Performance improvement of polyethylene-supported poly(methyl methacrylate-vinyl acetate)-co-poly(ethylene glycol) diacrylate based gel polymer electrolyte by doping nano-Al2O3

Polyethylene (PE)-supported poly(methyl methacrylate-vinyl acetate)-co-poly(ethylene glycol) diacrylate with and without doping nano-Al₂O₃, namely P(MMA-VAc)-co-PEGDA/PE and P(MMA-VAc)-co-PEGDA/Al₂O₃/PE, are prepared and their performances as gel polymer electrolytes (GPEs) for lithium ion battery are studied by mechanical test, scanning electron microscopy, thermogravimetric analyzer, electrochemical impedance spectroscopy, cyclic voltammetry, and charge/discharge test. It is found that the doping of nano-Al₂O₃ in the P(MMA-VAc)-co-PEGDA/PE improves the comprehensive performances of the GPE and thus the rate performance and cyclic stability of the battery. With doping nano-Al₂O₃, the mechanical and thermal stability of the polymer and the ionic conductivity of the corresponding GPE increases slightly, while the battery exhibits better cyclic stability. The mechanical strength and the decomposition temperature of the polymer increase from 15.9 MPa to 16.2 MPa and from 410 °C to 420 °C, respectively. The ionic conductivity of the GPE is from 3.4 × 10⁻³ S cm⁻¹ to 3.8 × 10⁻³ S cm⁻¹. The discharge capacity of the battery using the GPE with doping nano-Al₂O₃ keeps 90.9% of its initial capacity after 100 cycles and shows good C-rate performance.