Activated carbon from phenolic resin with controlled mesoporosity for an electric double-layer capacitor (EDLC)

Abstract

Activated carbon materials are prepared from phenolic resin precursors by physical activation to fabricate electrodes for electric double-layer capacitors (EDLCs). Pore size and surface area of the carbon materials are controlled during the synthesizing process and after the carbonization through activation in a CO₂ atmosphere to different levels of burn-off. The resultant carbon materials were evaluated as EDLC electrodes, using electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge (GCD) measurements with the organic electrolyte of spiro-(1,1′)-bipyrrolidinium tetrafluoroborate in propylene carbonate, SBPBF₄/PC. The results of the study showed that the capacitance of carbon materials, as well as energy density of the EDLC cells, increased by increasing the level of burn-off (activation). The 46% activated carbon gave a capacitance of ∼160 F g⁻¹ and an energy density of ∼35 W h kg⁻¹, at a current density of 1 mA cm⁻². The long term cycling tests showed high cycling stability of these carbon materials.