The synergistic effect of lithium bis(fluorosulfonyl)imide and lithium nitrate for high-performance lithium metal anode

Abstract Commercialization of the LMBs is subject to two formidable technical challenges, the instability of Li metal against all the organic solvents, and the short circuit caused by the dendritic lithium deposits. Lithium Bis(fluorosulfonyl)imide salt has exhibited an impressive performance for lithium-dendrite suppression and cycling efficiency improving at low current densities. Here, we use LiNO3 as the film-forming additive for further passivation of the Li metal anodes. Following the addition of LiNO3, the cycling performance of the cells with 2.5 M LiFSI-0.75 M LiNO3/DOL as electrolyte at high currents is improved obviously. The symmetrical lithium–metal cells can be cycled for 1000 cycles with more than 1000 h at 5 mA cm−2 with a stripping/plating capacity of 2 mAh cm−2. Moreover, the Li/Cu cell could be cycled for 400 cycles with a stable and high average Coulombic efficiency (CE) of 98.8% at 3 mA cm−2 with a capacity of 2 mAh cm−2. Besides, the electrolyte contains an well adaptability to the electrode of LiFePO4 and improves the cycling stability of the lithium metal. Consequently, LiNO3 demonstrates an excellent performance as a film-forming additive in the LiFSI/DOL electrolyte for further passivation of the Li metal anodes.