固态电解质电池锂枝晶生长机械应力-热力学相场模拟研究  

Mechanical stress-thermodynamic phase-field simulation of lithium dendrite growth in solid electrolyte battery

作　　者：耿晓彬 李顶根[1] 徐波[1] Geng Xiao-Bin;Li Ding-Gen;Xu Bo(School of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]华中科技大学能源与动力工程学院,武汉430074

出　　处：《物理学报》2023年第22期56-66,共11页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2018YFB0104104)资助的课题。

摘　　要：固态电池中的锂枝晶生长问题是困扰其进行商业化应用的重要因素,锂枝晶在锂金属阳极界面的生长不仅会导致电池能量效率降低,甚至会产生燃烧、爆炸等安全问题.为了探究抑制锂枝晶生长的因素和方法,本文针对聚合物固态电解质电池中锂枝晶的生长问题,利用相场理论进行模拟研究,建立了耦合机械应力和热力场的锂枝晶生长相场模型,讨论分析了环境温度、固态电解质杨氏模量以及外应力等关键物理因素对枝晶生长的影响以及作用原理.结果显示在高温、高固体电解质杨氏模量和外应力条件下锂枝晶生长缓慢,长枝晶数量少,电沉积较为均匀.此外,对比了常见范围内的固态电解质杨氏模量和环境温度对锂枝晶生长的影响,发现固态电解质杨氏模量改变对于最大锂枝晶长度的抑制效果相对于改变环境温度要高出19%.Growth of lithium dendrites in solid state batteries is an important factor that disturbs their commercial applications.The growth of lithium dendrites at the interface of lithium metal anode will not only lead to the decrease of battery energy efficiency,but also cause combustion,explosion and other safety problems.In order to explore the factors and methods that inhibit the growth of lithium dendrites,the phase-field theory is used to simulate the growth of lithium dendrites in polymer solid electrolyte batteries,and a phase-field model of lithium dendrite growth coupled with mechanical stress and thermal field is established.The effects of key physical factors such as ambient temperature,solid electrolyte Young’s modulus and external stress on dendrite growth and their acting principles are discussed and analyzed.The results show that under the conditions of high temperature,high solid electrolyte Young’s modulus and external stress,the growth of lithium dendrites is slow,the number of long dendrites is small,and the electrodeposition is more uniform.In addition,the effects of Young’s modulus of solid electrolyte and ambient temperature on the growth of lithium dendrites in a common range are compared with each other.It is found that the inhibition effect of changing Young’s modulus of solid electrolyte on the maximum length of lithium dendrites is 19%higher than that caused by the change of ambient temperature.

关 键 词：固态电池 锂枝晶 相场模型 机械应力 

分 类 号：TM912[电气工程—电力电子与电力传动]