Polymer‐based solid electrolytes (PSEs) offer great promise in developing lithium metal batteries due to their attractive features such as safety, light weight, low cost, and high processability. However, a PSE‐based lithium battery usually requires a relatively high temperature (60 °C or above) to complete charge and discharge due to the poor ionic conductivity of PSEs. Herein, a gel polymer electrolytes (GPEs) film with a supramolecular network structure through a facile one‐step photopolymerization is designed and developed. The crosslinked structure and quadruple hydrogen bonding fulfil the GPEs with high thermal stability and good mechanical property with a maximum tensile strain of 48%. The obtained GPEs possess a high ionic conductivity of 3.8 × 10−3 S cm−1 at 25 °C and a decomposition voltage ≥ 4.6 V (vs Li/Li+). The cells assembled with LiFePO4 cathode and Li anode, present an initial discharge specific capacity of 155.6 mAh g−1 and a good cycling efficiency with a capacity retention rate of 81.1% after 100 charges/discharge cycles at 0.1 C at ambient temperature. This work encompasses a route to develop high performance PSEs that can be operated at room temperature for future lithium metal batteries.

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The performance of classical lithium-ion technologies based on liquid electrolytes has made great advances in the last two decades, but safety issues are inevitable for batteries assembled with liquid electrolytes, which have intrinsic instability. In response to this issue, solid polymer electrolytes are developed in the lithium batteries field extensively for improving safety issues, as well as miniaturizing and enhancing the energy densities. Considering the great advantages of polymerized ionic networks, such as facile synthesis, high charge density, and high stability, two polymerized ionic networks (PDM-TFSI-1 and PDM-TFSI-2) with different polysubstituted benzene groups have been developed. The new type of polymerized ionic network with cross-linked structure was synthesized by the simple radical copolymerization of 2-(dimethylamino)­ethyl methacrylate and methyl methacrylate monomers, then the copolymer (M n = 14.5 kg mol−1) reacted with polysubstituted bromobenzene to form a cross-linked structure, and finally this was ion exchanged with bis­(trifluoromethane)­sulfonimide lithium salt (LiTFSI). The ionic networks filled with ionic liquid/LiTFSI mixture exhibit high ionic conductivity (1.0 × 10–4 and 1.9 × 10–4 S cm–1) and high decomposition potential (4.7 V vs Li/Li+) at 30 °C. The batteries were assembled by sandwiching the obtained polymer electrolytes between a LiFePO4 cathode and a lithium anode, exhibiting good cycling stability and specific capacity, suggesting that these novel kinds of solid polymer electrolyte are promising for application in next-generation lithium-ion batteries.

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