Hybrid carbon black / PEDOT:PSS nanocomposite for efficient energy storage in supercapacitor applications

In response to the growing demand for renewable energy sources, there is a critical need for efficient, eco-friendly, and cost-effective Energy Storage Systems (ESS). Supercapacitors (SCs) are promising devices that bridge the gap between electrostatic capacitors and batteries in terms of power and energy density. Among organic materials, Poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) is widely used due to its favourable properties. Nevertheless, performance enhancement is commonly achieved through the incorporation of costly nanomaterials, such as carbon nanotubes. In this work, a low-cost and environmentally sustainable PEDOT:PSS-based nanocomposite is developed and characterized using carbon black (CB), a combustion-derived waste material, as a reinforcing filler. The influence of varying CB loadings (0.01–0.05 wt%) on the nanocomposite properties is systematically investigated. The filler was first characterized for its composition, crystal structure, and particle size. Analysis tests of the liquid ink formulations showed that viscosity remained relatively unchanged with CB inclusion, whereas surface tension and contact angle significantly decreased from 79.95 mN m -1 and 85.32° to 54,10 mN m -1 and 49.03° for PEDOT:PSS and CB(0.05%)/PEDOT:PSS nanocomposite, respectively. Thin films prepared by drop casting and spin coating were analyzed, revealing superior structural characteristics for spin-coated layers. Scanning Electron Microscopy (SEM) observations showed carbon black aggregates with nanometric dimensions. Dimethyl Sulfoxide (DMSO) post-treatment significantly improved both electrical and electrochemical properties, with conductivity increasing from 825 S cm -1 (pure PEDOT:PSS) to 940 S cm -1 at 0.02 wt% CB and specific capacitance rising from 73 to 79 F g -1 . Furthermore, electrochemical impedance spectroscopy (EIS) analysis demonstrated a reduction in the charge-transfer resistance from 215 Ω for PEDOT:PSS to 177 Ω for the CB(0.02%)/PEDOT:PSS system, along with an improved capacitive response in the low-frequency region. Overall, the results demonstrate the potential of carbon black as a cost-effective filler to enhance PEDOT:PSS performance, promoting sustainable supercapacitor development within a circular economy framework.