Preparation and investigation of cheap polymer electrolyte membranes for fuel cells

Mikkel Juul Larsen, Yue Ma, Peter Brilner Lund, Eivind Morten Skou

Publikation: Konferencebidrag uden forlag/tidsskriftPosterForskning

Resumé

The electrolyte of choice for low temperature polymer electrolyte fuel cells (PEFCs) has tra­di­ti­o­nal­ly been DuPontTM Nafion® membranes or similar poly(perfluorosulfonic acid)s. The chemical struc­ture and morphology in the hydrated state of Nafion® is shown in figure 1 from which it is seen that the material consists of hydrophilic and hydrophobic domains. This structure gives hy­drated Nafion® very high proton conductivity as well as great stability.[i]

          However, the poly(perfluorosulfonic acid) membranes are very expensive materials, and their high water uptake, significant methanol crossover, and relatively poor thermal stability constitute seri­ous drawbacks with respect to their fuel cell use.[ii],[iii],[iv] These aspects propel the search for cheaper and better alternatives.

          In this study membrane systems consisting of a hydrophobic poly(ethylene-alt-tetra­fluoro­ethy­lene) (ETFE) backbone grafted by hydrophilic poly(styrene sulfonic acid) (PSSA) have been syn­the­siz­ed in a three-step procedure comprising electron beam irradiation, grafting polymeri­za­ti­on reaction, and sulfonation. The chemical structure of the resulting ETFE-g-PSSA is shown in fi­gure 2, and it is believed that the morphology upon hydration resembles that of the poly­(per­flu­oro­sulfonic acid)s.  The sta­bi­li­ty of the material has been improved by crosslinking by divinyl­benz­ene (DVB) and by in­fer­ring methyl- and tert-butyl sub­sti­tuents on the styrene aromatic ring.

          It has been found that crosslinking by divinylbenzene clear­ly improves the chemical stability of both sulfonated styrene- and methylstyrene/t-butylstyrene-grafted ETFE membranes. How­ever, the crosslinking reduces the proton conductivity due to decreased water uptake, thus downgrading the membranes' elec­tro­ly­tic pro­per­ti­es. Grafting with a fraction of DVB in the order of 1-2 vol-% of the total mo­no­mers seems to be advantageous for both of the two grafting sys­tems as a com­pro­mise between high chemical stability and good proton con­duc­tivity of the final membrane. The use of methyl­sty­rene and t-bu­tyl­styrene as grafting mo­no­mers instead of sty­rene gives the resulting membranes a significantly increased chem­i­cal stability, while a rea­son­able pro­ton conductivity can still be ob­tai­ned. Both membrane systems show a smaller methanol up­take than water uptake.

[i] Kreuer, K.-D.; Paddison, S. J.; Spohr, E.; Schuster, M.; Chemical Reviews 104 (2004) 4637-4678

[ii] Skou, E.; Kauranen, P.; Hentschel, J.; Solid State Ionics 97 (1997) 333-337

[iii] Fuel Cell Handbook; Seventh Edition; EG&G Technical Services, Inc.; 2004; p. 3.1-3.25

[iv] Doyle, M.; Rajendran, G. in Handbook of Fuel Cells - Fundamentals, Technology, and Applications, Volume 3: Fuel Cell Technology and Applications: Part 1 (edited by Vielstich, W.; Lamm, A.; Gasteiger, H. A.); John Wiley & Sons Ltd; Chichester; 2003; p. 351-395

OriginalsprogEngelsk
Publikationsdato2007
Antal sider1
StatusUdgivet - 2007
BegivenhedAnnual meeting of the Danish Electrochemical Society 2007 - Århus, Danmark
Varighed: 4. okt. 20075. okt. 2007

Konference

KonferenceAnnual meeting of the Danish Electrochemical Society 2007
LandDanmark
ByÅrhus
Periode04/10/200705/10/2007

Fingeraftryk

Electrolytes
divinyl benzene
Fuel cells
Polymers
Styrene
Membranes
Proton conductivity
Chemical stability
Crosslinking
Sulfonic Acids
Methanol
Water
Monomers
Sulfonation
Hydration
perfluorosulfonic acid
Electron beams
Thermodynamic stability
Polymerization
Irradiation

