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Energy-Dispersive X-ray Diffraction: Operando Visualization of Electrochemical Activity of Thick Electrodes
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2019-07-30 , DOI: 10.1021/acs.jpcc.9b04977 Andrea M. Bruck , Lei Wang , Alexander B. Brady , Diana M. Lutz , Brianna L. Hoff 1, 2 , Karen Li 3 , Nicholas Stavinski 2, 4 , David C. Bock 2 , Kenneth J. Takeuchi , Esther S. Takeuchi 2 , Amy C. Marschilok 2
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2019-07-30 , DOI: 10.1021/acs.jpcc.9b04977 Andrea M. Bruck , Lei Wang , Alexander B. Brady , Diana M. Lutz , Brianna L. Hoff 1, 2 , Karen Li 3 , Nicholas Stavinski 2, 4 , David C. Bock 2 , Kenneth J. Takeuchi , Esther S. Takeuchi 2 , Amy C. Marschilok 2
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Effective utilization of the electroactive material in thick electrodes could enable Li-based batteries to be developed with higher energy densities while simultaneously reducing the overall cost of the battery. Herein, we explore the lithiation of a multiple electron transfer conversion material, Fe3O4, and report tomographic-like mapping of the electroactive material utilization under operando electrochemical lithiation using energy-dispersive X-ray diffraction. A challenge for thick electrodes is limited Li+ diffusion resulting in an inability to fully access the active material. Our strategy to surmount this obstacle is the deliberate incorporation of acicular carbon nanotubes to the electrode where the design maximized the electron and ion access to the Fe3O4 active material within a thick electrode (∼500 μm). Based on whole pattern fitting of the diffraction data, the phase composition was determined with both spatial and temporal resolutions. The data allow identification of the electrochemical conversion products, Li2O and Fe metal, where interestingly, the Li2O crystallites increase in size after initial formation. The observation of increased crystallite size of Li2O after initial formation provides new insight into the time-dependent phenomena of conversion-type active materials and their reversibility. This investigation contributes to our understanding of Li+ transport in thick electrodes and provides insight into the design of battery electrodes that facilitate electroactive material utilization of energy storage systems crucial for the development of next-generation batteries.
中文翻译：
能量色散X射线衍射：厚电极的电化学活性的操作可视化
在厚电极中有效利用电活性材料可使锂基电池具有更高的能量密度，同时降低电池的总体成本。在这里，我们探索了一种多电子转移转换材料Fe 3 O 4的锂化，并报告了使用能量色散X射线衍射在操作性电化学锂化下对电活性材料利用的层析成像图。厚电极面临的挑战是Li +的限制扩散导致无法完全接触活性物质。我们克服这一障碍的策略是将针状碳纳米管有意识地并入电极中，该设计最大程度地利用了电子和离子进入厚电极（约500μm）内的Fe 3 O 4活性材料。基于衍射数据的整体模式拟合，可以在空间和时间分辨率下确定相组成。数据允许鉴定电化学转化产物Li 2 O和Fe金属，有趣的是，在初始形成后，Li 2 O微晶的尺寸增加。Li 2的微晶尺寸增加的观察初始形成后的O可提供有关转化型活性材料随时间变化的现象及其可逆性的新见解。这项研究有助于我们理解厚电极中的Li +传输，并为电池电极的设计提供了见识，这些电极促进了对下一代电池开发至关重要的储能系统的电活性材料的利用。
更新日期：2019-07-30
中文翻译：
能量色散X射线衍射：厚电极的电化学活性的操作可视化
在厚电极中有效利用电活性材料可使锂基电池具有更高的能量密度，同时降低电池的总体成本。在这里，我们探索了一种多电子转移转换材料Fe 3 O 4的锂化，并报告了使用能量色散X射线衍射在操作性电化学锂化下对电活性材料利用的层析成像图。厚电极面临的挑战是Li +的限制扩散导致无法完全接触活性物质。我们克服这一障碍的策略是将针状碳纳米管有意识地并入电极中，该设计最大程度地利用了电子和离子进入厚电极（约500μm）内的Fe 3 O 4活性材料。基于衍射数据的整体模式拟合，可以在空间和时间分辨率下确定相组成。数据允许鉴定电化学转化产物Li 2 O和Fe金属，有趣的是，在初始形成后，Li 2 O微晶的尺寸增加。Li 2的微晶尺寸增加的观察初始形成后的O可提供有关转化型活性材料随时间变化的现象及其可逆性的新见解。这项研究有助于我们理解厚电极中的Li +传输，并为电池电极的设计提供了见识，这些电极促进了对下一代电池开发至关重要的储能系统的电活性材料的利用。
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