Mechanochemically Activated Low-Temperature Synthesis of Vanadyl Ethylene Glycolate with Scale-Up Potential for Aqueous Zinc-Ion Batteries

Vanadyl ethylene glycolate (VEG) is a cathode material for aqueous multivalent-ion batteries that is typically synthesized under elevated temperature and pressure, posing a challenge for large-scale production. Here, we report a mechanochemically assisted polyol strategy for the low-temperature and ambient-pressure synthesis of VEG at 95 °C. Detailed structural analysis reveals the conversion from V2O5 to VEG together with a ligand coordination evolution from monodentate to bidentate, establishing a correlation between synthesis chemistry and electrochemical performance. The VEG synthesized under low-temperature conditions delivers a high specific capacity of 375 mAh g−1 at 0.2 A g−1, together with rate capability and cycling stability highly competitive with previously reported high-temperature counterparts. Mechanistic studies further reveal an irreversible crystalline-to-amorphous transition during the initial discharge, followed by reversible Zn2+/H+ co-intercalation within the resulting amorphous matrix. This work provides a scalable and integrated synthesis route for VEG and describes a contribution of amorphization to charge storage in aqueous zinc-ion batteries.