ZIF-67@MXene Structure Synergistically Improve Heat Storage and Photothermal Conversion of Phase Change Material

How to design and construct the MOF-based composite phase change materials (PCMs) with simultaneously enhanced heat storage and photothermal conversion to meet the performance requirement of solar energy uti-lization still remains a challenge. Herein, the polyethylene glycol was selected as PCM, the ZIF-67@MXene acted as supporting structure, a series of polyethylene glycol/ZIF-67@MXene form-stable composite PCMs (PZM fs-CPCMs) with improved latent heat and photothermal conversion were designed and prepared. All the PZM fs-CPCMs showed obvious heat storage and release characteristics, and their latent heat reached similar to 106.01 J/g. Furtherly, the latent heat loss of PZM40 was only 1 % after 100 phase change cycles, indicating outstanding thermal reliability, which was closely related to the structure and morphology of the PZM fs-CPCMs. More importantly, during irradiation, the maximum surface temperature of PZM fs-CPCMs regularly increased (42.5-45.2 degrees C) with increasing ZIF-67@MXene content, while during cooling, it regularly decreased (27.4-23.2 degrees C). Based on the surface temperature distribution results, the photothermal conversion ability and heat transfer rate of PZM fs-CPCMs were effectively improved, which was mainly attributed to the remarkable light absorption and conversion ability and high thermal conductivity of MXene. Meanwhile, the PZM fs-CPCMs showed good chemical compatibility, crystallinity characteristic and thermal stability, which was conducive to the solar energy utilization.