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

Abstract

Lithium nitrate (LiNO3) is attracting attention as a promising additive for dendrite suppression owing to its formation of Li3N during electrochemical decomposition and the formation of a spherical-like Li deposition morphology. However, LiNO3 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 LiNO3 into the electrolyte during cycling, the formation of a Li3N-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 LiNO3 embedded protective layer has the potential to enhance the performance of thin Li metal anodes in Li metal batteries.