Identifying the Origin and Contribution of Surface Storage in TiO2(B) Nanotube Electrode by In Situ Dynamic Valence State Monitoring. Issue 33 (3rd July 2018)

• Record Type: Journal Article
• Authors: Tang, Yuxin; Zhang, Yanyan; Malyi, Oleksandr I.; Bucher, Nicolas; Xia, Huarong; Xi, Shibo; Zhu, Zhiqiang; Lv, Zhisheng; Li, Wenlong; Wei, Jiaqi; Srinivasan, Madhavi; Borgna, Armando; Antonietti, Markus; Du, Yonghua; Chen, Xiaodong
• Is Part Of: Advanced materials. Volume 30:Issue 33(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-07-03
• Subjects: in situ XAS fast charging -- lithium‐ion batteries -- surface charging mechanism -- TiO2(B) nanotube anode; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201802200
• Languages: English
• ISSNs: 0935-9648

Abstract

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. Abstract : The origin and contribution of surface storage in a prototype TiO2 (B) nanotube electrode by an in situ dynamic valence state monitoring approach are identified. Benefited from this, non‐faradaic and faradaic capacity from the surface reaction are identified and quantified in conjunction with a cyclic voltammetry measurement, putting an end to the long‐time question on surface reaction over distinguishing its non‐faradaic and faradaic contributions.