Conventional electrochromic devices suffer from inherently coupled visible/near-infrared modulation, high fabrication costs and poor cycling stability, limiting their adaptive energy-saving applications in buildings. This work develops a high-performance aqueous electrochromic device based on a cation–anion co-intercalation mechanism. Rather than relying on intrinsically dual-band functional materials, the synergistic co-intercalation and de-intercalation of dual ions enables independent optical and thermal modulation at the device level. The fabricated device delivers fast switching kinetics, high optical contrast and excellent cycling stability, while the aqueous electrolyte system avoids the safety hazards and high costs of organic electrolytes. Further integrated with building-adaptive hierarchical control, the proposed strategy effectively resolves the trade-off between daylight utilization and thermal management, achieving optimized energy-saving performance for low-carbon buildings.
 

Electrochromic devices,multi-band modulation,cation-anion co-intercalation