Synthesis of nitrogen-containing ordered mesoporous carbons and their supercapacitor behaviors

Abstract

Electric double layer capacitors (EDLCs) have attracted much attention as energy storage devices due to high power density, better rate capability, and longer life cycle compared to modern secondary batteries. The storage of electronic charges is mainly based on the formation of electrical double layer at electrode/electrolyte interface, which accumulate electrical charges on the electrode surface. On the basis of the mechanism, porous electrode materials with high surface area, which makes it possible for high charge accumulation, are demanding for high capacitance. For this reason, activated carbons with high surface area have been widely used as an electrode for EDLCs since 1970s. However, currently, electrical systems which supply high electrical power density such as electrical vehicles with hybrid engine, cellular communication systems and uninterruptible power supplies require high performances of EDLC capacitors. Activated carbons as an EDLC electrode have some limitations to successfully achieve these applications. One of the limitations is mainly due to randomly distributed micropore sizes (< 2 nm) which often hinder the transport of electrolytes within carbon structure, resulting in limited charge storage at high current density. Recently, ordered mesoporous carbons using mesoporous silica as a template have been greatly interested for an EDLC electrode due to high surface area, uniform pore sizes, and various pore structures. These carbon materials with mesopores (> 2 nm) are highly desirable as an EDLC electrode. In addition to the pore structural properties, it was reported that carbon materials with heteroatoms and other functional groups could also enhance EDLC capacitances. This might be ascribed to the enhanced carbon surface affinity to electrolyte and pseudocapacitance induced by heteroatoms. Hence, development of synthesis route to mesoporous carbons containing heteroatom is expected to be highly demanding for the design of high-performa...