Fluorinated Aromatic Diluent for High-Performance Lithium Metal Batteries |
| |
Authors: | Dong-Joo Yoo Sungyun Yang Prof. Ki Jae Kim Prof. Jang Wook Choi |
| |
Affiliation: | 1. School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 Republic of Korea;2. Department of Energy Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029 Republic of Korea |
| |
Abstract: | In lithium metal batteries, electrolytes containing a high concentration of salts have demonstrated promising cyclability, but their practicality with respect to the cost of materials is yet to be proved. Here we report a fluorinated aromatic compound, namely 1,2-difluorobenzene, for use as a diluent solvent in the electrolyte to realize the “high-concentration effect”. The low energy level of the lowest unoccupied molecular orbital (LUMO), weak binding affinity for lithium ions, and high fluorine-donating power of 1,2-difluorobenzene jointly give rise to the high-concentration effect at a bulk salt concentration near 2 m , while modifying the composition of the solid-electrolyte-interphase (SEI) layer to be rich in lithium fluoride (LiF). The employment of triple salts to prevent corrosion of the aluminum current collector further improves cycling performance. This study offers a design principle for achieving a local high-concentration effect with reasonably low bulk concentrations of salts. |
| |
Keywords: | dendrite growth fluorinated aromatic diluent electrolytes lithium metal batteries solid electrolyte interphase |
|
|