Design and Synthesis of Cross-Linked Copolymer Membranes Based on Poly(benzoxazine) and Polybenzimidazole and Their Application to an Electrolyte Membrane for a High-Temperature PEM Fuel Cell
Elevated-temperature (100~200 °C) polymer electrolyte membrane (PEM) fuel cells have many features, such as their high efficiency and simple system design, that make them ideal for residential micro-combined heat and power systems and as a power source for fuel cell electric vehicles. A proton-conducting solid-electrolyte membrane having high conductivity and durability at elevated temperatures is essential, and phosphoric-acid-containing polymeric material synthesized from cross-linked polybenzoxazine has demonstrated feasible characteristics. This paper reviews the design rules, synthesis schemes, and characteristics of this unique polymeric material. Additionally, a membrane electrode assembly (MEA) utilizing this polymer membrane is evaluated in terms of its power density and lifecycle by an in situ accelerated lifetime test. This paper also covers an in-depth discussion ranging from the polymer material design to the cell performance in consideration of commercialization requirements.
References
[1]
Mehta, V.; Cooper, J.S. Review and analysis of PEM fuel cell design and manufacturing. J. Power Sources 2003, 114, 32–53, doi:10.1016/S0378-7753(02)00542-6.
[2]
Ahn, S.-Y.; Shin, S.-J.; Ha, H.Y.; Hong, S.-A.; Lee, Y.-C.; Lim, T.W.; Oh, I.-H. Performance and lifetime analysis of the kW-class PEMFC stack. J. Power Sources 2002, 106, 295–303, doi:10.1016/S0378-7753(01)01032-1.
[3]
Mallant, R.K.A.M. PEMFC systems: The need for high temperature polymers as a consequence of PEMFC water and heat management. J. Power Sources 2003, 118, 424–429, doi:10.1016/S0378-7753(03)00108-3.
[4]
Li, Q.; Jensen, J.O.; Savinell, R.F.; Bjerrum, N.J. High temperature proton exchange membranes based on polybenzimidazoles for fuel cells. Prog. Polym. Sci. 2009, 34, 449–477, doi:10.1016/j.progpolymsci.2008.12.003.
[5]
Kwon, K.; Kim, T.Y.; Yoo, D.Y.; Hong, S.-G.; Park, J.O. Maximization of high-temperature proton exchange membrane fuel cell performance with the optimum distribution of phosphoric acid. J. Power Sources 2009, 188, 463–467, doi:10.1016/j.jpowsour.2008.11.104.
[6]
Wannek, C.; Konradi, I.; Mergel, J.; Lehnert, W. Redistribution of phosphoric acid in membrane electrode assemblies for high-temperature polymer electrolyte fuel cells. Int. J. Hydrog. Energy 2009, 34, 9479–9485, doi:10.1016/j.ijhydene.2009.09.076.
[7]
He, R.; Li, Q.; Bach, A.; Jensen, J.O.; Bjerrum, N.J. Physicochemical properties of phosphoric acid doped polybenzimidazole membranes for fuel cells. J. Membr. Sci. 2006, 277, 38–45, doi:10.1016/j.memsci.2005.10.005.
[8]
Park, J.O.; Kwon, K.; Cho, M.D.; Hong, S.-G.; Kim, T.Y.; Yoo, D.Y. Role of binders in high-temperature PEMFC electrode. J. Electrochem. Soc. 2011, 158, B675–B681, doi:10.1149/1.3573773.
[9]
Mamlouk, M.; Scott, K. An investigation of Pt alloy oxygen reduction catalysts in phosphoric acid doped PBI fuel cells. J. Power Sources 2011, 196, 1084–1089, doi:10.1016/j.jpowsour.2010.08.021.
[10]
Andujar, J.M.; Segura, F. Fuel cells: History and updating. A walk along two centuries. Renew. Sustain. Energy Rev. 2009, 13, 2309–2322, doi:10.1016/j.rser.2009.03.015.
[11]
Debe, M.K. Electrocatalyst approaches and challenges for automotive fuel cells. Nature 2012, 486, 43–51, doi:10.1038/nature11115.
[12]
Steele, B.C.H. Material science and engineering: The enabling technology for the commercialization of fuel cell systems. J. Mater. Sci. 2001, 36, 1053–1068.
[13]
You, D.J.; Kwon, K.; Joo, S.H.; Kim, J.H.; Kim, J.M.; Pak, C.; Chang, H. Carbon-supported ultra-high loading Pt nanoparticle catalyst by controlled overgrowth of Pt: Improvement of Pt utilization leads to enhanced direct methanol fuel cell performance. Int. J. Hydrog. Energy 2012, 37, 6880–6885, doi:10.1016/j.ijhydene.2012.01.103.
