Fundamental insight into the surface charging mechanism of TiO₂(B) nanomaterials is limited due to the complicated nature of lithiation behavior, as well as the limitations of available characterization tools that can directly probe surface charging process. Here, an in situ approach is reported to monitor the dynamic valence state of TiO₂(B) nanotube electrodes, which utilizes in situ X‐ray absorption spectroscopy (XAS) to identify the origin and contribution of surface storage. A real‐time correlation is elucidated between the rate‐dependent electrode performance and dynamic Ti valence‐state change. A continuous Ti valence state change is directly observed through the whole charging/discharging process regardless of charging rates, which proves that along with the well‐known non‐faradaic reaction, the surface charging process also originates from a faradaic reaction. The quantification of these two surface storage contributions at different charging rates is further realized through in situ dynamic valence state monitoring combined with traditional cyclic voltammetry measurement. The methodology reported here can also be applied to other electrode materials for the real‐time probing of valence state change during electrochemical reactions, the quantification of the faradaic and non‐faradaic reactions, and the eventual elucidation of electrochemical surface charging mechanisms.

中文翻译：

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通过原位动态价态监测识别TiO2（B）纳米管电极中表面存储的起源和贡献

由于锂化行为的复杂性质以及可直接探测表面充电过程的可用表征工具的局限性，对TiO ₂（B）纳米材料的表面充电机理的基本见识受到限制。在这里，报道了一种原位方法来监测TiO ₂的动态价态（B）纳米管电极，它利用原位X射线吸收光谱（XAS）来识别表面存储的起源和贡献。阐明了速率相关的电极性能与动态Ti价态变化之间的实时相关性。无论充电速率如何，在整个充电/放电过程中都可以直接观察到连续的Ti价态变化，这证明，与众所周知的非法拉第反应一样，表面充电过程也源自法拉第反应。通过现场动态价态监测与传统循环伏安法测量相结合，进一步实现了在不同充电率下这两个表面存储贡献的量化。