High Resolution 4D In-Operando Imaging of High Energy Density Battery Electrode Cycling

这项研究结合了先进的成像和诊断技术，解决了用于运输的下一代锂电池的先进阳极所面临的挑战。该研究将建立并利用超高时空分辨率测试平台，利用纳米x射线计算机断层扫描（nano-CT）对电池进行4D （3D空间+时间）操作成像。科学目标是阐明最有希望用于电动和混合动力汽车的阳极化学物质的失效机制，包括锂金属，锡（Sn）和硅（Si）合金阳极。这项研究的结果可能对推进锂金属、硅和锡阳极电池技术有重大的好处，它们在性能和成本方面有可能大大超过目前的锂离子电池技术。如果成功，这些电池可以迅速推动电动汽车的采用，以减少排放，提高效率，并增加国内能源安全。PI将支持研究生和本科生的研究经验，将研究与课程相结合，并将工作与更广泛的社区进行交流。对于锂金属阳极，在高分辨率下的成像实验主要集中在标准电解质中枝晶成核和初始生长。成像将利用实验室级纳米级分辨率（50纳米）x射线计算机断层扫描（纳米ct）仪器。该仪器具有Zernike相衬光学成像低Z材料，如Li。纳米ct与透射或扫描电子显微镜相比的一个关键优势是不需要真空，可以使用标准电解质。此外，纳米ct成像的大体积与电极长度尺度相匹配，而不是液体TEM细胞的薄片。实验的重点是控制微/纳米尺度的物理和化学特征的引入，并表征它们对问题电镀和硅和锡阳极合金化控制的影响。一个关键的目标是确定表面和颗粒特征，使电极不稳定，导致枝晶成核和锂合金颗粒断裂。合金相形核和扩展的4D映射将为这些系统的稳定相、颗粒/电极形态效应和颗粒-颗粒相互作用提供新的见解。从这种成像中提取的基本知识可以应用于提高这些电极的性能和安全性。

This research addresses the challenges faced with advanced anodes for next generation lithium batteries for transportation applications, using a combination of advanced imaging and diagnostics. The research will establish and utilize an ultra-high spatial and temporal resolution test bed for 4D (3D space + time) in-operando imaging of batteries using nano-scale X-ray computed tomography (nano-CT). The scientific objective is to elucidate the failure mechanisms of the most promising anode chemistries for electric and hybrid vehicles, including Li metal, tin (Sn), and silicon (Si) alloying anodes. The results of this research could have significant benefits to advance battery technologies with Li metal, Si, and Sn anodes, which have the potential to significantly surpass current Li-ion battery technologies in terms of performance and cost. If successful, these batteries could rapidly advance the adoption of electric vehicles for reduced emissions, greater efficiency, and increased domestic energy security. The PI will support the research experiences of graduate and undergraduate students, integrate the research with courses, and communicate the work to the broader community.For Li metal anodes, the in-operando imaging experiments are focused on dendrite nucleation and initial growth at high resolution in standard electrolytes. The imaging will utilize the laboratory-scale nano-scale resolution (50 nm) X-ray computed tomography (nano-CT) instrument. The instrument features Zernike phase contrast optics for imaging low Z materials like Li. A key advantage of nano-CT versus transmission or scanning electron microscopy is there is no need for vacuum and standard electrolytes can be used. In addition, the nano-CT images large volumes that match electrode length scales rather than the thin slices of liquid TEM cells. The experiments focus on the controlled introduction of micro/nano-scale physical and chemical features and characterizing their impact on problematic electroplating and the control of alloying in Si and Sn anodes. A key goal is to identify the surface and particle features that destabilize electrodes and yield dendrite nucleation and Li-alloying particle fracture. The 4D mapping of alloy phase nucleation and propagation will offer new insight into the stable phases of those systems, the particle/electrode morphology effects, and particle-particle interactions. The fundamental knowledge extracted from this imaging can then be applied to advancing the performance and safety of these electrodes.