Physicochemical and Electrochemical Properties of 1,1,2,2‐Tetrafluoroethyl‐2,2,3,3‐Tetrafluoropropyl Ether as a Co‐Solvent for High‐Voltage Lithium‐Ion Electrolytes

Abstract

Although high-voltage positive electrode materials for high energy density lithium-ion batteries have gained a great attention, the lack of compatible electrolytes with sufficiently high oxidative stability to deliver an excellent cycling ability restricts their practical application. Fluorinated solvents are considered as promising candidates for high-voltage electrolyte solvents. In this study, we select 1,1,2,2-tetrafluoroethyl-2,2,3,3tetrafluoropropyl ether (TTE) with a high boiling point, low cost, and good SEI-filming ability as a co-solvent of fluoroethylene carbonate-based electrolytes and extensively investigate its physicochemical and electrochemical properties for applications in high-voltage lithium-ion batteries. Our experimental results show that the TTE-containing electrolyte exhibits not only a high oxidative stability up to 5.5 V (vs. Li/Li + ), but also excellent wettability with the separator. In addition to high discharge capacity and increased coulombic efficiency of the Li/ LiNi 0.5 Mn 1.5 O 4 half-cell assembled with the TTE-containing electrolyte cycled between 3.0 and 4.9 V, the cell also displays a high rate capability. This work shows that partially fluorinated ethers, e. g., TTE, are promising co-solvents for high-voltage electrolytes that can enable commercial development of high energy density lithium-ion batteries.[a] Dr.

Investigation of fluorinated ether‐containing electrolytes for high energy‐density nickel‐rich LiNi 0 . 8 Co 0 . 1 Mn 0 . 1Xia1, Miao2, Wang3 et al. 2021Int J Energy ResSelf Cite5010View full textAdd to dashboardCite

“…However, the FEC‐EMC electrolyte solution suffers from the oxidative decomposition around 5.0 V vs Li/Li + . When the fluorinated ether, HFPM or TTE, being added into the FEC‐EMC electrolyte solution, the oxidation potential of both FEC‐EMC‐HFPM and FEC‐EMC‐TTE electrolyte solutions increases to 5.5 V vs Li/Li + , which is in accordance with the DFT calculation results and our previous literature's reports 33,34 . On the cathodic scan, the electrochemical reduction of the FEC‐EMC‐TTE electrolyte starts at 3.5 V, which is prior to that of the FEC‐EMC‐HFPM electrolyte.…”

“…Pham et al achieved the maximum capacity (>230 mAh g −1 ) and good capacity retention (95% after 100 cycles) of NCM811 electrodes with charging to 4.5 V in a non‐flammable electrolyte with propylene carbonate (PC) and fluorinated linear carbonates 31 . In our previous work, 33,34 we found that the partially fluorinated ethers, such as 1,1,1,3,3,3‐hexafluoroisopropyl methyl ether (HFPM) and 1,1,2,2‐ tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether (TTE), as a co‐solvent of fluoroethylene carbonate (FEC)‐based electrolytes, demonstrated not only a good cycle stability in high‐voltage LNMO electrodes but also a good wettability with the separator. Here, we investigate these fluorinated ethers including TTE and HFPM as a co‐solvent for FEC‐based electrolytes to decrease electrolyte oxidative decomposition during NCM811 cycling process.…”

Low-Concentrated Lithium Hexafluorophosphate Ternary-based Electrolyte for a Reliable and Safe NMC/Graphite Lithium-Ion Battery

“…Hence, although in small quantities, the lithium ions adequately adhere in the vicinity of the graphite and NMC interfaces, attributed to the ability of TFE to maintain a high concentration gradient due to its high polarizability and low electronegativity (Scheme ). , …”

Fluorinated Ether‐Based Electrolyte for Supercapacitors with Increased Working Voltage and Suppressed Self‐discharge

“…Recently, fluorine-containing solvent such as 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), has been proposed as a co-solvent for the electrolytes of high-voltage lithium-ion batteries. [44] TTE-containing electrolytes exhibit a high oxidative stability up to 5.5 V because of the high electronegativity and low polarizability of fluorine atoms in TTE so the electrochemical oxidation of fluorinated solvents is difficult. In addition, a few studies have also been reported for using fluorine-containing solvents in electrolytes of batteries to reduce their self-discharge.…”