Flame-Retardant and Polysulfide-Suppressed Ether-Based Electrolytes for High-Temperature Li–S Batteries

Abstract

Lithium–sulfur (Li–S) batteries are drawing huge attention as attractive chemical power sources. However, traditional ether-based solvents (DME/DOL) suffer from safety issues at high temperatures and serious parasitic reactions occur between the Li metal anodes and soluble lithium polysulfides (LiPSs). Herein, we propose a polysulfide-suppressed and flame-retardant electrolyte operated at high temperatures by introducing an inert diluent 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl (TTE) into the high-concentration electrolyte (HCE). Li dendrites are also efficiently suppressed by the formed LiF-rich protective layer. Furthermore, the shuttle effect is mitigated by the decreased solubility of LiPSs. At 60 °C, Li–S batteries using this nonflammable ether-based electrolyte exhibit a high capacity of 666 mAh g–1 over 100 cycles at a current rate of 0.2C, showing the greatly improved high-temperature performance compared to batteries with traditional ether-based electrolytes. The improved electrochemical performance across a range of temperatures and the enhanced safety suggest that the electrolyte has a great practical prospect for safe Li–S batteries.

High-safety and high-efficiency electrolyte design for 4.6 V-class lithium-ion batteries with a non-solvating flame-retardant

“…As in previous reports, the drawbacks of high volatility and high flammability of ether and carbonate solvents can be overcome to a large degree owing to the much lower content of organic solvents in the high concentration electrolyte. 35,36 However, the flash point of E-TMP decreases significantly. It is likely that TMP will participate in the solvation structure of E-TMP, which will eventually lead to an increase in free DME molecules (Fig.…”

Advanced Nonflammable Organic Electrolyte Promises Safer Li‐Metal Batteries: From Solvation Structure Perspectives

“…In addition, when the H atoms in the solvent are substituted by the F atoms, the flammability of the organic solvents is also reduced. [74,75] As shown in [68] Copyright 2021, American Chemical Society. D) Reproduced with permission.…”

Thermal safety and thermal management of batteries

“…Due to the nonflammable nature of this electrolyte, the thermal risk is markedly reduced. Moreover, the solubility of LiPS is inhibited by reducing the activity of the solvent 91 …”