Non-flammable liquid electrolytes for safe batteries

Abstract

With continual increments in energy density gradually boosting the performance of rechargeable metal-ion (Li+, Na+, K+) batteries, their safe operation is of growing importance and needs to be considered during...

Glyme-based electrolytes: suitable solutions for next-generation lithium batteries

“…Despite DME is usually employed in Li-S battery due to the enhanced stability towards the lithium polysulfide intermediates formed by the conversion electrochemical process, the safety issues related to its relevant volatility and flammability are by now acknowledged, and the search for safer electrolyte solutions to achieve Li-S devices of practical interest is a deeply investigated topic. 33 Moreover, decrease of the electrolyte flashpoint may be achieved by using non-flammable co-solvents and flame retardant additives, such as phosphorous-containing (e.g., TMP, TEP, TPrP, TFEP) and fluorinated (e.g., FEMC, FEC, DFDEC, TTFE, PFPN) species, 34 or by functionalization of the glyme solvent. 35 Among the various strategies, solid electrolyte configurations may represent a viable strategy to increase the safety content of the battery due to enhanced chemical, thermal and mechanical stability.…”

“…, TMP, TEP, TPrP, and TFEP) and fluorinated ( e.g. , FEMC, FEC, DFDEC, TTFE, and PFPN) species, 34 or by functionalization of the glyme solvent. 35 Among the various approaches, solid electrolyte configurations may represent a viable strategy to increase the safety content of the battery due to enhanced chemical, thermal and mechanical stability.…”

Perspectives on Improving the Safety and Sustainability of High Voltage Lithium‐Ion Batteries Through the Electrolyte and Separator Region

“…There are two main mechanisms for inhibiting the combustion reaction in LEs. The first is by using gas-phase flame retardants, which scavenge the active agents of the combustion reaction (e.g., hydrogen radicals) in the gas phase and control the continuous combustion reactions (for example, with fluorinated or phosphorus-containing species [52,53] ). The second is by using condensed-phase flame retardants (such as alkyl phosphoruscontaining species), [54][55][56] which promote the formation of a carbonaceous layer on the substrate surface to slow heat and mass transfer with the gas phase.…”

“…[66,67] One example of this is shown in Figure 3b from Feng et al, where the addition of 12% pentafluoro(phenoxy)cyclotriphosphazene, FPPN, reduced the electrolyte flammability, as well as improving the overcharge behavior of the electrolyte, stabilizing it at 5.05 V versus Li/Li + and preventing electrolyte decomposition reactions from occurring. [63] However, despite these promising results, there are still some limitations to simply adding a flame retardant solvent to the LE to suppress the flammability, such as the poor anode passivation, [52,68,69] or that these flame retardant electrolytes still contain volatile and flammable solvents [68] and may be subject to combustion at high temperatures during abuse cases.…”

Fluorine‐Free Electrolytes for Lithium and Sodium Batteries

“…As an added bonus, the use of highly fluorinated solvents may also render the electrolyte nonflammable. [22] This increase in performance is perhaps most notable for Li metal cells, where the fluorinated solvents are beneficial for formation of a highly fluorinated, LiF-rich SEI. [19] High-rate stripping/plating can be done with higher stability and more longevity when 1-fluoroethylene carbonate (FEC) replaces EC as a co-solvent with dimethyl carbonate (DMC) in the electrolyte.…”