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A study of methanol concentration of a single chamber direct methanol fuel cell via electrochemical impedance spectroscop

A study of methanol concentration of a single chamber direct methanol fuel cell via electrochemical impedance spectroscop / Siew Seok Li
Sel Bahan Api Metanol (DMFC) telah menjadi salah satu jenis tenaga yang boleh diperbaharui disebabkan oleh metanol yang boleh sentiasa dihasilkan. Ianya juga ketumpatan kuasa yang tinggi. Dunia sedang menghadapi krisis tenaga dan DMFC ini berpotensi untuk menjadi salah satu penyelesaian utama kepada masalah tersebut. Kini, DMFC didapati boleh diaplikasikan pada peralatan elektrik mudah alih seperti computer riba, telefon bimbit dan sebagainya dan aplikasi ini lebih mencadangkan untuk dioperasi pada suhu bilik. Oleh itu, kajian mengenai DMFC yang beroperasi pada suhu bilik (25 ⁰C) dalam sistem kumpulan telah dijalankan bagi kepekatan metanol yang berlainan. Maksima arus elektrik yang dicatatkan oleh sistem tersebut adalah bagi 4M kepekatan metanol, iaitu 0.0021 mA. Teknik Elektrokimia Impedans Spectroskopi (EIS) telah digunakan untuk mendapatkan rintangan dalaman pada anod bagi pelbagai kepekatan metanol. Plot Nyquist telah diplot and rintangan dalaman didapati mengurang apabila kepekatan metanol mengurangkan. Model Litar Setaraf (ECM) telah dikaji untuk menunjukkan ciri-ciri sistem eletrokimia dan pengesahan data eksperimen. Dengan ini, kajian tentang rintangan dalaman, rintangan bagi tindak balas electro-pengoksidaan metanol, rintangan bagi tindak balas eletro-pengoksidaan carbon monoksida yang terjerap dan unsur kapasitif telah dilakukan. Jumlah rintangan dalaman yang paling kurang telah ditentukan oleh 3M kepekatan metanol iaitu 221.70 Ω.cm2 dengan jumlah sisa persegi 0.00049 manakala yang tertinggi adalah 5M kepekatan metanol iaitu 1027.21 Ω.cm2 dengan sisa persegi 0.0080. Hasil kajian ini telah menunjukkan ECM yang dicadangkan adalah sesuai dengan data eksperimen. Selain itu, pelbagai voltan luaran telah diaplikasikan pada sistem tersebut and implikasinya terhadap rintangan dalaman telah dikaji bagi kepekatan metanol yang berlainan. Hasil kajian telah menunjukkan bahawa rintangan dalaman menurun semasa aplikasi voltan luaran pada sistem meningkat. Eksperimen bagi 3M kepekatan metanol telah berulang untuk mengkaji konsisten data eksperimen. Dari seluruh kajian ini, impak kepekatan metanol pada arus elektrik dan rintangan dalaman telah dibentangkan. Kajian ini telah menunjukkan 3M and 4M kepekatan metanol adalah kepekatan yang paling sesuai digunakan dalan sistem tersebut disebabkan olen arus elektrik yang tinggi dan jumlah rintangan dalaman yang rendah. _______________________________________________________________________________________________________ Direct Methanol Fuel Cell (DMFC) is emerging as a new source of renewable energy due to the renewable methanol source and its high power density. The global is facing energy crisis and DMFC might be one of the key solution to this problem. Currently, DMFC was found that it has the ability to be applicable on various portable auxiliary and off-grid power applications such as laptop computers, two-way radios and mobile phones and all these were preferable to be at ambient temperature. Therefore, DMFC operating at room temperature (25 ⁰C) in a single batch system was investigated in this study for various methanol concentration. The maximum current for the system was recorded to be at 4M methanol concentration which was 0.0021mA. Electrochemical Impedance Spectroscopy (EIS) study was performed to determine the internal resistance at the anode electrode for various methanol concentration with no external voltage supplied. Nyquist Plot was presented and it was found that the impedance decreased with the methanol concentration. Equivalent Circuit Model (ECM) was then developed to represent the behavior of the electrochemical system and verified the experimental data by fitting it with the empirical data. The IR resistance, methanol electro-oxidation reaction resistance, electro-oxidation reaction resistance of adsorbed CO and the capacitive element were investigated. It was found that 3M gave the lowest total internal resistance and 5M gave the highest which were 221.70 Ω.cm2 and 1027.21 Ω.cm2, with residual sum square, x2 of 0.00049 and 0.0080 respectively. It was found that the experimental data is fitted well to the empirical model generated from the proposed ECM. The study was followed by investigating the effect of different external voltage supplied to the system on the impedance of the system. It was found that the impedance decreased as the applied voltage increased for respective methanol concentration. Since 3M methanol concentration gave the lowest total impedance value with high current profile, experiment was repeated for this methanol concentration to study the consistency of experimental data. It was found that the data was quite consistent despite the slight deviation. This research clearly demonstrated the impedance of a single batch system operating at room temperature for various methanol concentration as well as for various external voltage supplied. Through this experiment, it was found that 3M and 4M methanol concentration were the optimum concentration to be used for this system due to their relatively high current profile as well as low total impedance.
Contributor(s):
Siew Seok Li - Author
Primary Item Type:
Final Year Project
Identifiers:
Accession Number : 875006348
Barcode : 00003103741
Language:
English
Subject Keywords:
Direct Methanol Fuel Cell (DMFC); new source of renewable energy; methanol source
First presented to the public:
6/1/2016
Original Publication Date:
5/21/2018
Previously Published By:
Universiti Sains Malaysia
Place Of Publication:
School of Chemical Engineering
Citation:
Extents:
Number of Pages - 69
License Grantor / Date Granted:
  / ( View License )
Date Deposited
2018-05-21 14:36:50.099
Date Last Updated
2020-04-14 17:23:42.585
Submitter:
Mohd Jasnizam Mohd Salleh

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A study of methanol concentration of a single chamber direct methanol fuel cell via electrochemical impedance spectroscop1 2018-05-21 14:36:50.099