| In this dissertation, the design, synthesis and characterization of several different types of new materials with high ionic conductivity are described. These new materials include Lewis acid-lithium salt complexes, new polymer electrolytes, mixed alkali halides and anhydrous proton conductors.; Highly conductive materials were obtained by complex formation between lithium salts, such as CF3SO3Li, and Lewis acids, such as AlCl3 and NbF5. A room temperature ionic liquid containing the lithium cation was discovered in the CF3SO3Li-AlCl 3 system. This ionic liquid exhibits room temperature Conductivity higher than 10--3 S/cm.; New polymer electrolytes containing rigid polymers were synthesized and characterized. These novel polymer electrolytes exhibit high conductivity and good mechanical properties. The best conductivity, 10--4 S/cm at room temperature, was observed for the poly(1,3-dioxolan-2-one-4,5-(diyl oxalate)-LiCF3SO3 system. Many properties of these new polymer electrolytes are significantly different from traditional polymer electrolytes. Addition of salt usually softens these new polymer systems instead of stiffening the polymers as in conventional polymer electrolytes. Unlike traditional polymer electrolytes, where conductivity predominates in amorphous phases, these new polymer electrolytes exhibit conductivity in both crystalline and amorphous phases. These properties indicate that the ion conduction mechanism in these rigid polymer electrolytes is different from that in the conventional polymer electrolytes.; Solid electrolytes with high ionic conductivity were discovered in the LiI-MI systems, where M is K, Rb or Cs. The highest conductivity was observed with the LiI-RbI system. For example, Li2Rb3I5 exhibits a conductivity of 1.2 x 10--2 S/cm at 65°C. The conductive phases change to resistive phases at lower temperatures.; Solid anhydrous proton conductors, with room temperature conductivity higher than 10--3 S/cm, were discovered in the mixtures of hydrogen sulfate and sulfate salts. These materials include Li2SO 4-LiHSO4, BeSO4-Be(HSO4)2 and Al2(SO4)3-Al(HSO4)3. |
