Lithium nitrate regulated carbonate electrolytes for practical Li-metal batteries: Mechanisms, principles and strategies

Li-metal batteries (LMBs) regain research prominence owing to the ever-increasing high-energy requirements. Commercially available carbonate electrolytes exhibit unfavourable parasitic reactions with Li-metal anode (LMA), leading to the formation of unstable solid electrolyte interphase (SEI) and the breed of Li dendrites/dead Li. Significantly, lithium nitrate (LiNO3), an excellent film-forming additive, proves crucial to construct a robust Li3N/Li2O/LixNOy-rich SEI after combining with ether-based electrolytes. Thus, the given challenge leads to natural ideas which suggest the incorporation of LiNO3 into commercial carbonate for practical LMBs. Regrettably, LiNO3 demonstrates limited solubility (∼800 ppm) in commercial carbonate electrolytes. Thence, developing stable SEI and dendrite-free LMA with the incorporation of LiNO3 into carbonate electrolytes is an efficacious strategy to realize robust LMBs via a scalable and cost-effective route. Therefore, this review unravels the grievances between LMA, LiNO3 and carbonate electrolytes, and enables a comprehensive analysis of LMA stabilizing mechanism with LiNO3, dissolution principle of LiNO3 in carbonate electrolytes, and LiNO3 introduction strategies. This review converges attention on a point that the LiNO3-introduction into commercial carbonate electrolytes is an imperious choice to realize practical LMBs with commercial 4 V layered cathode.