Electrochemical Study of Functionalized Carbon Nano-Onions for High-Performance Supercapacitor Electrodes
详细信息 查看全文
- 作者：Rituraj Borgohain ; Juchuan Li ; John P. Selegue ; Y.-T. Cheng
- 刊名：The Journal of Physical Chemistry C
- 出版年：2012
- 出版时间：July 19, 2012
- 年：2012
- 卷：116
- 期：28
- 页码：15068-15075
- 全文大小：522K
- 年卷期：v.116,no.28(July 19, 2012)
- ISSN：1932-7455
文摘
Carbon nano-onions (NCNOs), concentrically multilayered fullerenes, are among the least studied carbon allotropes. NCNOs have high surface area, high mesoporosity, facile electrical conductivity, and electrochemical stability. NCNOs are chemically oxidized (ONCNOs) to introduce hydrophilic functional groups, improving their wettability for use in supercapacitor electrodes. RuO2路xH2O/ONCNOs composites are prepared by chemical precipitation of RuO2 on ONCNOs, optimized for homogeneous distribution and maximum utilization of the metal oxide nanoparticles. The materials are characterized by high-resolution transmission electron microscopy, N2 absorption鈥揹esorption isotherm, and thermogravimetric analysis. Electrochemical performance of the electrodes is studied by cyclic voltammetry, galvanostatic charge鈥揹ischarge, and electrochemical impedance measurements in 1.0 M H2SO4. While ONCNOs have specific capacitance of 45 F路gp>鈥? p>, a composite with 67.5 wt.% RuO2 has specific capacitance of 334 F路gp>鈥? p> at a potential sweep rate of 20 mV路sp>鈥? p> with high power (242.8 kW路kgp>鈥? p>) and high energy density (11.6 Wh路kgp>鈥? p>). Both the ONCNO and the composites show excellent capacitance behaviors even at very high potential scan rates (>8 V路sp>鈥? p>). Simple preparation of high-purity NCNOs and excellent electrochemical behavior of functionalized NCNOs make them a promising electrode material in supercapacitor applications.