Linking internal resistance with design and operation decisions in microbial electrolysis cells.

Area of Science:

• Electrochemistry
• Environmental Engineering
• Microbiology

Background:

• Internal resistance distribution in microbial electrolysis cells (MECs) is not well understood, limiting technological advancement.
• Optimizing MECs requires detailed knowledge of how design and operational factors influence internal resistance.

Purpose of the Study:

• To apply a novel method for quantifying internal resistance distribution in MECs.
• To investigate the impact of electrode spacing, fluid motion, and anode-to-cathode surface area ratio on internal resistance and overall performance.

Main Methods:

• Quantified internal resistance components (anode, cathode, solution) in single-chamber MECs.
• Systematically varied electrode spacing and introduced fluid motion.
• Adjusted the anode-to-cathode surface area ratio to optimize resistance balance.

Main Results:

• Baseline internal resistance: 210 Ω cm² (anode), 77 Ω cm² (cathode), 11 Ω cm²/M (solution).
• Fluid motion reduced resistance: 150 Ω cm² (anode), 47 Ω cm² (cathode), 5.3 Ω cm²/M (solution).
• Optimized resistance balance yielded high performance: 47 A/m² current density, 3.7 L-H₂/L-volume/day.

Conclusions:

• Quantifying internal resistance distribution is crucial for efficient MEC design and operation.
• The developed method accurately predicts MEC performance, validating its effectiveness.