Electrolyte Solutions for Rechargeable Magnesium Batteries Based on Organomagnesium Chloroaluminate Complexes

Abstract

Magnesium can be reversibly deposited from ethereal solutions of Grignard salts of the RMgX type aryl groups, and Cl, Br), and complexes of the type B; Br; R, or aryl groups, and These complexes can be considered as interaction products between bases and Lewis acids. The use of such complexes in ether solvents enables us to obtain solutions of reasonable ionic conductivity and high anodic stability, which can be suitable for rechargeable Mg battery systems. In this paper we report on the study of variety of complexes, where B, Sb, P, As, Fe, and Ta; Br, and F; and ethyl, phenyl, and benzyl (Bu, Et, Ph, and Bz, respectively) in several solvents, including tetrahydrofuran (THF), 2Me-THF, 1-3 dioxolane, diethyl ether, and polyethers from the “glyme” family, including dimethoxyethane (glyme), and (tetraglyme), as electrolyte solutions for rechargeable magnesium batteries. It was found that complexes (R, Bu and in THF or glymes constitute the best results in terms of the width of the electrochemical window from which magnesium can be deposited reversibly. These solutions were found to be suitable for use in rechargeable magnesium batteries. A variety of electrochemical and spectroscopic studies showed that these solutions have a complicated structure, which is discussed in this paper. It is also clear from this work that Mg deposition-dissolution processes in these solutions are far from being simple reactions of redox couple. The conditions for optimized Mg deposition-dissolution processes are discussed herein. © 2001 The Electrochemical Society. All rights reserved.