Quinoxalinophenazine- and Tetrabenzophenazine-Based Conjugated Microporous Polymer Electrodes Deliver High Capacitance and Efficient Cycling Stability

High Resolution Image Download MS PowerPoint Slide Quinoxalinophenazine (QP)- and tetrabenzophenazine (TBP)-based conjugated microporous polymers (CMPs) are promising supercapacitor electrode materials owing to their rigid π-conjugated frameworks, permanent microporosity, and nitrogen-rich redox sites. Herein, two phenazine-node CMPs, QP-THS and TBP-THS, were synthesized via Suzuki−Miyaura cross-coupling of 3,6,14,17-tetrabromodibenzo[a,c]dibenzo[5,6:7,8]quinoxalino[2,3-i]phenazine (QP-4Br) or 3,6,12,15-tetrabromotetrabenzo[a,c,h,j]phenazine (TBP-4Br) with 2,6-dibromobenzo[1,2-b:4,5-b′]dithiophene-4,8-dione (THS-2Br) and 1,4-phenylenediboronic acid (Ph-2BO). Structural analyses confirmed successful framework formation and nanorod-like architectures for both CMPs yet distinct physical properties: QP-THS featured a higher BET surface area (600 vs. 125 m 2 g −1 ), whereas TBP-THS exhibited higher thermal stability ( T d10 = 609 vs. 482.65 °C; char yield = 79.25 vs. 63.25%). In 3 M KOH, QP-THS and TBP-THS electrodes delivered high specific capacitances of 473 ± 22 and 424 ± 16 F g −1 at 0.5 A g −1, respectively, with excellent retention after 4000 cycles at 10 A g −1 (90.31 and 93.38% of initial capacitance, respectively). The QP-THS electrode exhibited faster charge-transfer kinetics than the TBP-THS electrode, with lower R s / R ct values (9.19/263.2 Ω vs. 10.37/500 Ω) and a higher capacitive contribution (78 vs. 65% at 200 mV s −1 ). A symmetric QP-THS device delivered a capacitance 270.23 F g −1 at 0.43 A g −1 and an energy density of 54.05 Wh kg −1 at 517.07 W kg −1 over 0−1.2 V, with 81.88% capacitance retention after 5000 cycles at 11.44 A g −1 . These results demonstrate that phenazine-node engineering is an effective strategy for optimizing porous π-conjugated polymer electrodes for high-performance energy-storage systems.