Carbon‐Based Materials for Rechargeable Magnesium Batteries: Multifunctional Roles, Mechanistic Insights, and Future Perspectives

ABSTRACT Rechargeable magnesium batteries (RMBs) have emerged as highly promising alternatives to lithium‐ion batteries because of the high volumetric capacity, natural abundance, and potentially improved safety of magnesium metal anodes. However, their practical development remains severely hindered by sluggish Mg 2+ transport kinetics, limited rate capability, and insufficient cycling reversibility. Carbon‐based materials, owing to their high electrical conductivity, low density, excellent chemical stability, corrosion resistance, and structural tunability, offer versatile opportunities to address these challenges and improve the electrochemical performance of RMBs. This review systematically examines the multifunctional roles of carbon‐based materials across different battery components, including their use as active hosts for Mg storage, conductive and structural supports for stabilizing electrode architectures, functional interlayers for regulating polysulfide behavior in magnesium–sulfur batteries, conductive additives, separator modifiers, and corrosion‐resistant current collectors. Particular emphasis is placed on the mechanisms by which carbon materials regulate charge transport, interfacial stability, reaction kinetics, and sulfur‐species conversion. By correlating carbon structure, surface chemistry, and dimensional architecture with electrochemical function, this review establishes structure–property–function relationships that distinguish the roles of carbon in RMBs from those in other battery chemistries. Finally, the remaining challenges and future research directions for the rational design of carbon‐based materials toward advanced RMBs are discussed.