The reduction of interfacial transfer barrier of Li ions enabled by inorganics-rich solid-electrolyte interphase

Abstract

The stable operation of lithium (Li) metal anode heavily relies on the intrinsic surface chemistry. However, the correlations between the composition of solid-electrolyte interphase (SEI) and its impact on working Li anode are insufficiently understood, which significantly restrains the efficiency of directional interfacial design. In this contribution, the interfacial transfer kinetics of solvated Li ions (Li+) regarding three model SEIs which possess similar components but various inorganic contents was systematically investigated. A general correlation was demonstrated that inorganics-rich SEI contributes to a lower energy barrier for the interfacial journey of solvated Li+, which involves a facile de-solvation process and a rapid ion diffusion through SEI. Lower overpotentials for both initial Li nucleation and interfacial activation processes were identified with a three-electrode cell configuration ascribed to the reduced energy barrier at the interphase, which potentially facilitate a compact and dense Li plating feature. This work sheds light on the relations between SEI property and the interfacial transfer kinetics of solvated Li+, aiming to provide more fundamental insights into the interfacial manipulation for a low-resistance and stable working Li metal batteries.