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Platelet CMK-5 as an Excellent Mesoporous Carbon to Enhance the Pseudocapacitance of Polyaniline

Lei, Zhibin, Sun, Xiuxia, Wang, Huanjing, Liu, Zonghuai, Zhao, X. S.
ACS Applied Materials & Interfaces 2013 v.5 no.15 pp. 7501-7508
aniline, capacitance, carbon, electrical equipment, electrochemistry, electrodes, energy density, polymerization, porous media, redox reactions, surface area
A high-performance supercapacitor electrode consisting of platelet ordered mesoporous carbon CMK-5 and polyaniline (PANi) was prepared by chemical oxidative polymerization of aniline in the presence of CMK-5. The PANi with uniform size of 2–5 nm was primarily confined in the mesochannels of CMK-5 at low PANi loadings (40 and 51 wt %), whereas at a high loading of 64 wt %, additional PANi thin films with thicknesses of 5–10 nm were coated on the surface of the CMK-5 particles. Such CMK-5-PANi composites afforded a high electrochemical active surface area for surface Faradic redox reactions, leading to a more than 50% utilization efficiency when considering the theoretical capacitance of PANi of about 2000 F/g. As a result, a specific capacitance of 803 F/g and an energy density of 27.4 Wh/kg were achieved for CMK-5-PANi composite electrode with 64 wt % PANi, showing substantial improvement as compared with symmetric capacitors configured with CMK-5 electrodes (10.1 Wh/kg) or pure PANi electrodes (16.4 Wh/kg). Moreover, an excellent rate capability and a substantially enhanced electrochemical stability with 81% capacitance retention as compared with 68% of pure PANi were also observed over 1000 charge–discharge cycles at a constant current density of 4.0 A/g.