Electrochromic Dynamic Windows with Redox Mediators

The construction and transportation sectors dominate global energy consumption, making intelligent opto-thermal regulation of building envelopes and vehicle windows critical for energy conservation and human comfort. While electrochromic (EC) dynamic windows offer significant potential, conventional technologies face scalability and cost barriers. Reversible metal electrodeposition (RME) presents a promising alternative, distinguished by its unique potential to efficiently control opto-thermal transmittance. However, the symmetric dual-electrode RME architectures, which are essential for uniform optical switching, have suffered from operational instability due to voltage-driven parasitic reactions. Herein, we introduce a unique strategy integrating redox mediators (RMs) into EC dynamic windows to overcome this limitation. Using poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) in the Cu and Bi-based RME hydrogel systems, we demonstrate accelerated interfacial kinetics and decreased overpotential. This reduces the operational voltage from -1.9 V to -1.2 V while enhancing long-term working stability (18,000 s vs. 180 s). The RM-engineered EC dynamic windows achieve 6 000 cycles without degradation and maintain stable optical modulation, with the apparent enhancement of optical switching speed. Crucially, the approach universally improves performance in traditional EC systems (e.g., tungsten oxides, viologen derivatives). This RM strategy establishes a material-agnostic platform technology, enabling scalable fabrication of next-generation dynamic glazing through a unified design paradigm.