Construction and performance of PVDF-HFP-matrix comb-like gel copolymer electrolyte for high-performance quasi-solid-state lithium-metal batteries

Rechargeable lithium metal batteries (LMBs) have encountered bottlenecks in energy density , durability, and safety issues. Designing functional polymer electrolytes has been considered as an effective way to develop high-performance of LMBs. In this study, PVDF-HFP-matrix polymeric electrolytes blended with co polymer P(MMA- co -PEGMEMA) (PPxPy) via a simple one-pot free-radical polymerization are successfully designed and prepared. It has been found that the PPxPy electrolytes can construct different comb -like networks via systematically tuning monomer ratios. The tailored PP5P5 gel electrolyte exhibited high ionic conductivity of 0.74 × 10 −3  S cm −1 at room temperature (RT), an enlarged electrochemical window up to 4.77 V, high lithium-ion transference number t Li+ of 0.65, and good mechanical property with Yang's modulus up to 131 MPa. Benefited from these good properties, the Li||LiFePO 4 batteries assembled with PP5P5 gel electrolyte achieved an exceptional discharge capacity of 152 mAh g −1 with nearly 100 % Coulombic efficiency after 150 cycles at 1C. Furthermore, the Li|PP5P5|NCM811 cell exhibits excellent reversible specific capacity of 188 mAh g −1 at 0.1C. Consequently, it can be anticipated the as-prepared functional polymer structure to provide a reliable method for the preparation of polymer electrolytes in quasi-solid-state batteries with high-energy-density.