Upgrading Ester-Based Electrolyte with LiNO₃ and GPE to Realize Dendrite-Free Lithium Deposition

The development of high-energy-density lithium metal batteries (LMBs) is significantly hindered by the interfacial degradation occurring at lithium metal anodes (LMAs) in ester-based electrolyte systems. Herein, multivalent acrylates, possessing two, three, and four carbonyl groups are investigated as functional co-solvents to enhance LiNO₃ solubility in ester-based electrolytes. The results reveal a positive correlation between carbonyl group number and LiNO₃ dissolution capability. Molecular dynamic simulations suggest that incorporating LiNO₃ through multivalent co-solvent reshapes the Li⁺ solvation sheath, favoring inorganic-rich solid electrolyte interphase (SEI) formation. A precursor liquid electrolyte containing 7.5 vol% neopentyl glycol diacrylate and 1.0 wt.% LiNO₃ is in situ polymerized to form gel polymer electrolyte (GPE-7.5). X-ray photoelectron spectroscopy and electrochemical impedance spectrum analyses show that GPE-7.5 can mitigate the decomposition of LiPF₆ and electrolyte solvents to construct an inorganic-rich SEI dominated by LiF and Li₃N and promote dendrite-free deposition on LMAs. The NCM622|GPE-7.5|Li cell delivers exceptional cycle stability and high Coulombic efficiency with minimal polarization growth, attributed to the inorganic-rich solid electrolyte interphase formed on both LMA and NCM622 surfaces. The strategy of incorporating LiNO₃ in GPE provides new insights for the design of advanced high-energy-density LMBs.