This article presents a novel composite polymer electrolyte designed to enhance the performance of lithium metal batteries. The electrolyte, named Ni-DMF, incorporates N,N-dimethylformamide (DMF) into a Hofmann framework, creating a locally DMF-rich interface that promotes Li⁺ conduction through a ligand-assisted transport mechanism. This design addresses the issues of DMF degradation and unstable solid-electrolyte interphase (SEI) formation, which are common in solid-state batteries. The Ni-DMF electrolyte exhibits a high ionic conductivity of 6.5 × 10⁻⁴ S cm⁻¹ at room temperature and demonstrates improved cycle life, with over 6000 hours of stable cycling at 0.1 mA cm⁻² in a Li | Li symmetric cell. When paired with sulfurized polyacrylonitrile cathodes, the full cell shows a prolonged cycle life of 1000 cycles at 1 C. The study also highlights the superior interfacial stability of the Ni-DMF electrolyte, which reduces the formation of anode active material loss and improves the SEI layer composition, leading to better Li⁺ transport and electrochemical performance. Overall, the Ni-DMF electrolyte shows promise for practical applications in solid-state lithium batteries.This article presents a novel composite polymer electrolyte designed to enhance the performance of lithium metal batteries. The electrolyte, named Ni-DMF, incorporates N,N-dimethylformamide (DMF) into a Hofmann framework, creating a locally DMF-rich interface that promotes Li⁺ conduction through a ligand-assisted transport mechanism. This design addresses the issues of DMF degradation and unstable solid-electrolyte interphase (SEI) formation, which are common in solid-state batteries. The Ni-DMF electrolyte exhibits a high ionic conductivity of 6.5 × 10⁻⁴ S cm⁻¹ at room temperature and demonstrates improved cycle life, with over 6000 hours of stable cycling at 0.1 mA cm⁻² in a Li | Li symmetric cell. When paired with sulfurized polyacrylonitrile cathodes, the full cell shows a prolonged cycle life of 1000 cycles at 1 C. The study also highlights the superior interfacial stability of the Ni-DMF electrolyte, which reduces the formation of anode active material loss and improves the SEI layer composition, leading to better Li⁺ transport and electrochemical performance. Overall, the Ni-DMF electrolyte shows promise for practical applications in solid-state lithium batteries.