| ¹H NMR (600 MHz, CDCl₃) | δ=5.85 (tt, J=55.5, 4.2 Hz, 1H; CF2H), 3.70–3.65 (m, 4H; CH2), 3.52–3.51 (m, 2H; CH2), 3.35 (s, 3H; CH3) |
|---|---|
| ¹³C NMR (150 MHz, CDCl₃) | δ=114.68 (t, J=241.4 Hz; CF2H), 71.94, 71.55, 70.72 (t, J=27.2 Hz; CH2), 59.14 |
| ¹⁹F NMR (282 MHz, CDCl₃) | δ=−126.97 (s, 2F; CF2H) |
| HRMS (GC–CI+) | m/z calcd for C₅H₉F₂O₂⁺: 139.0571 [M−H]⁺; found: 139.0570 |
Dongmin Park, Kyunam Lee, June Lee, Jisub Kim, Jihoon Oh, Insu Hwang, Sujin Kim, Inwoo Kim, Minkwan Kim, Ali Coskun, Jang Wook Choi. “Local acidity as a corrosiveness descriptor of fluorinated ether solvents in lithium metal batteries.” ChemRxiv (). https://doi.org/10.26434/chemrxiv.15003809/v2
| ¹H NMR (600 MHz, CDCl₃) | δ=5.94 (tt, J=53.4, 5.4 Hz, 1H; CF2H), 3.90–3.85 (m, 2H; OCH2CF2), 3.72–3.71 (m, 2H; CH2), 3.56–3.52 (m, 2H; CH2), 3.36 (s, 3H; CH3) |
|---|---|
| ¹³C NMR (150 MHz, CDCl₃) | δ=115.29 (tt, J=247.5, 25.5 Hz; CF2H), 109.32 (t, J=247.5 Hz; CF2), 72.02, 71.94, 68.51 (t, J=28.5 Hz; CH2), 59.19 |
| ¹⁹F NMR (282 MHz, CDCl₃) | δ=−127.49 (m, 2F; CF2H), −142.12 (m, 2F; CF2) |
| HRMS (GC–CI+) | m/z calcd for C₆H₁₁F₄O₂⁺: 191.0695 [M+H]⁺; found: 191.0693 |
| ¹H NMR (600 MHz, CDCl₃) | δ=3.96 (m, 2H; CH2CF2), 3.74 (m, 2H; CH2), 3.54 (m, 2H; CH2), 3.35 (s, 3H; CH3) |
|---|---|
| ¹³C NMR (150 MHz, CDCl₃) | δ=119.1 (qt, J=285.0, 35.0 Hz; CF3), 113.5 (tq, J=247.5, 37.5 Hz; CF2), 72.35, 72.12, 68.11 (t, J=25.5 Hz; OCH2), 59.17 (CH3) |
| ¹⁹F NMR (282 MHz, CDCl₃) | δ=−85.75 (s, 3F; CF3), −126.95 (s, 2F; CF2) |
| HRMS (GC–CI+) | m/z calcd for C₆H₁₀F₅O₂⁺: 209.0595 [M+H]⁺; found: 209.0606 |
| ¹H NMR (300 MHz, D₂O) | δ=3.99 (td, J=16.5, 1.5 Hz, 2H; OCH2CF2) |
|---|---|
| ¹³C NMR (150 MHz, D₂O) | δ=119.20 (q, J=288.0 Hz; CF3), 115.59 (t, J=251.6 Hz; CF2), 60.56 (t, J=22.5 Hz; OCH2) |
| ¹⁹F NMR (282 MHz, D₂O) | δ=−85.30 (s, 3F; CF3), −127.31 (s, 2F; CF2) |
| ⁷Li NMR (116.6 MHz, D₂O) | δ=0.11 (s) |
| HRMS (GC–CI+) | m/z calcd for C₃H₄F₅O⁺: 151.0182 [M−Li+2H]⁺; found: 151.0183 |
| GC-CI-MS | m/z 151, 131, and 111 |
|---|---|
| ¹³C NMR | Signals in the CF2/CF3 region (122–114 ppm) and a CH2 signal at 60.3–60.5 ppm; additional resonance at 168.3 ppm |
| ¹⁹F NMR | Peaks at −85.3 ppm (CF3) and −127.3 ppm (CF2) |
| ATR-FTIR | Strong C–O stretching band at 1413 cm⁻¹ and carbonate bending band at 860 cm⁻¹ |
| Ionic conductivity (room temperature) | 10.65 mS cm⁻¹ |
|---|---|
| Raman spectroscopy, FSI− symmetric stretching band near 719–760 cm⁻¹ | CIP-dominant solvation structure |
| SEM after the 5th Li plating at 1 mA cm⁻² and 1 mAh cm⁻² | relatively less compact Li deposits; thickness 5.80 μm |
| Ionic conductivity (room temperature) | 5.26 mS cm⁻¹ |
|---|---|
| Raman spectroscopy, FSI− symmetric stretching band near 719–760 cm⁻¹ | solvation structure only partially shifted toward AGG formation |
| SEM after the 5th Li plating at 1 mA cm⁻² and 1 mAh cm⁻² | relatively less compact Li deposits; thickness 5.99 μm |
| Ionic conductivity (room temperature) | 3.83 mS cm⁻¹ |
|---|---|
| Raman spectroscopy, FSI− symmetric stretching band near 719–760 cm⁻¹ | higher AGG fraction |
| SEM after the 5th Li plating at 1 mA cm⁻² and 1 mAh cm⁻² | dense and compact Li deposits; minimum thickness 4.62 μm |
| Ionic conductivity (room temperature) | 1.53 mS cm⁻¹ |
|---|---|
| Raman spectroscopy, FSI− symmetric stretching band near 719–760 cm⁻¹ | higher AGG fraction |
| SEM after the 5th Li plating at 1 mA cm⁻² and 1 mAh cm⁻² | less compact Li deposits; thickness 5.77 μm |
| F 1s XPS depth profiles | LiF (~685 eV) and an S–F/C–F component (~688 eV) |
|---|---|
| S 2p XPS depth profile, F4MEP | enhanced SO2F-related component throughout the depth |
| O 1s XPS, F4MEP and F5MEP | intensity of the SOx peak of F4MEP exceeded that of F5MEP |
| Electrochemical impedance spectroscopy after two Li plating/stripping cycles at 0.1 mA cm⁻² and 1 mAh cm⁻² | bulk resistance increased with the degree of fluorination; interfacial resistance was lowest for F4MEP and highest for F5MEP |
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