A novel mixture of diethylene glycol diethylether and non-flammable methyl-nonafluorobutyl ether as a safe electrolyte for lithium ion batteries

Abstract

A mixture of diethylene glycol diethylether and non-flammable methyl-nonafluorobutyl ether was introduced as a new electrolyte for lithium ion batteries. And a fluoroethylene carbonate additive was used in this electrolyte to improve the compatibility with the graphite anode. The non-flammability and high flash point of this electrolyte indicated its high safety. This electrolyte had low viscosity and its conductivity reached 3.8 mS cm À1 at 25 C. Graphite/LiFePO 4 coin cells with commercial electrodes were utilized to evaluate the performances of the electrolyte. The rate, cycle and low-temperature performances of the graphite/LiFePO 4 cells using this electrolyte were close to those of the cells using the conventional electrolytes with and without the fluoroethylene carbonate additive. These results indicated that this kind of safe electrolyte based on non-flammable hydrofluoroethers and solvents with a high flash point has great potential for practical application. Fig. 7 (a) Discharge capacity continuously cycled at different rates, (b) the corresponding charge-discharge curves of the 0.8 M LiTFSI-G2E/ MFE/FEC electrolyte, and (c) EIS plots after 3 cycles at 0.1C. J. Mater. Chem. A This journal is

Transport and Association of Ions in Lithium Battery Electrolytes Based on Glycol Ether Mixed with Halogen-Free Orthoborate Ionic Liquid

“…An appropriate organic solvent is critically important not only for the dissolution of lithium orthoborate salt but also for oxidative stability, thermally stability, satisfactory conductivity, cell performance and life cycle 28 .Ether based organic solvents (also known as glymes) are gaining attentions in lithium ion batteries due to a number of advantages such as low viscosity, high thermal stability and safety 29 , 30 . Recently, a number of studies have demonstrated that mixtures of ionic liquids and glymes possess excellent electrolyte properties and are promising solvents for lithium-ion batteries 31 – 35 .…”

Non-flammable liquid electrolytes for safe batteries

“…Later, Fang et al developed a non-flammable electrolyte containing the aforementioned MFE as a co-solvent. 43 In their work LiFePO 4 //graphite full cells with 0.8 M LiTFSI in diethylene glycol diethyl ether (G2E), MFE and FEC (50 : 45 : 5 wt%) showed promising electrochemical performance close to cells with conventional electrolytes (1.0 M LiPF 6 -EC : DMC : DEC) at room temperature, but even at elevated and low temperatures. The capacity retention at À20 1C was about 46% after 200 cycles (62 mA h g À1 ).…”

Reversible Copper Sulfide Conversion in Nonflammable Trimethyl Phosphate Electrolytes for Safe Sodium‐Ion Batteries

“…[ 21 ] Consequently, it is very important to develop safe, nonflammable liquid electrolytes with comparable ionic conductivity and interfacial resistance as obtained for the current organic carbonate electrolytes. As reported in the literature, fluoroethers, [ 22 ] fluorophosphite, [ 23 ] and organosilicon compounds [ 24 ] have been investigated as nonflammable solvents for LIBs. Moreover, the low‐molecular‐weight phosphate‐based solvents with high solubility of Li and Na salts are particularly promising as they could enable an ionic conductivity comparable to that of carbonate‐based electrolytes.…”