Fluoroethylene Carbonate Enabling a Robust LiF-rich Solid Electrolyte Interphase to Enhance the Stability of the MoS2 Anode for Lithium-Ion Storage.

As a high-capacity anode for lithium-ion batteries (LIBs), MoS2 suffers from short lifespan that is due in part to its unstable solid electrolyte interphase (SEI). The cycle life of MoS2 can be greatly extended by manipulating the SEI with a fluoroethylene carbonate (FEC) additive. The capacity of MoS2 in the electrolyte with 10 wt % FEC stabilizes at about 770 mAh g-1 for 200 cycles at 1 A g-1 , which far surpasses the FEC-free counterpart (ca. 40 mAh g-1 after 150 cycles). The presence of FEC enables a robust LiF-rich SEI that can effectively inhibit the continual electrolyte decomposition. A full cell with a LiNi0.5 Co0.3 Mn0.2 O2 cathode also gains improved performance in the FEC-containing electrolyte. These findings reveal the importance of controlling SEI formation on MoS2 toward promoted lithium storage, opening a new avenue for developing metal sulfides as high-capacity electrodes for LIBs.