Widening Electrochemical Window of Mg Salt by Weakly Coordinating Perfluoroalkoxyaluminate Anion for Mg Battery Electrolyte. Issue 8 (1st January 2019)

• Record Type: Journal Article
• Authors: Lau, Ka-Cheong; Seguin, Trevor J.; Carino, Emily V.; Hahn, Nathan T.; Connell, Justin G.; Ingram, Brian J.; Persson, Kristin A.; Zavadil, Kevin R.; Liao, Chen
• Is Part Of: Journal of the Electrochemical Society. Volume 166:Issue 8(2019)
• Page Start: A1510
• Page End: A1519
• Publication Date: 2019-01-01
• Subjects: Batteries -- Energy Storage -- Battery -- electrolyte -- weakly coordinating anion; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0751908jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Energy storage concepts based on multivalent ion chemistries, such as Mg 2+, promise very high volumetric energy density, however require improvements in electrolyte (Mg salt and solvent) electrochemical window to reach their full potential. Hypothetically the window of Mg salt could be widened by disfavoring the cathodic decomposition pathway of a thermodynamically and anodically stable anion, rendering it kinetically inert toward Mg + -mediated reduction. Computational and electrochemical analyses on Mg[TPFA]2 ([TPFA] − = [Al{OC(CF3 )3 }4 ] − ) support this hypothesis, and showcase a widened electrochemical window as a result of mitigated cathodic decomposition as well as enhanced anodic stability from electron-withdrawing CF3 groups. Detailed NMR and IR spectroscopy and scanning electron microscopy/energy-dispersive X-ray spectroscopy further support that the weak coordination to Mg 2+ in solution is important for maintaining the wide electrochemical window of Mg salt.