Why Tolerance is Required

Tolerance on cathode materials is required with the aim at developing direct methanol fuel cell (DMFC) systems. As it is well known, in DMFCs the methanol crossover occurs through the sohd electrolyte membrane from the anode to the cathode, where it is 

The tolerance of chalcogenide was reported a long time ago using the Chevrel Phase compound. Some years later this property was documented with the cluster-like compounds of RuxSCy comparing them with the platinum electrode performance coupling the mass spectrometry (DBMS) to the electrochemical cell.  

Another limiting factor to be mentioned is the slow kinetics of oxidation at the Pt-Rn anode. When in inflow of electrolyte in the flow cell system contains only methanol/sulfuric acid (mixed-reactant mode) the effect on Pt cathode in building a mixed-potential is dramatic, in contrast to RuxSCy, see Fig. 16. This again is in agreement with the results generated by OEMS (cf Fig. 13). The FFC voltage already breaks down to 0.33 V. This result confirms that RuxSCy performs better when methanol concentration exceeds 2 M due to its tolerance. 

The analysis of individual potentials showed that RuxSey improves its performance in the presence of methanol (1 to 7 M) by as much as 30 to 60% as compared to the absence of methanol. 

The advantage of the chalcogenide with respect to platinum is the fact that a two streams laminar electrolyte can be eliminated, thus decreasing complexity in designing power systems. 

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