A New Glass Forming Electrolyte Based on Lithium Glycerolate

The study of the interplay between structure and conductivity in lithium-conducting electrolytes is a pivotal point for the development of future secondary lithium batteries. The use of Glycerol as low molecular weight component in electrolytes is particularly interesting due to its glass forming behaviour and low glass transition temperature (-78.5°C). In addition a high flexibility of the alkyl backbone chain and the well know capability of oxygen functionalities to coordinate lithium cations, make Glycerol very appealing as ion-conducting media as well as building block for obtaining hybrid polymer electrolytes [1]. Following this information, a group of eleven electrolytes based on Lithium Glycerolate, with formula C3H8-xO3Lix, where 0 < x < 1, is prepared and investigated. In these electrolytes the Glycerolate (C3H8-xO3x-) component acts as a large and flexible macro-anion which is able to provide a high single-ion conductivity to the material (8.36×10-5 @ 20°C and 1.55×10-2 S/cm @150°C for x=0.25). Finally the Glycerol---Li+ interactions in these electrolytes are studied on T and x with particular reference to the detection of: a) the cation and macro-anion coordination sites, and b) the secondary structure of Glycerol chains. Insights on the long-range charge transfer mechanism and Glycerol relaxations events are also discussed. These studies are carried out by Inductively-Coupled Plasma Atomic Emission Spectroscopy, IR and Raman spectroscopy, DSC, TGA and Broadband Electrical Spectroscopy. Reference [1] V. Di Noto et. al J. Phys. Chem. B, 108 (49), 2004, 18832–18844