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1

Mathematical polymer-electrolyte-membrane fuel cell model

Siegel C., Bandlamudi G., Heinzel A.

Przegląd Elektrotechniczny

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2007

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R. 83, nr 11

153-156

EN

A non-isothermal model of a low temperature polymer-electrolyte-membrane fuel cell is presented. The model is based on conservation equations coupled along with physical, electrochemical and empirical expressions. The model focuses on the implemented electrical subsystem. The simulation results are compared with experimental life test investigations. The model can so be used for parametric studies on fuel cell performance and layout design.

PL

W artykule przedstawiono nieizotermiczny model niskotemperaturowego ogniwa paliwowego z elektrolitem polimerowym (PEMFC). Model bazuje na równaniach zachowawczych oraz zależnościach fizycznych, elektrochemicznych i empirycznych. Proponowany model skupia się na zaimplementowanym podsystemie elektrycznym. Wyniki symulacji komputerowych porównane zostały z rezultatami pomiarów. Model ten może również znaleźć zastosowanie w analizach parametrycznych dotyczących własności ogniw oraz ich projektowania.

2

Ogniwa paliwowe z elektrolitem polimerowym w Instytucie Chemii Przemysłowej

Piela P., Czerwiński A.

Chemik

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2007

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Vol. 60, nr 1

17-18

PL

Przedstawiono badania prowadzone w Instytucie Chemii Przemysłowej w Warszawie mające na celu opracowanie nowych materiałów do ogniw paliwowych z elektrolitem polimerowym posiadających cechy korzystniejsze od materiałów stosowanych obecnie. Zbudowano laboratorium do preparatyki tego typu ogniw oraz do ich wszechstronnego testowania. Prowadzone są obecnie testy pierwszych, zaprojektowanych i skonstruowanych całkowicie w Instytucie ogniw.

EN

This is an account of activity undertaken at the Industrial Chemistry Research Institute in Warsaw aimed at developing new, better-performing materials for polymer electrolyte fuel cells. A laboratory has been established for preparation and comprehensive testing of such fuel cells. First tests are currently underway of polymer electrolyte fuel cells designed and built entirely at the Institute.

3

Novel composite polymer-in-salt electrolytes based on a PVdF matrix obtained with a solvent-free technique

Piekarska J., Ptasińska M., Żukowska G., Wyciślik H., Siekierski M.

Materials Science Poland

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2006

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Vol. 24, No. 1

205--211

EN

Polymer-in-salt electrolytes have been widely investigated as potentially interesting materials for applications in both lithium devices and for basic studies of materials being halfway between polymeric electrolytes and conductive inorganic glasses. Novel composite "polymer-in-salt" electrolytes were synthesized based on a poly(vinylidene difluoride) matrix and various lithium salts. The polymer was chosen due to its high chemical, electrochemical, and thermal stability, widely known from the application in gel electrolytes in lithium batteries. On the other hand, it is well known that a solvent, once incorporated into a PVdF structure, is impossible to remove. Thus a novel method, based on thermal sintering of the composite, was developed to avoid contamination of the sample. Electrolytes of different polymer-to-salt molar ratios, varying from 0.5:1 to 2:1, were synthesized. The influence of preparation conditions (sintering time, temperature and the number of sintering cycles) was also examined. Impedance spectroscopy was used to measure electrical conductivity. Infrared spectroscopy was introduced to investigate ion-ion and ion-polymer interactions and the phase structure of the polymer matrix. Additionally, X-ray diffractometry was applied in structural studies.

4

Ionic conductivity of polymer electrolytes comprising acrylonitrile-butyl acrylate copolymer and a lithium salt

Łasińska A., Dygas J.R., Krok F., Marzantowicz M., Florjańczyk Z., Tomaszewska A., Zygadło-Monikowska E.

