Enhanced Pseudocapacitance of Ionic Liquid/Cobalt Hydroxide Nanohybrids

Title
Enhanced Pseudocapacitance of Ionic Liquid/Cobalt Hydroxide Nanohybrids
Authors
허윤석
Keywords
supercapacitor . redox reaction . ionic liquid . Co(OH)2 . Nanohybrid
Issue Date
2013
Publisher
ACS NANO
Series/Report no.
ACS NANO; vol.7 no.3 startpage 2453 endpage 2460
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 m2/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 cm2/s) and lower charge transfer resistance (1.53Ω) than those of bare Co(OH)2 (2.55 10 12 cm2/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.
URI
http://dspace.inha.ac.kr/handle/10505/32607
ISSN
1936-0851
Appears in Collections:
College of Engineering(공과대학) > Biotechnology (생명공학) > Local Access Journal, Report (생명공학 논문, 보고서)

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse