Radiation synthesis of metal-organic frameworks/poly(dimethylaminoethyl methacrylate) gel electrolytes and the performance in lithium metal batteries

Metal-organic frameworks (MOFs), as crystalline nanoporous materials, have great potential for applications in energy and separation fields. Herein, a UiO/PDME-Li composite gel electrolyte was synthesized via γ-ray radiation using dimethylaminoethyl methacrylate as the monomer, polyethylene glycol dimethacrylate as the crosslinker in the 1 mol/L LiTFSI commercial electrolyte, and the MOF material UiO-66 as an additive. The resultant composite gel electrolyte achieved an ionic conductivity of (4.65±0.10) mS/cm and exhibited good mechanical properties, with maximum compressive strain, maximum compressive stress, and compressive modulus of (60.9±1.2)%, (63.0±7.0) kPa, and (0.180±0.002) kPa, respectively. The addition of only 0.1% UiO-66 increased the Li+ transference number of the electrolyte to 0.59. A Li‖LiFePO4 lithium metal battery assembled with the composite gel electrolyte retained a discharge specific capacity of 129 mAh/g after 200 cycles at 0.5 C, corresponding to a capacity retention rate of 95.5%. Furthermore, a pouch battery of Li4Ti5O12‖UiO/PDME-Li‖LiFePO4 fabricated via radiation-induced in-situ preparation maintained a capacity retention rate of 77.3% after 150 cycles. The Li‖LiFePO4 pouch battery containing the UiO/PDME-Li electrolyte continued to work normally and powered an LED bulb even after undergoing 100 cycles of 180° bending and shear damage over 50% of its area, demonstrating excellent safety performance.