We present a fundamental study on [(µ-Cl)3Mg2(THF)6]+dimer electrolytes using various physical methods including Subambient Pressure Ionization with Nanoelectrospray Mass spectrometry (SPIN-MS), Raman spectroscopy, 25Mg{1H} NMR, 27Al{1H} NMR and electrochemical analysis. For the first time, long time sought THF solvated [MgCl]+ species was experimentally characterized by SPIN mass spectrometry in the solution of the Mgdimer containing electrolyte, confirming the mono-Cl- abstraction reaction between MgCl2 and an Al Lewis acid. Solvated MgCl2 in the electrolyte was confirmed by Raman spectroscopy. The experimental results establish the previously proposed dimerization equilibrium of solvated [MgCl]+ and MgCl2 with [(µ-Cl)3Mg2(THF)6]+. 25Mg{1H} NMR, 27Al{1H} NMR and electrochemical analysis on chloration reaction of [(µ-Cl)3Mg2(THF)6]AlPh3Cl with external Cl- led to further insights on the coordination chemistry of the dimer electrolyte. Finally, a comprehensive mechanism is proposed for the reversible electrochemical Mg deposition and stripping and Mg2+ and Cl- ion transports of the Mg dimer electrolytes in rechargeable Mg batteries.
Revised: July 10, 2015 |
Published: January 5, 2015
Citation
Liu T.L., J.T. Cox, D. Hu, X. Deng, J.Z. Hu, M.Y. Hu, and J. Xiao, et al. 2015.A Fundamental Study on the [(µ-Cl)3Mg2(THF)6]+ Dimer Electrolytes for Rechargeable Mg Batteries.Chemical Communications 51, no. 12:2312-2315.PNNL-SA-104532.doi:10.1039/c4cc07621d