Emneord

  • Brændselscelle, membran, polymerelektrolyt, podning, tværbinding, alkylsubstitution, fluorpolymer, ETFE, styren, divinylbenzen, DVB, methylstyren, tert-butylstyren, t-butylstyren

Citer dette

Larsen, M. J., Ma, Y., Lund, P. B., & Skou, E. M. (2007). Preparation and investigation of cheap polymer electrolyte membranes for fuel cells. Poster session præsenteret på Annual meeting of the Danish Electrochemical Society 2007, Århus, Danmark.
Larsen, Mikkel Juul ; Ma, Yue ; Lund, Peter Brilner ; Skou, Eivind Morten. / Preparation and investigation of cheap polymer electrolyte membranes for fuel cells. Poster session præsenteret på Annual meeting of the Danish Electrochemical Society 2007, Århus, Danmark.1 s.
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abstract = "The electrolyte of choice for low temperature polymer electrolyte fuel cells (PEFCs) has tra­di­ti­o­nal­ly been DuPontTM Nafion{\circledR} membranes or similar poly(perfluorosulfonic acid)s. The chemical struc­ture and morphology in the hydrated state of Nafion{\circledR} is shown in figure 1 from which it is seen that the material consists of hydrophilic and hydrophobic domains. This structure gives hy­drated Nafion{\circledR} very high proton conductivity as well as great stability.[i]          However, the poly(perfluorosulfonic acid) membranes are very expensive materials, and their high water uptake, significant methanol crossover, and relatively poor thermal stability constitute seri­ous drawbacks with respect to their fuel cell use.[ii],[iii],[iv] These aspects propel the search for cheaper and better alternatives.           In this study membrane systems consisting of a hydrophobic poly(ethylene-alt-tetra­fluoro­ethy­lene) (ETFE) backbone grafted by hydrophilic poly(styrene sulfonic acid) (PSSA) have been syn­the­siz­ed in a three-step procedure comprising electron beam irradiation, grafting polymeri­za­ti­on reaction, and sulfonation. The chemical structure of the resulting ETFE-g-PSSA is shown in fi­gure 2, and it is believed that the morphology upon hydration resembles that of the poly­(per­flu­oro­sulfonic acid)s.  The sta­bi­li­ty of the material has been improved by crosslinking by divinyl­benz­ene (DVB) and by in­fer­ring methyl- and tert-butyl sub­sti­tuents on the styrene aromatic ring.          It has been found that crosslinking by divinylbenzene clear­ly improves the chemical stability of both sulfonated styrene- and methylstyrene/t-butylstyrene-grafted ETFE membranes. How­ever, the crosslinking reduces the proton conductivity due to decreased water uptake, thus downgrading the membranes' elec­tro­ly­tic pro­per­ti­es. Grafting with a fraction of DVB in the order of 1-2 vol-{\%} of the total mo­no­mers seems to be advantageous for both of the two grafting sys­tems as a com­pro­mise between high chemical stability and good proton con­duc­tivity of the final membrane. The use of methyl­sty­rene and t-bu­tyl­styrene as grafting mo­no­mers instead of sty­rene gives the resulting membranes a significantly increased chem­i­cal stability, while a rea­son­able pro­ton conductivity can still be ob­tai­ned. Both membrane systems show a smaller methanol up­take than water uptake.[i] Kreuer, K.-D.; Paddison, S. J.; Spohr, E.; Schuster, M.; Chemical Reviews 104 (2004) 4637-4678[ii] Skou, E.; Kauranen, P.; Hentschel, J.; Solid State Ionics 97 (1997) 333-337[iii] Fuel Cell Handbook; Seventh Edition; EG&G Technical Services, Inc.; 2004; p. 3.1-3.25[iv] Doyle, M.; Rajendran, G. in Handbook of Fuel Cells - Fundamentals, Technology, and Applications, Volume 3: Fuel Cell Technology and Applications: Part 1 (edited by Vielstich, W.; Lamm, A.; Gasteiger, H. A.); John Wiley & Sons Ltd; Chichester; 2003; p. 351-395",
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Larsen, MJ, Ma, Y, Lund, PB & Skou, EM 2007, 'Preparation and investigation of cheap polymer electrolyte membranes for fuel cells' Annual meeting of the Danish Electrochemical Society 2007, Århus, Danmark, 04/10/2007 - 05/10/2007, .

