Markevich Elena, Salitra Gregory, Vestfrid Yulia, Afri Michal, Sriramulu Suresh, Sharratt Andrew, Venkataraman Karthik, Aurbach Doron
Department of Chemistry, Bar-Ilan University, Institute of Nano-Technology and Advanced Materials (BINA) and Israel National Institute for Energy Storage (INIES), Ramat Gan 5290002, Israel.
Orbia Fluor and Energy Materials, 950 Winter Street, Waltham, Massachusetts 02451, United States.
ACS Appl Mater Interfaces. 2024 Aug 21;16(33):43602-43616. doi: 10.1021/acsami.4c08870. Epub 2024 Aug 6.
The development of advanced liquid electrolytes for high-voltage/high-energy rechargeable Li metal batteries is an important strategy to attain an effective protective surface film on both the Li metal anode and the high-voltage composite cathode. Herein, we report a study of two CF-substituted ethylene carbonates as components of the electrolyte solutions for Li metal|NCM811 cells. We evaluated trifluoromethyl ethylene carbonate (CF-EC) and trans-ditrifluoromethylethylene carbonate Di-(CF)-EC as cosolvents and additives to the electrolyte solutions. Using CF-substituted ethylene carbonates as additives to a fluoroethylene carbonate (FEC)-based electrolyte solution enables improved capacity retention of high-power Li metal|NCM811 cells. The composition of the products from the transformations of CF-EC and Di-(CF)-EC in Li|NCM811 cells was studied by FTIR, XPS, and F NMR spectroscopy. We concluded that fluorinated Li alkyl carbonates are the main reaction products formed from these cyclic carbonates during the cycling of Li|NCM 811 cells, and fragmentation of the ring with the formation of CO, CO, or olefins is not characteristic of CF-substituted ethylene carbonates. The NCM 811 cathodes and Li metal anodes were characterized by X-ray diffraction, SEM, XPS, and FTIR spectroscopy. The role of CF-substituted ethylene carbonate additives in stabilizing high energy density secondary batteries based on Li metal anodes was discussed. A bright horizon for developing sustainable rechargeable batteries with the highest possible energy density is demonstrated.
开发用于高压/高能可充电锂金属电池的先进液体电解质是在锂金属阳极和高压复合阴极上均获得有效保护表面膜的重要策略。在此，我们报道了对两种含CF取代的碳酸亚乙酯作为锂金属|NCM811电池电解质溶液成分的研究。我们评估了三氟甲基碳酸亚乙酯（CF-EC）和反式二氟甲基碳酸亚乙酯Di-(CF)-EC作为电解质溶液的共溶剂和添加剂。使用含CF取代的碳酸亚乙酯作为添加剂添加到基于氟代碳酸亚乙酯（FEC）的电解质溶液中，可提高高功率锂金属|NCM811电池的容量保持率。通过傅里叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）和氟核磁共振光谱（F NMR）研究了Li|NCM811电池中CF-EC和Di-(CF)-EC转化产物的组成。我们得出结论，氟化锂烷基碳酸酯是Li|NCM 811电池循环过程中由这些环状碳酸酯形成的主要反应产物，并且环的断裂形成CO、CO或烯烃不是含CF取代的碳酸亚乙酯的特征。通过X射线衍射、扫描电子显微镜、XPS和FTIR光谱对NCM 811阴极和锂金属阳极进行了表征。讨论了含CF取代的碳酸亚乙酯添加剂在稳定基于锂金属阳极的高能量密度二次电池中的作用。展示了开发具有尽可能高能量密度的可持续可充电电池的光明前景。