[14]
Greeley, J.; Stephens, I.E.L.; Bondarenko, A.S.; Johansson, T.P.; Hansen, H.A.; Jaramillo, T.F.; Rossmeisl, J.; Chorkendorff, I.; N？rskov, J.K. Alloys of platinum and early transition metals as oxygen reduction electrocatalysts. Nat. Chem. 2009, 1, 552–556, doi:10.1038/nchem.367.
[15]
Petrii, O.A. Pt-Ru electrocatalysts for fuel cells: A representative review. J. Solid State Electrochem. 2008, 12, 609–642, doi:10.1007/s10008-007-0500-4.
[16]
Yang, H. Platinum-based electrocatalysts with core-shell nanostructures. Angew. Chem. Int. Ed. 2011, 50, 2674–2676, doi:10.1002/anie.201005868.
[17]
Strasser, P.; Koh, S.; Anniyev, T.; Greeley, J.; More, K.; Yu, C.; Liu, Z.; Kaya, S.; Nordlund, D.; Ogasawara, H.; Toney, M.F.; Nilsson, A. Lattice-strain control of the activity in dealloyed core-shell fuel cell catalysts. Nat. Chem. 2010, 2, 454–460, doi:10.1038/nchem.623.
[18]
Stamenkovic, V.R.; Fowler, B.; Mun, B.S.; Wang, G.; Ross, P.N.; Lucas, C.A.; Markovic, N. Improved oxygen reduction activity on Pt3Ni(111) via increased surface site availability. Science 2007, 315, 493–497, doi:10.1126/science.1135941.
Wang, J.X.; Ma, C.; Choi, Y.M.; Su, D.; Zhu, Y.; Liu, P.; Si, R.; Vukmirovic, M.B.; Zhang, Y.; Adzic, R.R. Kirkendall effect and lattice contraction in nanocatalysts: A new strategy to enhance sustainable activity. J. Am. Chem. Soc. 2011, 133, 13551–13557.
[23]
Watanabe, M.; Uchida, M.; Motoo, S. Preparation of Highly Dispersed Pt + Ru Clusters and the Activity for the Electrooxidation of Methanol. J. Electroanal. Chem. 1987, 229, 395–406, doi:10.1016/0022-0728(87)85156-2.
[24]
Wakisaka, M.; Mitsui, S.; Hirose, Y.; Kawashima, K.; Uchida, H.; Watanabe, M. Electronic Structures of Pt-Co and Pt-Ru Alloys for CO-Tolerant Anode Catalysts in Polymer Electrolyte Fuel Cells Studied by EC-XPS. J. Phys. Chem. B 2006, 110, 23489–23496.
[25]
Li, Q.; He, R.; Gao, J.-A.; Jensen, J.O.; Bjerrum, N.J. The CO Poisoning Effect in PEMFCs Operational at Temperatures up to 200°C. J. Electrochem. Soc. 2003, 150, A1599–A1605, doi:10.1149/1.1619984.
[26]
Skulason, E.; Tripkovic, V.; Bjorketun, M.E.; Gudmundsdottir, S.; Karlberg, G.; Rossmeisl, J.; Bligaard, T.; Jonsson, H.; Norskov, J.K. Modeling the electrochemical hydrogen oxidation and evolution reactions on the basis of density functional theory calculations. J. Phys. Chem. C 2010, 114, 18182–18197.
[27]
Markovic, N.M.; Grgur, B.N.; Ross, P.N. Temperature-dependent hydrogen electrochemistry on platinum low-index single-crystal surfaces in acid solutions. J. Phys. Chem. B 1997, 101, 5405–5413.
[28]
Murthi, V.S.; Urian, R.C.; Mukerjee, S. Oxygen reduction kinetics in low and medium temperature acid environment: Correlation of water activation and surface properties in supported Pt and Pt alloy electrocatalysts. J. Phys. Chem. B 2004, 108, 11011–11023, doi:10.1021/jp048985k.
[29]
Suzuki, A.; Oono, Y.; Williams, M.C.; Miura, R.; Inaba, K.; Hatakeyama, N.; Takaba, H.; Hori, M.; Miyamoto, A. Evaluation for sintering of electrocatalysts and its effect on voltage drops in high-temperature proton exchange membrane fuel cells (HT-PEMFC). Int. J. Hydrog. Energy 2012, 37, 18272–18289.
