The Production of a Silicon-Based Proton-Exchange Membrane with Different Porosity Layers

Year 2018, Volume: 11 Issue: 1, 58 - 65, 24.04.2018

Meltem Gör Bölen , Tevhit Karacalı

Abstract

The aim of this study, which combines renewable energy and porous silicon – two prominent issues in recent years – was to make a porous proton exchange membrane for a proton exchange membrane fuel cell. To make a membrane of the desired thickness, wet etching was performed on the 4.41 cm2 rear side of a double-sided, polished, p-type silicon wafer with a thickness of 200 μm and a resistivity of 0.001 to 0.005 Ω-cm. Then the silicon wafer was cleaned using the RCA cleaning method and the grid shape on the mask was printed on the front side of the silicon using photolithography. The 3.61 cm2 front face of the silicon was placed in a double-tank electrochemical cell designed by us and was anodized at various current densities for certain periods of time to allow the formation of a porous layer throughout the sample. Finally, the pore formation was completed by passing a high current through the rear surface of the silicon to ensure that the pore tips were opened. The thickness of the porous layer formed was observed by scanning electron microscopy. Electrochemical impedance spectroscopy was performed, with the help of a fuel passage test and with formic acid, to measure the usability of the porous silicon as a membrane. Ion passage was observed as a result of the experiments performed.

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Keywords

Porous silicon, Proton exchange membrane, Silicon etching, Electrochemical impedance spectroscopy, Electrolytic polishing

The Production of a Silicon-Based Proton-Exchange Membrane with Different Porosity Layers

Abstract

Son yıllarda dikkat çeken iki konu olan, yenilenebilir enerji ve gözenekli silikonu birleştiren bu çalışma, proton ileten membran yakıt hücresi için gözenekli silikon proton ileten membran yapmayı amaçlamaktadır. Bu amaçla, öncelikle istenilen kalınlıkta membran yapabilmek için 200μm kalınlık, 0.001-0.005 Ωcm özdirencine sahip çift yüzü parlak p tipi silikon dilimin 4.41 cm2’ lik arka yüzüne ıslak aşındırma yapılmıştır. Daha sonra RCA yöntemi ile silikon dilimin temizliği yapılıp silikonun ön yüze fotolitografi yardımı ile maske üzerindeki ızgara şekli basılmıştır. Bizim tarafımızdan tasarlanmış bir çift tanklı elektrokimyasal hücreye yerleştirilen silikonun 3.61 cm2’ lik ön yüzüne çeşitli akım yoğunluklarında belirli sürelerde anodizasyon yapılıp gözenekli tabakanın numune boyunca oluşumu sağlanmıştır. Son olarak gözenek uçlarının açıldığından emin olmak için silikonun arka yüzeyinden yüksek akım geçirilmek suretiyle gözenek oluşumu tamamlanmıştır. Oluşturulan gözenekli tabaka kalınlığı taramalı elektron mikroskobu ile gözlemlenmiştir. Gözenekli silikonun membran olarak kullanılabilirliğinin ölçüsü olarakta methanol yardımı ile yakıt geçiş testi ve formik asit yardımı ile elektrokimyasal empedans spektroskopi yapılmıştır. Yapılan deneyler sonucunda iyon geçişi gözlemlenmiştir.

Keywords

Gözenekli silikon, Proton ileten membran, Silikon aşındırma, Elektrokimyasal empedans spektroskopi, Elektrolitik parlatma

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