Dual metal Zn/Co-MOF based quasi-solid-state electrolyte enables uniform Li deposition for high-voltage lithium metal batteries

Metal–organic framework (MOF)-poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber membrane-based quasi-solid electrolytes (QSEs) for lithium metal batteries (LMBs) suffer from Li dendrite growth and unstable interface towards high-voltage cathode. Herein, a dual metal MOF-based QSE (PHZZS) is constructed by in situ growth of Zn/Co-MOF on PVDF-HFP nanofiber membrane, followed by in situ polymerization of poly(ethylene glycol) diacrylate/succinonitrile/lithium bis(trifluoromethanesulfonyl)imide (PEGDA/SN/LiTFSI) precursor. The Zn/Co-MOF improves precursor wetting and infiltration, enabling uniform formation of the PEGDA network. Meanwhile, Zn/Co Lewis acid sites and the porous structure in Zn/Co-MOF collectively confine SN and TFSI − migration, promoting LiTFSI dissociation to enhance Li + conduction. The restricted anion migration further alleviates interfacial concentration polarization and local current crowding, leading to more uniform Li deposition and enhanced interfacial stability toward high-voltage cathodes. Thus, PHZZS delivers an ionic conductivity of 1.78 mS cm −1 at 27 °C and enables stable Li||Li cycling for 2400 h. LFP||Li and NCM811||Li cells retain 99% and 75% of their initial discharge capacities, respectively, after 400 cycles at 0.5 C, while the NCM811||Li pouch cell maintains a specific capacity of 192 mAh g −1 after 50 cycles at 0.1 C. This study provides a viable strategy for designing MOF-based QSEs that combine fast Li + transport with high-voltage stability.