Effect of ionic liquid structure on the performance of DMFCs anode electrode

In recent years, utilization of ionic liquids (ILs) as electrolyte additives is considered as a new topic in studies of fuel cells and batteries. ILs are molten salts at ambient temperature which have considerable potential as high temperature electrolyte modifiers due to their unique properties such as non volatility, high ionic conductivity, non flammability and high thermal stability. In this work, effect of ILs structure on the performance of DMFCs anode has been studied by different electrochemical methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results show that with increasing of alkyl chain of IL cation, the electroactivity of catalyst decrease in methanol oxidation reaction related to the strice hindrance of IL cation. A possible explanation is that with increasing the number of alkyl chain, bulk resistance increased and proton transfer to the catalyst surface decreases as well. Finally by analyzing test results it could be concluded at low temperature ILs does not have any promising effect on the catalyst activity and the role of ILs became important at higher temperatures.

Keywords:

Ionic liquid , Direct methanol fuel cell , Methanol oxidation