Interface engineering-driven amino/sulfide dual-functionalized MXene aerogel for highly ion-accessible charge storage system

Abstract

In the global transition to renewable energy, supercapacitors based on transition metal carbides/nitrides (MXenes) have garnered extensive attention for advanced energy storage technologies. However, their practical use is hindered by sheet restacking and surface oxidation. Herein, a thiourea-induced low-temperature strategy is reported for the fabrication of a three-dimensional (3D) amine/sulfur-functionalized Ti3C2Tx MXene aerogel (3D-NS-Ti3C2Tx). Here, thiourea acts as both a structural cross-linker via NH4+ intercalation to expand the interlayer spacing and form 3D pores and as a chemical modifier to replace some −OH/−F with active −NH2/−S groups. This modified structure significantly increases its specific surface area and porosity, mitigates the restacking and oxidation, and provides abundant active sites. The optimized electrode delivers the specific capacitance of 364 F g−1 at 2 mV s−1 and retains 82% of its capacitance after 10,000 cycles at 1 A g−1. The resulting symmetric supercapacitor delivers an energy density of 11.83 Wh kg−1 at 85 W kg−1. This work offers an effective strategy for enhancing MXene-based electrodes via functionalization and 3D structuring.