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MFFC Technology Demo

Microbial Flow Fuel Cells Interactive Demo

Explore the breakthrough research from "High power density redox-mediated Shewanella microbial flow fuel cells" by Leyuan Zhang, Yucheng Zhang, Yang Liu, Sibo Wang, Calvin K. Lee, Yu Huang, Xiangfeng Duan(2024) showcasing revolutionary biofilm-free operation with 10x power improvements.

17.6 mW/cm² Peak Power
500x Resistance Reduction
Biofilm-Free Operation

Research Overview

Breakthrough Innovation

Microbial Flow Fuel Cells (MFFCs)

Biofilm-free operation with flowing planktonic bacteria

Eliminates mass transport limitations of conventional biofilm-based MFCs

10x higher
Improvement over conventional MFCs

Fundamental Equations

Lactate Oxidation (Anode)

C_3H_5O_3^- + 2H_2O → C_2H_3O_2^- + CO_2 + 4H^+ + 4e^-

Four-electron oxidation of lactate to acetate and CO2

Ferricyanide Reduction (Cathode)

[Fe(CN)_6]^3- + e^- → [Fe(CN)_6]^4-

One-electron reduction of ferricyanide at cathode

Redox Mediator Cycle

RM_ox + bacteria → RM_red + bacteria^ox

Mediator accepts electrons from bacteria metabolism

Electron Transfer to Electrode

RM_red + electrode → RM_ox + electrode + e^-

Reduced mediator transfers electron to carbon felt electrode

System Architecture

Flow-through architecture eliminates biofilm limitations

Components

anode Electrode:Porous carbon felt (2×2 cm²)
cathode Electrode:Porous carbon felt (2×2 cm²)
membrane:Nafion 211/212 proton exchange membrane
anolyte:S. oneidensis + lactate + redox mediator (40-120 mL)
catholyte:K3Fe(CN)6 + NaCl solution (40-120 mL)

Operating Conditions

flow Rate:20 ml/min (optimized)
temperature:25°C (room temperature)
p H:7.2 (neutral)
bacteria Concentration:OD600 ≈ 1.0
mediator Concentration:25 mM (FMN-Na, 2,7-AQDS)

Key Research Findings

Biofilm-free operation breakthrough

10x power density improvement

Eliminates fundamental tradeoff between biofilm thickness and mass transport

Redox mediator optimization

17.6 mW/cm² maximum power density

2,7-AQDS provides optimal balance of solubility and redox potential

Internal resistance reduction

From 1000+ ohms to ~2 ohms

500x reduction in total internal resistance vs conventional MFCs

Commercial viability pathway

Enables practical bioelectrochemical applications

Power densities approaching direct methanol fuel cells

Scalable flow architecture

Industrial wastewater treatment potential

Flow-through design enables modular scaling

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