基于相场法的固态电解质内锂枝晶生长的形貌调控及抑制策略  

Morphology Control and Suppression of Lithium Dendrite Growth in Solid-State Electrolytes Based on Phase-Field Simulation

作　　者：杨佳悦 赵莹[1] YANG Jiayue;ZHAO Ying(School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai 200092,P.R.China)

机构地区：[1]同济大学航空航天与力学学院,上海200092

出　　处：《应用数学和力学》2025年第3期324-339,共16页Applied Mathematics and Mechanics

基　　金：国家自然科学基金青年科学基金(12102305)。

摘　　要：传统液态电解质的易燃易爆性带来的安全隐患,推动了基于固态电解质系统的全固态锂电池开发.然而,锂枝晶生长问题仍然是阻碍固态锂电池商业化应用的一个亟待解决的关键难题.因此,深入探究固态电解质内锂枝晶生长的形貌调控机制及抑制策略,对于提高固态锂电池的循环寿命并推动其广泛应用至关重要.该工作基于相场法,通过构建力-电化学的多场耦合模型,动态地演示了锂枝晶生长形貌及其力学行为,并探讨了模型参数/条件对锂枝晶形貌的调控和抑制作用.结果表明:低水平的界面反应率系数能有效减缓锂枝晶的生长速度,同时还极大地降低了其根部承受大机械应力的范围;通过改变固态电解质材料内锂离子的各向异性扩散程度,可以实现枝晶形貌从纤维状到扁平状的转变;多晶成核对于晶间相互靠近的侧枝具有抑制作用,最高应力为单晶成核的3~5倍;高弹性模量的固态电解质对于锂枝晶生长有显著的力学抑制作用.该研究有望为固态电解质的优化设计以抑制固态锂金属电池的枝晶生长提供参考.The safety concerns regarding the flammability and explosivity of traditional liquid electrolyte(LE)lithium batteries have spurred the development of all-solid-state lithium batteries with solid-state electrolytes(SSE).However,the issue of lithium dendrite growth remains a critical challenge to be urgently addressed to commercialize solid-state lithium batteries.Hence,a thorough investigation of the morphology control mechanisms and suppression strategies for lithium dendrite growth within solid-state electrolytes is crucial for improving the cycle life of solid-state lithium batteries and promoting their widespread application.Based on the phase-field method,a multi-physical fields coupling model integrating mechanics and electrochemistry,was constructed to dynamically demonstrate the morphology and mechanical behavior of lithium dendrite growth.Then the model parameters and different conditions were explored to regulate and suppress the morphology of lithium dendrite.The results indicate that,a low-level interfacial reaction rate coefficient can effectively slow down the growth rate of lithium dendrite,while also significantly narrowing the high mechanical stress range at the dendrite root.With the change of the lithium-ion anisotropic diffusion degree within solid-state electrolyte materials,the transition of dendrite morphology from fibrous to flat can be achieved.The polycrystalline nucleation exhibits inhibitory effects on the lateral branches close to each other,with the maximum stress being 3 to 5 times higher than that of single-crystal nucleation.Solid-state electrolytes with a high elastic modulus exert notable mechanical inhibitory effects on lithium dendrite growth.This work can serve as a valuable reference for the optimization design of solid-state electrolytes to suppress dendrite growth in solid-state lithium metal batteries.

关 键 词：力-化-电耦合 枝晶生长与抑制 全固态电池 相场法 

分 类 号：O34[理学—固体力学]