A strategic tuning of interfacial Li+ solvation with ultrathin polymer layers for anode-free lithium metal batteries

Abstract

Although anode-free lithium metal batteries (AFLMBs) offer exceptional energy density, they suffer from rapid capacity fading attributable to interfacial instability and the absence of a lithium reservoir. An interfacial solvation tuning strategy using ultrathin (∼15 nm) polymer coatings on Cu current collectors via initiated chemical vapor deposition is presented in this study. The designed polymer poly(heptadecafluorodecyl methacrylate) (pPFDMA) exhibits strong electrolyte- and solvent-phobicity, suppressing parasitic reactions and inducing local salt enrichment within the polymer. This solvation environment promotes a thin, inorganic-rich solid-electrolyte interphase layer and ensures high bulk ionic conductivity, enhancing both the cycling stability and rate capability. Consequently, pPFDMA-coated Cu enables a threefold improvement in the cycle life of half-cells and achieves 413 Wh kg−1 and 826 W kg−1 in LiNi<inf>0.8</inf>Co<inf>0.1</inf>Mn<inf>0.1</inf>O<inf>2</inf> (NCM811)-based anode-free pouch cells. This work provides a practical and generalizable approach for interfacial engineering in AFLMBs, focusing on current collector-electrolyte interactions. © 2025 Elsevier Inc.