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.

Automated summary

In this study, a series of novel carbazole-based CMPs with redox activity were successfully synthesized and tested as dynamic electrodes for supercapacitors. Among them, Cz-TPA CMP exhibited the best electrochemical capacity and cycling stability.