Significantly Improving Energy Storage Performance of BOPP Films Based on Surface Polymer Layer

The lower energy storage density limits the further application of biaxially oriented polypropylene (BOPP) films. In this paper, a low-temperature plasma method was used to polymerize polymathic methacrylate with high dielectric constant on the surface of BOPP film in situ. The experimental results show that the PMMA layer with appropriate thickness can improve the direct current (DC) breakdown strength to 774.9 kV/mm, which is 8.4% higher than that of pure BOPP (715.1 kV/mm). The highest discharge energy density also reaches 5.72 J/cm3, accompanied by a charge-discharge efficiency of 91.4%. This paper can provide a new perspective and method for improving the dielectric and energy storage performance of BOPP films.