Impact of cation selection on proton exchange membrane fuel cell performance with trimethylethyl amide, ethylpyridinium and ethylmethyl imidazolium ionic liquid carried by poly(vinylidene fluoride) membrane as electrolyte

The cation impact of trimethylethyl amide ([N1114]+), ethyl pyridinium ([Epdy]) and ethylmethyl imidazolium ([Emim]+) on the performance of proton exchange membrane fuel cell (PEMFC) is studied. The cell performance with ionic liquid (IL) as the electrolyte is dramatically improved by replacing [Emim] cation with [N1114]. A maximum power density (MPD) of 65 mW cm−2 is obtained with [N1114]HSO4 as the electrolyte in PEMFC while the one with imidazolium ILs can only provide around 1 mW cm−2. Subsequently, the influence of cations of ILs on Pt/C catalyst is investigated by cyclic voltammogram, and it can be found that the imidazolium cation result in smaller electrochemical active surface areas (EAS) of Pt/C than those of [N1114]+ and pyridinium. In addition, theoretical calculation with the Gaussian 03 program implies that the adsorption energy of the [Emim]+ on the Pt catalyst surface is much higher than [N1114]+, thus decreasing EAS of Pt catalyst in fuel cells. Therefore, it indicates that the cation should be carefully selected when applying ILs as an electrolyte for fuel cells.