Mg2VO4/VO2 Nanocomposites as Aqueous Zinc Ion Battery Cathodes with High Capacity and High Ion Diffusion Rate

As one of the representative vanadium-based electrode materials for aqueous zinc ion batteries (AZIBs), VO2(B) owns excellent cycling stability and specific capacity, but the strong interlattice interactions lead to poor rate performance. Herein, multiphase, high ion diffusion rate Mg2VO4/VO2 (MVO/VO) heterostructures composed of nanoparticles were introduced and constructed based on a solid preinsertion method. The electrochemical results show that the MVO/VO electrode has excellent cycling stability and impressively high capacity and ion diffusion rate compared with pure VO2(B) (VO) and Mg2VO4 (MVO). Moreover, the reversible capacity of MVO/VO is found to be 393.6 mA h g–1 at a relatively low current density (0.3 A g–1). The MVO/VO electrode still exhibits a capacity retention of 83.6% even after 1000 charge/discharge applications, which indicates a stable performance. Finally, this contribution offers insights into the design of high-capacity and high ion diffusion rate AZIB cathode materials.