Polyaniline@graphdiyne composite films for high-performance electrochromism and radiative thermal management via synergistic optimization of electron/ion transport

The electrochromic performance of polyaniline (PANi) is primarily restricted by its wide energy bandgap ( E g ) and dense microstructure. In this study, PANi@graphdiyne (GDY) composite films featuring molecular-level interfacial coupling and a three-dimensional porous structure were fabricated via a one-step electrochemical deposition method. Density functional theory (DFT) calculations indicate that the π-π conjugative interaction between PANi and GDY narrows the E g from 4.14 eV to 1.37 eV, significantly enhancing the electron transport capability. The GDY-induced loose porous structure elevates the ion diffusion coefficient by four orders of magnitude (reaching 1.36 × 10 -8 cm 2 ·s -1 ). Benefiting from the synergistic optimization of dual-carrier (electron/ion) transport kinetics, the composite film delivers exceptional electrochromic performance, including a high optical contrast (65.97% at 1092 nm), a high coloration efficiency (97.18 cm 2 ·C -1 ), and superior cycling stability (retaining 76% of its initial contrast after 850 cycles). Meanwhile, the film achieves a radiative temperature tuning range of 11.2°C. The introduction of GDY not only overcomes the bottlenecks of low intrinsic conductivity and sluggish ion transport kinetics in PANi but also endows the film with exceptional thermal radiation modulation capability, providing a new strategy for designing high-performance electrochromic films and thermal management devices.