High-performance electric double-layer capacitor fabricated with nanostructured carbon black-paint pigment as an electrode

Abstract

Engineering the microstructure of the carbonaceous materials is a promising strategy to enhance the capacitive performance of supercapacitors. In this work, nanostructured Black Pearl (1500 BP) carbon which is a conductive carbon being commercially used in printing rolls, conductive packaging, conductive paints, etc. is analyzed for its feasibility as an electrode material for Electric Double-Layer Capacitors (EDLCs). To achieve that commercial Black Pearl (BP), carbon is treated with mild acid H₃PO₄ to remove the impurities and enhance the active sites by regulating the growth of agglomerates and creating micropores in the nano-pigments. Generally, the coalescence of nanoparticles owing to their intrinsic surface energy has tendency to create voids of different sizes that act like meso/micropores facilitating the diffusion of ions. The electrochemical performance of BP carbon before and after chemical activation is investigated in aqueous (H₂SO₄, KOH and KCl) and a non-aqueous electrolyte (1 M TEMABF₄ in acetonitrile) environment employing different electrochemical techniques such as Cyclic Voltammetry (CV), Galvanostatic charge/discharge (GCD) and Electrochemical Impendence Spectroscopy (EIS). The chemically activated BP carbon delivers the highest specific capacitance of ∼156 F g⁻¹ in an aqueous electrolyte, 6 M KOH. The highest specific power, ~ 15.3 kW kg⁻¹ and specific energy, 14.6 Wh kg⁻¹ are obtained with a symmetric capacitor employing non-aqueous electrolyte because of its high working potential, 2.5 V.