Redox Targeting of Anatase TiO2 for Redox Flow Lithium‐Ion Batteries |
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Authors: | Feng Pan Jing Yang Qizhao Huang Xingzhu Wang Hui Huang Qing Wang |
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Affiliation: | 1. Department of Materials Science and Engineering, Faculty of Engineering, NUSNNI‐NanoCore, National University of Singapore, Singapore;2. Surface Technology Group, Singapore Institute of Manufacturing Technology, Singapore |
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Abstract: | Anatase TiO2 is an extensively studied anode material for lithium‐ion batteries because of its superior capability of storing Li+ electrochemically. Here reversible lithium storage of TiO2 is achieved chemically using redox targeting reactions. In the presence of a pair of redox mediators, bis(pentamethylcyclopentadienyl)cobalt (CoCp* 2) and cobaltocene (CoCp2) in an electrolyte, TiO2 and its lithiated form Li x TiO2 can be reduced and oxidized by CoCp* 2 and CoCp2 +, respectively, which accompany Li+ insertion and extraction, albeit without attaching the TiO2 onto the electrode. The reversible chemical lithiation/delithiation and the involved phase transitions are unambiguously confirmed using density functional theory (DFT) calculations, UV‐vis spectroscopy, X‐ray photoelectron spectoscopy (XPS), and Raman spectroscopy. A redox flow lithium‐ion battery (RFLB) half‐cell is assembled and evaluated, which is a critical step towards the development of RFLB full cells. |
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Keywords: | anatase TiO2 redox targeting redox flow lithium‐ion batteries |
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