Bio-inspired high performance electrochemical supercapacitors based on conducting polymer modified coral-like monolithic carbon

Abstract

Inspired by the structure and function of coral in nature, a series of composite electrode materials were prepared via depositing conducting polymers, such as polyaniline (PANi), polythiophene (PTh) and polypyrrole (PPY), on the surface of monolithic coral-like porous carbon (MC). MC with a specific surface area as high as 1125 m² g⁻¹ was prepared by a facile dual-templating approach. A thin layer of the conducting polymer was formed on the carbon surface. The constitutive properties including the morphology, pore size and specific area were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller measurement (BET), respectively. The electrocapacitive properties of electrode materials were evaluated using cyclic voltammetry and galvanostatic charge–discharge cycling in a three electrode system. Compared with MC, the specific capacitances of composite materials had an obvious shift, which reached 1488 F g⁻¹ at a high current density (1.0 A g⁻¹) in an aqueous H₂SO₄ electrolyte. The coral-like hierarchical porous structure of the carbon favoured the diffusion of the electrolyte ions, hence not only improving the energy storage capacity but also enhancing the power density. The energy density reached 49.5 W h kg⁻¹, even when the maximum power density was 12 000 W kg⁻¹. In addition, such a composite electrode material also showed considerable electrochemical stability, with at least 76.7% of the capacitance being retained after 1000 cycles.