Fluorine-Free Lithium Metal Batteries with a Stable LiF-Free Solid Electrolyte Interphase

Abstract

Lithium fluoride (LiF), generated by the decomposition of fluoride in lithium metal batteries (LMBs), is considered an essential component for stabilizing metallic Li. However, the substantial introduction of fluorine in batteries raises potential environmental concerns. In this study, we designed a fluorine-free LMB by integrating a fluorine-free electrolyte and a fluorine-free binder to construct a B/O/N hybrid solid electrolyte interphase (SEI) capable of providing good stability and fast Li+ transport ability. At a test temperature of 60 °C, the LiF-free SEI can achieve a highly reversible Li plating/stripping efficiency, with a Coulombic efficiency of 98.8% under conditions of 3 mA cm–2 and 3 mAh cm–2. Furthermore, the F-free LMB battery exhibits a rapid charging/discharging rate of 100 C with a capacity exceeding 80 mAh g–1 and demonstrates stable cycling performance over 500 cycles at 50 C. The fast-charging capability was further verified in practical Li–LiFePO4 full cells.