Proton-Conducting Poly-γ-glutamic Acid Nanofiber Embedded Sulfonated Poly(ether sulfone) for Proton Exchange...

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Proton exchange membranes (PEMs) are critical for PEM fuel cell commercialization.
• Developing high-performance PEMs is essential for efficient energy conversion.

Purpose of the Study:

• To fabricate novel PEMs using gamma-poly(glutamic acid) (γ-PGA) nanofibers for enhanced proton conductivity.
• To investigate the proton conduction mechanism in γ-PGA and its application in composite membranes.

Main Methods:

• Solution blowing technique to fabricate γ-PGA/polylactic acid (PLA) nanofibers.
• Density functional theory (DFT) calculations to elucidate proton hopping mechanisms.
• Incorporation of γ-PGA/PLA nanofibers into sulfonated poly(ether sulfone) to create composite PEMs.

Main Results:

• γ-PGA nanofibers exhibited high proton conductivity (0.572 S cm⁻¹ at 80 °C/50% RH).
• DFT revealed low activation energy barriers for proton hopping in γ-PGA.
• Composite PEMs with 30 wt% NFs achieved high proton conductivity (0.261 S cm⁻¹ at 80 °C/100% RH) and power density (202.3 mW cm⁻²).

Conclusions:

• γ-PGA nanofibers offer efficient proton channels for advanced PEMs.
• The developed composite PEMs demonstrate superior performance compared to Nafion.
• These findings highlight the potential of γ-PGA-based materials for next-generation fuel cells.