Yamagishi Yuji, Morita Hiromi, Nomura Yuki, Igaki Emiko
Applied Materials Technology Center, Technology Division, Panasonic Corporation, 3-1-1 Yagumo-nakamachi, Moriguchi, Osaka 570-8501, Japan.
J Phys Chem Lett. 2021 May 20;12(19):4623-4627. doi: 10.1021/acs.jpclett.1c01089. Epub 2021 May 11.
A fundamental understanding of lithiation dynamics in composite electrodes is essential for the development of all-solid-state batteries with high capacity and rate capability. However, a comprehensive methodology to monitor the time evolution of lithiation in a composite electrode has not been fully established because of the limitations of the characterization techniques currently employed. In this study, we demonstrate the visualization of the transient distribution of Li in composite graphite anodes during cell operation using time-of-flight secondary ion mass spectrometry. Selective detection of Li in the graphite electrode was successfully achieved by mapping the Li fragment rather than the conventional mapping of positive Li-containing fragments. The results revealed the formation of a Li concentration gradient during charging, indicating that the reaction of the composite electrode is limited by the diffusion of Li ions inside the graphite. The demonstrated technique is expected to facilitate the investigation of the underlying lithiation mechanisms of composite electrodes in operating cells.
深入理解复合电极中的锂化动力学对于开发具有高容量和高倍率性能的全固态电池至关重要。然而，由于目前所采用表征技术的局限性，尚未完全建立起一种全面的方法来监测复合电极中锂化的时间演变。在本研究中，我们利用飞行时间二次离子质谱法展示了电池运行过程中复合石墨阳极中锂的瞬态分布可视化。通过绘制锂碎片图谱而非传统的含锂正离子碎片图谱，成功实现了对石墨电极中锂的选择性检测。结果揭示了充电过程中锂浓度梯度的形成，表明复合电极的反应受锂离子在石墨内部扩散的限制。所展示的技术有望促进对工作电池中复合电极潜在锂化机制的研究。
