Three-Dimensional\nPorous Carbon Derived from Polyindole\nHollow Nanospheres for High-Performance Supercapacitor Electrode

Abstract

Three-dimensional carbon materials\ncontaining oxygen/nitrogen functional\ngroups are facilely prepared by the carbonization of conjugated polyindole\nhollow nanospheres with the activation of 15 M KOH at 900 °C.\nThe pore structures, surface elemental composition, and hydrophilicity\nof samples are studied by nitrogen adsorption–desorption isotherms,\nX-ray photoelectron spectroscopy, X-ray diffraction, transmission\nelectron microscopy, energy-dispersive X-ray spectroscopy, scanning\nelectron microscopy, Raman, and contact angle, respectively. The specific\nsurface area of as-prepared carbon material with the micro/mesopore\nsize distribution of 0.5–4 nm and macropores more than 100\nnm is 2238 m² g^–1. The capacitance characterizations\ndemonstrate that the specific capacitance of as-prepared carbon can\nreach 328 F g^–1. The device built from such carbon\nmaterials exhibits high energy density of about 15 Wh/kg, and 91%\nretention of original capacity after 10000 cycles. These positive\ndata suggest that as-prepared three-dimensional materials will have\na certain potential in the application of the electrochemical energy\nstorage field.