Preparation and Photothermal Properties of Accordion‐Like MXene/Sodium Acetate Trihydrate Composite Phase Change Materials

Phase change materials (PCMs) are promising options for thermal energy storage. Combining sodium acetate trihydrate (SAT) with MXene, the composite phase change materials (CPCMs) have been prepared. The surface morphology, thermal storage performance, and solar energy photothermal conversion efficiency of the CPCMs with various MXene contents are analyzed. According to the microstructure morphology analysis, MXene is accordion‐shaped, and tightly associated with SAT. Differential scanning calorimetry measurement results show that CPCMs possess high latent heat and suitable phase change temperature for the applications of solar heat storage. The absorption wavelength range of SAT/MXene is extended from 200–258 nm to 200–497.7 nm with a photothermal conversion efficiency of 81.3%. SAT/MXene‐2%, SAT/MXene‐8%, and SAT/MXene‐14% have thermal conductivities of 0.84, 1.14, and 1.47 W/ (m · K), respectively, which are higher by 44.9%, 96.6%, and 153.4% than 0.59 W/ (m · K) of pure SAT. CPCMs exhibit excellent thermal stability and reliable cycling stability after 50 cycles, which show that MXene can prevent leakage during the solid‐liquid phase transition process. The expansion of PCM's practical applicability and MXene/SAT composites with good photothermal characteristics create a theoretical foundation for the effective use of renewable energy sources.