Materials Science Poland

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2006

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Vol. 24, No. 1

187--194

EN

New polymer electrolytes were prepared by mixing random copolymers of acrylonitrile and butyl acrylate (poly(AN-co-BuA)) with lithium bis(trifluoromethanesulfone) imide (LiTFSI). Electrical properties were studied by the impedance spectroscopy. The glass transition temperature was studied by DSC. Presented results concern a broad range of compositions, from a pristine copolymer to the system with 98 wt. % of salt. Correlation was established between the glass transition temperature, ionic conductivity, and salt content in the system. Mixtures of poly(AN-co-BuA) and LiTFSI exhibit much lower glass transition temperatures than the parent copolymer. Effects of ageing were observed for electrolytes with high salt content.

5

In-situ study of the influence of crystallization on the ionic conductivity of polymer electrolytes

Marzantowicz M., Dygas J.R., Krok F., Zygadło-Monikowska E., Florjańczyk Z.

Materials Science Poland

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2006

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Vol. 24, No. 1

195--203

EN

Simultaneous impedance measurements and optical observations of polymer electrolytes were conducted in an automated experimental setup, combining an impedance analyser, polarizing microscope with a heating stage and a digital camera. The polymer film was placed between glasses with indium tin oxide conductive layers, forming a transparent cell mounted in a custom-designed holder, which preserved an argon atmosphere. Results of in-situ studies for various compositions of poly(ethylene oxide) (PEO) with LiN(CF3SO2)2 salt (LiTFSI), as well as pure PEO, are presented. In the investigated systems, crystallization had a strong impact on ionic conductivity. It was found that the initial growth of crystalline structures caused only a small fraction of the total decrease of conductivity. A large decrease in conductivity was observed during the second stage of crystallization, when no significant changes in microscope picture were observed. In pure PEO and the PEO:LiTFSI 6:1 system, a dense crystalline structure developed, resulting in a decrease in conductivity of over two orders of magnitude. In dilute PEO:LiTFSI systems, a "loose" structure was formed, with amorphous areas preserved between crystallites, and conductivity decreased by only a factor of about 6.

6

Application of silicon and titanium alkoxylates as bifunctional additives for composite polymeric electrolytes

Sitarek A., Rajewski P., Żukowska G., Wyciślik H., Ciosek M., Siekierski M.

Materials Science Poland

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2006

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Vol. 24, No. 1

213--219

EN

Addition of ceramic grains is widely recognized as an important method for polymer matrix modification. As grain size plays an important role (smaller grains interact stronger), a serious problem appears for nano-sized grains due to their easy agglomeration and difficulties with homogenisation. On the other hand, residual water must be carefully removed from the electrolyte. In this work, we propose a method of simultaneous in-site filler generation and water trapping in the hydrolysis of silicon and titanium alkoxylates. Ti(OEt)4 and Si(OEt)4 used are both commercially available. Conductivity studies were correlated with FT-IR investigations to compare the effect of classical (thermo-vacuum) and chemical drying. Lithium perchlorate and lithium trifluoromethanosulfonate were used as doping salts. Low molecular weight polyglycol in the form of mono- and dimethyl ether was used as the polymer matrix. We observed the influence of drying on ion association in the electrolyte, together with respective conductivity changes. The drying process decreases the conductivity of the composite, whereas filler grain formation increases it. The sign of the final conductivity change varies with the matrix and salt type.

7

Numerical method of polymer electrolyte membrane fuel cell - single domain approach

Stępień M., Bogusławski A., Bourgeois M.

Turbulence : international journal

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2005

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Vol. 11

75-87

EN

The paper presents mathematical model of Polymer Electrolyte Fuel Cell. In the model steady state conditions were assumed. Electrochemical reactions take place in anode and cathode catalyst layers. The system of transport equations that describes the operation of the fuel cell was solved in flow channels, diffusion layers, catalyst layers and membrane using commercial CFD code Fluent. The electrochemical precesses occuring in certain elements of fuel cell were modelled by definition of special source terms in transport equations. Fluent software in basic version is not capable to model electrochemical reactions. Therefore it was necessary to perform some modifications of standard code by writing additional subroutines according to User Defined Functions coding capability of Fluent. After analysis of their possible aplica-tions it was assumed that they are suitable for modelling of electrochemical reactions which take place in PEM fuel cell.

