Interfacial utilization of lithium nitrate in carbonate electrolytes for practical lithium metal batteries

Lithium metal is an attractive anode for high-energy-density rechargeable batteries because of its high theoretical specific capacity and low redox potential. Carbonate electrolytes remain important for practical cells because of their manufacturing compatibility, suitable ionic conductivity, and compatibility with high-voltage cathodes. Direct contact with Li metal, however, causes persistent interfacial side reactions. LiNO₃ is widely studied as an interphase-forming additive because nitrate reduction can generate protective inorganic components, yet its effectiveness in carbonate electrolytes depends on more than solubility. Here, interfacial nitrate utilization describes whether nitrate supplied by a LiNO₃-containing formulation reaches the active Li/electrolyte interface, undergoes productive conversion, and remains available or is replenished during cycling. The discussion follows a five-element framework: dissolution and storage; interfacial delivery and availability; preferential reduction and productive interphase formation; sustained nitrate supply and dynamic solid electrolyte interphase (SEI) repair; and cathode compatibility as the full-cell boundary condition. Increasing bulk LiNO₃ solubility alone does not ensure sustained protection. Future work should resolve the balance among nitrate supply, conversion, and consumption and validate nitrate-regulation strategies in full cells with thin Li, lean electrolyte, and high cathode areal capacity.