储能科学与技术 ›› 2025, Vol. 14 ›› Issue (10): 3687-3696.doi: 10.19799/j.cnki.2095-4239.2025.0395

• 储能材料与器件 • 上一篇    下一篇

在纳米骨架和人工隔膜形貌优化下固态电池锂枝晶生长的相场法研究

包文彬(), 龚国庆()   

  1. 北京信息科技大学机电工程学院,北京 100192
  • 收稿日期:2025-04-23 修回日期:2025-05-16 出版日期:2025-10-28 发布日期:2025-10-20
  • 通讯作者: 龚国庆 E-mail:1240747961@qq.com;gonggy@126.com
  • 作者简介:包文彬(2000—),男,硕士研究生,研究方向为固态电池电化学仿真分析,E-mail:1240747961@qq.com

Phase-field study of lithium dendrite growth in solid-state batteries: Effects of nanoskeletons and artificial separator morphology optimization

Wenbin BAO(), Guoqing GONG()   

  1. College of Mechanical and Electrical Engineering, Beijing Information Science and Technology University, Beijing 100192, China
  • Received:2025-04-23 Revised:2025-05-16 Online:2025-10-28 Published:2025-10-20
  • Contact: Guoqing GONG E-mail:1240747961@qq.com;gonggy@126.com

摘要:

锂枝晶的生长在锂金属电池中普遍存在,该现象严重影响到了电池的使用寿命、效率和安全性。近年来,固态电池由于自身安全性高、循环稳定性高、能量密度大、循环寿命长等特点,成为新能源电池领域的主要研究对象。相较于液态电池,固态电池的固态电解质具有较高的机械强度,可以有效地抑制锂枝晶的生长,但是仍然难以完全抑制。本工作针对固态电池中锂枝晶的生长问题,基于力-热-电化学相耦合的相场模型,研究了不同形貌的纳米骨架和人工隔膜对锂枝晶的抑制情况。结果显示,粗糙度均匀且规则的纳米骨架可以有效抑制锂枝晶生长。在本工作构建的纳米管和分级结构纳米骨架中,锂枝晶高度分别下降了16.62%及21.04%,但随着不均匀程度增大,这种抑制效果会衰减;增加人工隔膜的厚度或减小其孔隙都能更有效抑制枝晶的生长,当孔隙相同时,随着人工隔膜厚度的增大,其对锂枝晶的抑制效果更加显著。同时,本工作构建的“瓦片”状截面的人工隔膜相比于传统的矩形截面的人工隔膜使锂枝晶的高度降低了12.75%。

关键词: 固态电池, 锂枝晶, 相场法, 纳米骨架, 人工隔膜

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%.

Key words: solid-state batteries, lithium dendrites, phase field method, nanoskeleton, artificial diaphragm

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