Enhancing High-Temperature Energy Storage Performance of PEI-Based Dielectrics by Incorporating ZIF-67 with a Narrow Bandgap
Xiaona Li, Hang Luo, Chenchen Yang, Fan Wang, Xun Jiang, Ru Guo, Dou Zhang
Abstract
Polymer dielectrics are crucial for use in electrostatic capacitors, owing to their high voltage resistance, high energy storage density, and ultrahigh reliability. Furthermore, high-temperature-resistant polymer dielectrics are applied in various emerging fields. Herein, poly(ether imide) (PEI)-based polymer dielectrics prepared by adding a low loading of dimethylimidazolium cobalt (ZIF-67) with a narrow bandgaps are investigated. The results show that the composites exhibit considerably increased Young’s modulus, suppressed conductivity loss, and improved breakdown strength compared with pure PEI. Consequently, a stable energy storage performance is realized for ZIF-67/PEI composites. Particularly, at 150 °C, 1 wt % ZIF-67/PEI composite affords an excellent energy storage density of 4.59 J/cm 3 with a discharge energy efficiency of 80.6%, exhibiting a considerable increase compared with the values obtained for PEI (2.58 J/cm 3 with a discharge energy efficiency of 68.8%). The results of this study reveal a feasible pathway to design polymer dielectrics with the potential for use in capacitive applications in harsh environments.