Asymmetric Solvent Enables Adaptive Electrolyte with Orientation‐Modulated Structure for Ultrafast Charging Magnesium Metal Batteries

ABSTRACT The further development of rechargeable magnesium batteries (RMBs) is limited by significantly degraded performance under harsh working conditions, such as high areal capacity and large current density. This work first explores the failure mechanism of the Mg metal anode during fast charging and reveals the critical role of interfacial strong solvent shielding in governing the high‐current performance. Then, we propose an electrolyte design strategy by introducing asymmetric cosolvents to regulate the interfacial solvation structure through electric‐field‐induced dipole reorientation. Specifically, the electric‐field‐induced orientational rearrangement of asymmetric cosolvents reduces the solvation reorganization energy, thereby lowering the electron‐transfer activation barrier and accelerating electron‐transfer kinetics. Simultaneously, this orientational reorganization also weakens solvent‐induced shielding of Mg 2+ at the interface, enabling preferential electron localization on Mg 2+ rather than solvent molecules. Consequently, this proposed electrolyte strategy enables rapid Mg 2+ migration and ultra‐stable Mg plating/stripping (<0.3 V overpotential at 10 mA cm −2 /1000 h). Moreover, the full cell paired with Mo 6 S 8 delivers 65 mAh g −1 capacity at 5C current density and when paired with fluorinated graphite exhibits excellent rate performance (over 350 mAh g −1 at 10C), establishing a kinetic paradigm for high‐rate multivalent battery systems.