Porous carbon synthesized by direct carbonization of potassium biphthalate for high-performance supercapacitors

Porous carbons have been synthesized by a direct carbonization of potassium biphthalate without an activation process. The experimental results demonstrate that the carbonization temperature plays a crucial role in determining the surface area and pore structure as well as the correlative capacitive performance. The carbon-700/800/900 samples display surface areas of 672, 1,023, and 1,380 m(2) g(-1) and total pore volumes of 0.38, 0.56, and 0.78 cm(3) g(-1), respectively. The specific capacitances of the carbon-700/800/900 samples are 300.4, 272.3, and 243.4 F g(-1), respectively, at a current density of 0.5 A g(-1). More importantly, the carbon-900 sample possesses the highest capacitance retention (similar to 98.4 %) even undergoing charge-discharge 10,000 times. The potassium biphthalate used as a carbon source is inexpensive and commercially available, making it promising for the large-scale production of porous carbons as an excellent electrode material for supercapacitors.