Nitrogen-Doped MXene Electrodes for High-Voltage Window Supercapacitors in Organic Electrolytes

MXene has excellent electrochemical performance in aqueous electrolytes; however, its narrow voltage window (hydrolysis voltage ≤ 1.2 V) limits the energy density of supercapacitors. Compared to conventional aqueous electrolytes, ionic liquid (IL) electrolytes exhibit a much larger voltage window, b...

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Main Authors: Yingyi Liao, Xiaoqing Bin, Jing Xu, Xuedong He, Wenxiu Que
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Chemistry
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Online Access:https://www.mdpi.com/2624-8549/7/1/13
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author Yingyi Liao
Xiaoqing Bin
Jing Xu
Xuedong He
Wenxiu Que
author_facet Yingyi Liao
Xiaoqing Bin
Jing Xu
Xuedong He
Wenxiu Que
author_sort Yingyi Liao
collection DOAJ
description MXene has excellent electrochemical performance in aqueous electrolytes; however, its narrow voltage window (hydrolysis voltage ≤ 1.2 V) limits the energy density of supercapacitors. Compared to conventional aqueous electrolytes, ionic liquid (IL) electrolytes exhibit a much larger voltage window, but their larger ion size limits the transport and intercalation of IL cations in MXene electrodes. Therefore, the electrochemical performances for three different types of organic electrolytes based on nitrogen-doped MXene electrodes in supercapacitors were investigated, with the voltage windows of the devices effectively widened to 2.4 V. In addition, the nitrogen-doped MXene electrodes also effectively adjusted the interlayer spacing of the MXene nanosheets, with the enlarged interlayer spacing (from 12.60 Å to 14.24 Å) being more favorable for the intercalation and de-intercalation of larger-sized organic ions within the electrodes, thus effectively storing a charge. Among them, the 1 M EMIMTFSI/LiTFSI/ACN electrolyte is optimal due to the introduction of a smaller ion size for Li<sup>+</sup>, and so the corresponding supercapacitor achieves the electrode capacitance of up to 147 F g<sup>−1</sup>, with the maximum energy density of 29.4 Wh kg<sup>−1</sup>. This work provides a new strategy for reasonably optimizing the design of organic electrolytes matching modified MXene electrodes to effectively enhance the energy density of supercapacitors.
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spelling doaj-art-e545e750a5ff4c4dab8bf991307173632025-08-20T02:44:49ZengMDPI AGChemistry2624-85492025-01-01711310.3390/chemistry7010013Nitrogen-Doped MXene Electrodes for High-Voltage Window Supercapacitors in Organic ElectrolytesYingyi Liao0Xiaoqing Bin1Jing Xu2Xuedong He3Wenxiu Que4Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, International Center for Dielectric Research, Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaElectronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, International Center for Dielectric Research, Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaElectronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, International Center for Dielectric Research, Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaElectronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, International Center for Dielectric Research, Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaElectronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, International Center for Dielectric Research, Shaanxi Engineering Research Center of Advanced Energy Materials and Devices, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, ChinaMXene has excellent electrochemical performance in aqueous electrolytes; however, its narrow voltage window (hydrolysis voltage ≤ 1.2 V) limits the energy density of supercapacitors. Compared to conventional aqueous electrolytes, ionic liquid (IL) electrolytes exhibit a much larger voltage window, but their larger ion size limits the transport and intercalation of IL cations in MXene electrodes. Therefore, the electrochemical performances for three different types of organic electrolytes based on nitrogen-doped MXene electrodes in supercapacitors were investigated, with the voltage windows of the devices effectively widened to 2.4 V. In addition, the nitrogen-doped MXene electrodes also effectively adjusted the interlayer spacing of the MXene nanosheets, with the enlarged interlayer spacing (from 12.60 Å to 14.24 Å) being more favorable for the intercalation and de-intercalation of larger-sized organic ions within the electrodes, thus effectively storing a charge. Among them, the 1 M EMIMTFSI/LiTFSI/ACN electrolyte is optimal due to the introduction of a smaller ion size for Li<sup>+</sup>, and so the corresponding supercapacitor achieves the electrode capacitance of up to 147 F g<sup>−1</sup>, with the maximum energy density of 29.4 Wh kg<sup>−1</sup>. This work provides a new strategy for reasonably optimizing the design of organic electrolytes matching modified MXene electrodes to effectively enhance the energy density of supercapacitors.https://www.mdpi.com/2624-8549/7/1/13MXenenitrogen dopedionic liquidhigh-voltage windowsupercapacitors
spellingShingle Yingyi Liao
Xiaoqing Bin
Jing Xu
Xuedong He
Wenxiu Que
Nitrogen-Doped MXene Electrodes for High-Voltage Window Supercapacitors in Organic Electrolytes
Chemistry
MXene
nitrogen doped
ionic liquid
high-voltage window
supercapacitors
title Nitrogen-Doped MXene Electrodes for High-Voltage Window Supercapacitors in Organic Electrolytes
title_full Nitrogen-Doped MXene Electrodes for High-Voltage Window Supercapacitors in Organic Electrolytes
title_fullStr Nitrogen-Doped MXene Electrodes for High-Voltage Window Supercapacitors in Organic Electrolytes
title_full_unstemmed Nitrogen-Doped MXene Electrodes for High-Voltage Window Supercapacitors in Organic Electrolytes
title_short Nitrogen-Doped MXene Electrodes for High-Voltage Window Supercapacitors in Organic Electrolytes
title_sort nitrogen doped mxene electrodes for high voltage window supercapacitors in organic electrolytes
topic MXene
nitrogen doped
ionic liquid
high-voltage window
supercapacitors
url https://www.mdpi.com/2624-8549/7/1/13
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AT xiaoqingbin nitrogendopedmxeneelectrodesforhighvoltagewindowsupercapacitorsinorganicelectrolytes
AT jingxu nitrogendopedmxeneelectrodesforhighvoltagewindowsupercapacitorsinorganicelectrolytes
AT xuedonghe nitrogendopedmxeneelectrodesforhighvoltagewindowsupercapacitorsinorganicelectrolytes
AT wenxiuque nitrogendopedmxeneelectrodesforhighvoltagewindowsupercapacitorsinorganicelectrolytes