Solid-Electrolyte-Interphase Formation and Effects on Li Metal Anodes

Abstract

Theoretically, lithium metal anodes are the optimal negative electrodes. In practice, several obstacles arising from the extreme lithium reactivity limit their applications. The surrounding environment in principle can modify lithium electronic structure, which determines its reactivity. For this purpose, a variety of electrolyte chemistries (liquid, solid, polymer, gel) have been and are continuously tested. Moreover, the solid-electrolyte interphase (SEI) that results from electron transfer from the anode to the electrolyte is usually a multicomponent film expected to exert a protective role controlling the high reactivity of the anode. The SEI is extremely sensitive to the chemistry of the electrolyte, but also to the structure of the anode. Here we discuss how the electrolyte chemistries affect SEI formation and Li metal nucleation, for typical liquid and solid electrolytes. Our first-principles analysis is complemented with experimental in situ observations.