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Giant dielectric macroporous graphene oxide foams with aqueous salt solutions: Impedance spectroscopy

Jayanthi, Swetha and Jayaraman, N and Chatterjee, Kaushik and Sampath, S and Sood, A K (2019) Giant dielectric macroporous graphene oxide foams with aqueous salt solutions: Impedance spectroscopy. In: CARBON, 155 . pp. 44-49.

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Official URL: http://dx.doi.org/10.1016/j.carbon.2019.08.045

Abstract

Ultralight and ultrathin dielectric materials with high dielectric permittivity and power densities are required to meet the ever-increasing demands of microelectronic and energy storage devices. In the present study, we demonstrate the feasibility of achieving giant dielectric performance of light weight, highly porous three-dimensional architectures of insulating graphene oxide (GO) foams by saturating the pores with liquid containing mobile ions. Dielectric behavior of GO foam is investigated over a range of frequencies (1 kHz-10 kHz) by employing electrochemical impedance spectroscopy. The relative permittivity of pristine GO foam is shown to improve by five orders upon saturating the pores with different concentrations of aqueous NaCl solutions. Dielectric constants of foams saturated with aqueous NaCl solutions are measured to be of the order of 10(6) at high frequencies (1 kHze10 kHz) and are observed to enhance to 10(8) at lower frequencies down to 0.01 Hz. Various contributions to the measured capacitance are deciphered by modelling the impedance data to an equivalent circuit in order to evaluate the exact contribution from dipole orientation. The plausible reasons for the enhanced dielectric behavior are emphasized. (C) 2019 Elsevier Ltd. All rights reserved.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to PERGAMON-ELSEVIER SCIENCE LTD
Keywords: ENERGY DENSITY; COMPOSITES; CAPACITORS; PERMITTIVITY; FREQUENCY; WATER
Department/Centre: Division of Chemical Sciences > Inorganic & Physical Chemistry
Division of Chemical Sciences > Organic Chemistry
Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Division of Interdisciplinary Research > Centre for Nano Science and Engineering
Division of Physical & Mathematical Sciences > Physics
Depositing User: Id for Latest eprints
Date Deposited: 20 Nov 2019 12:06
Last Modified: 20 Nov 2019 12:06
URI: http://eprints.iisc.ac.in/id/eprint/63798

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