Metallurgical slag modified monolayer graphene hybrid SA-based composite phase change materials for high thermal conductivity.

Phase change materials are thermal energy storage materials with high heat storage density, low temperature loss and long cycle life. However, they also show a weak light absorption ability and low thermal conductivity, limiting their applicability for solar thermal conversion and storage technologies. In this paper, in order to improve the relatively low thermal conductivity of stearic acid and enhance its thermal conductivity, SGC-T composites with enhanced thermal conductivity were prepared using metallurgical slag, via the melt blending method. The SEM and EDS, surface scanning tests, were used to determine the morphology characteristics of the composite phase change materials and verify the addition of metallurgical slag. The physical phase composition, structure, and absorption coefficients were analyzed by XRD, FT-IR, and UV-Vis-NIR analyses. The thermophysical properties were analyzed by DSC. The thermal stability was explored using TG testing. The thermal conductivity was explored by measuring the thermal conductivity coefficient value of the samples at the testing temperature of 25 ℃ using the hot disk method/transient flat plate heat source method. The heat storage and exothermic capabilities of the samples were evaluated by the photo-thermal warming system/infrared thermography test. The results showed that the thermal conductivity of SGC was 0.663 W·(m·K)−1, and that of SGC-2 T, SGC-6 T, SGC-10 T, SGC-14 T, were 0.695 W·(m·K)−1, 0.758 W·(m·K)−1, 0.824 W·(m·K)−1 and 0.872 W·(m·K)−1, respectively, which are comparable to SGC. Compared with SGC, the thermal conductivity values of the four composite phase change materials increased by 4.8%, 14.3%, 24.3%, and 31.5%, respectively. SGC-14 T has the best heat transfer performance, which significantly improves the heat transfer performance during latent heat storage and release. Therefore, the SGC-14 T material reported in this work is a promising candidate in the field of energy-saving conversion, and further expands the applicability of phase change materials. • Metallurgical slag was used to the preparation of PCMs with high thermal conductivity. • Composites with high light absorption and high thermal conductivity were prepared. • Composites have great potential for future applications in solar collector devices. • The support provided by the support of national development project (No. 2021YFC1910603). [ABSTRACT FROM AUTHOR]