Pore-Matched Sponge for Microorganisms Pushes Electron Extraction Limit in Microbial Fuel Cells

Area of Science:

• Electrochemistry
• Environmental Biotechnology
• Materials Science

Background:

• Microbial fuel cells (MFCs) show promise for wastewater treatment and energy generation.
• Current MFCs suffer from inefficient electron transfer, limiting their practical application.
• Developing effective bioanodes is crucial for improving MFC performance.

Purpose of the Study:

• To engineer a uniform electroactive biofilm using a pore-matched sponge strategy.
• To enhance direct electron transfer between microorganisms and electrodes in MFCs.
• To improve the power density and efficiency of MFCs for practical applications.

Main Methods:

• Fabrication of a core-shell polyaniline@carbon nanotube (PANI@CNT) sponge.
• Inoculation of microorganisms within the pore-matched PANI@CNT sponge to form a bioanode.
• Characterization of biofilm formation, electron transfer efficiency, and MFC performance.

Main Results:

• The PANI@CNT bioanode achieved a maximum power density of 7549.4 ± 27.6 mW m⁻², surpassing existing MFCs.
• A high coulombic efficiency of 91.7 ± 1.2% was recorded, indicating efficient charge recovery.
• The PANI@CNT sponge selectively enriched the exoelectrogen Geobacter and facilitated direct electron transfer by down-regulating the pilA gene.

Conclusions:

• The pore-matching strategy using PANI@CNT sponges offers a practical approach to developing high-performance MFC bioanodes.
• This method significantly boosts electron extraction efficiency, leading to superior MFC performance.
• The study provides mechanistic insights into enhancing direct interspecies electron transfer in MFCs.