Investigation of Passive DEFC Mini-Stacks at Ambient Temperature

Tuesday, 7 October 2014
Expo Center, 1st Floor, Center and Right Foyers (Moon Palace Resort)
A. Vélez-Denhez (Universidad del Valle, Escuela de Ingeniería Química, A. A. 25360, Cali, Colombia), M. O. Córdoba-Moreno, and W. H. Lizcano-Valbuena (Universidad del Valle, Departamento de Química, A. A. 25360, Cali, Colombia)
In this work we show the results of ministacks of direct ethanol fuel cells (DEFC) at 25 oC. Result obtained with a passive DEFC using 2 mgPtRu/C in anodes and 3 mg of Pt in cathodes, when the alcohol concentration was 1 M, showed a power density equal to 0.875 mWcm-2 for electrodes with area equal to 25 mm2 . Results related with Nafion content in the catalytic layers are discussed. Stacks using three  similar cells showed 2.4  mWcm-2 indicating the good performance of the system.
The performance of mini stacks operated with electrodes of 5 mm2 showed the dependence of the mass transport of ethanol and of the configuration of the stacks (zig zag and flip flop). The better results were obtained with a zig zag interconexion.
A comparison from fuel cell performance was done using ethanol and methanol. The best result of the stack using methanol (5M)  was 60% higher than when ethanol (2M) was used.