Effects of Mg and Pd Contents on the Structure and Electrochemical Properties of Ball-Milled Mg–Pd–Ni Alloys as Anodes in Ni–MH Batteries

The use of Mg-based alloys as anode materials in nickel–metal hydride (Ni–MH) batteries is significantly limited by rapid capacity loss during charge–discharge cycles. This study conducts a comprehensive examination of how variations in the concentrations of Mg and Pd impact the microstructural characteristics and electrochemical behavior of Mg–Pd–Ni ternary alloys, aiming to enhance cyclic durability and uncover the fundamental degradation mechanisms. This work demonstrates that increasing the Mg content tends to reduce the reversibility of electrochemical hydrogenation/dehydrogenation reactions and exacerbates the corrosion behavior of the milled Mg–Pd–Ni alloy electrodes, thus accelerating their capacity decay. On the contrary, raising the Pd content contributes to improving the reversibility of electrochemical hydrogenation/dehydrogenation reactions and the kinetic behavior of the alloys, yet it does not enhance corrosion resistance.