储能科学与技术 ›› 2022, Vol. 11 ›› Issue (3): 991-999.doi: 10.19799/j.cnki.2095-4239.2022.0022

• 储能新材料设计与先进表征专刊 • 上一篇    下一篇

杨氏模量微观表征新方法在锂电池中的应用

陈博文(), 崔瑞广, 沈炎宾(), 陈立桅   

  1. 中国科学院苏州纳米技术与纳米仿生研究所,江苏 苏州 215123
  • 收稿日期:2022-01-13 修回日期:2022-01-25 出版日期:2022-03-05 发布日期:2022-03-11
  • 通讯作者: 沈炎宾 E-mail:bwchen2019@sinano.ac.cn;ybshen2017@sinano.ac.cn
  • 作者简介:陈博文(1996—),男,硕士研究生,研究方向为锂离子电池中的离子运动表征,E-mail:bwchen2019@sinano.ac.cn
  • 基金资助:
    国家自然科学基金项目(21733012)

Application of a novel method for characterization of local Youngs modulus in lithiumionbatteries

Bowen CHEN(), Ruiguang CUI, Yanbin SHEN(), Liwei CHEN   

  1. Suzhou Insitute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, Jiangsu, China
  • Received:2022-01-13 Revised:2022-01-25 Online:2022-03-05 Published:2022-03-11
  • Contact: Yanbin SHEN E-mail:bwchen2019@sinano.ac.cn;ybshen2017@sinano.ac.cn

摘要:

锂(离子)电池电极表面的固态电解质中间相(solid electrolyte interphase,SEI)是电池安全性、使用寿命及倍率性能等的关键影响因素。提高SEI的力学性能,如杨氏模量,可以使其更好地包容锂离子脱嵌带来的电极材料体积变化。原子力显微镜(AFM)纳米压痕技术能够在获得样品表面形貌的基础上测量相应区域的杨氏模量,但这种方法通常需要在样品不同区域采集大量的力曲线,才能得到具有统计意义的杨氏模量数值,因此比较费时耗力。最近有文献报道利用AFM中的AM-FM(amplitude modulation-frequency modulation mode)方法可以在短时间内同时获得材料形貌图像和对应区域的杨氏模量,为测量材料杨氏模量提供了一种新思路。由于AM-FM技术尚处于应用的早期,本工作对该模式在锂电池SEI研究中应用的可行性进行了分析。首先,本工作论证了AM-FM技术可以用于快速定性区分同一个样品上的两种模量不同的材料。其次,本工作发现AM-FM模式测得的杨氏模量数值与AFM探针针尖半径密切相关,以特定针尖半径测得的两种标准样品杨氏模量为参考,可以评估用AM-FM模式测量的实验样品杨氏模量结果的准确性。结果表明目前用AM-FM模式获取的实验样品杨氏模量准确度还有待提升。因此,本工作证明了AM-FM可以用于快速定性区分材料的不同成分,未来对AM-FM技术的进一步改进将有望将其应用于快速定量获取样品杨氏模量,助力SEI力学性能的快速表征。

关键词: 锂电池, SEI, 杨氏模量, AFM, AM-FM, 力曲线

Abstract:

Solid-electrolyte interphase (SEI) largely affect the safety, cycle life, and rate capability of the Li (ion) batteries. Improving the mechanical properties, e.g. Young's modulus, of SEI helps to withstand the damages caused by volume changes of the electrode material resulted from lithium-ion intercalation/deintercalation. Atomic Force Microscopy (AFM) nanoindentation affords as an effective way to obtain both the morphology and Young's modulus of a specified area of a sample. However, in order to calculate the precise Young's modulus with statistical significance, a mass of forces curves from various areas of the samples are usually needed, which makes this method laborious. Recently, the newly-developed Amplitude Modulation-Frequency Modulation mode (AM-FM mode) of AFM has been reported as an efficient approach to measure the Young's modulus of materials, which provides both the morphology graph and Young's modulus map at the same time in several minutes. Since the development of AM-FM mode is still in its early stage, herein we studied the feasibility of applicating this technique in the SEI research. First, we demonstrated AM-FM can be applied on rapidly distinguishing materials with different Young's modulus on one sample. Then we found that the tip radius parameter in this mode has a huge impact on the Young's modulus value. We evaluated the accuracy of AM-FM as a quantitative method to quickly characterize Young's modulus of a studied sample by using standard materials with known Young's modulus. It turned out that the Young's modulus of studied samples obtained by AM-FM still needed to be further improved. To conclude, in this work we demonstrated that AM-FM method is a novel technique for quickly distinguishing different materials on one sample, after further improvement it could probably be used for quickly measuring the Young's modulus of SEI.

Key words: lithium battery, SEI, Young's modulus, AFM, AM-FM, force curve

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