Carbazole-conjugated microporous polymers from Suzuki–Miyaura coupling for supercapacitors

Conjugated microporous polymers (CMPs) were intensively exploited for many applications including optoelectronics, CO₂ adsorption, and catalysis. Nevertheless, CMPs based electrochemical supercapacitors as energy storing systems were largely unreconnoitered yet. This may be attributed mainly to some drawbacks relating to low structural/electrochemical stabilization, and somewhat poor specific capacitance, in addition to depressed energy density observed for most of the discovered CMPs. In this work, a set of novel carbazole-based CMPs with redox activity, Cz-Cz CMP, Cz-TPA CMP and Cz-TP CMP, have been successfully prepared and examined as dynamic electrodes for supercapacitors. The as-synthesized Cz-Cz and Cz-TPA CMPs possessed the highest and very close values of specific surface areas of 623 and 618 m² g⁻¹, respectively, with the corresponding pore sizes centered at of 0.49 and 0.40 nm, respectively. The electrochemical study of all CMPs has been measured by both cyclic voltammetry (CV), and galvanostatic charge/discharge (GCD). The obtained CV curves resembled rectangle shapes, suggesting a typical electric double-layer manner over the potential range and the scan rates. The Cz-TPA CMP were the best candidate with an electrochemical capacity of 271.82 F g⁻¹ at 0.5 A g⁻¹ current density, and rapid rate of charge/discharge cycle. In addition, it owned the excellence in cycling stability that was displayed to retain 99.87% of the capacitance after 2000 cycling times at 10 A g⁻¹. From all analysis data, one can conclude that, our polymers were among the best stable electrode materials.