Investigation of Degradation Effects of DMFC MEAs in the First Few Days of Operation

Kurzfassung

The selection of fuel cell-components like GDL, membrane, catalyst etc. and also the operating conditions are important issues to reach high power density and superior reliability. However, degradation of the cell performance is a factor which hampers the fast commercialization of DMFCs. In DMFC investigations a dramatic loss in performance can often be detected even in the first few days of operation. The motivation of this investigation is to classify the degradation mechanisms. Performance degradation of fuel cells is partly reversible and partly irreversible. Different MEAs were investigated in single cell measurements with respect to their performance during the first days of operation. To characterize the processes in the cell U/I characteristics, EIS measurements and water balances were used. The investigations show that the conditions for a favorable water management changes with time which has major impact on the cell performance. A large part of the decline in performance can be avoided by changing operating conditions or by using modified MEAs. However, due to the irreversible part of degradation the decline in performance can not be avoided totally.