Proton conducting polymer electrolytes acid

Other proton-conducting polymer electrolytes based on sulfonated aromatic condensation polymers also show the onset of thermal degradation at temperatures between 200 and 400 °C. Desulfonation of arylsulfonic acids occurs readily upon heating their aqueous solution up to 100-175 °C. Therefore, desulfonation imposes limitations on the thermal stability of sulfonated aromatic condensation electrolytes. It should be mentioned that the presence of bulky substituents attached to the phenyl rings can, to some extent, favour an increase in the onset of thermal degradation temperature. 

C. The thermal stability of alkylsulfonated polymer electrolytes can be attributed to the strong chemical bond between the alkyl and the sulfonic acid groups. The introduction of alkylsulfonic acid groups into thermostable polymers involving alkane sultone is one of the most important approaches to the preparation of thermostable proton-conducting polymer electrolytes. 

Recently, new proton-conducting polymer electrolyte membranes based on FBI - orthophosphoric and other strong acid complexes have been proposed for use in PEMFCs [181-188]. 

Yamada M, Honma I (2005) Anhydrous proton conducting polymer electrolytes based on poly (vinylphosphonic acid)-heterocycle composite material. Polymer 46 2986-2992... 

Sevil F, Bozkurt A (2004) Proton conducting polymer electrolytes on the basis of poly (vinylphosphonic acid) and imidazole. J Phys Chem Solids 65 1659-1662... 

Savinell R, Litt M (2000) Proton conducting polymer electrolyte prepared by direct acid casting. US Patent 6,099,988... 

Abstract During the last two decades, extensive efforts have been made to develop alternative hydrocarbon-based polymer electrolyte membranes to overcome the drawbacks of the current widely used perfluorosulfonic acid Nafion. This chapter presents an overview of the synthesis, chemical properties, and polymer electrolyte fuel cell applications of new proton-conducting polymer electrolyte membranes based on sulfonated poly(arylene ether ether ketone) polymers and copolymers. 

Proton-conducting polymer electrolytes based on heteropolyacids (HPA) encapsulated with polystyrene sulphonic acid (PSS)... 

Acar, O. Sen, U Bozkurt, A. and Ata, A., Blend membranes from poly(2,5-benzimidazole) and poly(styrene sulfonic acid) as proton-conducting polymer electrolytes for fuel cells, J. Mater. Set, 45 993-998 (2010) DOI 10.1007/ sl0853-009 030-6. 

As a proton-conducting polymer, Nafion (a perfluorosulfonic acid polymer) has high ionic conductivity and has also been investigated as an electrolyte for different types of solid-state ESs [852-858]. It has been found that high scan rates could be achieved for ESs with Nafion electrolytes [854,855,859]. 

Two inorganic acids - phosphonic and phosphoric acid - have been in the focus of several theoretical studies in connection with fuel-cell membranes. Phosphoric acid is used as a proton-conducting electrolyte, whereas phosphonic acid is used as a protogenic group in proton-conducting polymers (e.g. in polyvinyl phosphonic acid). 

Proton-exchange membrane fuel cells (PEMFC)—use solid-polymer proton-conducting membrane electrolyte at temperatures generally ranging from ambient to 90°C. Today s technology primarily uses the trifluoromethanesulfonic-acid-based electrolyte membrane, such as DuPont s Nafion . 

Over the last decade, several new proton exchange membranes have been developed. The new polymers in fuel cell applications are based mostly on hydrocarbon structures for the polymer backbone. Poly(styrene sulfonic acid) is a basic material in this field. In practice, poly(styrene sulfonic acid) and the analogous polymers such as phenol sulfonic acid resin and poly(trifluorostyrene sulfonic acid), were frequently used as polymer electrolytes for PEMFCs in the 1960s. Chemically and thermally stable aromatic polymers such as poly(styrene) [ 3 ], poly(oxy-1,4-phenyleneoxy-1,4-phenylenecarbony 1-1,4-phenylene) (PEEK) [4], poly(phenylenesulfide) [5], poly(l,4-phenylene) [6, 7], poly (oxy-1,4-phe-nylene) [8], and other aromatic polymers [9-11], can be employed as the polymer backbone for proton conducting polymers. These chemical structures are illustrated in Fig. 6.2. 

Polymer electrolyte membrane or proton exchange membrane fuel cells (PEMFC) use a thin (s50 im) proton conductive polymer membrane (such as perfluorosulfonated acid polymer) as the electrolyte. The catalyst is typically platinum supported on carbon with loadings of about 0.3mg/cm, or, if the hydrogen feed contains minute amounts of CO, Pt-Ru alloys are used. Operating temperature is typically between 60 and 80°C. PEM fuel cells are a serious candidate for automotive applications, but also for small-scale distributed stationary power generation, and for portable power applications as well. 

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