A Nanofiber-Based Gas Diffusion Layer for Improved Performance in Air Cathode Microbial Fuel Cells

Area of Science:

• Energy Conversion and Storage
• Materials Science
• Electrochemistry

Background:

• Microbial fuel cells (MFCs) offer a sustainable energy source, but their performance is often limited by inefficient oxygen reduction.
• Gas diffusion layers (GDLs) are critical components in MFCs, facilitating oxygen transport and managing water.
• Conventional GDLs face challenges in optimizing oxygen diffusion and preventing electrolyte leakage, hindering MFC efficiency.

Purpose of the Study:

• To develop and evaluate a novel nanostructured gas diffusion layer (nano-GDL) for enhanced air cathode single-chamber microbial fuel cell (a-SCMFC) performance.
• To improve the oxygen reduction reaction kinetics and overall energy output of a-SCMFCs.
• To create a GDL with tailored properties for efficient water management and gas transport.

Main Methods:

• Fabrication of nano-GDLs using electrospinning of polyvinylidene-difluoride (PVDF) and cellulose nanofibers directly onto a carbon-based electrode.
• Design of a dual-layer nano-GDL: a water-resistant PVDF outer layer and an oxygen-permeable cellulose inner layer.
• Performance testing of a-SCMFCs utilizing the novel nano-GDLs and comparing them against standard PTFE-based GDLs.

Main Results:

• The nano-GDL significantly enhanced the maximum current density of a-SCMFCs to 132.2 ± 10.8 mA m^-2, more than double that of standard GDLs (58.5 ± 2.4 mA m^-2).
• The energy recovery (EF) factor for a-SCMFCs with nano-GDL was 60.83 mJ m^-3, an order of magnitude higher than the 3.92 mJ m^-3 achieved with standard GDL.
• The nanostructured design effectively balanced water management and oxygen supply, promoting efficient direct oxygen reduction.

Conclusions:

• The developed nano-GDL represents a significant advancement in GDL technology for a-SCMFCs.
• The unique nanostructure and material composition of the nano-GDL lead to substantially improved power generation and energy efficiency.
• This approach offers a promising strategy for optimizing the performance of microbial fuel cells and other electrochemical devices.