[30]
Shao, M. Palladium-based electrocatalysts for hydrogen oxidation and oxygen reduction reactions. J. Power Sources 2011, 196, 2433–2444, doi:10.1016/j.jpowsour.2010.10.093.
[31]
Antolini, E. Palladium in fuel cell catalysis. Energy Environ. Sci. 2009, 2, 915–931, doi:10.1039/b820837a.
[32]
Serov, A.; Kwak, C. Review of non-platinum anode catalysts for DMFC and PEMFC application. Appl. Catal. B Environ. 2009, 90, 313–320, doi:10.1016/j.apcatb.2009.03.030.
[33]
Kwon, K.; Lee, K.H.; Jin, S.-A.; You, D.J.; Pak, C. Ceria-promoted oxygen reduction reaction in Pd-based electrocatalysts. Electrochem. Commun. 2011, 13, 1067–1069, doi:10.1016/j.elecom.2011.06.036.
[34]
Jin, S.-A.; Kwon, K.; Pak, C.; Chang, H. The oxygen reduction electrocatalytic activity of intermetallic compound of palladium-tin supported on tin oxide-carbon composite. Catal. Today 2011, 164, 176–180.
[35]
You, D.J.; Jin, S.-A.; Lee, K.H.; Pak, C.; Choi, K.H.; Chang, H. Improvement of activity for oxygen reduction by decoration of Ir on PdCu/C catalyst. Catal. Today 2012, 185, 138–142.
[36]
Antolini, E. Carbon supports for low-temperature fuel cell catalysts. Appl. Catal. B Environ. 2009, 88, 1–24, doi:10.1016/j.apcatb.2008.09.030.
[37]
Yang, Y.; Chiang, K.; Burke, N. Porous carbon-supported catalysts for energy and environmental application: A short review. Catal. Today 2011, 178, 197–205.
[38]
Dicks, A.L. The role of carbon in fuel cells. J. Power Sources 2006, 156, 128–141, doi:10.1016/j.jpowsour.2006.02.054.
[39]
Lee, H.I.; Stucky, G.D.; Kim, J.H.; Pak, C.; Chang, H.; Kim, J.M. Spontaneous phase separation mediated synthesis of 3D mesoporous carbon with controllable cage and window size. Adv. Mater. 2011, 23, 2357–2361, doi:10.1002/adma.201003599.
[40]
Pak, C.; Kim, J.M.; Chang, H. Mesoporous carbon-supported catalysts for direct methanol fuel cells. In Electrocatalysis of Direct Methanol Fuel Cells, 1st; Liu, H., Zhang, J., Eds.; WILEY-VCH Verlag GmbH & Co. KGaA: Weinheim, Germany, 2009; pp. 355–378.
[41]
Chang, H.; Joo, S.H.; Pak, C. Synthesis and characterization of mesoporous carbon for fuel cell applications. J. Mater. Chem. 2007, 17, 3078–3088.
[42]
Kwon, K.; Jin, S.-A.; Pak, C.; Chang, H.; Joo, S.H.; Lee, H.I.; Kim, J.H.; Kim, J.M. Enhancement of electrochemical stability and catalytic activity of Pt nanoparticles via strong metal-support interaction with sulfur-containing ordered mesoporous carbon. Catal. Today 2011, 164, 186–189.
[43]
Lee, H.I.; Joo, S.H.; Kim, J.H.; You, D.J.; Kim, J.M.; Park, J.-N.; Chang, H.; Pak, C. Ultrastable Pt nanoparticles supported on sulfur-containing ordered mesoporous carbon via strong metal-support interaction. J. Mater. Chem. 2009, 19, 5934–5939, doi:10.1039/b907514c.
[44]
Joo, S.H.; Pak, C.; You, D.J.; Lee, S.-A.; Lee, H.I.; Kim, J.M.; Chang, H.; Seung, D. Ordered mesoporous carbons (OMC) as supports of electrocatalysts for direct methanol fuel cells (DMFC): Effect of carbon precursors of OMC on DMFC performances. Electrochim. Acta 2006, 52, 1618–1626, doi:10.1016/j.electacta.2006.03.092.
[45]
Joo, S.H.; Kwon, K.; You, D.J.; Pak, C.; Chang, H.; Kim, J.M. Preparation of high loading Pt nanoparticles on ordered mesoporous carbon with a controlled Pt size and its effect on oxygen reduction and methanol oxidation reactions. Electrochim. Acta 2009, 54, 5746–5753, doi:10.1016/j.electacta.2009.05.022.
