Evaluation of nitrogen- and sulfur-doped porous carbon textiles as electrode materials for flexible supercapacitors

Abstract

With an objective to increase an electrochemical performance, simple and effective modifications of activated carbon fiber textiles (ACT) were carried out prior to their testing as supercapacitors. The modifications included a high-temperature treatment of the textile impregnated with N- and S-containing species (i.e. dicyandiamide, urea and thiourea). This led to an improvement in an electrical conductivity and in an enhanced mechanical strength with a preserved porosity. Compared to the performance of the initial unmodified carbon textile, a urea-functionalized material showed an enhancement in the electrochemical capacitance. An increase from 177 to 209 F g−1 at a scan rate 10 mV s−1 in an alkaline electrolyte was recorded (3-cell CV measurements) and from 138 to 166 F g−1 at 0.10 A g−1 (2-cell galvanostatic charge-discharge). The results suggested that mechanically stable, flexible and conductive ACT have a potential to be used in textile-based flexible supercapacitors. Benefits coming from the applied modification routes can be also adapted for the fabrication of other types of carbon-based composite electrode materials.