Asymmetric photothermal aerogels: A multifunctional strategy for adaptive building thermal management and energy efficiency

In the relentless pursuit of energy-efficient buildings, the development of thermal insulating materials with adaptive solar modulation stands as a game-changer for reducing the hefty energy consumption of heating, ventilation, and air conditioning systems. Herein, we introduce an innovative asymmetric assembly strategy to craft multifunctional aerogel materials exhibiting remarkable asymmetric photothermal properties. By synergistically integrating the solar-thermal conversion efficiency of black phosphorus (BP), the superior thermal insulation of cellulose nanofiber (CNF) aerogels, the unique asymmetric photothermal behavior of silver nanowire (AgNW)/eicosane (C20) structures, near-infrared radiation heating, electrical heating capabilities, and the latent heat compensation of C20, we have engineered a BP/CNF + AgNW/CNF/C20 bilayer multifunctional composite phase change aerogel. This avant-garde bilayer aerogel acts as a high-efficiency energy storage medium within buildings, effectively smoothing out internal temperature fluctuations. Impressively, it maintains a comfortable internal interface temperature of 41 °C even when the external environment dips to a chilly −5 °C, delivering superior thermal buffering through its phase change dynamics and insulation capabilities that far surpass existing insulation materials. This pioneering bilayer design opens up new horizons for the development of adaptive building thermal management systems suited to diverse environmental conditions.