[46]
Joo, S.H.; Lee, H.I.; You, D.J.; Kwon, K.; Kim, J.H.; Choi, Y.S.; Kang, M.; Kim, J.M.; Pak, C.; Chang, H.; Seung, D. Ordered mesoporous carbons with controlled particle sizes as catalyst supports for direct methanol fuel cell cathodes. Carbon 2008, 46, 2034–2045, doi:10.1016/j.carbon.2008.08.015.
[47]
Sharma, S.; Pollet, B.G. Support materials for PEMFC and DMFC electrocatalysts—A review. J. Power Sources 2012, 208, 96–119, doi:10.1016/j.jpowsour.2012.02.011.
[48]
Wang, Y.J.; Wilkinson, D.; Zhang, J. Noncarbon support materials for polymer electrolyte membrane fuel cell electrocatalysts. Chem. Rev. 2011, 111, 7625–7651, doi:10.1021/cr100060r.
[49]
Steele, B.C.H.; Heinzel, A. Materials for fuel-cell technologies. Nature 2001, 414, 345–352, doi:10.1038/35104620.
[50]
Kreuer, K.D. On the development of proton conducting polymer membranes for hydrogen andmethanol fuel cells. J. Membr. Sci. 2001, 185, 29–39, doi:10.1016/S0376-7388(00)00632-3.
[51]
Miyatake, K.; Chikashige, Y.; Higuchi, E.; Watanabe, M. Tuned polymer electrolyte membranes based on aromatic polyethers for fuel cell applications. J. Am. Chem. Soc. 2007, 129, 3879–3887.
[52]
Savadogo, O. Emerging membranes for electrochemical systems: Part II. High temperature composite membranes for polymer electrolyte fuel cell (PEFC) applications. J. Power Sources 2004, 127, 135–161, doi:10.1016/j.jpowsour.2003.09.043.
[53]
Mustarelli, P.; Quartarone, E.; Grandi, S.; Carollo, A.; Magistris, A. Polybenzimidazole-based membranes as a real alternative to Nafion for fuel cells operating at low temperature. Adv. Mater. 2008, 20, 1339–1343, doi:10.1002/adma.200701767.
[54]
Lee, S.-Y.; Ogawa, A.; Kanno, M.; Nakamoto, H.; Yasuda, T.; Watanabe, M. Nonhumidified intermediate temperature fuel cells using protic ionic liquids. J. Am. Chem. Soc. 2010, 132, 9764–9773.
[55]
Wainright, J.S.; Wang, J.-T.; Weng, D.; Savinell, R.F.; Litt, M. Acid-doped polybenzimidazoles: A new polymer electrolyte. J. Electrochem. Soc. 1995, 142, L121–L123.
[56]
Li, Q.; He, R.; Jensen, J.O.; Bjerrum, N.J. Approaches and recent development of polymer electrolyte membranes for fuel cells operating above 100 °C. Chem. Mater. 2003, 15, 4896–4915, doi:10.1021/cm0310519.
[57]
Zhang, J.; Xie, Z.; Zhang, J.; Tang, Y.; Song, C.; Navessin, T.; Shi, Z.; Song, D.; Wang, H.; Wilkinson, D.P.; Liu, Z.-S.; Holdcroft, S. High temperature PEM fuel cells. J. Power Sources 2006, 160, 872–891, doi:10.1016/j.jpowsour.2006.05.034.
[58]
Hogarth, W.H.J.; Diniz da Costa, J.C.; Lu, G.Q. Solid acid membranes for high temperature (at 140°C) proton exchange membrane fuel cells. J. Power Sources 2005, 142, 223–237, doi:10.1016/j.jpowsour.2004.11.020.
[59]
Shao, Y.; Yin, G.; Wang, Z.; Gao, Y. Proton exchange membrane fuel cell from lowtemperature to high temperature: Material challenges. J. Power Sources 2007, 167, 235–242, doi:10.1016/j.jpowsour.2007.02.065.
[60]
Li, Q.; He, R.; Jenson, J.O.; Bjerrum, N.J. PBI-based polymer membranes for high temperature fuel cells—Preparation, Characterization and Fuel Cell Demonstration. Fuel Cells 2004, 4, 147–159, doi:10.1002/fuce.200400020.
[61]
Lobato, J.; Ca？izares, P.; Rodrigo, M.A.; Linares, J.J.; Manjavacas, G. Synthesis and characterization ofpoly[2,2-(m-phenylene)-5,5-bibenzimidazole] as polymer electrolyte membrane for high-temperature PEMFCs. J. Membr. Sci. 2006, 280, 351–362, doi:10.1016/j.memsci.2006.01.049.
