Abstract:

Lithium metal batteries are considered to be a favorable choice for high energy density batteries due to its high theoretical compared capacity. However, the interface instability has always been the biggest challenge for the commercial development of lithium metal batteries. The evolution mechanism of the thermal field is a key factor affecting the cyclic life during the evolution of lithium metal interfaces. Here, the heat distribution evolution mechanism of the lithium metal anode interface is revealed and quantified through the solid electrolyte interface (SEI) heat distribution evolution model. The three influencing factors are as follows: the ratio of SEI to the diffusion capacity of electrolytes, the electrolyte properties, the anisotropy in the SEI. The results show that the maximum temperature gradient at an appropriate proportion is relatively small. The concentration of the electrolyte affects the performance of the electrolyte, which will affect the thermal distribution of the lithium metal anode interface. The SEI anisotropy can induce lateral growth of lithium dendrites, which is conducive to uniform distribution of interfacial heat. This work provides certain theoretical guidance for the interface design of lithium metal batteries.

Key words: lithium metal anode, thermal distribution, SEI, lithium dendrites

摘要：

锂金属电池由于极高的理论比容量而被认为是高能量密度电池的有利选择。然而界面不稳定性一直是锂金属电池商业化发展的最大挑战，热场演化机制是锂金属界面演化过程中影响电池循环寿命的关键因素。通过固体电解质界面（SEI）热分布演化模型揭示并量化了锂金属负极界面热量分布演化机制，3个影响因素是SEI与电解液扩散能力的比率、电解液性能和赋予SEI各向异性。结果表明，在适当的比例下界面处最大温度梯度相对较小；电解液浓度影响电解液的性能，进而影响锂金属负极界面的热量分布；赋予SEI各向异性可以诱导锂枝晶横向生长，有利于界面热量的均匀分布。这项工作可为锂金属电池的界面设计提供一定的理论指导。

关键词: 锂金属负极, 热分布, SEI, 锂枝晶