Widening Electrochemical Window of Mg Salt by Weakly Coordinating Perfluoroalkoxyaluminate Anion for Mg Battery Electrolyte

Widening Electrochemical Window of Mg Salt by Weakly Coordinating Perfluoroalkoxyaluminate Anion for Mg Battery Electrolyte

TitleWidening Electrochemical Window of Mg Salt by Weakly Coordinating Perfluoroalkoxyaluminate Anion for Mg Battery Electrolyte
Publication TypeJournal Article
Year of Publication2019
AuthorsKa-Cheong Lau, Trevor J Seguin, Emily V Carino, Nathan T Hahn, Justin G Connell, Brian J Ingram, Kristin A Persson, Kevin R Zavadil, Chen Liao
JournalJournal of The Electrochemical Society
Volume166
Issue8
PaginationA1510 - A1519
Date Published04/2019
ISSN0013-4651
Abstract

Energy storage concepts based on multivalent ion chemistries, such as Mg2+, 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 Mg2+ in solution is important for maintaining the wide electrochemical window of Mg salt.

DOI10.1149/2.0751908jes
Short TitleJ. Electrochem. Soc.
Refereed DesignationRefereed