High Performance PEM Fuel Cells - From Electrochemistry and Material Science to Engineering Development of a Multicell Stack.
Abstract
To increase the electrocatalytic activity of the air electrode and simultaneously minimize the transport limitations, mixture of a 10 wt.% alloy supported on carbon and a high platinum loading (40 wt.%) on carbon was used as the electrocatalyst. The presence of the alloy electrocatalyst enhances the electrocatalytic activity at low current densities and the presence of the Pt electrocatalyst preserves the open structure of the electrode in this way the performance enhancement is evident over the entire range of current densities. This experiment was repeated with 20 micrometers thick GORE-SELECT (TM) membrane and a similar effect was observed. One 3-cell stack of area 50 sq cm was assembled at BCS Technology, Inc. with MEAs prepared using a Nafion 112 membrane and electrodes containing a Pt loading of 4.5 mg/sq cm. At 2.1 V (0.7 V per cell), the current density was about 0.48 A/sq cm with air and about 0.65 A/sq cm with oxygen. The cells required slight pressurization on the air side of the cell. The performance of the third cell was found to be slightly lower, and required a rapid flow (flushing) of hydrogen periodically. This problem did not result from the quality of the MEAs used, but was probably due to a design problem associated with stacking or the internal manifolding. The stack was tested at CESHR for performance verification and approximately the same performance was observed as that at BCS. However, problems similar to those noted at BCS were also seen at CESHR.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 16, 1996
- Accession Number
- ADA324712
Entities
People
- A. J. Appleyby
- Supramaniam Srinivasan
Organizations
- Texas A&M University