Improved Energy Density and Charge Discharge Efficiency of Polypropylene Capacitor Film Based on Surface Grafting

In this paper, an advanced surface-grafting method is reported to improve the high-temperature performance of biaxially oriented polypropylene (BOPP) membranes. The leakage conductivity of the surface-grafted films decreases by 98% at 85 °C. The decline in the leakage loss contributes to the 99% charge-efficiency at 85 °C. The dielectric constant increases by 7%. The DC breakdown strength grows by 43% at 85 °C. The maximum energy storage density goes up from 1.45 to 2.77 J/cm³ at 85 °C. The surface-grafted BOPP film exhibits outstanding energy density and charge-discharge efficiency characteristics. This research provides a theoretical reference for improving the performance of capacitor film based on surface modification.