Passive isothermal film enabled by synergistic sky radiation energy harvesting and storage

The substantial energy demand associated with active heating, cooling, and ventilation presents a pressing challenge for sustainable development. Conventional systems rely heavily on electricity, contributing to environmental strain and high energy costs. Passive radiative cooling and solar heating offer promising alternatives but are often limited by the spatial-temporal mismatch between energy supply and demand, especially in arid climates with extreme diurnal temperature fluctuations. In a recent <i>Nature Communications</i> paper, Kim et al. reported a novel self-switchable passive isothermal film, co-driven by radiative cooling and solar heating, and coupled with sorption thermal energy storage and salt dissolution-based cold storage. This innovative design enables all-day temperature regulation in harsh climate conditions, offering a compelling solution for building energy conservation.