Enhanced Li‐Ion Accessibility in MXene Titanium Carbide by Steric Chloride Termination |
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| Authors: | Satoshi Kajiyama Lucie Szabova Hiroki Iinuma Akira Sugahara Kazuma Gotoh Keitaro Sodeyama Yoshitaka Tateyama Masashi Okubo Atsuo Yamada |
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| Affiliation: | 1. Department of Chemical System Engineering, The University of Tokyo, Bukyo‐ku, Tokyo, Japan;2. Center for Green Research on Energy and Environmental Materials and Center for Materials Research by Information Integration, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, Japan;3. Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan;4. Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Nishikyo‐ku, Kyoto, Japan;5. JST PRESTO, Saitama, Japan |
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| Abstract: | Pseudocapacitance is a key charge storage mechanism to advanced electrochemical energy storage devices distinguished by the simultaneous achievement of high capacitance and a high charge/discharge rate by using surface redox chemistries. MXene, a family of layered compounds, is a pseudocapacitor‐like electrode material which exhibits charge storage through exceptionally fast ion accessibility to redox sites. Here, the authors demonstrate steric chloride termination in MXene Ti2CTx (Tx : surface termination groups) to open the interlayer space between the individual 2D Ti2CTx units. The open interlayer space significantly enhances Li‐ion accessibility, leading to high gravimetric and volumetric capacitances (300 F g?1 and 130 F cm?3) with less diffusion limitation. A Li‐ion hybrid capacitor consisting of the Ti2CTx negative electrode and the LiNi1/3Co1/3Mn1/3O2 positive electrode displays an unprecedented specific energy density of 160 W h kg?1 at 220 W kg?1 based on the total weight of positive and negative active materials. |
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| Keywords: | hybrid capacitors intercalation MXene negative electrode pseudocapacitors |
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