Enhanced high-temperature energy storage performance of COC by suppressing carrier transport

Abstract

Polymer dielectric film capacitors serve as crucial energy storage devices in modern electronic systems. However, the conventional dielectric materials have high conduction loss at elevated temperature. Hence, we propose a synergistic regulation strategy based on molecular traps to improve the high-temperature energy storage performance of cyclic olefin copolymer (COC). Firstly, the polar group maleic anhydride (MAH) is introduced into the COC molecular chain through the structure design, which creates deep energy traps to suppress intrachain charge transport. Furthermore, the intermolecular charge trap is constructed by introducing molecular semiconductor PCBM, which has high electron affinity energy (2.6–2.8 eV), realizing the intramolecular and intermolecular charge transport co-inhibition. The results show that COC-g-MAH/PCBM-0.10 exhibits a maximum discharge energy density (U_e) of 4.47 J/cm³ under 620 kV/mm at 120 ℃, and the efficiency (η) above 90%, which is 85% higher than COC. It’s noteworthy that at 120 ℃ and 500 kV/mm, after 50,000 charge–discharge cycles, the η of COC-g-MAH/PCBM-0.10 still remains at 92%, proving it has excellent high-temperature cycling stability. This strategy based on trap design provides a new paradigm for advanced dielectric materials with high energy storage performance and stability, demonstrating significant potential for practical applications.