Basic properties of glyme-based electrolytes doped with lithium 2,4,5-tricyanoimidazolide (LiTIM)

Abstract

The article presents the electrolyte's basic physicochemical and electrochemical properties based on the new type of lithium salt for lithium batteries - lithium 2,4,5-tricyanoimidazolide (LiTIM). Two series of the electrolytes in diethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether were obtained and their electrochemical properties were examined by means of impedance spectroscopy and cyclic voltammetry. Thermal and rheological properties of the electrolytes were tested with differential scanning calorimetry (DSC) and rheometric methods. Single crystal X-ray analysis was performed for LiTIM-crown ethers adducts used as models for solvent-separated and solvent-shared ionic species. Raman spectroscopy was used to obtain a more detailed insight into ionic interactions in the material. The electrochemical stability for the tetraglyme based electrolytes with a salt concentration higher than 0.4 M was 4.7 V vs Li. The high solubility of LiTIM in tetraglyme (up to 6.8 M) and the ability to form an amorphous, stable solution make the electrolyte an interesting candidate for advanced lithium batteries.