TY - JOUR AU - Ka-Cheong Lau AU - Trevor J Seguin AU - Emily V Carino AU - Nathan T Hahn AU - Justin G Connell AU - Brian J Ingram AU - Kristin A Persson AU - Kevin R Zavadil AU - Chen Liao AB -

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.

BT - Journal of The Electrochemical Society DA - 04/2019 DO - 10.1149/2.0751908jes IS - 8 LA - eng N2 -

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.

PY - 2019 SP - A1510 EP - A1519 ST - J. Electrochem. Soc. T2 - Journal of The Electrochemical Society TI - Widening Electrochemical Window of Mg Salt by Weakly Coordinating Perfluoroalkoxyaluminate Anion for Mg Battery Electrolyte VL - 166 SN - 0013-4651 ER -