8

Li+ ionic conductivity calculations of solid electrolytes on polymeric basis

Rewiński A, Łukaszewicz T., Żmija J.

Journal of Technical Physics

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2005

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Vol. 46, no 2

97-105

EN

This paper presents a theoretical approach to Li+ ions diffusion in polymeric solid electrolytes. The following parameters were calculated and then compared with the experimental results: the mobility of lithium ions, diffusion coefficient and recombination probability. Ionic conductivity of the electrolyte was also calculated.

9

Half-liquid electrolyte in the abrasive flow machining.

Dąbrowski L., Marciniak M.

Advances in Manufacturing Science and Technology

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2003

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Vol. 27, nr 3

35-44

EN

The investigations of polymer electrolytes with non organic fillers applied in the Abrasive Flow Machining (AFM) are presented in this paper. A flow of cations and anions is discussed for half-liquid electrolyte. The influence of electrolyte flow velocity on the current density is estimated for constant inter-electrode gap value and constant voltage. The results of the anode surface roughness measurements are also placed in this paper.

PL

Wspomaganie obróbki przetłoczno-ściernej procesem elektrochemicznym (ECM) umożliwiają polimerowe elektrolity. Przewodnictwo jonowe polimerowych elektrolitów jest wielokrotnie mniejsze od przewodnictwa elektrolitów stosowanych w ECM. Dodawanie wypełniaczy nieorganicznych w postaci materiałów ściernych do tych elektrolitów powoduje dalsze zmiejszenie przewodności. Z tego względu szczelina międzyelektrodowa, przez którą przepływa elektrolit polimerowy, musi mieć mały wymiar. To z kolei zwiększa opory przepływu polimerowego elektrolitu, który ma konsystencję półpłynnej pasty. Istotną rolę odgrywają również właściwości reologiczne takich past ze względów użytkowych. W przeprowadzonych badaniach wygładzania powierzchni płaskich i zaokrąglania ostrych krawędzi wykorzystano polimerowe elektrolity w postaci polimerowych żeli oraz hydrożeli na bazie akryloamidu.

10

Proton conducting polymeric electrolytes for electrochromic systems

Florjańczyk Z., Wojda A., Zygadło-Monikowska E.

Zeszyty Naukowe. Chemia / Politechnika Śląska

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2001

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z. 146

103-106

EN

New proton conducting gel electrolytes for application in electrochromic devices are presented. The polymeric matrices in the gels studied were obtained in the copolymerization or terpolymerization of glycidyl methacrylate with various acrylic monomers (methyl methacrylate, acrylic acid, acrylonitrile) utilizing in the crosslinking process reactions involving epoxide groups. Phosphoric acid organic esters obtained in the reaction of phosphoric acid and propylene oxide were used as the proton donors. The thus obtained polymer gel electrolytes are characterized by high ionic conductivity of the order of 10-4S cm-1 at ambient temperature and 10-3 S cm-1 at 50 degrees C, only slightly changing with a rise in temperature.

11

Composite polymeric electrolytes comprising aluminum alkoxides

Florjańczyk Z., Zygadło-Monikowska E., Rogalska E.

Zeszyty Naukowe. Chemia / Politechnika Śląska

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1999

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z. 140

243-246

EN

The effect of the addition of dialkylaluminum alkoxides on the properties of composite polymeric alkoxides based on poly(ethylene oxide) complexes with inorganic lithium salts has been studied. The effect of the length of the oxyethylene substituent in the alkoxide and type of salt on the morphology of the membranes obtained and also on their conducting properties is presented.

PL

Badano wpływ dodatku dialkilowych alkoholanów glinu na właściwości kompozytów polimerowych opartych na kompleksach tlenku etylenu z nieorganicznymi solami litu. Przedstawiono wpływ długości podstawnika oksyetylenowego w alkoholanie oraz typu soli na mofrologię otrzymanych membran jak również ich przewodność.