Understanding the Interface between Electrolytes and Transition Metal Fluoride Cathodes

We request 4 days on NIMROD to determine the structure of LiFSI in N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (Pyr1,3 FSI) ionic liquid electrolyte at the interface with transition metal fluoride (TMF) conversion cathodes (FeF2 and CuF2). The absence of practical cost-effective high-energy density cathodes is currently hindering the advancement of battery storage capacity. TMF conversion cathodes can potentially fill this void possessing a substantially higher capacity at a lower cost compared to current intercalation cathodes. However, a limited cycling stability have impeded their practical use so far, with origins tied to the interface between the liquid electrolyte and the cathode. Here, we aim to investigate the solvent and ion structuring at the interface between the electrolyte and the FeF2 and CuF2 cathode nanorods, before and after cycling, to determine the molecular interactions involved in degradation mechanisms.