Ionogel Enhanced by Molecular Structure Engineering and Microphase Separation Synergy for Broadband Microwave Absorption and Light‐Controlled Thermal Management

ABSTRACT The development of materials that simultaneously offer broadband electromagnetic protection, optical transparency, mechanical flexibility, and intelligent responsiveness remains a formidable challenge in the advancement of next‐generation smart windows. In this study, a synergistic design strategy that integrates multi‐component molecular engineering with in‐situ microphase separation was introduced, leading to the successful fabrication of a novel multifunctional ionogel. This approach enables the spatial decoupling of the mechanical framework from ion transport and polarization domains within a nanoscale bicontinuous structure, effectively addressing the trade‐off between mechanical strength and ionic conductivity. The optimized ionogel demonstrates an ultra‐wide effective absorption bandwidth of 8.08 GHz at a remarkably thin thickness of 1.72 mm, along with high visible‐light transmittance exceeding 93% and excellent mechanical properties, including a fracture strain of 406%. Furthermore, by incorporating photochromic molecules, the material exhibits light‐gated microwave absorption characteristics with reversible bandwidth tuning and achieves passive radiative cooling exceeding 22.83°C under simulated sunlight. Differential charge density calculations further confirm electron accumulation at the hard/soft phase interfaces, providing atomic‐scale evidence for interfacial polarization. This work establishes a new paradigm of microstructure‐driven molecular design, opening a new avenue for the development of next‐generation electromagnetic protection and thermal management systems.