Interfacially Self-Assembled Ti3C2Tx Conductive Scaffolds for Enhanced Electrochromic Performance of WO3 Nanoparticle Films

Abstract Tungsten oxide (WO3) is a promising electrochromic (EC) material, yet its low electrical conductivity and sluggish ion-transport limit its switching kinetics and cycling stability. Herein, we construct a hierarchical two-dimensional/zero-dimensional (2D/0D) Ti3C2Tx MXene/WO3 composite film via interfacial self-assembly and electrochemical deposition. Interconnected Ti3C2Tx nanosheets serve as a conductive scaffold, and their excellent electrical conductivity significantly reduces the charge transport barrier, while uniformly distributed WO3 nanoparticles (≈65 nm) provide abundant electroactive interfaces and shortened ion-transport pathways. By optimizing the tungsten-ion concentration, deposition voltage, and deposition time, the Ti3C2Tx/WO3 composite film exhibits an optical modulation of 50.93% at 600 nm, with coloration and bleaching times of 12.06 and 13.29 s, respectively. The film retains 98.15% of its initial optical modulation after 1200 s of continuous cycling, compared with 58.41% for neat WO3. These improvements originate from the synergistic effect of Ti3C2Tx and WO3. Ti3C2Tx facilitates charge transport, whereas nanoscale WO3 enhances electrolyte accessibility and facilitates ion diffusion, collectively accelerating the electrochemical reaction kinetics. This work establishes a rational 2D/0D architecture for coupling rapid electron and ion transport and offers a viable strategy for high-performance electrochromic devices.