Ca-dimers, solvent layering, and dominant electrochemically active species in Ca(BH4)2 in THF

Authors: Ana Sanz Matias, Fabrice Roncoroni, Siddharth Sundararaman, David Prendergast

Published: 2024-02-15

DOI: 10.1038/s41467-024-45672-7

Source: Full article


Abstract

AbstractDivalent ions (Mg, Ca, and Zn) are being considered as competitive, safe, and earth-abundant alternatives to Li-ion electrochemistry, but present challenges for stable cycling due to undesirable interfacial phenomena. We explore the formation of electroactive species in the electrolyte Ca(BH4)2∣THF using molecular dynamics coupled with a continuum model of bulk and interfacial speciation. Free-energy analysis and unsupervised learning indicate a majority population of neutral Ca dimers and monomers with diverse molecular conformations and an order of magnitude lower concentration of the primary electroactive charged species – the monocation, $${\rm{CaBH}}_{4}^{+}$$