Minimizing Intersheet Junction Resistivity via Au₄Cu₂ Nanocluster-Based Connectivity in Mo₂TiC₂ MXene for Symmetric Supercapacitor Device

MXenes with their intrinsic metallic conductivity and redox versatility have emerged as frontrunners in the search for advanced energy storage materials. However, their energy storage capabilities are often hindered by the limited accessibility of electrolytes to active sites and enhanced electrical resistance due to the susceptibility to layer restacking. To address these challenges, a novel, ultrasmall Au₄Cu₂ nanocluster, strategically embedded within Mo₂TiC₂ MXene layers, is introduced. This integration is facilitated through precise interfacial local interactions, which govern the regulation of interlayer electron flow. The Au₄Cu₂ nanocluster modifies the local electron density, promoting a gradient in electronic conductivity throughout the MXene layers and acting as a nanoscopic bridge that counters the tendency for restacking. This approach markedly enhances the charge transfer efficiency and, consequently, the charge storage capacity. The nanoclusters/MXene composite-based symmetric supercapacitor provides superior energy density and power density. The findings reveal a sophisticated interface engineering strategy for the prevention of interlayer restacking of MXenes that significantly elevates their ability to store charge. © 2025 The Author(s). Small Structures published by Wiley-VCH GmbH.