MXene base high specific energy supercapacitor research progress

[ Instrument Network Instrument Development ] Recently, Wu Zhongshuai, a researcher of the 2D Materials and Energy Devices Research Group of the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, and Wang Xiaohui, a researcher at the Institute of Metal Research of the Chinese Academy of Sciences, collaborated on the use of two-dimensional metal carbide MXene as the negative electrode. The positive electrode, hydroquinone-reactive hydroquinone is a positive electrode electrolyte additive, and a hydrogen ion “rocking chair” type high specific energy supercapacitor is constructed. The related results are published in the American Society of Chemistry-Nano (ACS Nano).

MXene is a kind of two-dimensional metal carbon (nitrogen) nanosheet with high volume specific capacity (1500F/cm3) and high specific capacity (380F/g). It is a very promising supercapacitor electrode material. However, most of the current reports are water-based symmetric supercapacitors, which have a problem of a narrow operating voltage window (generally 0.6 V), resulting in lower energy density. Therefore, in order to fully utilize the high specific capacity of MXene, it is urgent to develop high voltage supercapacitors to obtain high energy density.

Recently, the research team used Ti3C2Tx MXene as the negative electrode, carbon nanotubes as the positive electrode, sulfuric acid solution and sulfuric acid-hydroquinone mixture as the negative electrode and positive electrode electrolyte respectively, and the proton-selectively permeable Nafion membrane was used as the separator to construct hydrogen. Ion "rocking chair" type asymmetric supercapacitor. During charging and discharging, hydroquinone adsorbed on carbon nanotubes undergoes reversible deprotonation and protonation, providing high tantalum capacitance for the positive electrode; meanwhile, with the insertion and extraction of negative hydrogen ions, Ti3C2Tx The titanium element undergoes a reversible redox reaction. The obtained MXene-based asymmetric supercapacitor not only realizes the reversible rapid movement of hydrogen ions between the positive and negative electrodes, but also has a high operating voltage of 1.6V and a high energy density of 62Wh/kg, which is the currently reported water system MXene-based super The highest value of the capacitor. This work provides a new idea for the construction of MXene-based asymmetric, high-power supercapacitors.

The above work was funded by the National Natural Science Foundation of China and the National Key Research and Development Program.

(Original title: MXene base high specific energy supercapacitor research progress)