Preparation and investigation of cheap polymer electrolyte membranes for fuel cells. / Larsen, Mikkel Juul; Ma, Yue; Lund, Peter Brilner; Skou, Eivind Morten.

2007. Poster session præsenteret på Annual meeting of the Danish Electrochemical Society 2007, Århus, Danmark.

Publikation: Konferencebidrag uden forlag/tidsskriftPosterForskning

TY - CONF

T1 - Preparation and investigation of cheap polymer electrolyte membranes for fuel cells

AU - Larsen, Mikkel Juul

AU - Ma, Yue

AU - Lund, Peter Brilner

AU - Skou, Eivind Morten

PY - 2007

Y1 - 2007

N2 - The electrolyte of choice for low temperature polymer electrolyte fuel cells (PEFCs) has tra­di­ti­o­nal­ly been DuPontTM Nafion® membranes or similar poly(perfluorosulfonic acid)s. The chemical struc­ture and morphology in the hydrated state of Nafion® is shown in figure 1 from which it is seen that the material consists of hydrophilic and hydrophobic domains. This structure gives hy­drated Nafion® very high proton conductivity as well as great stability.[i]          However, the poly(perfluorosulfonic acid) membranes are very expensive materials, and their high water uptake, significant methanol crossover, and relatively poor thermal stability constitute seri­ous drawbacks with respect to their fuel cell use.[ii],[iii],[iv] These aspects propel the search for cheaper and better alternatives.           In this study membrane systems consisting of a hydrophobic poly(ethylene-alt-tetra­fluoro­ethy­lene) (ETFE) backbone grafted by hydrophilic poly(styrene sulfonic acid) (PSSA) have been syn­the­siz­ed in a three-step procedure comprising electron beam irradiation, grafting polymeri­za­ti­on reaction, and sulfonation. The chemical structure of the resulting ETFE-g-PSSA is shown in fi­gure 2, and it is believed that the morphology upon hydration resembles that of the poly­(per­flu­oro­sulfonic acid)s.  The sta­bi­li­ty of the material has been improved by crosslinking by divinyl­benz­ene (DVB) and by in­fer­ring methyl- and tert-butyl sub­sti­tuents on the styrene aromatic ring.          It has been found that crosslinking by divinylbenzene clear­ly improves the chemical stability of both sulfonated styrene- and methylstyrene/t-butylstyrene-grafted ETFE membranes. How­ever, the crosslinking reduces the proton conductivity due to decreased water uptake, thus downgrading the membranes' elec­tro­ly­tic pro­per­ti­es. Grafting with a fraction of DVB in the order of 1-2 vol-% of the total mo­no­mers seems to be advantageous for both of the two grafting sys­tems as a com­pro­mise between high chemical stability and good proton con­duc­tivity of the final membrane. The use of methyl­sty­rene and t-bu­tyl­styrene as grafting mo­no­mers instead of sty­rene gives the resulting membranes a significantly increased chem­i­cal stability, while a rea­son­able pro­ton conductivity can still be ob­tai­ned. Both membrane systems show a smaller methanol up­take than water uptake.[i] Kreuer, K.-D.; Paddison, S. J.; Spohr, E.; Schuster, M.; Chemical Reviews 104 (2004) 4637-4678[ii] Skou, E.; Kauranen, P.; Hentschel, J.; Solid State Ionics 97 (1997) 333-337[iii] Fuel Cell Handbook; Seventh Edition; EG&G Technical Services, Inc.; 2004; p. 3.1-3.25[iv] Doyle, M.; Rajendran, G. in Handbook of Fuel Cells - Fundamentals, Technology, and Applications, Volume 3: Fuel Cell Technology and Applications: Part 1 (edited by Vielstich, W.; Lamm, A.; Gasteiger, H. A.); John Wiley & Sons Ltd; Chichester; 2003; p. 351-395

