Molecular structures driving pseudo-capacitance in hydrothermal nanostructured carbons

Abstract

The incorporation of nitrogen into hydrothermal carbon with (NH₄)₂SO₄ is shown to have a significant influence on its chemical composition and surface characteristics. This in turn boosts the pseudo-capacitive behavior of hydrothermal carbons and their overall electrochemical stability. A combination of X-ray photoelectron spectroscopy, Fourier transform infra-red spectroscopy (FTIR) and scanning electron microscopy (SEM), yielded insights on the influence of nitrogen doping on surface functionalities. 1- and 2-D solid state NMR established the molecular-level structure of both doped and non-doped hydrothermal carbon. Cyclic voltammetry and electrochemical impedance spectroscopy has established the electrochemical behaviour of these hydrothermal carbons, indicating that nitrogen doping enhances not only the capacitance but also the stability of the hydrothermal carbons.