Tsinghua-Berkeley Shenzhen Institute & Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China.
College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou, 310014, China.
Angew Chem Int Ed Engl. 2023 Apr 3;62(15):e202300966. doi: 10.1002/anie.202300966. Epub 2023 Mar 2.
High-voltage lithium metal batteries (LMBs) pose severe challenges for the matching of electrolytes with aggressive electrodes, especially at low temperatures. Here, we report a rational modification of the Li solvation structure to extend the voltage and temperature operating ranges of conventional electrolytes. Ion-ion and ion-dipole interactions as well as the electrochemical window of solvents were tailored to improve oxidation stability and de-solvation kinetics of the electrolyte. Meanwhile, robust and elastic B and F-rich interphases are formed on both electrodes. Such optimization enables Li||LiNi Mn O cells (90.2 % retention after 400 cycles) and Li||LiNi Co Mn O (NCM622) cells (74.0 % retention after 200 cycles) to cycle stably at an ultra-high voltage of 4.9 V. Moreover, NCM622 cells deliver a considerable capacity of 143.5 mAh g at -20 °C, showing great potential for practical uses. The proposed strategy sheds light on further optimization for high-voltage LMBs.
高压锂金属电池（LMBs）在匹配具有侵蚀性电极的电解质方面带来了严峻挑战，尤其是在低温环境下。在此，我们报告了一种对锂溶剂化结构的合理修饰方法，以扩大传统电解质的工作电压和温度范围。通过调整离子-离子和离子-偶极相互作用以及溶剂的电化学窗口，改善了电解质的氧化稳定性和去溶剂化动力学。同时，在两个电极上形成了坚固且有弹性的硼和氟富界面相。这种优化使 Li||LiNi Mn O 电池（循环 400 次后保持率为 90.2%）和 Li||LiNi Co Mn O（NCM622）电池（循环 200 次后保持率为 74.0%）能够在 4.9V 的超高电压下稳定循环。此外，NCM622 电池在-20°C 时可提供相当大的 143.5mAh·g-1 容量，显示出在实际应用中的巨大潜力。所提出的策略为高压 LMBs 的进一步优化提供了思路。
