Fluorine-donating electrolytes enable highly reversible 5-V-class Li metal batteries
| Autor: | Steve Greenbaum, Weijiang Xue, Chao Wang, Ju Li, Wanlu Yang, Liumin Suo, Yangxing Li, Yuming Chen, Mallory Gobet |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
chemistry.chemical_element 02 engineering and technology Electrolyte Lithium 010402 general chemistry 01 natural sciences law.invention Metal Electrolytes Electric Power Supplies law Graphite Electrodes Multidisciplinary Photoelectron Spectroscopy Fluorine 021001 nanoscience & nanotechnology Cathode 0104 chemical sciences Anode chemistry Chemical engineering visual_art Physical Sciences visual_art.visual_art_medium Gravimetric analysis 0210 nano-technology Oxidation-Reduction Faraday efficiency |
| Zdroj: | Proceedings of the National Academy of Sciences. 115:1156-1161 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.1712895115 |
| Popis: | Lithium metal has gravimetric capacity ∼10× that of graphite which incentivizes rechargeable Li metal batteries (RLMB) development. A key factor that limits practical use of RLMB is morphological instability of Li metal anode upon electrodeposition, reflected by the uncontrolled area growth of solid–electrolyte interphase that traps cyclable Li, quantified by the Coulombic inefficiency (CI). Here we show that CI decreases approximately exponentially with increasing donatable fluorine concentration of the electrolyte. By using up to 7 m of Li bis(fluorosulfonyl)imide in fluoroethylene carbonate, where both the solvent and the salt donate F, we can significantly suppress anode porosity and improve the Coulombic efficiency to 99.64%. The electrolyte demonstrates excellent compatibility with 5-V LiNi0.5Mn1.5O4 cathode and Al current collector beyond 5 V. As a result, an RLMB full cell with only 1.4× excess lithium as the anode was demonstrated to cycle above 130 times, at industrially significant loading of 1.83 mAh/cm2 and 0.36 C. This is attributed to the formation of a protective LiF nanolayer, which has a wide bandgap, high surface energy, and small Burgers vector, making it ductile at room temperature and less likely to rupture in electrodeposition. |
| Databáze: | OpenAIRE |
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