Redox-active a pyrene-4,5,9,10-tetraone and thienyltriazine-based conjugated microporous polymers for boosting faradaic supercapacitor energy storage

Abstract

Conventional supercapacitor electrodes typically suffer from drawbacks such as low energy density, short cycle life, and poor conductivity. In contrast, conjugated microporous polymers (CMPs) present a more advantageous option, providing higher surface area, greater cycle stability, and enhanced electrical properties. Utilizing pyrene-4,5,9,10-tetraone (PyTE) as a key redox-active component, we successfully prepare pyrene-4,5,9,10-tetraone-thiophene polymer (PyTE-Th Polymer) and Thienyltriazine-pyrene-4,5,9,10-tetraone conjugated microporous polymer (TTh-Ph-PyTE CMP). This particular set of materials has been tailored for supercapacitor applications, employing a nitrogen-rich triazine, conductive thiophene (Th), and redox-active pyrene-4,5,9,10-tetraone (PyTE), a creation through simple Suzuki coupling conditions. PyTE-Th Polymer and TTh-Ph-PyTE CMP exhibit comparable BET surface areas and demonstrate good thermal stability, with char yields exceeding 62 wt% for each material. Electrochemical measurements reveal that TTh-Ph-PyTE CMP, featuring a triazine group with abundant heteroatoms, exhibited exceptional cycle stability of 90 % after 5000 cycles at 10 A g⁻¹ and a specific capacitance of 1041 F g⁻¹ (1 A g⁻¹). Notably, TTh-Ph-PyTE CMP portrays the maximum specific capacitance at 1 A g⁻¹ compared to PyTE-Th polymer (486 F g⁻¹) and other porous materials, suggesting a synergistic effect of redox-active units and abundant heteroatoms.