Role of graded microstructure and electrolyte distribution in electrochemical capacitance of compressible three-dimensional carbon nanotubes-polymer foam based supercapacitor

Chauhan, PS and Sengupta, R and Kumar, S and Panwar, V and Sahoo, S and Bose, S and Misra, A (2023) Role of graded microstructure and electrolyte distribution in electrochemical capacitance of compressible three-dimensional carbon nanotubes-polymer foam based supercapacitor. In: Electrochimica Acta, 461 .

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Abstract

Three-dimensional microstructure of carbon materials has a prime importance in supercapacitor for energy storage. Carbon nanotubes (CNT) provide microstructurally porous structure via entangled nodes that dynamically changes with the uniaxial compression. A unique graded CNT-polymer based three-dimensional compressible cellular foam is used as an electrode material for the solid-state supercapacitor. A direct correlation was established between the applied strain and resulting electrochemical capacitance when the foam electrode was soaked and unsoaked in the electrolyte. In a novel finding, unsoaked electrodes revealed in an extraordinary enhancement of ∼1216% in gravimetric capacitance measured at a uniaxial strain of 80% and to no surprise, the electrochemical capacitance of electrolyte-soaked electrodes remained nearly invariant from its uncompressed state. The response of electrochemical capacitance under compression is also observed varying with the mode of compression i.e. quasi-static versus pre-compressed state to a targeted strain. The role of graded microstructure during uniaxial compression was verified by using as-grown CNT mat for the electrodes of a supercapacitor. The results demonstrated a dominating contribution of dynamic variation in the density of nodes in the compressed CNT mat. The impact of macroscopic variation on the response of electrochemical capacitance of a compressed cellular CNT-polymer foam was further understood using the separators of varying pore sizes. Our results pave the way to engineer the three-dimensional compressible cellular structures for extraordinarily large energy storage capacity.

Item Type:	Journal Article
Publication:	Electrochimica Acta
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to the Elsevier Ltd.
Keywords:	Capacitance; Electrochemical electrodes; Electrolytes; Energy storage; Foams; Microstructure; Pore size; Supercapacitor, Carbon material; Carbon nanotube mats; Electrochemical capacitance; Electrolyte distribution; Graded microstructures; Polymer based; Polymer foams; Porous structures; Three-dimensional microstructures; Uni-axial compression, Carbon nanotubes
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy) Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	14 Jul 2023 06:16
Last Modified:	14 Jul 2023 06:16
URI:	https://eprints.iisc.ac.in/id/eprint/82383

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