Heteroatom-doped multilocular carbon nanospheres with high surface utilization and excellent rate capability as electrode material for supercapacitors

Heteroatom-doped multilocular carbon nanospheres (HMCSs) are synthesized by carbonizing multilocular polyaniline nanospheres (MPSs) which are prepared via metal-catalyzed polymerization in the presence of cupric nitrate as catalyst and ammonium persulfate as oxidant. The impacts of carbonization temperature on the morphology, structure and property of HMCSs are investigated. The results show that the carbonized sample at 800 degrees C (HMCSs-800) has a specific surface area of 283 m(2) g(-1), nitrogen content of 7.15% and oxygen content of 8.78%, and exhibits the specific capacitance of 186 F g(-1) at the current density of 0.5 Ag-1. Most importantly, HMCSs-800 possesses high surface utilization (0.66 Fm-2) and excellent rate capability (73.8% retention at 20 A g(-1) relative to the capacitance of 0.5 Ag-1). These results are superior to that of other carbon materials in most reports. The specific capacitance still preserves 91.3% after 5000 charge/discharge cycles at the current density of 5 Ag-1, demonstrating good cyclic stability. The outstanding electrochemical performance of HMCSs-800 can be ascribed to the providential integrate of particular multilocular structure, high micropore content and proper heteroatom content. (C) 2017 Elsevier Ltd. All rights reserved.