Enhanced Pseudocapacitance of Ionic Liquid/Cobalt Hydroxide Nanohybrids
- 18 February 2013
- journal article
- Published by American Chemical Society (ACS) in ACS Nano
- Vol. 7 (3), 2453-2460
- https://doi.org/10.1021/nn305750s
Abstract
Development of nanostructured materials with enhanced redox reaction capabilities is important for achieving high energy and power densities in energy storage systems. Here, we demonstrate that the nanohybridization of ionic liquids (ILs, 1-butyl-3-methylimidazolium tetrafluoroborate) and cobalt hydroxide (Co(OH)2) through ionothermal synthesis leads to a rapid and reversible redox reaction. The as-synthesized IL-Co(OH)2 has a favorable, tailored morphology with a large surface area of 400.4 m(2)/g and a mesopore size of 4.8 nm. In particular, the IL-Co(OH)2-based electrode exhibits improvement in electrochemical characteristics compared with bare Co(OH)2, showing a high specific capacitance of 859 F/g at 1 A/g, high-rate capability (∼95% retention at 30 A/g), and excellent cycling performance (∼96% retention over 1000 cycles). AC impedance analysis demonstrates that the introduction of ILs on Co(OH)2 facilitates ion transport and charge transfer: IL-Co(OH)2 shows a higher ion diffusion coefficient (1.06 × 10(-11) cm(2)/s) and lower charge transfer resistance (1.53 Ω) than those of bare Co(OH)2 (2.55 × 10(-12) cm(2)/s and 2.59 Ω). Our density functional theory (DFT) calculations reveal that the IL molecules, consisting of anion and cation groups, enable easier hydrogen desorption/adsorption process, that is, a more favorable redox reaction on the Co(OH)2 surface.Keywords
This publication has 44 references indexed in Scilit:
- Hybrid structure of cobalt monoxide nanowire @ nickel hydroxidenitrate nanoflake aligned on nickel foam for high-rate supercapacitorEnergy & Environmental Science, 2011
- Nanoporous metal/oxide hybrid electrodes for electrochemical supercapacitorsNature Nanotechnology, 2011
- The role of nanomaterials in redox-based supercapacitors for next generation energy storage devicesNanoscale, 2011
- Manganese oxide-based materials as electrochemical supercapacitor electrodesChemical Society Reviews, 2010
- Nanosheets of Oxides and Hydroxides: Ultimate 2D Charge‐Bearing Functional CrystallitesAdvanced Materials, 2010
- Energy storage in electrochemical capacitors: designing functional materials to improve performanceEnergy & Environmental Science, 2010
- Advanced Materials for Energy StorageAdvanced Materials, 2010
- Ordered mesoporous α-MoO3 with iso-oriented nanocrystalline walls for thin-film pseudocapacitorsNature Materials, 2010
- Carbon-based materials as supercapacitor electrodesChemical Society Reviews, 2009
- Preparation of the Novel Nanocomposite Co(OH)2/ Ultra‐Stable Y Zeolite and Its Application as a Supercapacitor with High Energy DensityAdvanced Materials, 2004