A Multicomponent Saturated MgCl₂/Glucose/Isopropanol Electrolyte for Aqueous Magnesium-Ion Batteries

Magnesium-ion batteries (MIBs) have attracted increasing attention owing to their high theoretical capacity, intrinsic safety, and cost-effectiveness of metallic Mg anodes, as well as the natural abundance of magnesium. However, their development remains impeded primarily by the incompatibility between Mg anodes and conventional electrolytes. Herein, we report a novel multicomponent, high-concentration aqueous magnesium electrolyte design, realized by introducing isopropanol (IPA) and glucose (Glu) into a saturated MgCl₂ solution, denoted as SMIG. The incorporation of IPA and Glu disrupts the original hydrogen-bond network of the SM electrolyte, reducing the content of free water and thereby mitigating water-related side reactions. This synergistic effect alleviates the corrosion of the Mg alloy anode and inhibits the hydrogen evolution reaction (HER) during magnesium deposition. As a result, the assembled polyaniline//Mg alloy aqueous MIB (AMIB) delivers a high specific capacity of 127.9 mAh  g^-1 at a current density of 0.2 A g^-1 and retains 92.9% of its initial capacity after 300 cycles, with a Coulombic efficiency approaching 100%. This work provides a promising strategy toward developing high-performance and durable AMIBs.