[62]
He, R.; Li, Q.; Bach, A.; Jensen, J.O.; Bjerrum, N.J. Doping phosphoric acid in polybenzimidazole membranes for high temperature proton exchange membrane fuel cells. J. Polym. Sci. A Polym. Chem. 2007, 45, 2989–2997, doi:10.1002/pola.22053.
[63]
He, R.; Li, Q.; Xiao, G.; Bjerrum, N.J. Proton conductivity of phosphoric acid doped polybenzimidazole and its composites with inorganic proton conductors. J. Membr. Sci. 2003, 226, 169–184, doi:10.1016/j.memsci.2003.09.002.
[64]
Pu, H.; Meyer, W.H.; Wegner, G. Proton transport in polybenzimidazole blended with H3PO4 or H2SO4. J. Polym. Sci. B Polym. Phys. 2002, 40, 663–669, doi:10.1002/polb.10132.
Weng, D.; Wainright, J.S.; Landau, U.; Savinell, R.F. Electro-osmotic drag coefficient of water and methanol in polymer electrolytes at elevated temperatures. J. Electrochem. Soc. 1996, 143, 1260–1263, doi:10.1149/1.1836626.
Kim, T.-H.; Lim, T.-W.; Lee, J.-C. High temperature fuel cell membranes based on mechanically stable para-ordered polybenzimidazole prepared by direct casting. J. Power Sources 2007, 172, 172–179, doi:10.1016/j.jpowsour.2007.07.040.
[69]
Wang, J.-T.; Savinell, R.F.; Wainright, J.; Litt, M.; Yu, H. A H2O2 fuel cell using acid doped polybenzimidazole as polymer electrolyte. Electrochim. Acta 1996, 41, 193–197, doi:10.1016/0013-4686(95)00313-4.
[70]
Samms, S.R.; Wasmus, S.; Savinell, R.F. Thermal stability of proton conducting acid doped polybenzimidazole in simulated fuel cell environments. J. Electrochem. Soc. 1996, 143, 1225–1232, doi:10.1149/1.1836621.
[71]
Asensio, J.A.; Gómez-Romero, P. Recent developments on proton conducting poly(2,5-benzimidazole) (ABPBI) membranes for high temperature polymer electrolyte membrane fuel cells. Fuel Cells 2005, 5, 336–343, doi:10.1002/fuce.200400081.
[72]
Kim, H.J.; Lim, T.H. PBI derivatives: Polymer electrolyte fuel cell membrane for high temperature operation. J. Ind. Eng. Chem. 2004, 10, 1081–1085.
[73]
Kim, S.-K.; Kim, T.-H.; Ko, T.; Lee, J.-C. Cross-linked poly(2,5-benzimidazole) consisting of wholly aromatic groups for high-temperature PEM fuel cell applications. J. Membr. Sci. 2011, 373, 80–88, doi:10.1016/j.memsci.2011.02.039.
[74]
Kim, H.-J.; Cho, S.Y.; An, S.J.; Eun, Y.C.; Kim, J.-Y.; Yoon, H.-K.; Kweon, H.-J.; Yew, K.H. Synthesis of poly(2,5-benzimidazole) for use as a fuel cell membrane. Macromol. Rapid Commun. 2004, 25, 894–897, doi:10.1002/marc.200300288.
[75]
Asensio, J.A.; Borrós, S.; Gómez-Romero, P. Polymer electrolyte fuel cells based on phosphoric acid impregnated poly(2,5-benzimidazole) membranes. J. Electrochem. Soc. 2004, 151, A304–A310, doi:10.1149/1.1640628.
[76]
Kim, T.-H.; Lim, T.-W.; Park, Y.-S.; Shin, K.; Lee, J.-C. Proton-conducting zirconium pyrophosphate/poly(2,5-benzimidazole) composite membranes prepared by a PPA direct casting method. Macromol. Chem. Phys. 2007, 208, 2293–2302, doi:10.1002/macp.200700261.
[77]
Wannek, C.; Lehnert, W.; Mergel, J. Membrane electrode assemblies for high-temperature polymer electrolyte fuel cells based on poly(2,5-benzimidazole) membranes with phosphoric acid impregnation via the catalyst layers. J. Power Sources 2009, 192, 258–266, doi:10.1016/j.jpowsour.2009.03.051.
[78]
Burke, W.J. 3,4-Dihydro-1,3,2H-Benzoxazines. Reaction of p-substituted phenols with N,N-dimethylolamines. J. Am. Chem. Soc. 1949, 71, 609–612, doi:10.1021/ja01170a063.
[79]
Burke, W.J.; Kolbezen, M.J.; Stephens, C.W. Condensation of naphthols with formaldehyde and primary amines. J. Am. Chem. Soc. 1952, 74, 3601–3605, doi:10.1021/ja01134a039.
