Flexible Polyolefin with Enhanced Dipolar Polarization for Energy Storage Capacitors

Polymer dielectrics endowed with high dielectric constant and high breakdown strength are critical for high-power systems and compact electronics to realize ultrahigh energy density. Nevertheless, the constrained energy density attainment of prevalent commercial polymers such as BOPP has been impeded by their inadequately satisfied dielectric constant. A polynorbornenes-BP (PNB-BP) is introduced in this paper, which features a rigid backbone composed of bicyclic aliphatic, while the incorporation of an electron acceptor and aromatic groups facilitates the formation of an enhanced dipole, endowing it with a satisfied dielectric constant of 3.72. Leveraging its high breakdown strength, the PNB-BP polymer achieves a notable energy density of 12.7 J/cm³ at room temperature. Furthermore, the PNB-BP polymer exhibits commendable thermal properties, including a high glass transition temperature (Tg) of 220°C, and satisfactory thermal stability as evidenced by the observed dielectric constants. The design strategy uncovered in this work unveils the to realize the ultrahigh energy density of the capacitor by introducing the enhanced dipole.