The multifunctional 2-Trifluoroacetyl furan electrolyte additive for suppressing lithium dendrite growth

Abstract

Constructing electrode-electrolyte interphase and enhancing wettability between separator and electrolyte are vital to electrochemical performances of Lithium-metal batteries, especially for suppressing the growth of Li dendrites. In this work, 2-Trifluoroacetyl furan is developed as the multifunctional additive to inhibit Li dendrite growth, and then enhance the cycling time and rate performance of Li||LiNi0.6Co0.2Mn0.2O2 (NCM622) cells. TFFE additive can enhance the Li ion flowing efficiency by improving wettability between separator and electrolyte and providing more channel of Li ions. Furthermore, TFFE can not only form solid electrolyte interphase (SEI) on the surface of Li anode, but also forms cathode electrolyte interphase (CEI) on the surface of NCM622 electrode. Finally, TFFE could stabilize the LiPF6-based electrolyte by removing hydrogen fluoride (HF) and H2O, protecting the generated SEI/CEI layer. As a result, introducing 1.0 wt% TFFE additive, the Li||Li symmetric cells could achieve stable cycling for 780 h at 0.5 mA cm−2, which is higher than that in baseline electrolyte (350 h). And, Li||NCM622 cells in the 1.0 wt% TFFE-contained electrolyte displays remarkably enhanced capacity of 90 % almost after 200 cycles.