[80]
Burke, W.J.; Hammer, C.R.; Weatherbee, C.J. Bis-m-oxazines from Hydroquinone. J. Org. Chem. 1961, 26, 4403–4407, doi:10.1021/jo01069a053.
[81]
Burke, W.J.; Glennie, E.L.M.; Weatherbee, C. Condensationof halophenols with formaldehyde and primary amines. J. Org. Chem. 1964, 29, 909–912, doi:10.1021/jo01027a038.
[82]
Burke, W.J.; Bishop, J.L.; Glennie, E.L.M.; Bauer, W.N., Jr. A new aminoalkylation reaction. Condensation of phenols with dihydro-1,3-aroxazines. J. Org. Chem. 1965, 30, 3423–3427.
[83]
Gardziella, A.; Pilato, L.; Knop, A. Pilato, Phenolic Resins, Chemistry, Applications, Standardization, Safety, and Ecology and Performance, Future Directions, 2nd ed.; Springer-Verlag: Heidelberg, Germany, 2000.
[84]
Ning, X.; Ishida, H. Phenolic materials via ring-opening polymerization of benzoxazines: Effect of molecular structure on mechanical and dynamic mechanical properties. J. Polym. Sci. B Polym. Phys. 1994, 32, 921–927, doi:10.1002/polb.1994.090320515.
[85]
Ning, X.; Ishida, H. Phenolic materials via ring-opening polymerization: Synthesis and characterization of bisphenol—A based benzoxazines and their polymers. J. Polym. Sci. A Polym. Chem. 1994, 32, 1121–1129, doi:10.1002/pola.1994.080320614.
[86]
Ishida, H.; Rodriguez, Y. Curing kinetics of a new benzoxazine-based phenolic resin by differential scanning calorimetry. Polymer 1995, 36, 3151–3158, doi:10.1016/0032-3861(95)97878-J.
[87]
Ishida, H.; Allen, D.J. Physical and mechanical characterization of near-zero shrinkage polybenzoxazines. J. Polym. Sci. B Polym. Phys. 1996, 34, 1019–1030, doi:10.1002/(SICI)1099-0488(19960430)34:6<1019::AID-POLB1>3.0.CO;2-T.
[88]
Ishida, H. Process for Preparation of Benzoxazine Compounds in Solventless Systems. U.S. Patent 5,543,516, 6 August 1996.
[89]
Ghosh, N.N.; Kiskan, B.; Yagci, Y. Polybenzoxazines—New high performance thermosetting resins: synthesis and properties. Prog. Polym. Sci. 2007, 32, 1344–1391, doi:10.1016/j.progpolymsci.2007.07.002.
[90]
Lee, M.-J.; Choi, S.-W.; Sun, H.-Y.; Jeon, W.-S. Electrolyte Membrane using Polybenzoxazine Based Compound and Method of Manufacturing the Same. U.S. Patent 7,858,668, 5 September 2006.
[91]
Choi, S.-W.; Sun, H.-Y.; Lee, M.-J.; Jeon, W.-S. Polybenzoxazine-Based Compound, Electrolyte Membrane Including the Same, and Fuel Cell Employing the Electrolyte Membrane. U.S. Patent 8,034,508, 1 September 2006.
[92]
Choi, S.-W.; Sun, H.-Y.; Jeon, W.-S. Polybenzoxazine-Based Compound, Electrolyte Membrane Including the Same, and Fuel Cell Employing the Electrolyte Membrane. U.S. Patent 8,148,028, 3 May 2007.
[93]
Choi, S.-W.; Lee, J.-C.; Park, J.O. Cross-Linked Polyazole, Method of Preparing the Polyazole, Electrode for Fuel Cell including the Cross-Linked Polyazole, Electrolyte Membrane for Fuel Cell. U.S. Patent 20100273087A1, 23 April 2010.
[94]
Kim, S.-K.; Choi, S.-W.; Jeon, W.S.; Park, J.O.; Ko, T.; Pak, C.; Chang, H.; Lee, J.-C. Cross-linked benzoxazine-benzimidazole copolymer electrolyte membranes for fuel cells at elevated temperature. Macromolecules 2012, 45, 1438–1446, doi:10.1021/ma202694p.
[95]
Seel, D.C.; Benicewicz, B.C.; Xiao, L.; Schmidt, T.J. High-temperature polybenzimidazole-based membranes. In Handbook of Fuel Cells—Advances in Electorocatalysis, Materials, Diagnostics and Durability; Vielstich, W., Yokokawa, H., Gasteiger, H.A., Eds.; John Wiley & Sons: Hoboken, NJ, USA, 2009; Volume 5, pp. 1–13.
