Layered (NH4)2V6O16·1.5H2O nanobelts as a high-performance cathode for aqueous zinc-ion batteries

Abstract

Rechargeable aqueous zinc-ion batteries have shown great potential for grid-scale applications owing to their high safety, low cost and sustainability. However, they are still limited by the lack of suitable cathode materials with high energy density and satisfactory cycling stability. Herein, a highly reversible zinc-ion battery system with (NH₄)₂V₆O₁₆·1.5H₂O nanobelts as the cathode materials and aqueous ZnSO₄ solution as the electrolyte has been developed. The (NH₄)₂V₆O₁₆·1.5H₂O nanobelts deliver a superior reversible specific capacity of 479 mA h g⁻¹ at 0.1 A g⁻¹ with a desirable energy density of 371.5 W h kg⁻¹ and exhibit an impressive cycling stability, i.e. 152 mA h g⁻¹ retained after 3000 cycles at 5 A g⁻¹. The high energy density and long-term cycling stability make (NH₄)₂V₆O₁₆·1.5H₂O a promising candidate for grid-scale energy storage. This work could be extended to choose and construct other ideal high-performance cathode materials for ZIBs and other multivalent metal ion storage systems.