Facilitating uniform lithium deposition via nanoconfinement of free amide molecules in solid electrolyte complexion for lithium metal batteries

Abstract

As a facile method to facilitate the uniform lithium deposition on the lithium metal anode, a unique solid electrolyte complexion consisted of polyethylene oxide, UiO-66-NH2, and deep eutectic solvents (PEMD) with nanoconfinement significantly improves the lithium metal cycling stability. Specifically, the free amide molecules of deep eutectic solvents are nanoconfined by UiO-66-NH2 in the polyethylene oxide (PEO) matrix, and an excellent symmetrical electrochemical cycling performance more than 3600 h is achieved, extended by ∼10 times comparing to the reference. Furthermore, the Li || PEMD || LiFePO4 cell not only exhibits satisfactory electrochemical performance at 60 °C inherited from PEO, but also presents unexpected capacity reversibility, cycling stability, and enhanced rate capability at low temperatures down to 10 °C. The design of the solid electrolyte complexion with nanoconfinement opens an innovative avenue to the practical implementation of the PEO based lithium metal batteries.