Power generation using adjustable Nafion/PTFE mixed binders in air-cathode microbial fuel cells

Area of Science:

• Electrochemistry
• Materials Science
• Environmental Engineering

Background:

• Microbial fuel cells (MFCs) are promising for sustainable energy generation.
• Catalyst binders are crucial for MFC cathode performance and stability.
• Nafion and poly(tetrafluoroethylene) (PTFE) are common binder materials.

Purpose of the Study:

• To evaluate Nafion, PTFE, and Nafion-PTFE mixtures as catalyst binders in air-cathode MFCs.
• To determine the effect of binder composition on MFC power density and long-term performance.

Main Methods:

• Fabrication of MFC cathodes using Nafion, PTFE, and Nafion-PTFE mixtures (1:2 and 2:1 ratios).
• Performance testing of MFCs with different binders to measure maximum power density.
• Multi-cycle testing (25 cycles) to assess binder stability and Coulombic efficiency.

Main Results:

• Maximum power density increased from 549 to 1060 mW/m² with increasing Nafion content (0% to 100%).
• Multi-cycle tests showed a 4-6% decrease in maximum voltage across all binders.
• Coulombic efficiency increased by 20-29% with Nafion binder and 17-26% with other binders.

Conclusions:

• Nafion-PTFE mixed polymers are effective and applicable catalyst binders for MFC cathodes.
• Binder composition, particularly Nafion percentage, directly impacts MFC power density.
• Adjustable Nafion/PTFE ratios offer a balance between cost and performance for MFC applications.