Zwitterion-Containing Ionogel Electrolytes
liquids (ILs) are promising next-generation electrolytes featuring negligible vapour
pressures, high thermal and electrochemical stability, and high ionic conductivities.
Supporting ILs with a polymer matrix to form solid-state ionogels can yield safer
electrolytes that prevent IL leakage. It is presently accepted that some fraction of the
ions comprising an IL are not fully ... read moredissociated, and thus unable to migrate freely in an
electric field. In this work, zwitterions were used to promote ion pair dissociation in
a well-studied hydrophobic IL with the goal of obtaining a novel class of ionogels.
Zwitterion-containing ionogels were successfully synthesised using two different
zwitterionic molecules, one of which was polymerisable. Compression testing led to
observations of increased elastic moduli with increasing zwitterionic content,
indicating the presence of ordered zwitterionic domains. The non-polymerisable
zwitterion-containing ionogels exhibited tunable mechanical properties and moderate
ionic conductivities; the polymerised zwitterion-containing ionogels displayed even more
promising results. Remarkably, increasing zwitterion concentration for fixed total
polymer content resulted in nearly equivalent ionic conductivity in spite of increased
elastic modulus. Evidence for enhanced ion dissociation due to strong charge-dipole
interactions between the IL ions and zwitterionic molecules was observed. Cyclic
voltammetry testing showed that the electrochemical stability of the
zwitterion-containing ionogels was essentially unchanged from that of the neat IL.
Additionally, zwitterion-containing ionogels exhibited high thermal stability, up to 310
Thesis (M.S.)--Tufts University, 2016.
Submitted to the Dept. of Chemical and Biological Engineering.
Advisor: Matthew Panzer.
Committee: Ayse Asatekin, and Iryna Zenyuk.
Keywords: Chemical engineering, and Energy.read less