Cellulose-derived hierarchical porous carbon for high-performance flexible supercapacitors

Hierarchical porous carbon was synthesized using the spray drying method with cellulose as the carbon source. It was found that thermal treatment temperature had a significant influence on the microstructure of the carbon. A sample obtained at thermal treatment temperature of 1000 degrees C displayed a high specific surface area of 1096 m(2)/g, a large pore volume (1.59 cm(3)/g), and an appropriate pore system suitable for aqueous sodium chloride electrolyte. A flexible symmetric supercapacitor cell fabricated with this carbon as both electrode exhibited a high specific capacitance (194 F/g at current density 1 A/g), a good rate performance (137 F/g at 10 A/g) and long cycle life (only 4.8% capacitance loss after 5000 cycles). The cell delivered a specific energy of 15.2 Wh/Kg at a specific power of 751 W/Kg, and maintain its stable electrocapacitive performance and good flexibility at the bending condition. (C) 2018 Elsevier Ltd. All rights reserved.