Directly carbonized lotus seedpod shells as high-stable electrode material for supercapacitors

In this work, we demonstrate a simple and effective activation-free carbonization method to prepare porous carbon from lotus seedpod shellaEuro center dot a kind of natural biomass. It reveals that the carbonization temperature plays a crucial role in the determination of surface areas and capacitive performances of as-obtained porous carbon samples. The pore size and specific surface area of the samples were measured to be in the ranges of 2.0-2.2 nm and 261.7-563.4 m(2) g(-1), respectively. The carbon sample obtained at a carbonization temperature of 600 A degrees C (carbon-600) exhibits the maximum Barrett-Emmett-Teller (BET) surface area of 563.4 m(2) g(-1) and the highest specific capacitance of 165 F g(-1) at a current density of 0.5 A g(-1). More importantly, the carbon-600 sample reveals unexceptionable capacitance retention of 95.3 % after 10,000 charge-discharge cycles, clearly indicating its excellent cycling stability. This work gives a simple and efficient approach for producing cost-effective porous carbons with high performance for supercapacitors.