Rational Design of Mixed Solvent and Porous Graphene-Supported Spinel Oxide Electrodes for High-Rate and Long Cycle-Life Mg Batteries

The development of Mg batteries based on the interfacial charge storage mechanism, where the capacity originates from capacitive processes and the solvent-related interfacial reactions, could efficiently circumvent the challenge of intercalation-based Mg batteries with sluggish kinetics. In this work, the proposed Mg organohaloaluminate mixture electrolyte is reported to improve the charge storage performance of the graphene-supported cathodes, resulting in both high cycling stability (91% capacity retention after 2000 cycles) and high rate capability (51% capacity retention when the current density increases by 100 times). The experimental and computational studies have revealed that the exceptional cell performance originates from the optimized electrode/electrolyte interface, where the highly reversible interfacial reactions occur with the 1,2-dimethoxyethane additive in the typical all-phenyl complex electrolyte. The fast charge-transfer kinetics along the surface of highly porous and conductive graphene-supported electrodes have also been observed.