Electrochromic Smart Windows with On‐Demand Photothermal Regulation for Energy‐Saving Buildings

Abstract

Abstract Electrochromic smart windows with dynamic photothermal management can enhance living comfort and reduce building energy consumption. However, they usually suffer from low selectivity and optical modulation in visible (VIS) and near‐infrared (NIR) regions owing to the coupled mechanism restriction. Here, the reversible deposition and ion adsorption in WO 3 //MnO 2 ‐based smart windows are decoupled using a hybrid electrolyte, realizing their independent and efficient VIS–NIR regulation. The Cu 2+ /Mn 2+ ions in the hybrid electrolyte enhance proton adsorption on the WO 3 surface while impeding proton insertion, imparting state‐of‐the‐art NIR regulation to the WO 3 electrode. Moreover, the synergy of protons and Cu 2+ /Mn 2+ ions facilitates reversible MnO 2 electrodeposition on the electrode, triggering independent tuning of VIS light with an optical modulation of 94%. The outdoor test and simulation reveal that the smart window achieves cooling at 5–10 °C, an energy savings of 73.2 MJ m −2 and a reduction of 14.4 kg of CO 2 emissions per square meter of the building annually. This work would contribute to energy‐saving and emission‐reduction solutions in widespread applications.