Enhancement of the Comprehensive Energy Storage Performance of Epoxy Film Achieved by Chain Segment Saturation Adjustment

Rapid advancements in areas like new energy generation systems, energy conversion equipment, and electric vehicles have necessitated capacitor films with high comprehensive energy storage performance. In contrast, current commercially biaxially oriented polypropylene film (BOPP) is gradually unable to meet diverse requirements, particularly in terms of energy storage density and operating temperatures. Epoxy is a classic polymer widely used in electrical insulation, due to its excellent dielectric properties. And it has also been proven to be a potential energy storage film when polarizing for higher permittivity and dielectric strength. However, epoxy films face the issue of relevantly higher loss compared to BOPP, in which the unsaturated benzene ring structure is often considered the main reason. Few reports have been found specifically studying the issue. In this manuscript, the comprehensive energy storage properties of the polymer films with various segment saturation degrees are investigated. The findings demonstrate that the epoxy material achieves higher energy storage density and maintains outstanding efficiency by partially reducing its unsaturation to optimize the comprehensive energy storage characteristics.