Original Research ARTICLE
Elucidating Non-aqueous Solvent Stability and Associated Decomposition Mechanisms for Mg Energy Storage Applications from First-Principles
- 1Lawrence Berkeley National Laboratory, United States Department of Energy (DOE), United States
- 2Sandia National Laboratories (SNL), United States
- 3University of California, Berkeley, United States
Rational design of novel electrolytes with enhanced functionality requires fundamental molecular-level understanding of structure-property relationships. Here we examine the suitability of a range of organic solvents for non-aqueous electrolytes in secondary magnesium batteries using density functional theory (DFT) calculations as well as experimental probes such as cyclic voltammetry and Raman spectroscopy. The solvents considered include ethereal solvents (e.g., glymes) sulfones (e.g., tetramethylene sulfone), and acetonitrile. Computed reduction potentials show that all solvents considered are stable against reduction by Mg metal. However, solvents in contact with partially reduced Mg cations (Mg2+ → Mg+) formed during cycling (e.g. deposition) was explored with reaction profiles of decomposition pathways. Most solvents, including some proposed for secondary Mg energy storage applications, exhibit decomposition pathways that are surprisingly exergonic. Interestingly, the stability of these solvents is largely dictated by magnitude of the kinetic barrier to decomposition. This insight should be valuable towards rational design of improved Mg electrolytes.
Keywords: multivalent batteries, Electrolytes, Density Functional Theory, decomposition mechanism, bifurcation
Received: 16 Nov 2018;
Accepted: 06 Mar 2019.
Edited by:Alexandre Ponrouch, Instituto de Ciencia de Materiales de Barcelona (ICMAB), Spain
Reviewed by:Masaki Matsui, Kobe University, Japan
Elena Arroyo, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Spain
Copyright: © 2019 Seguin, Hahn, Zavadil and Persson. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Kristin Persson, Lawrence Berkeley National Laboratory, United States Department of Energy (DOE), Berkeley, United States, firstname.lastname@example.org