A MOF-derived layered K-VO heterojunction material as a high-performance cathode for aqueous zinc ion batteries

Abstract

Aqueous zinc ion batteries (AZIBs) are considered to be an attractive energy storage system due to their low cost, environmental friendliness and high safety. In this work, a novel multi-layer rhombus K_0.5V₂O₅ and KVO₃ heterojunction compound (3K-VO) was synthesized using a MOF precursor as an excellent AZIB cathode material, achieving excellent electrochemical performance. After 100 cycles at 0.5 A g⁻¹, 3K-VO exhibits a high specific capacity of 301 mA h g⁻¹. After 2000 cycles at current densities of 5 A g⁻¹ and 10 A g⁻¹, the reversible specific capacities are 114.6 and 103.1 mA h g⁻¹, respectively, and the capacity retention rates are 93.2% and 88.5%, respectively. Through ex situ X-ray diffraction and various characterization techniques, it is revealed that the excellent performance of the 3K-VO cathode is due to its structural stability, sufficient active sites and high conductivity. This work provides a new design strategy for the preparation of efficient cathode materials for AZIBs and other fields.