Lithium Metal Anodes with an Adaptive “Solid-Liquid” Interfacial Protective Layer

TLDR

Lithium metal offers high specific capacity but suffers from static solid electrolyte interphases that cannot accommodate its volume changes, leading to side reactions, dendrite growth, and poor deposition. The study demonstrates that a dynamically cross‑linked polymer with solid‑liquid hybrid behavior can serve as an adaptive interfacial layer for lithium metal anodes. The polymer reversibly switches between liquid and solid states in response to lithium growth rates, providing uniform surface coverage and dendrite suppression to stabilize electrode operation. This adaptive Li/electrolyte interface presents a promising new strategy to overcome the intrinsic challenges of lithium metal anodes.

Abstract

Lithium metal is an attractive anode for the next generation of high energy density lithium-ion batteries due to its high specific capacity (3,860 mAh g-1) and lowest overall anode potential. However, the key issue is that the static solid electrolyte interphase cannot match the dynamic volume changes of the Li anode, resulting in side reactions, dendrite growth, and poor electrodeposition behavior, which prevent its practical applications. Here, we show that the "solid-liquid" hybrid behavior of a dynamically cross-linked polymer enables its use as an excellent adaptive interfacial layer for Li metal anodes. The dynamic polymer can reversibly switch between its "liquid" and "solid" properties in response to the rate of lithium growth to provide uniform surface coverage and dendrite suppression, respectively, thereby enabling the stable operation of lithium metal electrodes. We believe that this example of engineering an adaptive Li/electrolyte interface brings about a new and promising way to address the intrinsic problems of lithium metal anodes.