Surface Redox Pseudocapacitance of Partially Oxidized Titanium Carbide MXene in Water-in-Salt Electrolyte

Journal article (2022)

Authors

Xuehang Wang RST/Storage of Electrochemical Energy - AS , Drexel University
Seong Min Bak Brookhaven National Laboratory
Meikang Han Drexel University
Christopher E. Shuck Drexel University
Conlan Mchugh Drexel University
Ke Li Drexel University
Jianmin Li Drexel University
J. Tang Drexel University
Yury Gogotsi Drexel University
Research Group
RST/Storage of Electrochemical Energy (AS) (TU Delft)
Copyright: © 2022 Xuehang Wang, Seong Min Bak, Meikang Han, Christopher E. Shuck, Conlan Mchugh, Ke Li, Jianmin Li, J. Tang, Yury Gogotsi
DOI
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https://doi.org/10.1021/acsenergylett.1c02262
More Info
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Published Date

2022

Language

English

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Faculty

Applied Sciences

Department

RST/Radiation, Science and Technology

Research Group

RST/Storage of Electrochemical Energy

Abstract

Achieving pseudocapacitive intercalation in MXenes with neutral aqueous electrolytes and driving reversible redox reactions is scientifically appealing and practically useful. Here, we report that the partial oxidation of MXene intensifies pseudocapacitive Li+ intercalation into Ti3C2Tx MXene from neutral water-in-salt electrolytes. An in situ X-ray absorption near-edge structure analysis shows that the Ti oxidation state changes during the Li+ intercalation, indicating the presence of a surface redox reaction. The Ti oxidation/reduction is further confirmed by an in situ extended X-ray absorption fine structure analysis, which shows a reversible contraction/expansion of the Ti-C interatomic distance. The intensified Li+ pseudocapacitive intercalation can be explained by the higher oxidation state of Ti at the open circuit potential. This work demonstrates the possibility of tuning the pseudocapacitive intercalation by adjusting the initial oxidation state of the transition metal on the MXene and offers a facile way to enhance the pseudocapacitance of various MXenes.