Polyimide nanocomposites for high‐temperature capacitive energy storage applications by incorporating functional graphene oxide nanosheets: Design, preparation, and mechanism.

Herein, graphene oxide (GO) and its derivative, reduced GO (rGO) and p‐phenylenediamine (PPD) functionalized GO (GO‐g‐PPD) were first synthesized and selected as dielectric fillers, and then GO/polyimide (PI), rGO/PI, and GO‐g‐PPD/PI dielectric nanocomposites were fabricated through in situ polymerization‐composition strategy. Fourier transform infrared, Ram, and x‐ray diffraction analysis confirmed the success synthesis of rGO and GO‐g‐PPD dielectric fillers. The mechanical properties showed that GO‐g‐PPD/PI nanocomposites exhibited the highest tensile strength and elasticity modulus. TGA analysis revealed that the enhancement of thermal stability by addition of dielectric fillers. The dielectric constant of 2.5 wt.% GO‐g‐PPD/PI nanocomposites reached 25.05, which was 8.55 times that of pure PI (2.93). Energy storage performance tests showed that the energy storage density of GO‐g‐PPD/PI containing 2 wt.% filler reached 0.77 J/cm3, which was 71% higher than pure PI. These findings underscore the potential of GO derivative as a cost‐effective reinforcement for PI dielectric nanocomposites for high‐temperature capacitive energy storage applications. [ABSTRACT FROM AUTHOR]