Hydrothermal Carbonization to Produce Materials for Electrochemical Capacitors

Hydrothermal carbonization has gained increased interest over the last 15 years as a highly effective and environmentally friendly way to produce highly functional carbon materials. Compared to other carbon doping methods, hydrothermal carbonization represents one of the simplest and easiest routes, as elements dissolved in the initial hydrothermal solution are readily incorporated into the carbon structure. In terms of electrochemical performance, nitrogen doped into the carbon structure has been found to significantly improve the electrochemical performance of supercapacitors by increasing pseudocapacitive behaviour. In this study, we have investigated the chemical structure, morphology and electrochemical performance of hydrothermal carbons produced from sucrose which contain varying degrees of nitrogen doping. The hydrothermal treatment produced carbons with a spherical morphology with a wide variety of carbon functionalities littering the surface. Electrochemically, these carbons displayed a wide range of psudocapacitive behaviour as well as electrical double layer capacitance, delivering capacitance up to 120 F/g in three cell electrodes with 0.5 M H₂SO₄ as the electrolyte.