Electrical and thermal properties of the gel polymer electrolytes based on morpholinium ionic liquids

Abstract

Ionic liquids, defined as salts with melting temperatures below 100℃, evolved from traditional high temperature molten salts. They have many novel properties; high ionic conductivity, wide electrochemical windows, negligible volatility, non-flammability, high thermal stability, sub-ambient temperature operation. Prior to be applied to the industrially important processes such as the liquid - liquid extractions and absorption heat pump systems physical properties of [bmim][Br], [bmim][I], and [bmim][$BF_4$], and vapor pressures of binary systems for [bmim][Br] + water, [bmim][$BF_4$] + water, [hydemim][$BF_4$] + water, [bmim][Br] + 2,2,2 - trifluoroethanol (TFE), and [bmim][$BF_4$] + TFE were measured in order to secure the basic physical properties of ILs. And in secondary lithium battery solid state is preferred to liquid state from mechanical and fabrication standpoints. Solid state gel polymer electrolytes which have the properties of liquid were prepared using ionic liquids. The gel polymer electrolytes without propylene carbonate can be used as solid state electrolyte until 400℃. And those showed ionic conductivity $10^{-3}$ S/cm at 60℃. But the gel polymer electrolytes containing propylene carbonate only can be used until 60℃ but showed ionic conductivity $10^{-2}S/cm$ at 60℃.