Solid–Liquid Coexisting LiNO 3 Electrolyte for Extremely Stable Lithium Metal Anodes on a Bare Cu Foil

Li dendrite growth restricts the promising application of lithium (Li) metal anodes in high-energy-density batteries. The host matrix, solid electrolyte, and surface modification of Li were widely studied to suppress Li dendrite growth. However, material preparation and process modification are complex and high-cost. Herein, a simple and effective solid–liquid coexisting lithium nitrate (SLC-LiNO 3 ) electrolyte was proposed, and excellent Li plating/stripping properties were obtained on a planar and bare Cu foil without a host matrix and surface modification. It is confirmed that a robust LiF-rich solid electrolyte interface (SEI) layer was formed in the SLC-LiNO 3 electrolyte and the Li + transference number was obviously enlarged due to the induced action of solid LiNO 3 particles. As a result, uniform Li deposition without uncontrollable Li dendrite growth was achieved. In the SLC-LiNO 3 electrolyte, a high coulombic efficiency (98% for 300 cycles) was obtained on a planar Cu foil and the stable Li plating/stripping cycling times were up to 2500 and 700 h (i.e., 1250 and 700 cycles) at 1 and 2 mA cm –2, respectively. This provides a promising and convenient method to suppress lithium dendrite growth in lithium metal batteries.