Tang, Y. X.; Zhang, Y. Y.; Malyi, O. I.; Bucher, N.; Xia, H. R.; Xi, S. B.; Zhu, Z. Q.; Lv, Z. S.; Li, W. L.; Wei, J. Q.; Srinivasan, M.; Borgna, A.; Antonietti, M.; Du, Y. H.; Chen, X. D., Identifying the origin and contribution of surface storage in TiO2(B) nanotube electrode by in situ dynamic valence state monitoring. Advanced Materials 2018, 30 (33), DOI: 10.1002/adma.201802200.
Abstract:
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.
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Funding Info:
This work was funded by Singapore MOE Tier 2 (MOE2015-T2-1-110), Singapore National Research Foundation (Nanomaterials for Energy and Water Management CREATE Programme Phase II) and the Research Council of Norway (ToppForsk project: 251131).
Description:
This is the peer reviewed version of the following article: Tang, Y. X.; Zhang, Y. Y.; Malyi, O. I.; Bucher, N.; Xia, H. R.; Xi, S. B.; Zhu, Z. Q.; Lv, Z. S.; Li, W. L.; Wei, J. Q.; Srinivasan, M.; Borgna, A.; Antonietti, M.; Du, Y. H.; Chen, X. D., Identifying the origin and contribution of surface storage in TiO2(B) nanotube electrode by in situ dynamic valence state monitoring. Advanced Materials 2018, 30 (33), DOI: 10.1002/adma.201802200, which has been published in final form at https://doi.org/10.1002/adma.201802200. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.