To address the paradox of mutually exclusive confusions between the breakdown strength and polarization of the polymer-based composites at high-temperature, a dynamic multisite bonding network is constructed by connecting the –NH₂ groups of polyetherimide (PEI) and Zn²⁺ in metal–organic frameworks (MOFs). Owing to the multisite bonding network being dynamically stable at high-temperature, the composites possess a high breakdown strength of 588.1 MV m⁻¹ at 150 °C, which is 85.2% higher than that of PEI. Importantly, the multisite bonding network could be thermally activated at high-temperature to generate extra polarization, which is because the Zn–N coordination bonds are evenly stretched. At similar electric fields, the composites show higher energy storage density at high-temperature compared with that at room temperature, and present excellent cycling stability even with increased electrode size. Finally, the reversible stretching of the multisite bonding network against temperature variation is confirmed by the in situ X-ray absorption fine structure (XAFS) and theoretical calculations. This work presents a pioneering example of the construction of self-adaptive polymer dielectrics in extreme environments, which might be a potential method for designing recyclable polymer-based capacitive dielectrics.

Enhancing the high electric field resistance and energy storage capacity of polymer dielectrics has been a long-standing challenge for the iterations of power equipment. Synergistic inhibition of carrier injection and transport is vital to energy storage performance improvement. Herein, promising polymer polyetherimide (PEI) was employed as a matrix and wider bandgap boron nitride nanosheets (BNNSs) were used as a reinforcing filler. Utilizing high-throughput stochastic breakdown simulations with the distribution characteristics of BNNSs as parameters, a series of topological gradient structures with the potential to enhance performance were obtained, thereby shortening the experimental cycle. Changing the BNNS distribution of symmetric/asymmetric and positive/inverse gradients, as well as the total and gradient contents of BNNSs, means that the position and condition of the surface barrier layer and central hinder layer change, which influences the energy storage performance of the polymer at room temperature and high temperature. Remarkably, the asymmetric gradient structure composite dielectrics exhibited excellent performances. Among them, the PEI-based composite dielectric with 2 vol% BNNS asymmetric inverse gradient distribution (gradient content of 1 vol%) achieved energy densities of 8.26 and 4.78 J cm⁻³ at room temperature and 150 °C, respectively. The asymmetric gradient structure design strategy holds great promise for optimizing the energy storage capacity of polymer dielectric capacitors.