Suspended Lithium Nitrate‐Based Electrolytes: Electrostatic Interactions for Mutually Rewarding Interface Optimization Strategies

Designing a stable electrode-electrolyte interface (EEI) is critical for developing lithium metal batteries with high energy density, enhanced safety, and broad applicability. Lithium nitrate (LiNO₃) is an attractive sacrificial additive for lithium metal anode, while its poor solubility in high-voltage-resistant ester/nitrile electrolytes severely limits its utility. To solve it, a novel suspension electrolyte strategy is proposed that uniformly disperses LiNO₃ particles in an ester/nitrile mixed electrolyte to stabilize the electrode interface. The suspended LiNO₃ particles exhibit dual functionality: LiNO₃ enhances the compatibility between the electrode and the electrolyte by affecting the Li⁺ solvation environment and preferentially adsorb on the electrode surface; moreover, the in situ formed LiN_xO_y-rich EEI by LiNO₃ decomposition with accelerated Li⁺ transport kinetics, effectively suppresses parasitic reactions and improves rate performance. The optimized electrolyte makes Li||NCM523 battery run stably for 100 cycles with a high capacity retention of 90.05% at 60 °C and stably operated at low temperature (-10 °C). Moreover, the electrolyte shows excellent electrochemical stability at a high-voltage of 4.5 V. This work presents a dual-strategy advancement featuring wide-temperature electrolyte formulation and precision interface engineering, synergistically achieving high-specific-energy lithium metal batteries.