Synchronously promoted discharged energy density and discharged efficiency in PVDF films through a linear dielectric polymer PP blending approach

Owing to the large dielectric constant, ferroelectric poly(vinylidene fluoride) (PVDF) has emerged as an ideal potential component for dielectric capacitors with high energy density ( U e ). However, the intrinsic polarity of PVDF induces a large hysteresis loss, which dramatically reduces the discharged efficiency ( η ) and thus hinders its practical application. Herein, we demonstrate a simple modified polymer blending approach to enhance the η and meanwhile U e of PVDF through the employment of nonpolar polypropylene (PP). Despite the poor miscible nature of PVDF and PP, we realized the homogenous dispersion of PP within PVDF and their good interaction using a nonequilibrium manufacturing process. A minor addition of PP (< 15 wt%) demonstrated to be effective in depressing the hysteresis loss without degrading the polarization of PVDF, inducing superior η and U e . By further constructing a sandwich-structured for PP/PVDF blend composites, η and U e can be maximized to be 8.1 J/cm 3 and 75%, respectively.