Modifying a proton conductive membrane by embedding a "barrier"

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Developing proton conductive membranes for fuel cells faces challenges in balancing proton conductivity and methanol permeability.
• Perflorosulfonated membranes like Nafion-112 are widely used but suffer from high methanol crossover.

Purpose of the Study:

• To propose a novel strategy for creating proton conductive membranes with reduced methanol permeability.
• To enhance fuel cell performance by incorporating a proton conductive barrier within a perflorosulfonated matrix.

Main Methods:

• Embedding amphoteric sulfonated poly(phthalazinone ether sulfone kentone) (SPPESK) into a semicrystalline perflorosulfonic acid polymer matrix (FSP).
• Annealing the composite membrane to form a proton conductive barrier through acid-base interactions.
• Characterizing the membrane's proton conductivity, methanol permeability, and fuel cell performance.

Main Results:

• The embedded SPPESK formed a barrier via ionic and hydrogen-bonded acid-base interactions.
• The barrier effectively blocked methanol crossover, achieving 30% of Nafion-112's permeability.
• The developed membrane demonstrated excellent fuel cell performance at 80 °C, comparable to Nafion-112.

Conclusions:

• The strategy of embedding a proton conductive barrier successfully addresses the dilemma of proton conductivity versus methanol permeability.
• The novel membrane offers a promising alternative for high-performance fuel cell applications.