Ionic-liquid-based proton conducting membranes for anhydrous H2/Cl2 fuel-cell applications

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Anhydrous proton-conducting membranes are crucial for advanced fuel cell technologies.
• Poly(benzimidazole) (PBI) is a promising polymer for high-temperature fuel cells.
• Ionic liquids offer potential to enhance membrane properties.

Purpose of the Study:

• To develop and evaluate an ionic-liquid-doped PBI membrane for anhydrous H2/Cl2 fuel cells.
• To investigate the suitability of diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]) as an dopant.
• To analyze the proton transfer mechanisms within the composite membrane.

Main Methods:

• Fabrication of PBI/[dema][TfO] hybrid membranes.
• Electrochemical characterization including ionic conductivity measurements.
• Performance evaluation in an anhydrous H2/Cl2 fuel cell.
• Analysis of proton transport mechanisms.

Main Results:

• The PBI/[dema][TfO] hybrid membrane exhibited good compatibility, high stability, and ionic conductivity of 20.73 mS cm(-1) at 160 °C.
• [dema][TfO] demonstrated superior electrode reaction kinetics compared to other ionic liquids.
• The composite electrolyte functioned effectively in an anhydrous H2/Cl2 fuel cell.
• Both proton-hopping and diffusion mechanisms were identified for proton transfer.

Conclusions:

• Diethylmethylammonium trifluoromethanesulfonate doped PBI membranes are suitable for anhydrous H2/Cl2 fuel cells.
• The hybrid membranes offer a viable pathway for developing novel electrolytes for non-aqueous fuel cell applications.
• Understanding proton transfer mechanisms is key to optimizing performance.