Surficial Cross‐Linking Hydrogen Bonds Enabling High‐Rate and Robust Solid‐State Lithium Metal Batteries

Abstract Solid‐state lithium metal batteries have attracted much attention due to their enhanced energy density and safety. However, high‐rate solid‐state lithium metal batteries still face many challenges due to their low ionic conductivity, poor interfacial compatibility, and lithium dendrite growth issue. In this work, an electrostatically spun fiber membrane coated with polydopamine (PDA) is proposed, where the abundant functional groups (such as ─OH and ─NH 2 ) in PDA both construct a continuous and complex hydrogen bond network. The addition of polyacrylonitrile neutralizes the rigidity of the PDA, which provides a certain degree of deformability for the electrolyte. In situ polymerization of 1,3‐dioxolane with this multifunctional membrane, a solid‐state electrolyte with high ionic conductivity (1.2 mS cm −1 ), high t Li+ (0.82), and both rigidity and flexibility, is fabricated. The LiFePO 4 //Li full cells with this electrolyte can operate over 1800 cycles at 5 C and 700 cycles at 8 C (with an 86.4% capacity retention rate). This simple and effective strategy provides high rate for solid‐state batteries with polymer electrolytes by constructing a multidimensional hydrogen bond network and opens up more possibility to realize high‐rate applications.