Revealing the intrinsic connection between residual strain distribution and dissolution mode in Mg-Sc-Y-Ag anode for Mg-air battery

• Two Mg- Sc -Y-Ag anodes with different residual strain distribution were developed. • The dissolution mode of anodes changes by altering the residual strain concentration. • A new sight for designing capacity-energy density synergy Mg-air battery is proposed. The dominated contradiction in optimizing the performance of magnesium-air battery anode lies in the difficulty of achieving a good balance between activation and passivation during discharge process. To further reconcile this contradiction, two Mg-0.1Sc-0.1Y-0.1Ag anodes with different residual strain distribution through extrusion with/without annealing are fabricated. The results indicate that annealing can significantly lessen the “pseudo-anode” regions, thereby changing the dissolution mode of the matrix and achieving an effective dissolution during discharge. Additionally, p-type semiconductor characteristic of discharge product film could suppress the self-corrosion reaction without reducing the polarization of anode. The magnesium-air battery utilizing annealed Mg-0.1Sc-0.1Y-0.1Ag as anode achieves a synergistic improvement in specific capacity (1388.89 mA h g -1 ) and energy density (1960.42 mW h g -1 ). This anode modification method accelerates the advancement of high efficiency and long lifespan magnesium-air batteries, offering renewable and cost-effective energy solutions for electronics and emergency equipment.