Conversion of spent coffee beans into reduced graphene oxide by Hummer's method as electrode for vanadium redox applications

The vanadium redox flow battery (VRB) is a renowned electrochemical energy storage device that has been used widely due to its promising storage capability. However, finite and non-renewable based pristine graphite such as TF6 graphite plates, are commonly used for commercial applications in VRB. Th...

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Main Author: Eng, Xue Er
Other Authors: Lim Tuti Mariana
Format: Final Year Project
Language:English
Published: Nanyang Technological University 2020
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Online Access:https://hdl.handle.net/10356/139125
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-1391252020-05-15T09:03:12Z Conversion of spent coffee beans into reduced graphene oxide by Hummer's method as electrode for vanadium redox applications Eng, Xue Er Lim Tuti Mariana School of Civil and Environmental Engineering Environmental Engineering Research Centre Nanyang Environment and Water Research Institute TMLim@ntu.edu.sg Engineering::Environmental engineering The vanadium redox flow battery (VRB) is a renowned electrochemical energy storage device that has been used widely due to its promising storage capability. However, finite and non-renewable based pristine graphite such as TF6 graphite plates, are commonly used for commercial applications in VRB. Thus, this project focuses on the feasibility of converting spent coffee beans to an electrode material in replacement of commercial graphite plates. The spent coffee beans are first converted to biochar by pyrolysis and then chemically activated using Hummer’s method. Afterwards, a reduction by hydrohalic acid is performed to synthesize reduced graphene oxide (rGO). The material properties of the samples obtained are characterised by CHNS analysis, Thermogravimetry analysis, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, Brunauer-Emmette-Teller, Transmission electron microscopy and Field emission scanning electron microscope while the electrochemical characteristic and performance of these samples are carried out using Electrochemical impedance spectroscopy, Cyclic voltammetry and Galvanostatic charge-discharge test. The overall results show that the energy efficiency of these samples ranges from 84% to 90% and the efficiency does not deteriorate significantly after a total of 65 cycles. Among these rGO synthesized sample, the 850°C rGO samples are identified as potential low-cost replacement to that of TF6 graphite as their energy efficiency performance are quite comparable within ~2% difference which may be attributed to increase ohmic resistance due to the slight increase in electrode thickness. Bachelor of Engineering (Environmental Engineering) 2020-05-15T09:03:12Z 2020-05-15T09:03:12Z 2020 Final Year Project (FYP) https://hdl.handle.net/10356/139125 en application/pdf Nanyang Technological University
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Engineering::Environmental engineering
spellingShingle Engineering::Environmental engineering
Eng, Xue Er
Conversion of spent coffee beans into reduced graphene oxide by Hummer's method as electrode for vanadium redox applications
description The vanadium redox flow battery (VRB) is a renowned electrochemical energy storage device that has been used widely due to its promising storage capability. However, finite and non-renewable based pristine graphite such as TF6 graphite plates, are commonly used for commercial applications in VRB. Thus, this project focuses on the feasibility of converting spent coffee beans to an electrode material in replacement of commercial graphite plates. The spent coffee beans are first converted to biochar by pyrolysis and then chemically activated using Hummer’s method. Afterwards, a reduction by hydrohalic acid is performed to synthesize reduced graphene oxide (rGO). The material properties of the samples obtained are characterised by CHNS analysis, Thermogravimetry analysis, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, Brunauer-Emmette-Teller, Transmission electron microscopy and Field emission scanning electron microscope while the electrochemical characteristic and performance of these samples are carried out using Electrochemical impedance spectroscopy, Cyclic voltammetry and Galvanostatic charge-discharge test. The overall results show that the energy efficiency of these samples ranges from 84% to 90% and the efficiency does not deteriorate significantly after a total of 65 cycles. Among these rGO synthesized sample, the 850°C rGO samples are identified as potential low-cost replacement to that of TF6 graphite as their energy efficiency performance are quite comparable within ~2% difference which may be attributed to increase ohmic resistance due to the slight increase in electrode thickness.
author2 Lim Tuti Mariana
author_facet Lim Tuti Mariana
Eng, Xue Er
format Final Year Project
author Eng, Xue Er
author_sort Eng, Xue Er
title Conversion of spent coffee beans into reduced graphene oxide by Hummer's method as electrode for vanadium redox applications
title_short Conversion of spent coffee beans into reduced graphene oxide by Hummer's method as electrode for vanadium redox applications
title_full Conversion of spent coffee beans into reduced graphene oxide by Hummer's method as electrode for vanadium redox applications
title_fullStr Conversion of spent coffee beans into reduced graphene oxide by Hummer's method as electrode for vanadium redox applications
title_full_unstemmed Conversion of spent coffee beans into reduced graphene oxide by Hummer's method as electrode for vanadium redox applications
title_sort conversion of spent coffee beans into reduced graphene oxide by hummer's method as electrode for vanadium redox applications
publisher Nanyang Technological University
publishDate 2020
url https://hdl.handle.net/10356/139125
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