The effect of AlF3 as an electrolyte additive on Li anode in Li-O2 batteries

Li metal is considered as an ideal anode for Li-O2 batteries because of its unbeatably theoretical specific capacity and low electrode potential. Unfortunately, the growth of Li dendritic and the sensitivity to electrolyte and O2 hinder the practical applications of Li anode. Herein, AlF3 as an electrolyte additive is firstly employed in a Li-O2 battery, which can boost the formation of LiF@Al-Li@Al2O3-rich SEI film via in-situ spontaneous reactions of AlF3 with Li anode in O2 atmosphere. The generated SEI film contributes to inducing the homogeneous nucleation of Li and reducing the disgusting side reactions, which can suppress the growth of Li dendrite and improve the cyclability of Li anode. Benefiting from the rational design, both the Li-O2 and the Li|Li symmetric batteries with AlF3 electrolyte exhibit low overpotential and good cycling stability. We hope this work could provide a facile way to in-situ construct a stable SEI film to alleviate the uneven Li nucleation for Li-O2 batteries.