Enhanced anodic charge storage in asymmetric hybrid supercapacitor featuring dione–diimide-based electron deficient conjugated polymers

Abstract

Conjugated polymers (CPs) are emerging as promising candidates for pseudocapacitive electrodes because of their structural diversity, redox capability, and exceptional electronic conductivity. While n-type CP-based electrodes, which enable reductive charge storage, demonstrate superior charge carrier mobility and stability compared to their p-type counterparts, their development has been hindered by synthetic complexities and limited material availability. This study presents, two novel n-type CPs: BDD-NDI and BDD-PDI, featuring highly electron-deficient scaffolds, benzodithiophenedione (BDD), and naphthalene diimide (NDI) or perylene diimide (PDI), respectively. Incorporating redox-active scaffolds into the dual acceptor (A1–A2) design resulted in n-type CPs exhibiting enhanced anodic charge storage and stability by improving charge transport in the negative potential range. Among these, BDD-PDI exhibits remarkable pseudocapacitive performance, delivering a specific capacitance of 205 F g⁻¹ and 76% capacitance retention over 10 000 cycles at 5 A g⁻¹. When integrated into an asymmetric supercapacitor with activated carbon as cathode and BDD-PDI as anode, the device achieves an impressive energy density of 66.8 Wh kg⁻¹ and a power density of 12.9 kW kg⁻¹, facilitated by its broad operating potential window. This research offers valuable insights into the development of novel n-type pseudocapacitive electrodes, aiming for cost-effective and sustainable energy storage solutions.