Perspective—Fluorinating Interphases

Electrode/electrolyte interphase in Li-ion batteries is a critical component that ensures reversible cell reactions far from thermodynamic equilibria. The desired chemical composition and morphology for such interphase, however, remain controversial. Recent advances in battery chemistries and their electrolytes demonstrated that the presence of fluorine in the interphase, either in the form of simple inorganic fluorides (LiF) or organofluoro-moieties, brought positive impacts on the electrochemical performances. Beside the identification of chemical composition, understanding how these fluorinated species exists and distribute in the interphase might constitute the key know-how for the next generation battery chemistries. This is a topic that the battery research community should focus their attention on.