The Impact of Aluminum Doping on the Performance of MgV₂O₄ Spinel Cathodes for High-Rate Zinc-Ion Energy Storage

This study explores the development of aluminum doped MgV2O4 spinel cathodes for aqueous zinc-ion batteries (AZIBs), aiming to overcome the challenges of poor ion diffusion and structural instability. Al3+ ions were pre-inserted into the spinel structure using a sol-gel method, enhancing the material's structural stability and electrical conductivity. The Al3+ doping mitigates the electrostatic interactions between Zn2+ ions and the cathode, improving ion diffusion and facilitating efficient charge/discharge processes. The resulting Al-MgV2O4 cathode demonstrates excellent electrochemical performance, retaining a capacity of 254.3 mAh g−1 at an ultra-high current density of 10 A g−1 after 1000 cycles, with a capacity retention of 93.6%. At an ultra-high current density of 20 A g−1, the material retains 186.8 mAh g−1 after 2000 cycles, with a capacity retention of 90.2%, making it a promising candidate for high-rate energy storage applications.