Long-cycling lithium-metal batteries via an integrated solid–electrolyte interphase promoted by a progressive dual-passivation coating

Stabilizing lithium (Li) metal anodes has long been hindered by the challenge of forming a stable solid–electrolyte interphase, stemming from the inherently high reactivity of Li metal with liquid electrolytes. Here we developed a progressive dual-passivation polymer coating strategy to stabilize Li-metal anodes, achieving exceptional cycle life of Li-metal batteries in carbonate electrolyte. Unlike current approaches, the synthesized copolymer coating passivates the Li-metal anode while also tailoring the Li-ion solvation structure by facilitating selective anion decoordination in a binary salt carbonate electrolyte. This process leads to the formation of an integrated solid–electrolyte interphase, featuring a chemical passivation outer layer predominant in LiF generated by the polymer coating and an anion-derived Li₂O-prevalent inner layer from the electrolyte decomposition. Consequently, this coating strategy remarkably enhances the stability of Li-metal anodes, enabling double-layer Li||NMC811 pouch cells to maintain 80% of their initial capacity up to 611 cycles under a low electrolyte/capacity (E/C) ratio of 2.0 g Ah⁻¹.