(Invited) Understanding and Controlling Electrolyte Solvation-Stability Relationships Toward Energy Dense Multivalent Batteries

Abstract

High energy density multivalent batteries, primarily those based on Mg or Ca metal anodes, have remained theoretically promising but practically elusive for many years. Simultaneous development of novel electrolytes and cathode materials has been undertaken across the globe in an attempt to make such batteries practical. However, a relative dearth of effective solid-electrolyte-interphase (SEI) chemistry in these systems imposes stability challenges for the electrolyte at the strongly reducing metal anode and strongly oxidizing transition metal oxide cathode interfaces. Therefore, electrolyte advances have been driven primarily by the utilization of constituents having exceptional reductive and/or oxidative stability. Addressing these intrinsic stability criteria are, however, only half the battle; the solvation interactions of these constituents with the strong Lewis acid working cations and the resultant stability effects must be considered as well.In this presentation I will describe recent insights and approaches in Mg and Ca battery electrolyte design from the solvation science perspective incorporating both theory and experiment. I will focus especially on strategies for managing solvent-cation interactions to achieve electrolyte stability toward both anodes and cathodes. From this discussion, I will provide some perspective on opportunities and considerations for future advancement in multivalent (or other) battery electrolytes.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.