Evaluation of (CF3SO2)2N− (TFSI) Based Electrolyte Solutions for Mg Batteries. Issue 13 (1st January 2015)

• Record Type: Journal Article
• Authors: Shterenberg, Ivgeni; Salama, Michael; Yoo, Hyun Deog; Gofer, Yosef; Park, Jin-Bum; Sun, Yang-Kook; Aurbach, Doron
• Is Part Of: Journal of the Electrochemical Society. Volume 162:Issue 13(2015)
• Page Start: A7118
• Page End: A7128
• Publication Date: 2015-01-01
• Subjects: ether solutions -- LiTFSI -- Mg batteries -- Mg salts -- MgTFSI2; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0161513jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : MgTFSI2 is the only ether-soluble "simple" magnesium salt. The poor electrochemical performance of Mg electrodes in its solutions hinders its practicality as a viable electrolyte for Mg batteries. MgTFSI2 /DME solutions were demonstrated to dissolve large quantities of MgCl2 and produce electrolyte solutions with superior performance, though the electrochemical performance, mainly in terms of reversibility, of MgTFSI2 /MgCl2 (DME) solutions cannot yet compete with that of organometallic based electrolyte solutions. We believe that the solutions' purity level governs the overall electrochemical performance, especially in solutions where a strong reductant (i.e Grignard reagent) is not present to act as an impurity scavenger. In this work, we alter the performance of the MgTFSI2 /MgCl2 (DME) solutions through chemical and electrochemical conditioning and demonstrate the effect on the solutions' electrochemical characteristics. We demonstrate relatively high reversible behavior of Mg deposition/dissolution with crystalline uniformity of the Mg deposits, complemented by a fully reversible intercalation/de-intercalation process of Mg ions into Mo6 S8 cathodes. We also investigated LiTFSI/MgCl2 solutions which exhibited even higher reversibility than MgTFSI2 /MgCl2 (DME) solutions, which we attribute to the higher purity level available for the LiTFSI salt.