Simple Synthesis of Carboxylate–Rich Porous Carbon Microspheres for High-Performance Supercapacitor Electrode Materials

Carboxylate–rich porous carbon microspheres with high specific surface area were synthesized via a simple hydrothermal carbonization method by using starch and acrylic acid as starting materials, followed by stream activation at 800 °C in nitrogen atmosphere for 1 h. The resulting materials were characterized using various methods including, X–ray diffraction (XRD), Raman spectrum, infrared spectrum (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and BET measurements. Cyclic voltammetry and galvanostatic charge/discharge experiments were adopted to investigate their electrochemical behaviors. The cyclic voltammetry (CV) measurement shows that the synthesized porous microspheres exhibited a super capacitance of 190 F g–1 at the scanning rate of 2 mv s–1. The galvanostatic charge/discharge shows it exhibited a large specific capacitance up to 212 F g–1 with the current density of 0.5 A g–1. The experimental results indicate that carboxyl groups and high surface area could enhance both specific capacitance and electrochemical stability of the resultant microspheres.