Journal of Experiental Mechanicals

全固态锂金属电池充放电内部损伤演化及刚度衰减实验研究

Experimental study on the internal damage evolution and stiffness decay of all-solid-state lithium metal battery charging and discharging

Received:April 01, 2023 Revised:May 12, 2023

DOI：10.7520/1001-4888-23-062

中文关键词: 固态锂对称电池 X-CT 固态电解质孔隙率刚度衰减

英文关键词:solid-state lithium symmetrical batteries X-CT solid electrolytes porosity stiffness degradation

基金项目:国家自然科学基金项目(12072229)

Author Name	Affiliation
XIN Lipan	1.Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China 2.Tianjin Key Laboratory of Modern Engineering Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
YANG Siyuan	1.Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China 2.Tianjin Key Laboratory of Modern Engineering Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
HOU Yanan	1.Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China 2.Tianjin Key Laboratory of Modern Engineering Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
LI Chuanwei*	1.Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China 2.Tianjin Key Laboratory of Modern Engineering Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
WANG Zhiyong	1.Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China 2.Tianjin Key Laboratory of Modern Engineering Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
LI Linan	1.Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China 2.Tianjin Key Laboratory of Modern Engineering Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
WANG Shibin	1.Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China 2.Tianjin Key Laboratory of Modern Engineering Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300350, China

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中文摘要:

全固态锂金属电池(Li-SSB)因具有较高的安全性、灵活的可设计性以及较大的能量密度等优点，近年来受到广泛关注。针对固态电解质在长服役周期中的内部损伤演化及刚度衰减问题，采用高分辨率X射线计算机扫描成像重建技术(X-CT)对Li_6.4La₃Zr_1.4TaO₁₂(LLZTO)固态氧化物电解质在Li-SSB长周期充放电过程中的损伤演化过程进行研究。分别对Li/LLZTO/Li对称电池结构在0.3mA/cm和0.5mA/cm两种电流密度工况下不同循环次数的内部结构进行三维重建，利用图像的灰度特征提取方法定量得到了LLZTO电解质的内部孔隙演化规律;通过建立LLZTO固态电解质多孔结构的无量纲弹性模量模型，研究了LLZTO固态电解质充放电过程中的模量衰减效应。实验结果表明：Li-SSB中电解质的力学损伤速度随电流密度增大而增大，电池服役阶段电解质损伤程度与循环极化电压高度正相关，电池短路后电解质损伤演化呈现先剧烈后缓和的演化规律。上述结果揭示了在电化学循环过程中电池的内部损失演化规律，对改进和设计高性能的全固态锂金属电池具有一定意义。

英文摘要:

All-solid-state lithium metal batteries (Li-SSB) have received a lot of attention in recent years due to their high safety, flexible designability and large energy density. This paper addresses the issue of internal damage evolution and stiffness degradation of solid-state electrolytes during long service cycles, and investigates the damage evolution of Li_6.4La₃Zr_1.4TaO₁₂ (LLZTO) solid oxide electrolytes during the long-cycle charge and discharge of Li-SSB using high-resolution X-ray computed tomography (X-CT).The internal structure of the Li/LLZTO/Li symmetric cell structure at two current density operating conditions of 0.3mA/cm² and 0.5mA/cm² with different cycle times was obtained for three-dimensional reconstruction, and the internal pore evolution law of the LLZTO electrolyte was obtained quantitatively by using the grey-scale feature extraction method of the image, and the dimensionless elastic modulus of the porous structure of the LLZTO solid-state electrolyte was studied by establishing the decay effect of the modulus of the LLZTO solid electrolyte with the charging and discharging process was studied by establishing a model.The experimental results show that the mechanical damage rate of the electrolyte in Li-SSB increases with increasing current density, the degree of electrolyte damage in the service phase of the battery is highly positively correlated with the cyclic polarization voltage, and the evolution of electrolyte damage after short-circuiting of the battery shows an evolutionary pattern of intense first and then gentle. The result of this paper further reveals the law of internal cell loss evolution during electrochemical cycling, which has implications for the improvement and design of high-performance all-solid-state lithium metal batteries.

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