Bottom‐Up Construction of Conjugated Microporous Polyporphyrin‐Coated Graphene Hydrogel Composites with Hierarchical Pores for High‐Performance Capacitors

Three‐dimensional (3D) graphene hydrogel (GH) architectures are of great interest in applications towards electronics, environmental fields, catalysis devices, and sensors. However, due to the structure constraints of graphene, only macropore and low specific surface areas are obtained. Conjugated microporous polymers always possess a micro‐ and mesopore structure simultaneously, but the conductivity is very poor. However, both the conductivity and the pore parameter are important factors affecting the performance of capacitor. Here, we propose a facile and highly efficient method to improve the microstructure of GH, enlarging the conductivity of CMPs, simultaneously. Porphyrin‐based conjugated microporous polymer (CMP) gels were integrated tightly on the surface of GH via a room‐temperature oxidative homocoupling reaction, resulting a new composite (GH‐CMP) with excellent conductivity, enlarged BET surface area, and hierarchical pore structure. The fabricated GH‐CMP was used as the electrode material for capacitors. The hierarchical pore structure is beneficial for mass transfer, facilitates the diffusion, and further enhances the specific capacitance. The resultant supercapacitor electrodes presented a high capacitance of 208 F g −1 at 20 mA g −1 and an excellent cycle stability with a retained capacitance of about 92.6 % after 10 000 cycles at 2 A g −1 . The integration of CMPs and GH makes graphene hydrogel films an ideal electrode material for supercapacitors.