battery not only exhibits an excellent cycle lifespan of 310 mA h g−1 after 100 cycles (0.1 A g−1), but delivers a high energy density of 320 Wh kg−1 at the power density of 77 W kg−1. These results demonstrate that the Zn//(NH4)2V10O25·8H2O nanobelts battery possesses significantly enhanced electrochemical performances, which is superior to most state-of-the-art cathode materials for ARZIBs. Furthermore, the reaction mechanism of the reversible Zn2+ intercalation/deintercalation into (NH4)2V10O25·8H2O is studied by multiple analytical methods. This work not only demonstrates that (NH4)2V10O25·8H2O nanobelts can act as a promising cathode candidate, but also provides an attractive solution for the synthesis of cathode materials for ARZIBs and other multivalent metal-ion batteries.