A tetraethylene glycol dimethylether-lithium bis(oxalate)borate (TEGDME-LiBOB) electrolyte for advanced lithium ion batteries

Abstract

Tetraethylene glycol dimethylether-lithium bis(oxalate)borate (TEGDME-LiBOB) electrolyte is here studied. Electrochemical impedance spectroscopy (EIS) measurements demonstrate that the electrolyte has conductivity higher than 10(-3) S cm(-1) at room temperature and about 10(-2) S cm(-1) at 60 degrees C, while thermogravimetry indicates a stability extending up to 180 degrees C. Sweep voltammetry of the electrolyte shows anodic stability extending over 4.6 V vs. Li and cathodic peak at about 1.5 V vs. Li/Li+, caused by a decomposition of LiBOB salt, and following prevented by using a pre-treated Sn-C anode. Furthermore, LiFePO4 electrode is successfully used as cathode in a lithium cell using the TEGDME-LiBOB electrolyte. The promising electrochemical results, the low cost and the very high safety level candidate the electrolyte here reported as a valid alternative to the conventional electrolyte based on fluorinated salts presently used in the lithium ion battery field.