Polyaniline microspheres using potassium polyvinyl sulfate as template for large-area broadband electrochromic device with large infrared emissivity variation.

• The polyaniline film's morphology and performance were improved by using potassium polyvinyl sulfate as a soft template. • A large-area electrochromic device with a size of 20 × 20 cm ² was prepared. • The device achieved emissivity changes of 0.55 (3-5 μm), 0.46 (8-14 μm) and 0.46 (2.5-15 μm). • At a background temperature of 70 ℃, the device achieved an infrared temperature change of 10.4 ℃. • The electrochemical activity of the device did not decay in a high-temperature environment of 30 ℃ to 70 ℃. In the development of polyaniline (PANI) based large-area broadband electrochromic devices, we employed a controlled deposition process using potassium polyvinyl sulfate (PVSK) as a template to regulate the morphology of PANI. This resulted in consistent spherical particle morphology and heightened electrochemical activity in PVSK-PANI films. The simple structure of PVSK, coupled with its similar IR absorption to polyethylene and sulfuric acid, mitigated any detrimental effects on the broadband electrochromic properties. In small-area (2 × 2 cm²) PVSK-PANI electrochromic devices, we observed maximum emissivity changes of 0.47, 0.51, and 0.49 in the 3-5 μm, 8-14 μm, and 2.5-15 μm ranges, respectively. Expanding our approach to large-area devices (20 × 20 cm2), we achieved even more promising results. The PVSK-PANI based electrochromic devices achieved maximum emissivity changes of 0.55, 0.46, and 0.46 within the same spectral ranges of 3-5 μm, 8-14 μm, and 2.5-15 μm, respectively. Notably, these large-area electrochromic devices demonstrated a remarkable capacity to modulate infrared temperature by up to 10.4 °C at a background temperature of 70 °C. By introducing PVSK as a soft template during the electrochemical deposition process of PANI, the micro-morphology of PANI is effectively controlled. This has led to the fabrication of a high-performance, large-area (20 × 20 cm²) ECD. [Display omitted] [ABSTRACT FROM AUTHOR]