High Energy Storage Under the Regulation of Polymer Phase Structure

Abstract Dielectric nanocomposites have garnered significant interest owing to their potential applications in energy storage. However, achieving high energy density ( U e ) and charge/discharge efficiency ( η ) remains a challenge in their fabrication. In this paper, core‐shell structured BaTiO 3 @Polyvinylpyrrolidone (BT@PVP) nanoparticles are prepared, and incorporated into a semi‐crystalline polyvinylidene fluoride (PVDF) matrix. The BT@PVP/PVDF nanocomposite film loaded with 5 vol.% BT@PVP nanoparticles show a maximum U e of 18.39 J cm −3 at 458 MV m −1 , which is almost 4 and 9 times greater than those of BT/PVDF (5.14 J cm −3 at 303 MV m −1 ) and biaxially oriented polypropylene (BOPP) (2 J cm −3 at 640 MV m −1 ), respectively. Notably, the highest charge/discharge efficiency of 79.80% has been achieved so far for ferroelectric inorganic‐filled PVDF composites. The reason why there are such excellent performances is mainly because of the interface coupling of inorganic–organic nanocomposite film and PVDF β phase transition with coating and extrusion of PVP molecules and large polarization of BT respectively. This research introduces a convenient and effective approach to designing high‐performance dielectric polymer nanocomposites.