摘要
Abstract
Lithium dendrite growth is ubiquitous in lithium-metal batteries and severely affects their service life,efficiency,and safety.In recent years,Solid-state batteries have become the main research focus in the field of new energy vehicle batteries in recent years due owing to their high safety,cycling stability,and energy density as well as long cycle life.These batteries can more effectively inhibit dendrite growth compared with liquid-state batteries because of the higher density of solid-state electrolytes;however,complete inhibition remains challenging.Studies have shown that external conditions(e.g.,temperature,boundary pressure,voltage)and electrochemical parameters(e.g.,anisotropy intensity,interfacial mobility,barrier height)influence dendrite growth.The inhibitory effects of nanoskeletons and artificial separators are key issues.For nanoskeletons,the nanotube array's tube length and intertube gap,as well as the volume fraction of porous skeletons in multihierarchical structures,were identified as key variables inhibiting dendrite growth.For artificial separators,a double-layer porous architecture reduces lithium dendrite height by regulating lithium-ion transport.Herein,using a phase-field model with coupled mechanical-thermal-electrochemical fields,we analyze how nanoskeleton and separator morphologies inhibit dendrites.In our model,the primary dendrite backbone height decreases by 16.62%and 21.04%for nanotube-array and hierarchical/multilevel nanoskeletons,respectively.With increasing roughness and uneven distribution,the maximum dendrite height increases by 17.87%and 25.57%in these two skeletons,respectively.Increasing separator thickness and decreasing porosity inhibit dendrite growth;however,thickening from 0.2 to 0.4 μm only marginally improves the inhibition effect.Joint optimization of thickness and pore spacing enhances suppression:at 0.4 μm thickness with 0.4 μm pore spacing,dendrite height decreases by 17.70%,whereas at 0.2 μm thickness with 0.5 μm spacing,it decreases by 6.95%.Relative to optimizing the thickness alone,the combined optimization further reduces dendrite height by 10.75%.In this model,modifying the cross-sectional morphology reduces dendrite height by 12.75%.关键词
固态电池/锂枝晶/相场法/纳米骨架/人工隔膜Key words
solid-state batteries/lithium dendrites/phase field method/nanoskeleton/artificial diaphragm分类
信息技术与安全科学
