Raman study of the polybenzimidazole–phosphoric acid interactions in membranes for fuel cells

Conti, Fosca; Majerus, Anne; Noto, Vito Di; Korte, Carsten; Lehnert, Werner; Stolten, Detlef

doi:10.1039/c2cp40553a

Cited by 56 publications

(39 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Phosphoric acid is the most common electrolyte used in the HT-PEFCs at present [7,8]. Owing to the properties of phosphoric acid, the proton conductivity increases with the concentration until the maximum and then decreases [9].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Interaction Between Phosphoric Acid and Catalyst Layers on the Properties of HT‐PEFCs

Liu

Mohajeri

et al. 2014

Fuel Cells

View full text Add to dashboard Cite

The performance of high‐temperature polymer electrolyte fuel cells is influenced by the components in the cell. In order to determine the effects of the platinum loading and the thickness of the anode and the cathode as well as of the phosphoric acid content on the cell performance, a three‐level factorial plan encompassing 15 experimental points was designed and carried out. The experimental results were analyzed statistically and expressed as graphic cubes in the range studied. It was found that each factor and their interactions have strong effects on the cell performance. The interactions are attributed to the distribution of phosphoric acid and gases in the membrane electrode assembly. The water vapor transport influences the concentration of phosphoric acid, which modifies not only the proton conductivity but also the cathode kinetics. The optimized cell performance was obtained with an acid amount of 20 mg cm–2, a cathode thickness of 125 μm (platinum loading of 1.0 mg cm–2), and an anode thickness of 75 μm (platinum loading of 0.6 mg cm–2).

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of the Interaction Between Phosphoric Acid and Catalyst Layers on the Properties of HT‐PEFCs

Liu

Mohajeri

et al. 2014

Fuel Cells

View full text Add to dashboard Cite

show abstract

“…For Fumapem AM-55 these peaks are shifted slightly and located at 1550 and 1576 cm À1 . These results can be compared with signals from ATR-FTIR spectra and theoretical calculations of normal modes for small molecular models [21,23].…”

Section: Raman Spectramentioning

confidence: 91%

“…We recently investigated H 3 PO 4 -doped PBI-type membranes with Raman [21], NMR [22] and IR spectroscopy [23]. In these preceding studies, only the total weight increases by H 3 PO 4 and H 2 O uptake were determined.…”

Section: Introductionmentioning

confidence: 99%

Uptake of protic electrolytes by polybenzimidazole-type polymers: absorption isotherms and electrolyte/polymer interactions

Korte¹,

Conti

Wackerl³

et al. 2015

J Appl Electrochem

Self Cite

View full text Add to dashboard Cite

Polybenzimidazole (PBI) membranes doped with phosphoric acid are used as proton-conducting membrane in high-temperature polymer electrolyte fuel cells. There is no general model for the thermodynamics of the absorption process over the whole accessible doping range for all published data. The interactions between H 3 PO 4 and polymer chains, the polycondensation equilibria of H 3 PO 4 and the implications on proton conductivity are still largely unknown. In this study, we demonstrate that the uptake of a protic electrolyte by a polymer with basic moieties, i.e. a PBI-type polymer, can be described satisfactorily with a BET-like absorption isotherm. The absorption equilibria of the uptake process are analysed using literature data on the H 3 PO 4 , H 2 SO 4 and HClO 4 uptake of non-crosslinked m-PBI and AB-PBI as well as using our own investigations on the H 3 PO 4 uptake of a commercial crosslinked PBI derivative, Fumapem AM-55. In addition to the thermodynamic data of the absorption process, Raman data on m-PBI taken from the literature and our own Raman investigations on Fumapem AM-55 are taken into account. It is possible to correlate domains in the absorption isotherms with specific features in the Raman spectra. Two stages for the uptake of a protic electrolyte can be distinguished: (i) the protonation of the polymer chains and thus coulombic interactions with the electrolyte anions, (ii) the formation of H bonds directly with the chains and with electrolyte molecules that are still absorbed.

show abstract

“…When the doping level of the membrane reaches a value of about 280 wt%, no further changes occur in the analyzed spectral regions (18). However, a new peak VHHPV WR IRUP DW ௗFP í1 (marked with a circle LQ )LJௗ5).…”

Section: Raman Investigationmentioning

confidence: 97%

Thermogravimetric and Spectroscopic Investigation of the Interaction between Polybenzimidazole and Phosphoric Acid

et al. 2013

Self Cite

View full text Add to dashboard Cite

Poly(2,5-benzimidazole) (ABPBI) doped with different acid concentrations were analyzed by means of conductivity and thermogravimetric measurements as well as Raman spectroscopy. The conductivity is measured as a function of temperature and relative humidity. The condensation of the phosphoric acid can be observed in the signal of the proton conductivity under dry conditions. Raman spectroscopic measurements of variously doped membranes are performed to investigate the ABPBI - phosphoric acid interactions. The results are correlated to those obtained from the conductivity measurements. The dehydration of the acid is confirmed by thermogravimetric analysis of pure phosphoric acid and doped ABPBI

show abstract

Raman study of the polybenzimidazole–phosphoric acid interactions in membranes for fuel cells

Cited by 56 publications

References 40 publications

Influence of the Interaction Between Phosphoric Acid and Catalyst Layers on the Properties of HT‐PEFCs

Influence of the Interaction Between Phosphoric Acid and Catalyst Layers on the Properties of HT‐PEFCs

Uptake of protic electrolytes by polybenzimidazole-type polymers: absorption isotherms and electrolyte/polymer interactions

Thermogravimetric and Spectroscopic Investigation of the Interaction between Polybenzimidazole and Phosphoric Acid

Contact Info

Product

Resources

About