Low-Cost and Large-Scale Preparation of H2O and Mg2+ Co-Preintercalated Vanadium Oxide with High-Performance Aqueous Zn-Ion Batteries

Rechargeable zinc-ion batteries (ZIBs) are considered the most promising energy storage device to replace lithium-ion batteries (LIBs) due to their high security and environment-friendly feature. However, the synthesis of high-performance cathode materials usually requires harsh conditions (such as high temperature and high pressure), which limits the practical application of ZIBs. Herein, a facile large-scale preparation of H2O and Mg2+ co-intercalated vanadium oxide is realized by heating vanadium pentoxide and magnesium sulfate solution in a water bath at low temperature. Through in-depth investigation, it is found that the introduced H2O and Mg2+ not only expand the layer spacing of vanadium pentoxide but also improve the structural stability of V–O layers and ion diffusion. As a result, the obtained product displays an excellent specific capacity of 473 mAh g–1 at 0.1 A g–1 and superior cycle performance when used as the cathode material of ZIBs. Such a result indicates that H2O and Mg2+ co-intercalated vanadium oxide shows a good application prospect.