The magnesium nitrate hexahydrate with Ti4O7 composite phase change material for photo-thermal conversion and storage

• The MCT-10 has optical absorption and thermal storage properties. • The absorption capacity of the composite phase change materials is 83.86%. • The optical photo-thermal conversion and storage efficiency is 78.60%. • Ti 4 O 7 was an importance factor in facilitating solar to heat for MNH based phase change materials. Photo-thermal conversion and storage phase change material has been obtained much attention recently because that the solar radiation energy can be absorbed, the absorbed solar energy is converted into heat energy and the heat energy can be stored in materials. In this paper, Ti 4 O 7 was selected as the photo-thermal conversion material with full band light absorption (200–2500 nm) and high conversion capacity from light to thermal. Magnesium nitrate hexahydrate/Ti 4 O 7 composites were prepared via melt mixing technique. The comprehensive and systematical characterizations were performed, including X-ray diffraction (XRD), Differential scanning calorimeter (DSC), Fourier transform infrared spectroscopy (FTIR), photo-thermal conversion performances, corrosion test, etc. Experiment results showed Ti 4 O 7 as photothermal conversion materials played an important effect to improve the absorption capacity of composites from 46.54% of pure MNH to 83.86% of MCT-10. MCT-10 has a high energy storage density of 192.17 kJ·kg −1 and the efficiency of photo-thermal conversion and storage is approximately 78.60%. Therefore, this new phase change material is an attractive and efficient heat utilization method for solar thermal storage energy systems which contributes to alleviate the energy crisis.