A High-Performance Magnesium Triflate-based Electrolyte for Rechargeable Magnesium Batteries
Dan Thien Nguyen, Alex Yong Sheng Eng, Man‐Fai Ng, Vipin Kumar, Zdeněk Sofer, Albertus D. Handoko, Gomathy Sandhya Subramanian, Zhi Wei Seh
Abstract
The quest for a suitable electrolyte formulation is pivotal to the success of rechargeable magnesium batteries. A simple conventional electrolyte having high compatibility with magnesium anode and cathode material is in great demand. Herein, we report a simple yet effective electrolyte formulation, comprising magnesium triflate (Mg(OTf)2) and magnesium chloride in monoglyme, that can enable highly reversible, conditioning-free, and homogeneous magnesium deposition. Galvanostatic Mg plating/stripping demonstrates an average Coulombic efficiency of 99.4% over 1,000 cycles. The cells show excellent performance at current densities up to 3 mA cm−2 and areal capacities up to 5 mAh cm−2. Post mortem analysis unveils the formation of a robust solid electrolyte interphase, which leads to improved kinetics at the magnesium electrode. A prototype Mg battery with Mo6S8 cathode demonstrates stable cycling performance over 100 cycles. This study shows that rational design of Mg(OTf)2-based electrolytes is a promising direction toward the realization of high-performance magnesium batteries.