Synthesis, characterization and electrochemical properties of S-doped carbon aerogels

Heteroatom doping in carbon aerogels is critical for improving the surface areas and electronic properties of these aerogels. This paper demonstrates doping sulfur (S) atom into carbon aerogels. S-doped carbon aerogels (S-CAs) were prepared via a sol-gel process using phloroglucinol (P), resorcinol (R) and formaldehyde as the polymerization precursors with sodium carbonate (Na2CO3) as the basic catalyst and sodium 4-hydroxybenzenesulfonate (HBS) as the surfactant. The as-synthesized products were dried in normal temperature and carbonized with temperature-programmed. The effects of S-doping on the surface area and electronic properties of the S-CAs were studied by a surface area analyzer and electrochemical workstation. When the S loading was up to 1.38%, the corresponding S-CA exhibited the most optimal surface area and specific capacitance. The textural properties were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), a surface area analyzer, an X-ray diffraction spectrometer, a Raman spectrometer, the X-ray photoelectron spectroscopy (XPS) spectra, an elemental analyzer and an EDX detector, and the electrochemical properties were measured using cyclic voltammetry, galvanostatic charge-discharge measurements and electrochemical impedance spectroscopy (EIS). When the molar ratio of HBS/(P + R) was 0.05, the S loading was 1.38%, the specific surface area of the as-synthesized CA was 831 m2/g, and its specific capacitance was 105 F/g.