High-temperature energy storage performances of ‘‘isomer-like’’ polyimide and its thermoplastic polyurethane blending system

Liu, Xue-Jie, Zheng, Ming-Sheng, Chi, Qingguo, Zhang, Yiyi, Dang, Zhi-Min, Chen, George and Zha, Jun-Wei (2022) High-temperature energy storage performances of ‘‘isomer-like’’ polyimide and its thermoplastic polyurethane blending system. Journal of Materials Chemistry C, 10 (45), 17326-17335. (doi:10.1039/D2TC03043H).

Abstract

With the rapid development of high-temperature energy storage devices, polyimide films with excellent thermal stability have become candidates for capacitor materials. However, the energy density (U _e) and efficiency (η) of the most commonly used polyimide (common PI) decrease exponentially at high temperatures. In this work, the “isomer-like” of common PI (i-PI) is prepared by optimizing the structure of the repeating unit of common PI. Compared with the common PI film (U _e of 0.59 J cm ⁻³ and η of 24% at 150 °C), the i-PI film obtains a high U _e of 3.48 J cm ⁻³ with an η of 54% at 150 °C. The adjustment of the position of the ether bond reduces the interchain space of the polymer, which decreases the free volume for electron acceleration resulting in a better insulation performance. Then, flexible thermoplastic polyurethane (TPU) with high dielectric permittivity is introduced into i-PI, which further reduces the interchain space. The obtained TPU/i-PI film achieves a synergistic improvement in dielectric permittivity and breakdown strength. At 150 °C, the high U _e of 4.23 J cm ⁻³ with η of 73% is achieved. Compared with those of common PI, U _e and η of TPU/i-PI film are improved by 617% and 204%, respectively. Therefore, reducing the interchain space by optimizing the polymer chains is a feasible method to enhance the high-temperature capacitive performance.

This record has no associated files available for download.

Contributors

Download statistics