Lithium salts make batteries powerful but expensive. An ultralow-concentration electrolyte based on the lithium salt LiDFOB may be a more economical and more sustainable alternative. Cells using these electrolytes and conventional electrodes have been demonstrated to have high performance, as reported by a research team in the journal Angewandte Chemie International Edition. In addition, the electrolyte could facilitate both production and recycling of the batteries. Lithium-ion batteries (LIBs) provide power to smartphones and tablets, drive electric vehicles, and store electricity at power plants. The main components of most LIBs are lithium cobalt oxide (LCO) cathodes, graphite anodes, and liquid electrolytes that deliver mobile ions for the decoupled cathode and anode reactions. These electrolytes determine the properties of the interphase layer that forms on the electrodes and thus affect features such as battery cycling performance. However, commercial electrolytes are still mostly based on a system formulated more than 30 years ago: 1.0 to 1.2 mol/L lithium hexafluorophosphate (LiPF6) in carboxylic acid esters ("carbonate solvent"). Over the last 10 years, high-concentration electrolytes (> 3 mol/L) have been developed, increasing battery performance by favoring the formation of robust inorganic-dominated interphase layers. However, these electrolytes have high viscosity, poor wetting ability, and inferior conductivity. The large amounts of lithium salts required also make them very expensive, often a critical parameter for feasibility. To reduce costs, research has also begun into ultralow-concentration electrolytes (< 0.3 mol/L). The drawback for these has been that the battery cell decomposes more solvent than the few salt anions, which leads to an organic-dominated and less stable interphase layer. A team led by Jinliang Yuan, Lan Xia, and Xianyong Wu at Ningbo University (China) and the University of Puerto... |