High-performance reflective-type Zn-ions electrochromic devices toward visible-to-infrared broadband dynamic regulation

Broadband electrochromic devices with reversible optical properties from visible to infrared wavelengths are highly desirable for various applications. Most current efforts are committed to increasing the broadband electrochromic performance of the materials or devices, while in-depth research about electrochromic mechanisms and ion transport processes is rarely reported. Herein, the Zn-ions migration kinetics at the atomic level of the reflective-type electrochromic electrode were systematically demonstrated by combining in-depth experimental analyses and theoretical calculations. Benefiting from the complementary synergistic effect between WO₃ electrochromic film and the bottom Au reflector, the obtained reflective-type Zn-ions electrochromic devices (ZECDs) not only could achieve a reversible color switch between yellow and black-green but also could dynamically adjust their infrared emissivity via applying different voltages. Importantly, the prototype thin-thickness and lightweight reflective-type ZECDs also exhibited reversible and stable electrochromic performances at various applied voltages and can still be maintained even at high temperatures. This work will provide a viable pathway to develop high-performance reflective-type ZECDs for dynamic broadband military camouflage and thermal management.