Effect of reaction time and PVP contents on morphologies of hierarchical 3D flower-like ZnCo2O4 microstructures for energy storage devices

Gutturu, RR and TVM, S and Rajavaram, R and Borelli, DPR and Dillip, GR and Nagajyothi, PC and Shim, J (2020) Effect of reaction time and PVP contents on morphologies of hierarchical 3D flower-like ZnCo2O4 microstructures for energy storage devices. In: International Journal of Energy Research, 44 (14). pp. 11233-11247.

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Abstract

Hierarchical 3D flower-like ZnCo2O4 (ZCO) microstructures assembled from petal-like nanosheets/flakes of non-uniform sizes were engineered by a polyvinylpyrrolidone (PVP)-assisted hydrothermal method. Four different samples/morphologies of ZCO were obtained (PVP-L@6, PVP-H@6, PVP-L@12, and PVP-H@12) by altering the reaction parameters such as surfactant concentration (PVP) and reaction time, which can play a significant role in the formation of flower-/petal-/flake-like architectures. The alteration of the reaction parameters not only resulted in morphological changes but also affected the surface area, pore size/volume, crystalline nature, non-stoichiometry of Zn, Co, and O in ZCO, and their electrochemical performance. The metal (Zn/Co)/O deficiencies of ZCO samples were investigated via X-ray photoelectron spectroscopy and supported by the Rietveld refinement method. Furthermore, a plausible growth mechanism for these flower-like ZCO microstructures was projected based on the experimental results. The four dissimilar samples/morphologies of ZCO, which exhibit different electrochemical performances, were investigated. Our results show that PVP-H@12 exhibits higher specific capacitance (761/680 F g�1 at 0.35/1 A g�1) and good cycling constancy (90 capacitive retention after 2000 cycles at 5 Ag�1) among all the four samples. © 2020 John Wiley & Sons Ltd

Item Type:	Journal Article
Publication:	International Journal of Energy Research
Publisher:	John Wiley and Sons Ltd
Additional Information:	Copyright to this article belongs to John Wiley and Sons Ltd
Keywords:	Energy storage; Microstructure; Pore size; Rietveld refinement; X ray photoelectron spectroscopy; Zinc metallography, Electrochemical performance; Hydrothermal methods; Morphological changes; Polyvinyl pyrrolidone; Reaction parameters; Rietveld refinement method; Specific capacitance; Surfactant concentrations, Zinc compounds
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	30 Jul 2021 05:48
Last Modified:	30 Jul 2021 05:48
URI:	http://eprints.iisc.ac.in/id/eprint/66394

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