Interfacial anionic competition-driven electrochemical evolution in FeF3 conversion electrodes (opens in new tab)

Iron trifluoride demonstrates poor performance as a multi-electron conversion positive electrode in conventional ester-based electrolytes, yet exhibits higher capacity retention in ether-based electrolytes. This contrast has long remained unresolved in high-energy-density metal fluoride-lithium batteries. Here, we show that the electrolyte-dependent behavior originates from interfacial anion competition within the cathode-electrolyte interphase. Spectroscopic and electrochemical analyses reve...