Achieving superior high-temperature energy storage performance in polycarbonate via small molecule traps and hydrogen bonding

Abstract

The high-temperature performance of polymer capacitors plays a crucial role in the development of advanced electrical systems. However, at elevated temperatures, polymer capacitors face issues such as a significant increase in carrier transport as well as a reduction in energy storage density and charge–discharge efficiency. To overcome these issues, this work successfully developed a fully organic polymer dielectric by incorporating the small molecule 4,5,7,8,12,13,15,16-octafluoro[2.2]paracyclophane (PF) into a polycarbonate (PC) matrix. Both theoretical calculations and experimental results demonstrate that PF, which possesses a wider bandgap than PC, can form electronic traps in conjunction with the polymer matrix. In addition, the hydrogen bond interaction between PF and PC functions as a trap, which inhibits carrier transport and consequently suppresses the conduction loss at high temperatures. This synergistic effect enhances the breakdown strength of the polymer dielectric and improves its overall energy storage capacity. At 150 °C and an applied electric field of 540 kV mm⁻¹, the polymer dielectric achieves an energy storage density of 4.015 J cm⁻³ and a charge–discharge efficiency of 84% while maintaining stable performance over 10 000 charge–discharge cycles. This work presents a promising strategy for the development of fully organic dielectrics with simultaneous high-temperature reliability and high energy storage performance.