Interfacial Film Regulation and Electrochemical Performance Using Cyclopropane Sulphonic Amide Functionalized Electrolyte to Stabilize Lithium Metal Batteries with a LiNi0.8Mn0.1Co0.1O2 Cathode

Designing a reasonable functionalized electrolyte to regulate the interface properties of two electrodes is the most effective method to enhance the performance of high-capacity lithium metal batteries (LMBs). In this work, a functional electrolyte of 1% cyclopropane sulphonic amide (CPSA) dissolved in 1 mol L–1 lithium bis(fluorosulfonyl)imide, (LiFSI)/1,3-dioxolane (DOL), and 1,2-dimethoxyethane (DME) (DOL/DME = 1:1, by weight) is designed to stabilize the electrochemical performance of LMBs with a LiNi0.8Mn0.1Co0.1O2 (NCM811) cathode. In comparison with the LMBs without CPSA, after 180 cycles, the Coulomb efficiency and capacity retention of the batteries with CPSA additive increase from 56.14 and 62.03% to 99.29 and 82.39%, respectively. The electrochemical and spectroscopic characterization indicate that CPSA can consume HF to slow down the decomposition of lithium salt and take priority to react at the electrodes to form thin films with low impedance, so as to effectively improve the battery performance. These results reveal that the CPSA molecule is a promising interfacial film-forming additive in the application of LMBs with a high-nickel cathode.