Abstract
Neutron imaging was used to study cathode water content over time in a three-dimensional-cathode enzyme fuel cell (EFC). A porous carbon felt cathode allowed air to flow through the electrode. A solution with laccase and a mediator formed an aqueous layer on the electrode surface. Water loss was observed in situ via neutron imaging for varying experimental conditions, including flow rates of hydrogen and air, cathode inlet humidity, volume of enzyme solution, and its composition. Cathode water loss occurred for all experimental conditions, but the loss rate was noticeably reduced when a high-salt-concentration enzyme solution was used in the cathode in conjunction with increased humidity in the air feed stream. Results from neutron imaging and power density analysis were used in analyzing the causes that could contribute to EFC water loss. An increase in temperature due to the exothermic cathode reaction is considered a plausible cause of cathode water loss via evaporation. This is the first reported application of neutron imaging as a technique to study EFC water management. The results suggest that neutron imaging can be employed to provide a better understanding of EFC phenomena and thereby contribute to design and operational improvements of EFCs.
| Original language | English |
|---|---|
| Pages (from-to) | 1769-1775 |
| Number of pages | 7 |
| Journal | Journal of Power Sources |
| Volume | 196 |
| Issue number | 4 |
| DOIs | |
| State | Published - Feb 15 2011 |
Funding
This work was supported by the American Chemical Society, Petroleum Research Fund – Green Chemistry Initiative at Georgia Institute of Technology . EFC work at Oak Ridge National Laboratory was supported by the Laboratory Directed Research and Development Program of ORNL. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. Neutron imaging was performed at the National Institute of Standards and Technology, Center for Neutron Research. The authors acknowledge Mr. Eli Baltic of the NIST for technical assistance in carrying out the neutron radiography experiments. This work was supported by the U.S. Department of Commerce, the NIST Ionizing Radiation Division, the Director's office of NIST, the NIST Center for Neutron Research, and the Department of Energy through Interagency Agreement No. DE-AI01-01EE50660.
Keywords
- Enzyme fuel cell
- Laccase
- Neutron imaging
- Three-dimensional cathode
- Water management