Glutamate as a bio-compatible electrolyte additive for sustainable high-performance magnesium-air batteries

Screening electrolyte additives that effectively inhibit anode self-corrosion while enhancing cell voltage is a critical challenge for advancing sustainable battery technologies. Herein, glutamate, a common food flavoring agent, is proposed as a bio-compatible electrolyte additive for Mg-air batteries. The employing glutamate not only address the challenge, leading to an exceptional energy density of 2.52 kWh·kg -1 in a half-cell discharge test, but also surpasses most reported additives in terms of environmental friendliness, cost-effectiveness, and broad applicability to various Mg anodes. Insights into the mechanistic understanding of the effect of glutamate on anode self-corrosion processes were provided. Advanced synchrotron microtomography analysis revealed the glutamate-triggered anodic chunk effect, while in-operando scanning localized microprobe techniques were employed to investigate oxygen reduction at the anode surface. Besides, a novel 3D equilibrium predominance diagram was constructed to determine optimal glutamate concentrations, showing strong alignment with experimental findings. In summary, this work presents a robust strategy for designing electrolyte compositions, accurately quantifying Mg anode weight loss attributable to the chunk effect, and providing a potential bio-compatible electrolyte additive for implantable Mg batteries.