Engineering of High Entropy System in Functionalized Polypropylene for Ultra‐High‐Efficiency Capacitive Energy Storage

ABSTRACT Polypropylene (PP) is renowned for its high crystallinity, low cost, and excellent compliance characteristics, but its low polarity restricts its use in power electronics. Overcoming the trade‐off between crystallinity and polarization antagonism in polypropylene (PP) dielectrics represents a critical challenge for advancing high discharge efficiency capacitive energy storage. In an innovative departure from conventional methodologies, we report a molecular‐level high entropy engineering protocol that constructs a gradient polar interface within a polypropylene‐graft‐benzyl acrylate (PP‐ g ‐BA) system. This entropy‐stabilized microstructure effectively suppresses the formation of conducting pathways by controlling crystalline domain size and orientation, while the graduated polarity profile enables efficient charge injection blocking and dipole alignment. Arising from this synergistic mechanism, the optimized material achieves an unparalleled discharge energy density of 7.5 J cm −3 at 700 MV m −1 with superior efficiency retention over 95%, outperforming all previously reported PP‐based dielectrics at equivalent efficiency. This work underscores the transformative potential of entropy‐driven design in breaking traditional property trade‐offs in polymer dielectrics for next‐generation energy storage capacitors.