Unlocking Mg ²⁺ Transport in Magnesium Batteries: Aromatic Architectures and Systemic Co‐Design

ABSTRACT Magnesium batteries have attracted interest as post‐lithium energy‐storage systems because Mg metal offers high volumetric capacity, dendrite‐free deposition under many conditions, and favorable elemental abundance. However, their practical development remains limited by sluggish Mg ²⁺ transport across length scales, including interfacial ion desolvation and solid‐state diffusion. Against this backdrop, aromatic compounds have emerged as a platform for magnesium‐battery design, not simply because they provide redox‐active motifs, but because their low‐electronegativity frameworks, delocalized π‐electron systems, and molecular programmability can mitigate localized electrostatic trapping and regulate Mg ²⁺ migration pathways. This review discusses how aromatic chemistry can address the key bottlenecks of magnesium batteries from three interconnected perspectives: cathode design, anode interphase engineering, and electrolyte compatibility. Particular emphasis is placed on perylene diimide (PDI)‐based systems, which provide a rare model platform in which molecular structure, conjugation mode, steric distortion, ion‐accessible geometry, and storage mechanism can all be deliberately tuned. We further discuss aromatic artificial interphases for Mg‐metal protection, including fullerene‐derived networks as mechanistically illustrative examples, and analyze how electrolyte chemistry governs storage species, interfacial compatibility, and active‐material stability. Rather than treating cathodes, anodes, and electrolytes as isolated components, this review emphasizes mechanism‐oriented co‐design and critically assesses the limitations of aromatic materials for magnesium batteries.