Unlocking High-Voltage Cathode Compatibility of Amine-Based Solvents through Enhanced Cation–Solvent Interaction for Rechargeable Mg Batteries

Conventional amine-based electrolytes exhibit superior compatibility with Mg metal anodes, but their practical application is fundamentally constrained by both a restricted electrochemical stability window (+ solvation structure to alleviate overly strong amine coordination, while the rest can serve as a pseudo-diluent, promoting a reduced cathode desolvation energy barrier and enhanced ion transport. Finally, the Mg//LiFePO4 battery delivers a stable plateau of 2.7 V and a high energy density at the electrode level. This work proposes an efficient electrolyte design paradigm that simultaneously balances Mg anode reversibility, high-voltage cathode compatibility, and a facile preparation method in Mg batteries for the first time, revealing a comprehensive exploration process for high-voltage Mg batteries.