MXenes have shown record-breaking redox capacitance in aqueous electrolytes, but in a limited voltage window due to oxidation under anodic potential and hydrogen evolution under high cathodic potential. Coupling Ti3C2Tx MXene negative electrode with RuO2 or carbon-based positive electrodes expanded the voltage window in sulfuric acid electrolyte to about 1.5 V. Here, we present an asymmetric pseudocapacitor using abundant and eco-friendly vanadium doped MnO2 as the positive and Ti3C2Tx MXene as the negative electrode in a neutral 1 M Li2SO4 electrolyte. This all-pseudocapacitive asymmetric device not only uses a safer electrolyte and is a much less expensive counter-electrode than RuO2, but also can operate within a 2.1 V voltage window, leading to a maximum energy density of 46 Wh/kg. This study also demonstrates the possibility of using MXene electrodes to expand the working voltage window of traditional redox-capable materials.[Figure not available: see fulltext.]
Bibliographical noteKAUST Repository Item: Exported on 2021-06-08
Acknowledged KAUST grant number(s): OSR-CRG2016-2963
Acknowledgements: This work was financially supported by the National Natural Science Foundation of China (Nos. 51972124, 51902115, and 51872101). Research reported in this publication was also supported by King Abdullah University of Science and Technology (KAUST) under the KAUST-Drexel Competitive Research Grant (No. OSR-CRG2016-2963 sub 11206). The authors express their gratitude to late Prof. J. Zhou for valuable discussions. The authors thank to the facility support of the Center for Nanoscale Characterization & Devices, WNLO-HUST and the Analysis and Testing Center, HUST.
ASJC Scopus subject areas
- Materials Science(all)
- Electrical and Electronic Engineering