Enhanced high‐temperature energy storage density of polypropylene‐based materials by micro‐crosslinked structure design with N‐type organic semiconductor

Abstract In this study, the authors proposed a promising structure design, the micro‐crosslinked polypropylene (PP), to enhance the high‐temperature energy storage density. With the grafting of 1,6,7,12‐tetrachlorinated perylene‐ N ‐2‐aminoethyl acrylate‐ N ′‐dodecylamine‐3,4,9,10‐tetracarboxylic bisimide (PTCDA) onto PP molecules, the obtained PP‐g‐PTCDA achieved a superior energy storage density of 2.34 J/cm 3 at 120°C with the discharge efficiency above 90%, which was 585% higher than that of neat PP. The great enhancement, on the one hand, originated from the micro‐crosslinked structure, since the restricted molecular motion can lead to the suppression of electrons' hopping across the molecular chains. On the other hand, deep traps were also introduced in PP‐g‐PTCDA, which restricted the electrons' hopping along the molecular chains simultaneously. This work provided an orientation to enhance the energy storage density at an elevated temperature of 120°C.