AB - The electrolyte of choice for low temperature polymer electrolyte fuel cells (PEFCs) has tra­di­ti­o­nal­ly been DuPontTM Nafion® membranes or similar poly(perfluorosulfonic acid)s. The chemical struc­ture and morphology in the hydrated state of Nafion® is shown in figure 1 from which it is seen that the material consists of hydrophilic and hydrophobic domains. This structure gives hy­drated Nafion® very high proton conductivity as well as great stability.[i]          However, the poly(perfluorosulfonic acid) membranes are very expensive materials, and their high water uptake, significant methanol crossover, and relatively poor thermal stability constitute seri­ous drawbacks with respect to their fuel cell use.[ii],[iii],[iv] These aspects propel the search for cheaper and better alternatives.           In this study membrane systems consisting of a hydrophobic poly(ethylene-alt-tetra­fluoro­ethy­lene) (ETFE) backbone grafted by hydrophilic poly(styrene sulfonic acid) (PSSA) have been syn­the­siz­ed in a three-step procedure comprising electron beam irradiation, grafting polymeri­za­ti­on reaction, and sulfonation. The chemical structure of the resulting ETFE-g-PSSA is shown in fi­gure 2, and it is believed that the morphology upon hydration resembles that of the poly­(per­flu­oro­sulfonic acid)s.  The sta­bi­li­ty of the material has been improved by crosslinking by divinyl­benz­ene (DVB) and by in­fer­ring methyl- and tert-butyl sub­sti­tuents on the styrene aromatic ring.          It has been found that crosslinking by divinylbenzene clear­ly improves the chemical stability of both sulfonated styrene- and methylstyrene/t-butylstyrene-grafted ETFE membranes. How­ever, the crosslinking reduces the proton conductivity due to decreased water uptake, thus downgrading the membranes' elec­tro­ly­tic pro­per­ti­es. Grafting with a fraction of DVB in the order of 1-2 vol-% of the total mo­no­mers seems to be advantageous for both of the two grafting sys­tems as a com­pro­mise between high chemical stability and good proton con­duc­tivity of the final membrane. The use of methyl­sty­rene and t-bu­tyl­styrene as grafting mo­no­mers instead of sty­rene gives the resulting membranes a significantly increased chem­i­cal stability, while a rea­son­able pro­ton conductivity can still be ob­tai­ned. Both membrane systems show a smaller methanol up­take than water uptake.[i] Kreuer, K.-D.; Paddison, S. J.; Spohr, E.; Schuster, M.; Chemical Reviews 104 (2004) 4637-4678[ii] Skou, E.; Kauranen, P.; Hentschel, J.; Solid State Ionics 97 (1997) 333-337[iii] Fuel Cell Handbook; Seventh Edition; EG&G Technical Services, Inc.; 2004; p. 3.1-3.25[iv] Doyle, M.; Rajendran, G. in Handbook of Fuel Cells - Fundamentals, Technology, and Applications, Volume 3: Fuel Cell Technology and Applications: Part 1 (edited by Vielstich, W.; Lamm, A.; Gasteiger, H. A.); John Wiley & Sons Ltd; Chichester; 2003; p. 351-395

KW - Brændselscelle, membran, polymerelektrolyt, podning, tværbinding, alkylsubstitution, fluorpolymer, ETFE, styren, divinylbenzen, DVB, methylstyren, tert-butylstyren, t-butylstyren

KW - Fuel cell, membrane, polymer electrolyte, grafting, crosslinking, alkyl substitution, fluoropolymer, ETFE, styrene, divinylbenzene, DVB, methylstyrene, tert-butylstyrene, t-butylstyrene

M3 - Poster

ER -

Larsen MJ, Ma Y, Lund PB, Skou EM. Preparation and investigation of cheap polymer electrolyte membranes for fuel cells. 2007. Poster session præsenteret på Annual meeting of the Danish Electrochemical Society 2007, Århus, Danmark.