Simulation and resolution of voltage reversal in microbial fuel cell stack

Area of Science:

• Electrochemistry
• Microbiology
• Bioengineering

Background:

• Microbial fuel cell (MFC) stacks are promising for sustainable energy generation.
• Voltage reversals in MFC stacks can negatively impact performance and longevity.
• Understanding the factors contributing to voltage reversals is crucial for optimizing MFC stack design and operation.

Purpose of the Study:

• To investigate the biotic and non-biotic factors contributing to voltage reversals in MFC stacks.
• To compare simulation results with experimental data from a real MFC stack.
• To identify strategies for mitigating voltage reversals in MFC stacks.

Main Methods:

• Simulated an electronic MFC stack to analyze voltage reversal contributions.
• Compared simulation data with experimental results from a 3-liter triple MFC stack with shared anolyte.
• Manipulated biofilm properties through electrical circuit alternation and electrostimulation.
• Investigated the effects of anolyte recirculation and increased nutrient supply.

Main Results:

• Voltage reversals in MFC stacks are attributed to biofilm variability and external load.
• Creating homogenous biofilms on all anodes significantly reduced the likelihood of voltage reversals.
• Electrical circuit alternation and electrostimulation promoted homogenous biofilms.
• Anolyte recirculation and increased nutrient supply postponed reversals but allowed unfavorable voltage asymmetries to persist.

Conclusions:

• Voltage reversals, while often detrimental, can occur even in high-performing MFC stacks.
• Homogenizing anode biofilms is an effective strategy for managing voltage reversals.
• A simplified MFC architecture with shared anolyte can contribute to manageable voltage reversals.