Improved energy storage performance of BOPP sandwich structured films by modulating the topological structure

As the basis of the modern electronics industry, electronic functional materials provide powerful support for the development of science and technology. Biaxially oriented polypropylene (BOPP) dielectric films are widely used in capacitors for excellent dielectric advantages. In this paper, a topological-structured multilayer sandwich dielectric film was designed. BOPP was used as the outer layer, the blend of chlorinated polypropylene/polyvinylidene fluoride (CPP/PVDF) as the middle layer, and two-dimensional boron nitride nanosheets (BNNS) were added to the CPP/PVDF blend to enhance its breakdown strength. The sandwich-structured films had the highest discharged energy density of 5.17 J cm^-3at 3 vol% addition of BNNS in the middle layer, and the charge-discharge efficiency maintained at a high level of 82.1%. The dielectric and energy storage properties of BOPP sandwich films were effectively improved by the introduction of large aspect ratio fillers.