Fuel Cells

Thermophysical Properties and Proton Transport Mechanisms of Trialkylammonium and 1-Alkyl-1H-imidazol-3-ium Protic Ionic Liquids

“…Lee et al reported the melting point of [HN 1 2 2 ][OTf] to be −6 °C . Yoshizawa-Fujita and Ohno reported the melting temperatures of [HN 1 2 2 ][OMs], [HN 1 2 2 ][OTf], and [HN 2 2 2 ][OMs] to be 10.6, −13.1, and 17.4 °C, respectively . The lower melting temperatures observed in these previous studies could be due to acid, base, or water impurities in the PIL samples.…”

Unexpected Energy Applications of Ionic Liquids

“…Thus, while there are not many neat ZIs that are liquid at room temperature—that requires very delocalized positive and negative charges—there are many possible ZI/Li salt combinations that melt below room temperature. [ 142,144 ] Furthermore, in the same way that the advantageous transport properties of other high salt content electrolytes has been recognized in recent years, [ 145 ] these high salt content ZI mixtures exhibit promising conductivities and transference numbers. Thus, there is substantial scope for the development of ZI‐based electrolytes, through new cationic and anionic groups, exploration of different salt combinations (for example, using sodium salts), and their incorporation into gel or polymer electrolytes.…”

“…Of course, the concept of zwitterions (ZIs or “inner salts”) is not new, and indeed zwitterionic liquids have been pioneered by the Yoshizawa‐Fujita and Ohno group for over two decades. [ 142 ] Nevertheless, on the back of advances in zwitterion‐based electrolytes for lithium and sodium batteries—in both liquid and solid form—it is worth highlighting this intriguing class of material. Much of the impetus behind the development of ZI‐based electrolytes is that as the cationic and anionic species are covalently tethered, the ZI will not migrate in an electric field (i.e., during battery operation) and thus should not compete with the transport of the target ions, such as Li + and Na + , resulting in a high transference number.…”

“…Zwitterions are highly polar and thus have mostly been used as additives to enhance target ion dissociation or electrochemical stability in polymer electrolytes, [ 142 ] and more recently polymeric zwitterions with excellent properties have been reported. [ 143 ] Nevertheless, as for ILs, there is great scope in the design of ZI structures through the type and size of the cationic and anionic species and the linker length, and thus the physical and thermal properties (e.g.…”