Facile synthesis of carbon nanofibers-bridged porous carbon nanosheets for high-performance supercapacitors

A facile and one-step method is demonstrated to prepare carbon nanofibers (CNFs)-bridged porous carbon nanosheets (PCNs) through carbonization of the mixture of bacterial cellulose and potassium citrate. The CNFs bridge PCNs to form integrated porous carbon architecture with high specific surface area of 1037 m(2) g(-1), much higher than those of pure PCNs (381 m(2) g(-1)) and CNFs (510 m(2) g(-1)). As a consequence, the PCN/CNF composite displays high specific capacitance of 261 F g(-1), excellent rate capability and outstanding cycling stability (97.6% of capacitance retention after 10000 cycles). Moreover, the assembled symmetric supercapacitor with PCN/CNF electrodes delivers an ultrahigh energy density of 20.4 Wh kg(-1) and outstanding cycling life (94.8% capacitance retention after 10000 cycles) in an aqueous electrolyte. (C) 2015 Elsevier B.V. All rights reserved.