High-Stretchable Solid–Solid Phase Change Aerogel Surface-Modified with Ni-MOF for Efficient Photothermal Energy Conversion-Storage and Thermal-Induced Shape Programming

Phase change materials (PCMs) hold significant potential for thermal energy storage, yet their application is often hindered by leakage and structural instability. Therefore, a high molecular weight polyethylene glycol (HPEG)-based solid–solid phase change aerogel (SSPCA) is fabricated, exhibiting high stretchability and outstanding energy storage efficiency. More importantly, the solid–solid phase change process completely avoids leakage. After surface-modification with Ni 3 (2, 3, 6, 7, 10, 11-hexaiminotriphenylene) 2 (Ni-HITP) metal-organic framework (MOF), the obtained nanofunctionalized SSPCA (HPA/Ni-HITP aerogel) is endowed with efficient photothermal conversion capability. HPA/Ni-HITP aerogel exhibits high encapsulation efficiency ( E en , 98.6%), phase change enthalpy (123.48 J g −1 ), low thermal conductivity (0.062 W m −1 K −1 ) and excellent mechanical property (elongation of 535%), thermal stability and reliability with outstanding shape-stability, and infrared light-thermal conversion and storage efficiency of 90.15%. Moreover, HPA/Ni-HITP aerogel presents distinctive thermal-induced shape memory and reconfigurability, enabling programmable transformations via thermal stimuli. These attractive features make HPA/Ni-HITP aerogel a potential material for flexible wearable thermal management, energy conversion storage, and shape programming applications, which provides a promising method for fabricating multifunctional solid–solid phase change aerogel without leakage.