A hybrid FeF<sub>2</sub>/PVDF protective layer for stable metallic lithium anode

Abstract

A FeF2/PVDF protective layer modified metallic lithium anode was prepared by coating a hybrid layer of ferrous fluoride (FeF2) and polyvinylidene fluoride (PVDF) on the surface of the lithium foil. The morphology of the electrode before and after cycling was characterized by scanning electron microscopy (SEM). The electrochemical properties of the modified metallic lithium anode were analyzed by the galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS) and rete test. Compared with the traditional lithium foil anode, the metallic lithium anode with protective layer has no lithium dendrite and “dead lithium” on the surface after cycling. Therefore, it shows good cyclic stability, and the voltage hysteresis between charge and discharge keeps steady at 20 mV after galvanostatic (1 mA/cm2) charge/discharge cycling for 360 h. A full battery using modified metallic lithium anode and lithium iron phosphate cathode into also exhibits excellent rate performance, whose discharge specific capacity can still reach 110 mAh/g at the current density of 3 C.