Highly reversible cycling with Dendrite-Free lithium deposition enabled by robust SEI layer with low charge transfer activation energy

Abstract

Li dendrite growth and poor Coulombic efficiency still prevent the practical use of Li metal anodes. Here, we report a stable solid electrolyte interphase (SEI) layer consisting of Li3N and LiF by employing lithium nitrate (LiNO3) in carbonate electrolytes for the improved cycle performance with dendrite-free Li deposition for Li metal anodes. We demonstrate that the lower charge transfer activation energy is realized with the Li3N-rich SEI layer and LiF-rich SEI layer in carbonate electrolytes. With the Li3N and LiF composite SEI layer, outstanding improvements are achieved in that the very low charge transfer activation energy of 46.64 KJ mol−1 and stable electrochemical performances with dendrite-free Li deposition. With those benefits, the Li || Cu cell shows stable cyclability with high Coulombic efficiency of ∼ 97% at a current density of 0.5 mA cm−2 with a capacity of 0.5 mAh cm−2 over 200 cycles, and Li can be densely plated with lower porosity of 10.1 % with a plated Li of 2 mAh cm−2. Finally, the outstanding cyclability is demonstrated in full cells consisting of LiNi0.8Co0.1Mn0.1O2 as a cathode and thin Li metal electrode with a thickness of 20 μm in lean electrolytes of 8 μL mAh−1.