Composite Anodes with Dual-Stage Charging for Efficient Dual-Band Electrochromic Devices

Achieving efficient and selective modulation in dual-band electrochromic devices remains challenging, due to the limited progress in controlling the spectral response of electrochromic anodes that can complement the advances in dual-band cathodes. In this work, we designed a composite anode consisting of layered vanadium oxide and nickel oxide nanocrystal films that operates through a dual-stage charging process. We demonstrate its performance in a full device in conjunction with a niobium oxide dual-band cathode. During coloration, vanadium oxide undergoes faradaic oxidation first, enabling near-infrared modulation of niobium oxide with minimal visible coloration. Upon further charging, nickel oxide contributes charge via capacitive processes, inducing visible-range tinting and thereby enhancing the overall dynamic optical response of the full device. As a result, the dual-band device employing this composite anode exhibits a high optical contrast of 56.1% at 550 nm and 71.2% at 1600 nm, with a dark mode transmittance of below 2% at 550 nm.