Composite Sulfonated Polyether-Ether Ketone Membranes with SBA-15 for Electrochemical Energy Systems

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Conventional Nafion® membranes face limitations in demanding electrochemical applications.
• Development of advanced electrolyte materials is crucial for efficient energy conversion systems.
• Sulfonated Poly Ether-Ether Ketone (S-PEEK) offers potential as a proton exchange membrane material.

Purpose of the Study:

• To evaluate S-PEEK composite membranes modified with Santa Barbara Amorphous-15 (SBA-15) and phosphotungstic acid-impregnated SBA-15 (PWA/SBA-15).
• To assess these composites as alternatives to Nafion® for Proton Exchange Membrane Fuel Cells (PEMFC) and Electrochemical Hydrogen Pumping (EHP).
• To investigate the impact of SBA-15 and PWA/SBA-15 fillers on membrane properties and performance.

Main Methods:

• Composite membranes were synthesized using S-PEEK with varying loadings of SBA-15 and PWA/SBA-15.
• Morphological analysis was performed using Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS).
• Physicochemical properties including water uptake, ion exchange capacity, proton conductivity, and methanol permeability were evaluated. Performance was tested in PEMFC and EHP systems.

Main Results:

• The S-PEEK membrane with 10 wt.% SBA-15 exhibited the highest performance in PEMFC tests.
• Inclusion of inorganic fillers in EHP applications led to back-diffusion, limiting compression capacity.
• Composite membranes with 5 wt.% and 10 wt.% SBA-15 demonstrated the lowest methanol crossover.

Conclusions:

• S-PEEK/SBA-15 composite membranes show promise as alternatives to Nafion® for PEMFC applications, particularly at 10 wt.% SBA-15 loading.
• The presence of inorganic fillers can influence performance in EHP systems, necessitating further optimization.
• Reduced methanol permeability in S-PEEK/SBA-15 composites is advantageous for specific fuel cell designs.