2,2′-Bithiophene and thieno[3,2-b]thiophene-tethered conjugated microporous polymers as organic electrodes for supercapacitor energy storage

Abstract

Many current supercapacitor (SCs) electrodes still face persistent challenges, including restricted cycle durability, low energy density, and inadequate electrical conductivity. To overcome these drawbacks, conjugated microporous polymers (CMPs) have been proposed as an up-and-coming category of materials stemming from their tunable porosity and extended π-conjugation. In this study, we designed and synthesized two novel CMPs—TPBZ-BTh and TPBZ-TTh—by integrating 1,2,4,5-tetrakis-(4-aminophenyl)benzene (TPBZ-4NH 2 ) with 2,2′-Bithiophene-5,5′-dicarboxaldehyde [BTh–2CHO], and thieno[3,2- b ]thiophene-2,5-dicarbaldehyde [TTh-2CHO] units through a [4 + 2] condensation Schiff-base reaction. Both CMPs exhibited outstanding thermal stability, well-developed porous structures, and efficient charge-transport pathways, all of which are crucial for improving electrochemical properties. Among these two, TPBZ-TTh CMP demonstrated a remarkable specific capacitance of 536 F g −1 [1 A g −1 ] and sustaining 96.6% capacitance retention even after prolonged cycling, reflecting its excellent stability and reversibility. To further evaluate its practical potential, a symmetric coin-cell supercapacitor was fabricated using TPBZ-TTh CMP material. The symmetric coin cell achieved the specific capacitance of 207 F g −1 (recorded at 1 A g −1 ), alongside impressive power and energy densities, confirming its viability for real-world SCS applications. These findings underscore the power of rational design of CMPs frameworks with BTh and TTh for next-generation high-performance, durable, and sustainable supercapacitor materials. • TPBZ-BTh and TPBZ-TTh CMPs were prepared through a [4 + 2] condensation Schiff-base. • TPBZ-TTh CMP achieved a specific capacitance of 536 F g −1 in the three-electrode system. • TPBZ-TTh CMP achieved exceptional capacitance stability of 96.6% after 5000 cycles. • The symmetric TPBZ-TTh CMP device delivers a specific capacitance of 207 F g −1 . • The symmetric TPBZ-TTh CMP device delivers an energy density of 36.1 Wh kg −1 .