High power density from a miniature microbial fuel cell using Shewanella oneidensis DSP10

Area of Science:

• Microbiology
• Electrochemistry
• Bioengineering

Background:

• Microbial fuel cells (MFCs) offer a sustainable energy source but often face limitations in power density and scalability.
• Optimizing electrode materials and device architecture is crucial for enhancing MFC performance.

Purpose of the Study:

• To develop and characterize a miniature microbial fuel cell (mini-MFC) with high power output per device cross-section and volume.
• To evaluate the performance of different electrode materials (reticulated vitreous carbon and graphite felt) in the mini-MFC.
• To investigate the effect of electron mediators on MFC power generation.

Main Methods:

• A mini-MFC was constructed using Shewanella oneidensis DSP10 as the microbial catalyst.
• Reticulated vitreous carbon (RVC) and graphite felt (GF) were employed as anode electrode materials.
• Power and current densities were measured with and without the addition of exogenous electron mediators.

Main Results:

• Maximum power densities of 24 and 10 mW/m² were achieved with RVC and GF electrodes, respectively, without mediators.
• Short circuit current densities reached 100 mA/m² for RVC and 32 mA/m² for GF anodes.
• The addition of electron mediators increased current and power by 30-100%.
• The mini-MFC design, featuring short diffusion lengths and a high surface-area-to-chamber volume ratio, significantly enhanced power density.

Conclusions:

• The developed mini-MFC demonstrates superior power density compared to macroscopic MFCs.
• The device architecture and electrode selection are critical factors for maximizing microbial fuel cell efficiency.
• Further optimization with electron mediators shows potential for even greater power output.