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Title:	Pembangunan himpunan elektrod membran ketumpatan arus tinggi untuk PEMFC mudah alih
Authors:	Dedi Rohendi (P57323)
Supervisor:	Assoc. Prof. Dr. Edy Herianto Majlan
Keywords:	Sel fuel membran penukar proton Sel fuel Himpunan elektrod membran Ketumpatan arus Proton exchange membrane fuel cells.
Issue Date:	30-Sep-2014
Description:	Sel fuel membran penukar proton atau Proton Exchange Membrane Fuel Cell (PEMFC) merupakan sel fuel yang sesuai untuk kenderaan, kuasa pegun dan sistem mudah alih kerana kecekapan tenaga tinggi dan pencemaran sifar. Himpunan elektrod membran atau Membrane Electrode Assembly (MEA) yang menjadi tapak tindak balas antara hidrogen dan oksigen merupakan komponen paling penting dan menentukan prestasi PEMFC. Kajian ini bertujuan menghasilkan MEA dengan ketumpatan arus tinggi untuk penggunaan dalam PEMFC mudah alih. Kajian dimulakan dengan mengkaji kesan kandungan politetrafluoroetilena (PTFE) (15 - 45 % berat) dan suhu pensinteran (175 - 400 o C) terhadap sifat-sifat lapisan penyokong. Pengaruh kandungan serbuk karbon dalam MPL pun turut dikaji dalam penyelidikan ini. Sementara itu, kajian mengenai lapisan mangkin dan MEA meliputi; membandingkan kaedah tuangan, kaedah semburan satu lapisan dan tiga lapisan, mengkaji pengaruh kandungan mangkin platinum, menjalankan MEA pada suhu dan jenis membran berlainan, serta pengaruh tekanan balik. Seterusnya, ujian kemerosotan prestasi MEA dilakukan pada suhu 80°C dan tekanan balik 10 psi selama 100 jam pada keadaan voltan litar terbuka (OCV). MEA dengan kandungan mangkin optimum kemudiannya diuji dalam PEMFC berbilang tindan dan dibandingkan dengan MEA komersil. Hasil kajian menunjukkan bahawa kandungan PTFE tidak boleh melebihi 35% berat (dalam julat 15 - 35 %) dan suhu pensinteran terbaik ialah 350°C untuk lapisan penyokong. Hasil pencirian dan pengujian prestasi didapati elektrod yang dihasilkan dengan kaedah semburan menunjukkan prestasi lebih baik berbanding kaedah tuangan dan kandungan serbuk karbon 3 mg.cm -2 dalam MPL mempunyai prestasi lebih baik berbanding dengan kandungan 1.5 mg.cm -2 . Selain itu, elektrod dengan kaedah semburan tiga lapisan mangkin mempunyai prestasi lebih tinggi berbanding satu lapisan pada kandungan platinum yang sama. Sementara itu, MEA dengan kandungan mangkin platinum 0.5 mg.cm -2 merupakan MEA dengan kandungan mangkin optimum dan menghasilkan ketumpatan arus setinggi 719.92 mA.cm -2 pada 0.6 V. Seterusnya, tekanan balik 10 psi pada PEMFC mampu meningkatkan ketumpatan arus setinggi 25 % dan suhu sel sehingga 70 o C mampu meningkatkan ketumpatan arus setinggi 53 % berbanding suhu bilik pada 0.6 V. Hasil kajian juga menunjukkan bahawa penggunaan membran nafion 212 menghasilkan prestasi lebih baik berbanding nafion 112 terutamanya pada suhu tinggi. Ujian ketahanan MEA menunjukkan bahawa selepas 100 jam beroperasi, prestasi sel pada suhu 80 °C menurun 20 % berbanding sel tanpa pemanasan. Sebaliknya, penerapan tekanan balik 10 psi mempunyai kesan kepada prestasi dalam mempertahankan OCV. Berdasarkan pencirian melalui SEM-EDX, TEM dan XRD, kemerosotan prestasi MEA selepas 100 jam disebabkan oleh pengumpulan platinum dan pembentukan sebatian PtS yang kurang aktif. Hasil ujian prestasi PEMFC mudah alih yang terdiri daripada 18 MEA menunjukkan ketumpatan kuasa tertinggi 1.30W.cm -2 , lebih tinggi 38.3% berbanding PEMFC komersil. Hasil kajian ini telah berjaya menerangkan secara jelas mengenai pengaruh kandungan bahan, kaedah pembuatan elektrod dan keadaan operasi terhadap prestasi MEA untuk PEMFC mudah alih.,Proton Exchange Membrane Fuel Cell (PEMFC) is a fuel cell that suitable for vehicles, stationary power, and portable system because of its high energy efficiency and zero pollution. Membrane Electrode Assembly (MEA) is a very important component in PEMFC where the reaction takes place between hydrogen and oxygen. This research has been conducted to produce MEA with high current density for portable PEMFC applications. The study began by assessing the effect of polytetrafluoroethylene (PTFE) content (15–45 wt%) and sintering temperature (175- 400 o C) to the properties of backing layer. Influence of carbon powder content in the MPL was also investigated in this research. The investigation regarding catalyst layer and MEA covering; the comparison between casting method, the spraying method of one and three layers, studying the effect of platinum catalyst content, conducting MEA at different temperature and membrane types, also effect of back pressure. The performance degradation test of MEA has been conducted at 80°C and back pressure of 10 psi for 100 hours in open circuit voltage (OCV). The MEAs with optimum catalyst content were tested in a multi stack of PEMFC compared with commercial MEAs. The result showed that PTFE content cannot exceed 35 wt% (it is in the range of 15 - 35 %) and the best sintering temperature is 350 °C for backing layer. The result of characterization and performance test of electrode shows that the electrode produced by using spraying method has a better performance in compare to casting method and 3 mg.cm -2 of carbon powder content shows a better performance than 1.5 mg.cm -2 . In addition, three layers spraying method gives a higher performance than one layer spraying method with the same platinum content. The MEA with optimum catalyst content of 0.5 mg.cm -2 exhibited high current density of 719.92 mA.cm -2 at 0.6 V. Furthermore, back pressure applied on PEMFC was found to increase the current density up to 24.98 %, while the cell temperature at 70 o C could increase the current density up to 52.645 % compared with the cell at room temperature at 0.6 V. The result also shows that nafion 212 membrane is produce better performance in compare to nafion 112 especially at high temperature. The performance degradation test of MEA result shows that after 100 hours, cell performance that operated at 80 o C is decline to 20 % in compare to run with room temperature. Conversely, implementation of back pressured 10 psi has impacted in maintaining OCV. Based on the SEM-EDX, TEM and XRD results, degradation of MEA performance after 100 hours is caused by agglomeration of platinum and formation of less active PtS compound. The performance test of portable PEMFC with 18 MEAs showed the power density reached 1.30 W.cm -2 , which is 38.29 % higher than the commercial PEMFC. This research provided information regarding the influence of the material content, method of electrode fabrication and operating conditions on the performance of MEA for portable PEMFC.,Ph.D
Pages:	183
Call Number:	K2933.P76 D474 2014 3
Publisher:	UKM, Bangi
Appears in Collections:	Fuel Cell Institute / Institut Sel Fuel

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