Incorporation of Embedded Protective Layers to Circumvent the Low LiNO₃Solubility Problem and Enhance Li Metal Anode Cycling Performance

Lithium nitrate (LiNO 3 ) is attracting attention as a promising additive for dendrite suppression owing to its formation of Li 3 N during electrochemical decomposition and the formation of a spherical-like Li deposition morphology. However, LiNO 3 has very low solubility in carbonate electrolytes, and it is continuously decomposed during cycling; thus, we infuse it into a ceramic composite protective layer coated on a thin Li metal surface (thickness: 20 μm) to act as a reservoir during battery cycling. This allows for a slow release of LiNO 3 into the electrolyte during cycling, the formation of a Li 3 N-infused solid electrolyte interface layer, and dendrite suppression. Here, this results in enhanced Li/Li symmetric cell cycling performance for ∼345 h at 0.5 mA cm –2 (0.25 mAh cm –2 ) and ∼250 cycles, with ∼96% initial discharge capacity retention and ∼99% Coulombic efficiency for Li/LMO cells. Because of the facile nature and effectiveness of the process, the LiNO 3 embedded protective layer has the potential to enhance the performance of thin Li metal anodes in Li metal batteries.