Porous carbon is a widely studied electrode material for supercacitors due to its low cost and high chemical stability. However, its electrochemical performance is limited because its charge storage mechanism is limited to storage via electric double-layer capacitance (EDLC). Recently, nitrogen-doped porous carbon has attracted great attention because of its altered chemical structure and additional pseudocapacitance originating from nitrogen dopants.Here, a hierarchically structured nitrogen-doped porous carbon is synthesized from nitrogen-containing isorecticular metal-organic framework (IRMOF-3) using an in situ one-step synthesis. In this approach, IRMOF-3 is directly carbonized without an additional carbon source, nitrogen source, and template since IRMOF-3 itself contains carbon and nitrogen precursors and acts as a porous template. Our method is simple and scalable up to multi-gram quantities. The surface area (391 to 553 m2 g-1) and nitrogen content (3.3 to 7 at%) are easily controlled by simply altering carbonization temperature (600 to 950 ?C). High carbonization temperatures (~950 ?C) generate high surface areas and less defective nitrogen-doped porous carbons, identified by nitrogen adsorption-desorption measurements and Raman spectroscopy. However, the nitrogen content decreases from 7 to 3.3 at% when carbonization temperature increases from 600 to 950 ?C. The electrochemical performance of the nitrogen-doped porous carbons was evaluated in aqueous two-electrode symmetric coin cells, yielding capacitances as high as 239 F g-1. On the contrary, undoped porous carbon with similar surface area and porosity exhibited a low capacitance of 24 F g-1. The enhanced performance of nitrogen-doped porous carbon is attributed to the additional pseudocapacitance as well as an enhanced electrode/electrolyte interface originating from nitrogen dopants. The nitrogen-doped porous carbon electrode shows no obvious decay in capacitance even after 10,000 cycles, which indicates its excellent physical and chemical stabilities.

In situ one-step synthesis of hierarchical nitrogen-doped porous carbon for high performance supercapacitors

248th National Meeting (2014)

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