Optimization of a passive direct methanol fuel cell with different current collector materials

Abstract

Towards the introduction of passive direct methanol fuel cells in the market, it is mandatory to achieve an optimum balance between its cost, efficiency and durability. To achieve that and knowing that the current collectors are responsible for about 80% of these systems weight, different current collector materials were tested in the anode and cathode sides of a passive direct methanol fuel cell, towards a cost and weight reduction. The best configuration was used to assess the lifetime of the developed passive direct methanol fuel cell. The cell performance and lifetime was evaluated through polarization measurements and these results were explained under the light of the electrochemical impedance spectroscopy data. A major novelty of this study is the use of an innovative equivalent electric circuit that accurately describes a passive direct methanol fuel cell, which allowed the identification and quantification of the different performance losses that negatively affect these systems efficiency.The maximum power density of 5.23 mW/cm2 was achieved using Titanium as anode current collector and Stainless Steel as cathode current collector and a methanol concentration of 7 M. The durability tests showed a lifetime of 200 h and a loss of efficiency of 41%.