Microbial Fuel Cell

Introduction

We are running a project to produce power using bacteria in a bacterial fuel cell. We plan to research the operating principles and engineer the devices to maximize their power output.

Goals

• Understand the KeegoTech MudWatt fuel cell's physical construction, configuration, and operating principles
• Achieve successful sustained power output with the MudWatt (demonstrated when the cell can continuously flash its LED)
• Construct our own fuel cell from basic materials and open source the design [ongoing]
• Conduct a review of research in the academic literature [ongoing]
• Assemble a multi-cell test-bed to quantify power output under different conditions
• Demonstrate the ability to reliably duplicate a functioning baseline control fuel cell
• Document and open source the baseline protocol
• Identify design parameters to vary to improve performance
• Observe the microbial cultures on the electrodes to determine what organisms are effective and how they function (are they building nano-wire networks, using direct contact, or exchanging charge through biomolecules?)
• Systematically vary the design parameters to identify those important for optimizing power output
• Potentially design and implement an open source experimental control and monitor system
• Ultimately exceed the power output of AA cells batteries, then use our cells to power electronic devices

Progress

• 2011 Dec 29 - Flushed the non-performing 01 mud mix from the fuel cell and replaced it with new mud sampled from Bachmann Lake at coordinates 32.859801, -96.855976, mixed with activated charcoal (and ion exchange resin, which should not hurt) from a Brita water filter cartridge (mud mix 02).
• 2012 Jan 5 - We are measuring approximately 43 mV from our 02 mix test cell; low, but the polarity is correct.
• 2012 Jan 12 - First success! The cell fueled with fuel mix 02 is now outputting a steady voltage of 322 mV, and is flashing its LED.
• 2012 Jan 26 - The fuel cell is outputting constant voltage of 340 mV. We are sourcing carbon fabric electrodes to begin fabricating our own cells.
• 2012 Feb 2 - The fuel cell was outputting constant voltage of 357 mV. After settling it by shaking it, the output voltage increased to a steady 385 mV. We think the upper electrode comes out of full contact with the fuel mix and shaking the fuel cell seats it more fully.
• 2012 Feb 9 - The fuel cell seems to now be outputting a constant voltage of 363 mV. We have ordered carbon fiber electrodes (for muscle stimulators, from a medical supply company) and next week should try building our own fuel cell from scratch. We are beginning initial planning for the experimental monitor system.
• 2012 Feb 16 - The electrodes are in; we are ready to start building our own fuel cells. The electrodes have a gel on them that may be antimicrobial. Strategies to try involve leaving it on to see if it matters, letting it dry out, and/or removing it w/ alcohol. Temporarily slowed by lab reorganization.
• 2012 Mar 22 - The fuel cell is now be outputting a constant voltage of 430 mV.
• 2012 Apr 12 - The fuel cell is now be outputting a constant voltage of 446 mV. Lab reorganization is complete, but David R's personal time constraints are impairing progress on the project.
• 2012 May 5 - The fuel cell is now be outputting a constant voltage of 458 mV.

References

Microbial Fuel Cell

• KeegoTech, makers of our first test fuel cell
• Discussion of microbial fuel cells on the DIY Bio email list
• Activated Carbon Cloth as Anode for Sulfate Removal in a Microbial Fuel Cell (Environ. Sci. Technol., 2008, 42 (13), pp 4971–4976) - concludes that Activated Carbon Cloth (ACC) is superior to graphite foil (GF) and carbon fiber veil (CFV) as an anode for sulfate removal in microbial fuel cells
• Pubmed searches
• Sources for carbon cloth electrodes: Fuel Cell Earth, Jamestown Distributors, Fiberglass Supply

Not yet read through

• ACS subscription info
• Electricity-producing bacterial communities in microbial fuel cells
• Power generation using an activated carbon fiber felt cathode in an upflow microbial fuel cell
• Bifunctional Silver Nanoparticle Cathode in Microbial Fuel Cells for Microbial Growth Inhibition with Comparable Oxygen Reduction Reaction Activity