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

Abstract 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.