聚合物基复合固态电解质中锂枝晶生长的相场模拟研究  

Phase-field Simulation of Lithium Dendrite Growth in Polymer-based Composite Solid-state Electrolytes

作　　者：翟艳芳 杨佳悦 邓齐波 宋树丰 赵莹[2] 胡宁 Yanfang Zhai;Jiayue Yang;Qibo Deng;Shufeng Song;Ying Zhao;Ning Hu(College of Aerospace Engineering,Chongqing University,Chongqing,400044;School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai,200092;School of Mechanical Engineering,Hebei University of Technology,Tianjin,300401)

机构地区：[1]重庆大学航空航天学院,重庆400044 [2]同济大学航空航天与力学学院,上海200092 [3]河北工业大学机械工程学院,天津300131

出　　处：《固体力学学报》2024年第5期587-594,共8页Chinese Journal of Solid Mechanics

基　　金：重庆市技术创新与应用发展专项重点项目(Z20230084);河北省创新群体项目(A2020202002);河北省重点研发项目(202030507040009);天津市科技计划项目(20ZYJDJC0030)资助。

摘　　要：固态锂金属电池是最具潜力的下一代高能量密度储能技术,但其面临的一个最迫切问题是锂枝晶的不均匀生长.目前低模量复合固态电解质,特别是低模量多相复合固态电解质,抑制锂枝晶生长的机制还没有被完全明确.因此,本文通过相场法构建了力学-化学模型,研究了复合固态电解质不同弹性模量对于锂枝晶生长的影响,结果表明电解质模量越高,锂金属的应力越大,易使锂枝晶发生塑性形变,从而抑制锂枝晶的生长.本文的研究加深理解了低模量多相复合固态电解质抑制锂枝晶的机制,并为复合固态电解质的设计提供了指导.Lithium metal is a highly promising anode material due to its high theoretical capacity and low reduction/oxidation potential,and has received extensive attention.However,the formation and growth of lithium dendrites poses the biggest challenge to its commercialization.The use of solid-state electrolyte,instead of liquid electrolyte,has become a potential path to inhibit the growth of lithium dendrites.However,issues such as poor metal-lithium interface contact and low ionic conductivity in solid-state electrolytes persist.Composite solid-state electrolytes,prepared by combining polymers with inorganic ceramic electrolytes,have shown effectiveness in inhibiting the growth of lithium dendrites.Although these composite solid electrolytes typically have high ionic conductivity,their elastic moduli are low.Currently,the mechanism of dendrite suppression by low-modulus composite solid-state electrolytes,especially low-modulus multiphase composite solid-state electrolytes,remains incompletely clarified.Therefore,this paper considers the mechanical effects of solid electrolytes and builds a mechanical-chemical model using the phase field method.By taking poly(ethylene oxide)(PEO)-based composite-state electrolyte as an example,the study investigates the influence of composite solid electrolyte modulus on dendrite growth.The results show that the higher the electrolyte modulus,the greater the stress on the lithium metal,leading to a more uniform distribution of lithium ions on the interface between the electrolyte and the lithium anode electrode.The higher stress also tends to cause the plastic deformation of lithium dendrites,thus inhibiting their growth.This research deepens the understanding of the mechanism of inhibition of lithium dendrites by low-modulus multiphase composite solid electrolytes,and provides guidance for the design of composite solid electrolytes.

关 键 词：应力 复合固态电解质 相场法 锂枝晶 

分 类 号：O646[理学—物理化学] TM912[理学—化学]