MXene-carbon nanotube composite electrodes for high active mass asymmetric supercapacitors

This article describes for the first time the fabrication of an asymmetric device, which is based on negative Ti3C2Tx (MXene)-multiwalled carbon nanotube (MCNT) electrodes and positive polypyrrole (PPy) coated MCNT electrodes. The approach involves the feasibility studies of new strategies for achieving enhanced electrochemical performance of high active mass (AM) MXene electrodes. Good material performance at high AM of 35 mg cm(-2) is linked to the application of multifunctional chelating dispersants for co-dispersion of Ti3C2Tx and MCNT and advanced water insoluble hydrophilic binders. The experimental results reveal the effect of the chemical structure of the dispersants and binders on electrode performance. Another important finding is the ability of achieving high capacitance of PPy-coated MCNT positive electrodes in a complementary potential range. The analysis of cyclic voltammetry data in Na2SO4 electrolyte for Ti3C2Tx-MCNT electrodes shows areal capacitance of 1.93 F cm(-2) which is substantially higher than literature results for pure Ti3C2Tx and Ti3C2Tx composites. Moreover, high capacitance is obtained at much lower electrical resistance. Especially important is the possibility of achieving higher capacitance equal to 0.94 F cm(-2) for the asymmetric supercapacitor in 0-1.6 V window, compared to literature data for symmetric supercapacitors with significantly lower capacitances in smaller voltage windows.

Automated summary

This article presents the fabrication of an asymmetric device using negative Ti3C2Tx-MCNT electrodes and positive PPy-coated MCNT electrodes, achieving enhanced electrochemical performance. Experimental results highlight the significance of multifunctional chelating dispersants and advanced water insoluble hydrophilic binders in improving electrode performance, as well as the high capacitance ability of PPy-coated MCNT positive electrodes. Additionally, the asymmetric supercapacitor demonstrated higher capacitance compared to symmetric supercapacitors in a wider voltage window, showcasing the potential for improved energy storage applications.