A Simple Halogen-Free Magnesium Electrolyte for Reversible Magnesium Deposition through Cosolvent Assistance

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

12 Scopus Citations
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Author(s)

  • Shengqi Fan
  • Genevieve M. Asselin
  • Baofei Pan
  • Hao Wang
  • John T. Vaughey
  • Niya Sa

Detail(s)

Original languageEnglish
Pages (from-to)10252-10260
Journal / PublicationACS Applied Materials and Interfaces
Volume12
Issue number9
Online published30 Jan 2020
Publication statusPublished - 4 Mar 2020
Externally publishedYes

Abstract

Rechargeable Mg batteries are one of the most investigated polyvalent-metal storage batteries owing to the increased safety associated with the nondendritic nature of Mg electrodeposition, high volumetric capacity, and low cost. To realize the commercial applications of Mg batteries, there are still a number of challenges remaining unsolved, in particular, the lack of halogen-free Mg electrolytes, as the use of the halogens remains a major limiting factor to achieving high voltage cathodes. Work presented here introduces an innovative approach to prepare a halogen-free Mg-based electrolyte in a simple, nonsynthetic method that can plate and strip Mg reversibly. Results suggest that by introducing a secondary amine cosolvent the magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) salt can be easily dissolved into a wide array of polar but aprotic ether solvents. A systematic structural investigation of a representative Mg(TFSI)2 electrolyte in the cosolvent systems with the secondary amine was performed using pair distribution function (PDF) analysis, single crystal diffraction analysis, and NMR. The experimental atomic scale understanding reveals an ion pair structure of Mg2+ coordinated with six oxygen donors from the bis(trifluoromethanesulfonyl)imide (TFSI) anions and the THF solvent located in the first solvation shell. The as-formed neutral ion pair structure acts as the active component for reversible Mg deposition. We believe this new route of preparing Mg electrolytes can extend the current understanding of Mg electrolyte functionality for rechargeable Mg batteries and offers more guidance for the future electrolyte design.

Research Area(s)

  • Mg electrolyte, non-halogen Mg electrolyte, rechargeable Mg battery, reversible Mg deposition

Citation Format(s)

A Simple Halogen-Free Magnesium Electrolyte for Reversible Magnesium Deposition through Cosolvent Assistance. / Fan, Shengqi; Asselin, Genevieve M.; Pan, Baofei; Wang, Hao; Ren, Yang; Vaughey, John T.; Sa, Niya.

In: ACS Applied Materials and Interfaces, Vol. 12, No. 9, 04.03.2020, p. 10252-10260.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review