Magnesium alloys as alternative anode materials for rechargeable magnesium-ion batteries: Review on the alloying phase and reaction mechanisms

• The issues with mg metal anodes, such as dendrite formation, passive film development, poor corrosion resistance, and electrolyte compatibility, were thoroughly detailed. • To address issues with pure magnesium anodes, this review discusses using alloying elements combined with magnesium. • The alloying mechanisms of elements combined with magnesium from groups 13, 14, 15, alkali metals, alkaline earth metals, and transition metals were detailed. Magnesium-ion batteries (MIBs) are promising candidates for lithium-ion batteries because of their abundance, non-toxicity, and favorable electrochemical properties. This review explores the reaction mechanisms and electrochemical characteristics of Mg-alloy anode materials. While Mg metal anodes provide high volumetric capacity and dendrite-free electrodeposition, their practical application is hindered by challenges such as sluggish Mg²⁺ ion diffusion and electrolyte compatibility. Alloy-type anodes that incorporate groups XIII, XIV, and XV elements have the potential to overcome these limitations. We review various Mg alloys, emphasizing their alloying/dealloying reaction mechanisms, their theoretical capacities, and the practical aspects of MIBs. Furthermore, we discuss the influence of the electrolyte composition on the reversibility and efficiency of these alloy anodes. Emphasis is placed on overcoming current limitations through innovative materials and structural engineering. This review concludes with perspectives on future research directions aimed at enhancing the performance and commercial viability of Mg alloy anodes and contributing to the development of high-capacity, safe, and cost-effective energy storage systems.