Acidic Ionic Liquids Enabling Intermediate Temperature Operation Fuel Cells

Herein we show that protic ionic liquids (PILs) are promising electrolytes for fuel cells operating in the temperature range 100-120 degrees C. N,N-Diethyl-N-methyl-3-sulfopropan-1-ammonium hydrogen sulfate ([DEMSPA][HSA]), N,N-diethyl-N-methyl-3-sulfopropan-1-ammonium triflate ([DEMSPA][TfO]), N,Ndiethyl-3-sulfopropan-1-ammonium hydrogen sulfate ([DESPA][ HSA]), and N,N-diethyl-3-sulfopropan-1-ammonium triflate ([DESPA][TfO]) are investigated in this study with regard to their specific conductivity, thermal stability, viscosity, and electro-chemical properties. The [DEMSPA][TfO] and [DESPA][TfO] electrolytes offer high limiting current densities for the oxygen reduction reaction (ORR) on platinum electrodes, that is, about 1 order of magnitude larger than 98% H3PO4. This is explained by the minor poisoning of the Pt catalyst and the significantly larger product of the oxygen self-diffusion coefficient and concentration in these two PILs.

Automated summary

This study demonstrates that certain protic ionic liquids show promising electrolyte performance in the temperature range of 100-120 degrees Celsius. In particular, [DEMSPA][TfO] and [DESPA][TfO] electrolytes exhibit high limiting current densities for the oxygen reduction reaction on platinum electrodes.