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1

Hybrid blend membrane using PVA–g–PMA for direct methanol fuel cell applications

Gajbhiye Pratima, Tiwari A.K., Mann Karan, Kahlon J.S., Upadhyay H.

Chemical and Process Engineering

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2022

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Vol. 43, nr 2

251--254

EN

In the present study, a novel PVA–g–PMA hybrid membrane was developed for application in direct methanol fuel cell (DMFC). Maleic anhydride (MA) was grafted on polyvinyl alcohol (PVA) both ionically and chemically using potassium persulfate (KPS), for the first time. The PVA–g–PMA thus synthesized was then blended with 3–Amino–4–[3–(triethylammonium sulfonato)phenyl amino]phenylene hydrochloride. The prepared membranes were characterized by FT–IR, TGA. 0.0104 S/cm of proton conductivity was found for the membrane. The ion exchange capacity was found to be 2.175 meq/g and the water uptake capacity as 14.9%. The single-chamber fuel cell power density was higher (34.72 mW/cm2) and current density (62.11 mA/cm2) when compared to Nafion 117 membrane.

2

A high gain variable boost DC-DC converter for low-voltage hybrid direct methanol fuel cell batteries

Ali M. S., Sarker Mahidur R., Ibrahim Ahmad Asrul, Mohamed Ramizi

Przegląd Elektrotechniczny

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2021

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R. 97, nr 11

1--10

EN

Direct Methanol Fuel Cells (DMFCs) are emerging as primary power sources for portable applications due to their high energy density, easy-to-handle liquid fuel, and low temperature. They have a longer cell lifetime and are small and lightweight. However, there are several problems associated with typical DMFCs due to their slow dynamic response, long start-up time, and issues related to their unregulated low-level output voltage and current. This study describes the development of a DC-DC converter for a low-voltage (i.e., less than 5 V) DMFC. This study also presents a hybrid power source that consists of a battery and a DMFC and analyses, via software simulation, every component of the boost converter that influences its output. The proposed DC-DC converter is capable of boosting the voltage of the DMFC from 3 V to 60 V. The output voltage of this converter is regulated and applied to an LED lamp.

PL

Ogniwa paliwowe z bezpośrednim metanolem (DMFC) stają się coraz ważniejszym źródłem zasilania w zastosowaniach przenośnych ze względu na ich wysoką gęstość energii, łatwe w obsłudze paliwo ciekłe i niską temperaturę. Mają dłuższą żywotność ogniw i są małe i lekkie. Istnieje jednak kilka problemów związanych z typowymi DMFC ze względu na ich powolną reakcję dynamiczną, długi czas rozruchu oraz problemy związane z ich nieregulowanym napięciem i prądem wyjściowym niskiego poziomu. Niniejsze badanie opisuje rozwój konwertera DC-DC dla niskonapięciowego (tj. poniżej 5 V) DMFC. W niniejszym opracowaniu przedstawiono również hybrydowe źródło zasilania, które składa się z akumulatora i DMFC oraz analizuje, za pomocą symulacji programowej, każdy element przetwornicy doładowania, który wpływa na jego moc wyjściową. Proponowana przetwornica DC-DC jest w stanie podnieść napięcie DMFC z 3 V do 60 V. Napięcie wyjściowe tej przetwornicy jest regulowane i podawane na lampę LED.

3

Characteristics of carbon dioxideand product water exhausts in a directmethanol fuel cell with serpentine channels

Nakashima Kohei

Journal of KONES

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2019

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Vol. 26, No. 3

137--144

EN

This study utilized a transparent direct methanol fuel cell, with serpentine channels with a width of 2 mm and an initial depth of 2 mm, and investigated the relationship between the behaviours of carbon dioxide (CO2) slugs, product water accumulations, and voltage fluctuation. It examined the exhaust volumes of CO2 slugs and product water accumulations from the channels over time, comparing an anode channel with a depth of 1.2 mm to one with a depth of 2 mm (without changing the cathode depth of 2 mm, nor the width of 2 mm in both the anode and the cathode). Results indicated that cell voltage fluctuated, rising while CO2 slugs were ejected, and falling between ejections. In the case of an anode channel depth of 2 mm and a lower methanol-water solution flow rate, CO2 slugs were ejected less frequently, so cell voltage fluctuated widely. (Product water accumulations in the cathode had a minimum effect on this cell voltage fluctuation.) In the case of a higher methanol-water solution flow rate, CO2 slugs were ejected more frequently, with less exhaust volume per CO2 slug, reducing the fluctuation in cell voltage. Finally, with an anode channel depth of 1.2 mm, the exhaust volume per CO2 slug became even smaller, and these small CO2 slugs were rapidly ejected. With this shallow depth, the cell voltage increased with a lower methanol-water solution flow rate, but decreased with a higher methanol-water solution flow rate by crossover.

4

Role of structural modifications of montmorillonite, electrical properties effect, physical behavior of nanocomposite proton conducting membranes for direct methanol fuel cell applications

Abidin K. S., Kannan R., Palani P. B., Rajashabala S.

Materials Science Poland

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2017

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Vol. 35, No. 4

707--716

EN

Proton exchange membranes have been synthesized from polyimide (PI) doped with different contents of montmorillonite (MMT) which was obtained by solution casting technique. The enhancement of conductivity was achieved through modification with the MMT. Prepared membranes were systematically characterized in terms of ion exchange capacity, water uptake, methanol uptake, swelling behavior and proton conductivity. Fourier transform infrared spectroscopy and X-ray diffraction measurements were used to confirm the structures of the PI/MMT composite electrolyte membranes. SEM surface morphological images of the composite membranes showed that the MMT nanoclay particles were dispersed uniformly within the membrane what was also reflected in XRD results which indicated a good compatibility of MMT particles with the polymer complex. The TGA spectra showed that the thermal stability of the membrane was reduced by adding MMT into the polymer network. The prepared membrane with 10 wt.% of modified MMT exhibited the highest proton conductivity value of 7.06 × 10-2 S·cm-1 at 70 °C. These results imply the potential application of the PI/MMT composite membranes as improved PEMs for DMFC applications.

5

Carbon supported Pt-Ni nanoparticles as catalysts in direct methanol fuel cells

Dipti S. S., Chung U. C., Chung W. S.

Materials Science Poland

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2009

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Vol. 27, No. 2

521--528

EN

Two types of carbon supported Pt-Ni nanoparticles were fabricated as catalysts for the cathode part of a direct methanol fuel cell, and were characterized by X-ray diffraction, transmission electron microscopy and cyclic voltammetry analyses. TEM and XRD analyses pointed to a good dispersion of the catalysts with carbon black and carbon nanotubes (CNTs) having sizes of ca. 2-6 nm, which is very important for supporting catalysts of the methanol fuel cell. CV analysis showed that the catalytic activity of a Pt-Ni/CNTs catalyst is more efficient than that of other catalysts. We also noticed that it is more appropriate to use a glassy carbon electrode rather than carbon paper as the working electrode for the methanol electrooxidation of Pt Ni/CNTs catalysts.