Enhanced Cycle Stability of Rechargeable Li–O₂ Batteries by the Synergy Effect of a LiF Protective Layer on the Li and DMTFA Additive

Li metal is an ideal anode for rechargeable Li–O 2 batteries because of its large theoretical capacity (3860 mAh g –1 ). However, problems with the growth of dendrites and reaction with electrolytes and moisture during cycling have prevented its practical application. Herein, we report that the use of a 2 wt % N, N -dimethyltrifluoroacetamide (DMTFA) additive in a dimethyl sulfoxide (DMSO) electrolyte with a LiF layer on the Li anode allows for good cycling performance in Li–O 2 batteries. Indeed, a Li–O 2 cell with a multiwalled carbon nanotube (MWCNT) cathode, 1.0 M LiNO 3 /DMTFA + DMSO (2:98 v/v) electrolyte, and a LiF layer on the Li anode could be cycled 92 times at a current density of 1000 mA g –1 with a 1000 mAh g –1 .