Sodium ion and sodium-air rechargeable battery technologies have theoretical energy densities slightly lower than their lithium counterparts, but use a much cheaper and more abundant metal namely sodium. One aspect of optimizing these systems is to focus on the electrolyte in order to design efficient next generation batteries. This requires an understanding of the solvation and dynamics of the charge transport species in the electrolyte. While most conventional metal-ion energy storage devices use electrolytes with a salt concentration of 1 M, the optimum salt concentration for certain electrolytes for sodium-ion and sodium-air systems could be much higher.  A joint computational-experimental study was carried out on sodium triflate in digylme, an electrolyte that has shown significant potential in sodium–air battery technology. An empirical force field was developed for this electrolyte based on data from ab initio molecular dynamics simulations in conjunction with the variational force-matching method. The qualitative accuracy of this empirical model was validated by comparing atomistic simulations of this electrolyte with results from Fourier transform infrared (FTIR) experimental studies, and the results demonstrated its transferability across different concentrations. The model has also been extended to larger glyme based electrolytes. The results from this work on the solvation structure and the dynamics of the charge transport ions in different glyme based electrolytes as a function of changes in environment, from salt concentration to the presence of applied electric field, will be presented. <br/>

Structure and dynamics of glyme based electrolytes for sodium based rechargeable batteries

253rd National Meeting (2017)

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