High‐Temperature Dielectric Polymers With Highly Disordered Molecular Chain Structures by Design

ABSTRACT The design of dielectric polymers for extreme‐temperature energy storage faces the challenge that the structural optimization towards improved insulating/capacitive performance is usually at the expense of reduced thermal resistance. Here, we present a design of high‐temperature dielectric polymers that does not rely on any specific chemical structures that compromise the thermal resistance, but capitalizes on the disordered combining sequences of monomers that are all of high thermal resistance, thus improving the capacitive performance while maintaining the temperature capability. The high positional and energetic disorders were demonstrated in the polyimides by design, synthesized through co‐polymerization with an optimal combination of 13 monomers. The enhanced disorder of molecular chains was found to regulate the inherent charge transport behavior of polymers, leading to approximately 2 orders of magnitude augmentation in electrical resistivity and unprecedented capacitive performance at an extremely high temperature of 300°C.