Phenazine-based conjugated microporous polymers: Influence of planarity and imine content on energy storage performance

Conjugated microporous polymers (CMPs) have been extensively employed across diverse applications. Nevertheless, there remains a necessity for more advancements in the fields of CMP-based supercapacitor electrodes. In this study, we present the synthesis of three redox-active phenazine based-CMPs through the coupling of redox-active 3,6,14,17-tetrabromodibenzo[a,c]dibenzo[5,6:7,8]quinoxalino[2,3-i]phenazine (QP-4Br) with various linkers of 1,3,6,8-tetrakis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrene (Py-4Bor), 2,4,6-tris(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pyridine (TPP-3Bor), and 2,4,6-tris(4-(4,5-dimethyl-1,3,2-dioxaborolan-2-yl)phenyl)− 1,3,5-triazine (TPT-3Bor) those possess various degree of planarity and imine contents. Output CMPs display high thermal stability with char yields of up to 82.5% and improved surface areas of up to 527.22 m² g^-1. Interestingly, the ability to modulate the performance of energy storage and the mechanism of energy storage is influenced by the variability in the degree of planarity and imine contents of the linkers. The TPT-QP CMP has superior planarity and imine content, resulting in exceptional specific capacitance and energy density values of 121.9 F g^-1 and 16.93 Wh Kg^-1, respectively. Further, it shows high specific capacitance retention, recording 96% after 5000 cycles, and then their capacitances are comparable to other earlier reported porous materials. This research presents an effective approach for developing electrochemical redox CMPs to advance supercapacitor technology in the future.