Micro-mesoporous carbon spheres derived from carrageenan as electrode material for supercapacitors

The polysaccharide carrageenan is used as a natural precursor to prepare micro-mesoporous carbon spheres. The carbon spheres were synthesized by hydrothermal carbonization of carrageenan, and subsequent chemical activation by KOH at different temperatures. The obtained micro-mesoporous carbon spheres have high surface area (up to 2502 m(2) g(-1)) and large pore volume (up to 1.43 cm(3) g(-1)). Moreover, the micro- and mesoporosity can be finely tuned be modifying the activation temperatures in the range of 700-900 degrees C. The carbon spheres activated at 900 degrees C present high specific capacitance of 230 F g(-1) at a current density of 1 A g(-1) and good ion transport kinetics. The good capacitive performance can be ascribed to the high specific surface area, well-controlled micro- and mesoporosity and narrow pore size distribution. (C) 2014 Elsevier B.V. All rights reserved.