Intermolecular Interaction Adjustment for LiNO₃ Solubility Promotion toward High-Performance Li||NCM811 Batteries.

Abstract

Incorporating lithium nitrate (LiNO₃) as a film-forming additive into carbonate-based electrolytes presents a promising strategy to enhance the stability of high-energy-density Li||NCM811 batteries. However, the small size of Li⁺ and the high donor number (DN) of NO₃^- hinder the dissociation of LiNO₃, and its limited solubility (<800 ppm) in carbonate-based electrolytes poses significant challenges for practical application. To address this issue, we propose a "Small-Sized Carrier" strategy that enhances the solubility of LiNO₃ in carbonate solvents by modulating the intermolecular interactions within the solvent system. This approach employs vinylene carbonate (VC), a small molecule with moderate polarity, to enhance the dissolution of LiNO₃ without compromising the compatibility of the electrolyte with the lithium metal anode. The introduction of the "Small-Sized Carrier" additive system simultaneously enhances the stability of the electrode-electrolyte interfaces and optimizes the solvation structure of the electrolyte. As a result, the electrolyte developed through this strategy demonstrates outstanding electrochemical performance, with Li||NCM811 batteries achieving a capacity retention of 83.8% after 600 cycles. This work provides an insightful approach to designing advanced electrolytes tailored to high-energy-density lithium metal batteries (LMBs).