BNNS/GO/PVA hybrid aerogel-stabilized paraffin wax phase change composites for integrated solar-thermal-electric conversion and thermal management

BNNS/GO/PVA hybrid aerogel with 3D anisotropic network is fabricated by ice-templating. • HGBP/PW composite achieves 91.17% PW loading and 197.8 J/g melting enthalpy with 121.83% enthalpy efficiency. • Vertical thermal conductivity of HGBP5/PW is enhanced by 360% to 1.15 W/(m·K) vs pure PW. • HGBP5/PW realizes 97.80% photothermal conversion efficiency and 228.9 mV photo-thermal-electric output voltage. • HGBP/PW composite exhibits excellent shape stability and robust cycling durability with negligible leakage. Phase change materials (PCMs) are promising for solar thermal energy storage but suffer from leakage, low light absorption and thermal conductivity. Herein, a shape-stabilized composite PCM (HGBP/PW) was prepared by encapsulating paraffin wax (PW) into a BNNS/GO/PVA hybrid aerogel via ice-templating and vacuum impregnation. The 3D anisotropic network is constructed with GO as framework and photo-thermal absorber, BNNS for thermal conduction, and PVA as mechanical support. HGBP/PW exhibits 91.17% PW loading, a melting enthalpy of 197.8 J/g and 121.83% enthalpy efficiency. Its vertical thermal conductivity reaches 1.15 W/m·K, 360% higher than pure PW. It reduces LED chip temperature by 46.41%, shows 97.8% photo-thermal conversion efficiency and excellent cycling stability. Efficient solar-thermal-electric conversion is also achieved under simulated and natural sunlight, with a maximum output voltage of 228.9 mV and maintaining a reliable 118.2 mV output. This work offers a scalable strategy for multifunctional PCMs toward thermal management and efficient solar energy utilization.