Preparation of mesoporous carbons from amphiphilic carbonaceous material for high-performance electric double-layer capacitors

Amphiphilic carbonaceous material (ACM), with nanoscale dispersion in alkaline aqueous solutions, is synthesized from green needle coke. As a special precursor with small particle size, plenty of functional groups and widened d(002) simultaneously, ACM guarantees subsequent ACM-based activated carbons (AACs) with high specific surface area over 3000 m(2) g(-1) as well as well-developed mesoporous structure after KOH activation. Such pore properties enable AACs' high performances as electrode materials for electric double-layer capacitors (EDLCs). In particular, surface area up to 3347 m(2) g(-1) together with notable mesopore proportion (26.9%) gives sample AAC814 outstanding EDLC behaviors during a series of electrochemical tests including galvanostatic charge/discharge. CV and electrochemical impedance spectroscopy. The electrode gets satisfactory gravimetric and volumetric specific capacitance at the current density of 50 mA g(-1), up to 348 F g(-1) and 162 F cm(-3), respectively. Furthermore, for the mesoporosity, there is only a slight capacitance reduction for AAC814 as the current density reaches 1000 mA g(-1), indicating its good rate performance. It is all the ACM's unique characteristics that make AACs a sort of competitive EDLC electrode materials, both in terms of specific capacitance and rate capability. (C) 2010 Elsevier B.V. All rights reserved.