Study on the photothermal conversion enhancement performance and application of the metal-polyphenol phase-change microcapsules modified by molybdenum disulfide

Aiming to improving photothermal conversion and heat storage efficiency, layered molybdenum disulfide (MoS2) was prepared with hydrothermal method, which was used as the thermally conductive and photothermal conversion material to modify metal-polyphenol (MPN) /paraffin (PA) microcapsules. The fabricated phase-change microcapsules (MoS2/MPN@PA-MEPCM) exhibits excellent thermal conductivity, photothermal conversion and heat storage performance. The effect of the additive amount of MoS2 on the leakage performance, microstructure, thermal conductivity, heat storage capacity, thermal stability and photothermal conversion performance of MoS2/MPN@PA-MEPCM was investigated. Furthermore, the enhancement mechanisms of the thermal conductivity and photothermal conversion were analyzed. The results show that when the additive amount of MoS2 is 10 wt%, the phase-change enthalpy of MoS2/MPN@PA-MEPCM reaches 127.1 J/g with an encapsulation ratio of 53.74 %. Compared to MPN@PA-MEPCM, the thermal conductivity of MoS2/MPN@PA-MEPCM increases by 88.45 % and the photothermal conversion and heat storage efficiency reaches 90.78 %. When the solar radiation intensity is 800 W/m2 and 1000 W/m2, the thermal efficiency of PFPSC is 57.17 % and 59.45 % respectively, which is higher than that of FPSC. The operation time of PFPSC is extended by 2435 s and 2750 s, respectively, improving the operational stability of flat plate solar water heaters. The developed microcapsules in this study demonstrate significant potential for highly efficient solar energy utilization and thermal energy storage in the fields of seawater desalination, solar water heating system and building heating.