Investigation on high performance and stabilized surface of AlF3-coated V2O5 micro-flower for zinc energy storage

Vanadium oxide (V2O5) cathode material, possessing abundant reserves and high theoretical capacity, has been extensively researched in aqueous zinc ion batteries (ZIBs). However, its electrochemical performance is significantly hindered by insufficient electronic conductivity, vanadium dissolution into electrolyte, and slow diffusion kinetics. In this study, the V2O5 micro-flower was first synthesized by a solvothermal method, and then modified by coating with AlF3 passivation layer, forming AlF3@V2O5 hybrid material. Impressively, AlF3@V2O5 exhibits excellent electrochemical and kinetic properties due to the special structure of V2O5 and the interfacial protection of AlF3. An exceptional rate property (325 mAh g−1 at 0.1 A g−1, 188 mAh g−1 at 15 A g−1) as well as extraordinary cycling stability with 89.3% capacity retention after 6000 cycles at 10 A g−1 can be attained with 2 wt% AlF3 addition (that is AF-2@V2O5). The computation based on density functional theory (DFT) suggests that AlF3 coating can reduce the interlayer electrostatic interaction and adsorption energy barrier between the intercalated Zn2+ and V2O5 host, thereby enabling fast redox kinetics. This study showcases the efficacy of interfacial modification of passivated coatings and presents an influential approach for material design in ZIBs.