Regulation of sei formation by anion receptors to achieve ultra-stable lithium metal battery

Abstract

Despite high specific capacity (3860 mAh g -1 ), the utilization of Li-metal anodes in rechargeable batteries are still hampered due to their insufficient cyclability. Herein, we report an anion-receptor-mediated carbonate electrolyte with improved performance and can ameliorate the solid electrolyte interphase (SEI) composition comparing to the blank electrolyte. It demonstrates a high average Coulombic efficiency (97.94%) over 500 cycles in the Li/Cu cell at a capacity of 1 mAh cm -2 . Raman spectrum and molecular modelling further clarify the screening effects of the anion receptor on the Li + -PF 6 - ion coupling that results in the enhanced ion dynamics. The X-ray photoelectron spectroscopy (XPS) distinguishes the disparities in the SEI components of the developed electrolyte and the blank one, which is rationalized by the molecular insights of the Li-metal/electrolyte interface. Thus, we prepare a 2.5 Ah prototype pouch cell, exhibiting a high energy density (357 Wh kg -1 ) with 90.90% capacity retention over 50 cycles.