Toward the design of high voltage magnesium–lithium hybrid batteries using dual-salt electrolytes

Abstract

We report a design of high voltage magnesium–lithium (Mg–Li) hybrid batteries through rational control of the electrolyte chemistry, electrode materials and cell architecture. Prototype devices with a structure of Mg–Li/LiFePO₄ (LFP) and Mg–Li/LiMn₂O₄ (LMO) have been investigated. A Mg–Li/LFP cell using a dual-salt electrolyte 0.2 M [Mg₂Cl₂(DME)₄][AlCl₄]₂ and 1.0 M LiTFSI exhibits voltages higher than 2.5 V (vs. Mg) and a high specific energy density of 246 W h kg⁻¹ under conditions that are amenable for practical applications. The successful demonstrations reported here could be a significant step forward for practical hybrid batteries.