Methylene blue functionalized 3D MXene aerogel: Self-assembly by interfacial electrostatic interaction for asymmetric supercapacitors

2D MXene materials show great potential in energy storage systems. However, 2D layered materials always face challenges of stacking and collapsing, inhibiting its application. Herein, an efficient and facile strategy has been employed to induce self-assembly of MXene nanosheets by introducing Methylene blue (MB) molecule, forming a 3D porous MXene/MB (MX/MB) composite. The unique structure suppresses stacking and oxidation of MXene flakes, ensures sufficient electrochemical active sites as well as shortens ion transport length. At the mass ratio of MXene/MB is 3/1, MX/MB-3 exhibits optimal specific capacitance of 327 F g-1 at 2 A g-1 and retains its initial capacitance without attenuation (10,000 cycles at 10 A g 1). Furthermore, the as-assembled TH/N-rGO//MX/ MB-3 asymmetric device not only possesses high energy density of 23.3 Wh kg-1 at power density of 780.2 W kg-1, but also demonstrates excellent cycling stability (94.4% capacitance retention after 10,000 cycles). This device design demonstrates that the preparation of high-performance MXene-based electrodes is an effective strategy to facilitate the development of energy storage device.

Automated summary

2D MXene materials have potential in energy storage systems, but their application is hindered by challenges of stacking and collapsing. This study introduces an efficient and facile strategy to induce self-assembly of MXene nanosheets by using Methylene blue (MB) molecule, forming a 3D porous MXene/MB composite. The resulting MX/MB-3 exhibits optimal specific capacitance of 327 F g-1 at 2 A g-1 and retains its initial capacitance without attenuation after 10,000 cycles at 10 A g-1. Furthermore, the assembled TH/N-rGO//MX/MB-3 asymmetric device shows high energy density of 23.3 Wh kg-1 at power density of 780.2 W kg-1 and excellent cycling stability (94.4% capacitance retention after 10,000 cycles).