Solvent-Free Electrolytes with Aqueous Solution-Like Conductivities
Wu Xu and
C. Austen Angell*
Aqueous solutions are generally assumed to be superior electrolytic
conductors because of the unique dielectric and fluid properties
of water. We show that their conductivities can be matched by
liquid electrolytes that contain no solvent. These are proton
transfer salts that are liquid at ambient temperature. The high
conductivities are due to the high fluidity and ionicity rather
than some sort of Grotthus mechanism, although in certain cases
a mobile proton population may make a non-negligible contribution.
The highest conductivities have been obtained when both cations
and anions contain protons. At 25°C, values of >150 millisiemens
per centimeter (mS cm
–1) appear possible; at 100°C,
470 mS cm
–1 has been measured. Because of the combination
of high ionicity and proton exchange kinetics with low vapor
pressure, the systems we describe also make excellent fuel cell
electrolytes.
* To whom correspondence should be addressed. E-mail: caa{at}asu.edu
