Asymmetric Structure Design of Polymer Gel Electrolyte with a Functional Metal–Organic Framework Layer for Stable Lithium–Metal Batteries

High Resolution Image Download MS PowerPoint Slide Ionogel electrolytes (IGEs) containing ionic liquids (ILs) as the unique liquid component can guarantee high ionic conductivity, a wide electrochemical window, and high thermal stability simultaneously for developing stable and safe Li metal batteries. Li + transport in IGEs depends on the content of IL; however, increasing the IL content improves ionic conductivity but sharply decreases mechanical properties and leads to low Li + transference, limiting the ability to resist Li dendrites. Thus, IGEs must strike a balance between ionic conductivity and mechanical properties. Herein, we adopt a new strategy to suppress Li dendrites by introducing a functional metal–organic framework (MOF) layer onto IGE. The IGE provides an asymmetric SSE (ASSE) with good interfacial contact, whereas the MOF layer regulates uniform dissolution/deposition of lithium and inhibits Li dendrite growth. Thereby, the ASSE not only demonstrates excellent ion-transport properties at 30 °C with an ionic conductivity of 1.1 × 10 –4 S cm –1, but also enables the Li symmetric battery to cycle for 900 h stably. Besides, the full cell (LiFePO 4 cathode) maintains 94.1% capacity after 200 cycles at 0.5C.