The inherent nature of PILs of having protons available for proton conduction, without needing to be acidic, makes them highly suitable as electrolytes, such as in fuel cells and batteries. A perspective article by MacFarlane et al. on the potential use of aprotic and protic ILs in various energy applications highlighted the broad range of possible applications, which are due to fundamental properties associated with ILs such as high thermal stability, high proton conductivity, and low vapor pressures. As outlined below, the properties of PILs can be tailored for specific applications to achieve wide electrochemical windows, high conductivity, and/or other desirable properties. This can be done through changes to the structure of the cation or anion, or through the presence of an additional solvent.

http://pubs.acs.org/doi/full/10.1021/acs.chemrev.5b00158