Recent progress of magnesium electrolytes for rechargeable magnesium batteries

Magnesium batteries have attracted considerable interest due to their favorable characteristics, such as a low redox potential (−2.356 V vs. the standard hydrogen electrode (SHE)), a substantial volumetric energy density (3833 mAh cm−3), and the widespread availability of magnesium resources on Earth. This facilitates the commercial production of magnesium batteries for widespread applications. Nonetheless, The progression of magnesium battery technology faces hindrances from the creation of a passivated film at the interface between the magnesium anode and electrolyte, along with the slow diffusion kinetics of Mg2+. Accordingly, exploring magnesium electrolytes is regarded as a viable approach to address the previously mentioned obstacles. This review presents a comprehensive overview of recent advancements in magnesium electrolytes, encompassing organic Grignard reagents and their derived systems, magnesium–aluminum-chloride complex (MACC) systems, boron-based systems, and molten salt systems. Specifically, it systematically examines various promising strategies for magnesium electrolytes, primarily focusing on improving the efficient reversible Mg deposition/stripping within the electrolyte. Ultimately, the present state of electrolyte advancement is concisely outlined, and the prospective directions of magnesium battery evolution are delineated. This brief review aims to furnish researchers with insights into the prevailing challenges and inspire researchers to formulate magnesium electrolytes suitable for commercial applications.