A quantitative understanding of the Li distribution inside all-solid-state Li-ion batteries is important for improving the performance of batteries. We constructed a time-of-flight (TOF) elastic recoil detection analysis (ERDA) system for operando measurements of thin-film Li-ion batteries. The TOF-ERDA measurement provides elementally resolved spectra with a depth resolution much higher than that of conventional stopper-foil ERDA. The Li depth profiles in a cathode film and solid electrolyte were obtained quantitatively to a depth of 100 nm using a 9-MeV Cu ion beam with reflection geometry. In this study, we conducted TOF-ERDA for a thin-film battery having a cathode made from LiCoO2, an oxide-based solid electrolyte [lithium aluminum titanium phosphate (LATP)], and an anode made from Fe2(MoO4)3 to demonstrate the ability of the measurement system and reveal the Li distribution near the interface with improved resolution. The depth resolution at the interface (30 nm from the surface) was estimated to be 12–14 nm. We quantitatively obtained the Li density in the LiCoO2 cathode and the variation in the Li distribution around the LiCoO2/LATP interface and inside the LATP electrolyte upon charging/discharging. TOF-ERDA is thus a powerful tool for the high-resolution quantitative depth analysis of Li in thin-film batteries in operando.

中文翻译：

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使用 TOF-ERDA 对薄膜全固态电池进行高分辨率锂深度分析


定量了解全固态锂离子电池内部的锂分布对于提高电池的性能非常重要。我们构建了一个飞行时间 (TOF) 弹性反冲检测分析 (ERDA) 系统，用于薄膜锂离子电池的操作测量。 TOF-ERDA 测量提供了元素分辨光谱，其深度分辨率远高于传统的塞箔 ERDA。使用具有反射几何结构的 9-MeV Cu 离子束定量获得 100 nm 深度的阴极薄膜和固体电解质中的 Li 深度分布。在本研究中，我们对薄膜电池进行了 TOF-ERDA，该电池具有由 LiCoO2 制成的阴极、氧化物基固体电解质 [磷酸铝钛锂 (LATP)] 和由 Fe2(MoO4)3 制成的阳极，以证明测量系统的能力，并以更高的分辨率揭示界面附近的锂分布。界面处（距表面 30 nm）的深度分辨率估计为 12–14 nm。我们定量获得了 LiCoO2 正极中的 Li 密度以及充电/放电时 LiCoO2/LATP 界面周围和 LATP 电解质内部的 Li 分布变化。因此，TOF-ERDA 是对薄膜电池中的 Li 进行高分辨率定量深度分析的强大工具。