Dual-Functional Polyimide-Based Phase Change Composite Aerogels with Latent Heat Storage and Radiative Cooling Capabilities for Energy-Efficient Buildings
Building heating and cooling account for 60% of operational energy consumption, and conventional radiative coolers suffer from thermal accumulation and high-temperature damage under continuous solar irradiance. This work reports a dual-functional polyimide (PI)-based phase change composite aerogel that integrates latent heat storage with radiative cooling. Carbonized PI fibers (CPIF) were fabricated via electrospinning, dispersed in polyamic acid aqueous solution, and freeze-dried followed by thermal imidization to yield CPIF/PI aerogels (CPs). Vacuum impregnation with molten polyethylene glycol (PEG) produced CPIF/PI phase change materials (CPPCMs), which were surface-coated with boron nitride (BN) to obtain shape-stable BN@CPPCMs. CPIF enhances thermal conductivity and, through compatibility with the PI matrix, improves structural stability. The BN coating raises solar reflectivity, suppressing operational temperature rise. The composite prevents single-function radiative coolers from thermal accumulation and high-temperature damage, achieving high enthalpy efficiency and effective temperature regulation. The protocol addresses the bottleneck of insufficient indoor temperature regulation in energy-efficient buildings by combining solar-thermal conversion and storage with passive radiative cooling in a single shape-stable architecture.