[96]
Gasteiger, H.A.; Kocha, S.S.; Sompalli, B.; Wagner, F.T. Activity benchmarks and requirements for Pt, Pt-alloy, and non-Pt oxygen reduction catalysts for PEMFCs. Appl. Catal. B Environ. 2005, 56, 9–35, doi:10.1016/j.apcatb.2004.06.021.
[97]
Janssen, G.J.M.; Sittersa, E.F.; Pfrang, A. Proton-exchange-membrane fuel cells durability evaluated by load-on/off cycling. J. Power Sources 2009, 191, 501–509, doi:10.1016/j.jpowsour.2009.02.027.
[98]
Asghari, S.; Akhgar, H.; Imani, B. Design of thermal management subsystem for a 5kW polymer electrolyte membrane fuel cell system. J. Power Sources 2011, 196, 3141–3148, doi:10.1016/j.jpowsour.2010.11.077.
[99]
Andreasen, S.; K？r, S. Modelling and evaluation of heating strategies for high temperature polymer electrolyte membrane fuel cell stacks. Int. J. Hydrog. Energy 2008, 33, 4655–4664, doi:10.1016/j.ijhydene.2008.05.076.
[100]
Pfeifer, P.; Wall, C.; Jensen, O.; Hahn, H.; Fichtner, M. Thermal coupling of a high temperature PEM fuel cell with a complex hydride tank. Int. J. Hydrog. Energy 2009, 34, 3457–3466, doi:10.1016/j.ijhydene.2009.02.041.
[101]
Song, T.W.; Choi, K.H.; Kim, J.R.; Yi, J.S. Pumpless thermal management of water-cooled high-temperature proton exchange membrane fuel cell. J. Power Sources 2011, 196, 4671–4679, doi:10.1016/j.jpowsour.2010.12.108.
[102]
Asensio, J.A.; Sánchez, E.M.; Gómez-Romero, P. Proton-conducting membranes based on benzimidazole polymers for high-temperature PEM fuel cells. A chemical quest. Chem. Soc. Rev. 2010, 39, 3210–3239, doi:10.1039/b922650h.
[103]
Kim, S.-K.; Ko, T.; Choi, S.-W.; Park, J.O.; Kim, K.-H.; Pak, C.; Chang, H.; Lee, J.-C. Durable cross-linked copolymer membranes based on poly(benzoxazine) and poly(2,5-benzimidazole) for use in fuel cells at elevated temperatures. J. Mater. Chem. 2012, 22, 7194–7205.
[104]
Kim, S.-K.; Kim, T.-H.; Jung, J.-W.; Lee, J.-C. Copolymers of poly(2,5-benzimidazole) and poly[2,2-bep-phenylene)-5,5'-bibenzimidazole] for high-temperature fuel cell applications. Macromol. Mater. Eng. 2008, 293, 914–921, doi:10.1002/mame.200800179.
[105]
Antalek, B. Using pulsed gradient spin echo NMR for chemical mixture analysis: How to obtain optimum results. Concepts Magn. Reson. 2002, 14, 225–258, doi:10.1002/cmr.10026.
[106]
Chen, A.; Wu, D.; Johnson, C.S., Jr. Determination of molecular weight distributions for polymers by diffusion-ordered NMR. J. Am. Chem. Soc. 1995, 117, 7965–7970.
[107]
Viel, S.; Capitani, D.; Mannina, L.; Segre, A. Diffusion-ordered NMR spectroscopy: Aversatile tool for the molecular weight determination of uncharged polysaccharides. Biomacromolecules 2003, 4, 1843–1847, doi:10.1021/bm0342638.
Gorkom, V.; Leon, C.M.; Hancewicz, T.M. Analysis of DOSY and GPC-NMR experiments on polymers by multivariate curve resolution. J. Magn. Reson. 1998, 130, 125–130.
[111]
Bovey, F.A.; Mirau, P.A. The solution characterization of polymers. In NMR of Polymers, 1st ed.; Academic Press, Inc.: San Diego, CA, USA, 1996; Volume 3, pp. 155–242.
[112]
Wang, Y.-X.; Ishida, H. Synthesis and properties of new thermoplastic polymers from substituted 3,4-dihydro-2H-1,3-benzoxazines. Macromolecules 2000, 33, 2839–2847, doi:10.1021/ma9909096.
