Lithium (Li) metal is one of the most promising anodes for next-generation energy storage systems. However, the Li dendrite formation and unstable solid-electrolyte interface (SEI) have hindered its further application. Lithium nitrate (LiNO₃) is extensively used as an effective electrolyte additive in ether-based electrolytes to improve the stability of lithium metal. Nevertheless, it is rarely utilized in carbonate electrolytes due to its low solubility. Here, a novel gel polymer electrolyte (GPE) consisting of poly(vinylidene fluoride) (PVDF), poly(methyl methacrylate) (PMMA), poly(ethylene oxide) (PEO) with LiNO₃ additive is proposed to solve this issue. In this GPE, polyether-based PEO serves as a matrix for dissolving LiNO₃ which can be decomposed into a fast Li-ion conductor (Li₃N) in conventional carbonate electrolytes to enhance the stability and Li⁺ conductivity of the SEI film. As a result, dendrite formation is effectively suppressed, and a significantly improved average Coulombic efficiency (CE) of 97.2% in Li-Cu cell is achieved. By using this novel GPE coupled with Li anode and LiNi_0.5Mn_0.3Co_0.2O₂ (NMC532), excellent capacity retention of 94.1% and high average CE of over 99.2% are obtained after 200 cycles at 0.5 C. This work presents fresh insight into practical modification strategies on high-voltage Li metal batteries.

锂（Li）金属是下一代储能系统最有希望的阳极之一。然而，锂枝晶的形成和不稳定的固体电解质界面（SEI）阻碍了其进一步的应用。硝酸锂（LiNO ₃）被广泛用作醚基电解质中的有效电解质添加剂，以提高锂金属的稳定性。然而，由于其低溶解度，它很少用于碳酸盐电解质中。在此，提出了一种由聚偏二氟乙烯（PVDF），聚甲基丙烯酸甲酯（PMMA），聚环氧乙烷（PEO）和LiNO ₃添加剂组成的新型凝胶聚合物电解质（GPE），以解决该问题。在该GPE中，基于聚醚的PEO用作溶解LiNO ₃的基质它可以分解成常规碳酸盐电解质中的快速锂离子导体（Li ₃ N），以增强SEI膜的稳定性和Li ⁺电导率。结果，有效地抑制了枝晶的形成，并且实现了Li-Cu电池中97.2％的平均库仑效率（CE）的显着提高。通过将这种新型GPE与Li阳极和LiNi _0.5 Mn _0.3 Co _0.2 O ₂（NMC532）结合使用，在0.5 C下循环200次后，可获得94.1％的出色容量保持率和99.2％的高平均CE。这项工作提供了新的见解。应用于高压锂金属电池的实际改装策略。