Microstructural Aspects of Electrode Material Degradation Mechanisms in Li-ion Batteries

锂离子电池电极材料降解机制的微观结构

• 批准号: 46774-2013
• 负责人: Alpas, Ahmet
• 金额: $ 3.21万
• 依托单位: University of Windsor
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=568995
• 关键词: Microstructural; Aspects; Electrode; Material; Degradation

Li-ion batteries are state-of-the-art energy storage systems that are being employed in a wide range of rechargeable portable electronic devices and also considered for mass-produced hybrid and electric vehicles. Understanding microstructural aspects of the electrode degradation mechanism during charging and discharging of Li-ion batteries is of key importance in order to design energy efficient batteries with low impedance growth and high capacity. The proposed research program aims at developing advanced characterization methods for identifying the micromechanisms of surface and subsurface damage in negative battery electrodes produced typically from graphite or silicon. The implementation of an in-situ observation system during electrochemical tests using a digital optical microscope and a Raman spectrometer will determine severity of surface degradation damage due to exfoliation and fragmentation of particles on electrode surfaces. The compositional changes that occur during the electrolyte decomposition and formation of solid electrolyte interface will be simultaneously identified. Application of FIB and TEM microscopy to samples excised from model electrode materials, such as HOPG with graphene layers parallel and normal to the interface, and Si samples with known crystallographic orientations, will elucidate details of crack initiation and propagation processes that operate in these electrodes. Attention will be given to the determination of local stresses and stress intensities at crack tips that are expected to rationalize the role of the intercalation products in controlling the crack growth rates. The results will be summarized in the form of diagrams or Electrode Damage Maps that will show the damage features as a function of cycling time and temperature, voltage scan rate and the electrolyte composition. By correlating the microscopic information to electrochemical performance, new design methods for improved electrode microstructures will arise. At least six HQP will be trained to the benefit of emerging energy materials sectors of the Canadian economy.

锂离子电池是一种最先进的能量存储系统，被广泛应用于可充电的便携式电子设备，也被考虑用于大规模生产的混合动力和电动汽车。了解锂离子电池充放电过程中电极退化机理的微观结构对于设计低阻抗增长、高容量的节能电池具有重要意义。拟议的研究计划旨在开发先进的表征方法，以确定通常由石墨或硅生产的负极电池电极表面和亚表面损伤的微观机制。 在使用数字光学显微镜和拉曼光谱仪进行电化学测试期间实施现场观察系统，将确定由于电极表面颗粒剥落和碎裂而造成的表面退化损害的严重程度。在电解质分解和固体电解质界面形成过程中发生的成分变化将同时被识别。对于从模型电极材料中取出的样品，例如具有平行和垂直于界面的石墨烯层的HOPG样品，以及具有已知晶体取向的Si样品，应用FIB和TEM显微镜将阐明在这些电极中操作的裂纹萌生和扩展过程的细节。将注意确定裂纹尖端的局部应力和应力强度，以使插层产物在控制裂纹扩展速率中的作用合理化。 结果将以图表或电极损伤图的形式进行总结，这些图表将显示作为循环时间和温度、电压扫描速率和电解液成分的函数的损伤特征。通过将微观信息与电化学性能相关联，将出现改进电极微结构的新的设计方法。至少六名HQP将接受培训，以造福于加拿大经济的新兴能源材料行业。