Plasticized Hybrid Network Solid Polymer Electrolytes for Lithium‐Metal Batteries

Incorporating solid polymer electrolyte (SPE) into lithium metal batteries has the benefit of employing the electrolyte as the electrode separator while inhibiting the growth of lithium dendrites. The two main models on lithium dendrite growth show that either ionic conductivity or mechanical property affect lithium dendrite nucleation and growth rate. In this work, with a well‐controlled hybrid network SPE as the model system, the modulus and conductivity of the hybrid SPEs are systematically tuned by plasticizing the network with low molecular with diluents. This systematic property control allows for establishing the correlation between mechanical/electrochemical properties of the SPEs with their propensity of lithium dendrite resistance using galvanostatic polarization and cycling experiments. It is further demonstrated that lithium metal batteries can be operated at 30 °C for the plasticized SPEs due to the dramatically improved conductivity. A series of plasticized hybrid network solid polymer electrolytes (SPEs) for functional lithium metal batteries is synthesized to demonstrate correlations between mechanical and electrochemical properties of the SPEs with their property of lithium dendrite resistance evaluated by galvanostatic polarization and cycling experiments in lithium metal symmetric cells.