Three-Dimensional Porous Carbon Derived from Polyindole Hollow Nanospheres for High-Performance Supercapacitor Electrode

Three-dimensional carbon materials containing oxygen/nitrogen functional groups are facilely prepared by the carbonization of conjugated polyindole hollow nanospheres with the activation of 15 M KOH at 900 degrees C. The pore structures, surface elemental composition, and hydrophilicity of samples are studied by nitrogen adsorption-desorption isotherms, X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, Raman, and contact angle, respectively. The specific surface area of as-prepared carbon material with the micro/mesopore size distribution of 0.5-4 nm and macropores more than 100 nm is 2238 m(2) g(-1). The capacitance characterizations demonstrate that the specific capacitance of as-prepared carbon can reach 328 F g(-1). The device built from such carbon materials exhibits high energy density of about 15 Wh/kg, and 91% retention of original capacity after 10000 cycles. These positive data suggest that as-prepared three-dimensional materials will have a certain potential in the application of the electrochemical energy storage field.