[113]
Leykin, A.Y.; Fomenkov, A.I.; Galpern, E.G.; Stankevich, I.V.; Rusanov, A.L. Some aspects of polybenzimidazoles’ synthesis in P2O5 containing condensation media. Polymer 2010, 51, 4053–4057, doi:10.1016/j.polymer.2010.06.053.
[114]
Oh, S.-Y.; Yoshida, T.; Kawamura, G.; Muto, H.; Sakai, M.; Matsuda, A. Inorganic-organic composite electrolytes consisting of polybenzimidazole and Cs-substituted heteropoly acids and their application for medium temperature fuel cells. J. Mater. Chem. 2010, 20, 6359–6366, doi:10.1039/c0jm00318b.
[115]
Zhang, J.; Tang, Y.; Song, C.; Zhang, J. Polybenzimidazole-membrane-based PEM fuel cell in the temperature range of 120-200 °C. J. Power Sources 2007, 172, 163–171, doi:10.1016/j.jpowsour.2007.07.047.
Marrony, M.; Barrer, R.; Quenet, S.; Ginocchio, S.; Montelatici, L.; Aslanides, A. Durability study and lifetime prediction of baseline proton exchange membrane fuel cell under severe operating conditions. J. Power Sources 2008, 182, 469–475, doi:10.1016/j.jpowsour.2008.02.096.
[118]
Pei, P.; Chang, Q.; Tang, T. A quick evaluating method for automotive fuel cell lifetime. Int. J. Hydrog. Energy 2008, 33, 3829–3836, doi:10.1016/j.ijhydene.2008.04.048.
[119]
Zhang, S.; Yuan, X.; Wang, H.; Mérida, W.; Zhu, H.; Shen, J.; Wu, S.; Zhang, J. A review of accelerated stress tests of MEA durability in PEM fuel cells. Int. J. Hydrog. Energy 2009, 34, 388–404, doi:10.1016/j.ijhydene.2008.10.012.
[120]
Zelenay, P.; Scharifker, B.R.; O’M Bockris, J.; Gervasio, D. A comparison of the properties of CF3SO3H and H3PO4 in relation to fuel cells. J. Electrochem. Soc. 1986, 133, 2262–2267, doi:10.1149/1.2108390.
[121]
Razaq, M.; Razaq, A.; Yeager, E.; DesMarteau, D.D.; Singh, S. Perfluorosulfonimide as an additive in phosphoric acid fuel cell. J. Electrochem. Soc. 1989, 136, 385–390, doi:10.1149/1.2096641.
[122]
Hsueh, K.-L.; Gonzolez, E.R.; Srinivasan, S. Effects of phosphoric acid concentration on oxygen reduction kinetics at platinum. J. Electrochem. Soc. 1984, 131, 823–828, doi:10.1149/1.2115707.
[123]
Qingfeng, L.; Hjuler, H.A.; Bjerrum, N.J. Oxygen reduction on carbon supported platinum catalysts in high temperature polymer electrolytes. Electrochim. Acta 2000, 45, 4219–4226, doi:10.1016/S0013-4686(00)00554-5.
Seland, F.; Berning, T.; Borresen, B.; Tunold, R. Improving the performance of high-temperature PEM fuel cells based on PBI electrolyte. J. Power Sources 2006, 160, 27–36, doi:10.1016/j.jpowsour.2006.01.047.
[126]
Zecevic, S.K.; Wainright, J.S.; Litt, M.H.; Gojkovic, S.L.; Savinell, R.F. Kinetics of O2 reduction on a Pt electrode covered with a thin film of solid polymer electrolyte. J. Electrochem. Soc. 1997, 144, 2973–2982, doi:10.1149/1.1837946.
[127]
Liu, Z.; Wainright, J.S.; Litt, M.H.; Savinell, R.F. Study of the oxygen reduction reaction (ORR) at Pt interfaced with phosphoric acid doped polybenzimidazole at elevated temperature and low relative humidity. Electrochim. Acta 2006, 51, 3914–3923, doi:10.1016/j.electacta.2005.11.019.
[128]
Schmidt, T.J.; Baurmeister, J. Properties of high-temperature PEFC Celtec？-P 1000 MEAs in start/stop operation mode. J. Power Sources 2008, 176, 428–434, doi:10.1016/j.jpowsour.2007.08.055.
[129]
Park, J.O.; Choi, S.-W.; Jeon, W.-S.; Yi, J.-S.; Oemer, U. A Composition Containing a Uniformly Dispersed Polyoxazine-Based Compound, a Method of Preparing the Composition, an Electrode Including the Composition, and a Fuel Cell Including the Electrode. U.S. Patent 0217627A1, 3 March 2011.
