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

Abstract Herein, graphene oxide (GO) and its derivative, reduced GO ( r GO) and p ‐phenylenediamine (PPD) functionalized GO (GO‐ g ‐PPD) were first synthesized and selected as dielectric fillers, and then GO/polyimide (PI), r GO/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 r GO 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/cm 3 , 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.