In recent years, all-solid-state batteries (ASSBs) have been attracting attention as the next generation batteries for electric vehicles, energy storage systems, etc. Despite the growing interest, there are still many challenges faced in the commercial use of ASSBs. One of the biggest issues is the internal resistance, especially generated at the interface between solid electrolyte and electrode. The internal resistance at the interface limits the charge-discharge cycling performances. In order to solve this issue, it is necessary to examine the chemical and physical interactions at the interface. In this study, we have performed a detailed characterization of a LiPON/LiCoO₂ interface using time-of-flight secondary ion mass spectrometry, x-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and low-energy inverse photoelectron spectroscopy to obtain information on chemical species, chemical compositions, chemical states, and energy band diagrams. These powerful techniques have revealed that an interlayer between LiPON and LiCoO₂ was formed due to the temperature rise during the manufacturing process. The temperature rise caused a change of the LiPON network structure and stimulated Co reduction in the LiCoO₂ layer near the interface. Energy band diagram analysis suggests that the electron diffusion from LiPON to LiCoO₂ may have triggered the reduction of Co. We concluded that the chemical changes that occur at the interface caused an increase in interfacial impedance. Preventing the chemical reduction of Co would be a key to minimize the internal resistance. In this article, the detailed chemical interactions between the LiPON and LiCoO₂ layers will be discussed.

中文翻译：

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使用 TOF-SIMS、XPS 和 UPS/LEIPS 表征全固态电池中的阴极-电解质界面

近年来，全固态电池（ASSBs）作为电动汽车、储能系统等的下一代电池备受关注。尽管越来越受到关注，但ASSBs的商业应用仍面临诸多挑战。最大的问题之一是内阻，尤其是在固体电解质和电极之间的界面处产生的内阻。界面处的内阻限制了充放电循环性能。为了解决这个问题，有必要检查界面处的化学和物理相互作用。在这项研究中，我们对 LiPON/LiCoO ₂进行了详细的表征界面使用飞行时间二次离子质谱、X 射线光电子能谱、紫外光电子能谱和低能逆光电子能谱来获取有关化学种类、化学成分、化学状态和能带图的信息。这些强大的技术表明，由于制造过程中的温度升高，在LiPON 和 LiCoO ₂之间形成了中间层。温度升高引起了 LiPON 网络结构的变化，并刺激了界面附近LiCoO ₂层中的 Co 还原。能带图分析表明，从 LiPON 到 LiCoO ₂的电子扩散可能触发了 Co 的减少。我们得出结论，界面处发生的化学变化导致界面阻抗增加。防止 Co 的化学还原将是最小化内阻的关键。在本文中，将讨论LiPON 和 LiCoO ₂层之间的详细化学相互作用。