High-temperature electrical breakdown and energy storage performance of ladderphane copolymer enhanced by molecular bondage and deep trapping

The advancement of renewable energy urgently needs dielectric capacitors with high energy storage performance at elevated temperatures. The energy loss and energy storage density are the core performance of these capacitors, which are determined by the conductivity and breakdown characteristics that are significantly influenced by the parameters such as trap characteristics, free volume, thermal expansion, and polymer chains displacement. Therefore, it is imperative to establish a quantitative correlation between microscopic parameters and energy storage performance of the ladderphanes for its substantial enhancement in energy storage density presently, to elucidate this mechanism and further improve the performance. In this paper, the criterion of breakdown caused by the long displacement of polymer chains under the action of electric and thermal fields was proposed. Combining charge transport, heat transfer and polymer chains motion, a joint simulation model of conductivity-breakdown-energy storage was established. The simulation results were consistent with the experimental results of high-temperature breakdown and energy storage. It was unveiled that the aggregate structure enhances the high-temperature breakdown and energy storage capabilities of ladderphane copolymer by restraining polymer chains motion and impeding charge transitions.