High-performance supercapacitor based on nanocages with nanoporous thin-walled graphitic shells

Thin-walled graphitic nanocages (GNCs) made up from highly nanoporous shells have been prepared by removing nitrogen-doping (N-doping) template. N-doping template is carboxyl groups and nitro-groups, which have formed from oxidation of N-doped structure of GNCs by acid-treatment. After partially removing N-doping template by annealing in vacuum, nanopores are created in the shells of the thin walled GNCs. Thus, their specific surface area (1100 vs. 700 m(2) g(-1)) and specific capacitance (370 vs. 300 F g(-1) at current density of 0.1 A g(-1)) are sharply raised. With current density increasing to 1 A g(-1), the capacitance of the GNCs is still high (230 F g(-1)), indicating such GNCs is a superb electrode material of supercapacitor. (C) 2016 Elsevier Inc. All rights reserved.