Thermally induced flexible phase change composites with enhanced thermal conductivity for solar thermal conversion and storage

Abstract

Organic phase change materials (PCMs) composites with thermally induced flexibility, lower interfacial thermal resistance, excellent stability, photo-absorption, higher thermal conductivity, good photo-thermal conversion and storage properties present better prospects in solar thermal application. This research prepared flexible PCMs composite by taking palmitic acid (PA) as PCMs, olefin block copolymers (OBC) as carriers and graphene nanoplatelets (GNP) as additive by blending and hot-pressing method. The unique block structure of OBC, excellent performance of GNP and interaction between GNP and PA provide OBC/GNP/PA composites good flexibility, excellent stability and thermal reliability. GNP as effective solar trap and thermal conductive additive are attribute to the sunlight capture, high solar energy conversion and transportation. The photo-thermal conversion efficiency of OBC/GNP/PA PCMs composites with 4 wt % GNP reaches 86.21%. The thermal conductivity is 155% higher than PA/OBC. The phase change enthalpy is 145.52 J/g for adsorbing 77.6 wt% PAand 4 wt% GNP. PCMs composites show excellent energy storage properties. Practical and easy preparation method and excellent performances of OBC/GNP/PA composites provide a good idea and more possibility for flexible PCMs composites with enhanced thermal conductivity in low and medium temperature solar thermal application. • Thermal induced flexible PCM composites with enhanced thermal conductivity for high-efficiency solar thermal conversion and storage is developed. • The OBC/GNP/PA composites exhibit excellent thermally induced flexibility, good shape stability and thermal reliability. • The highest efficiency of photo-thermal conversion is up to 86.21%. • The thermal conductivity is 155% improvement over PA/OBC. • High photo-thermal energy storage and practical preparation show huge potential for solar thermal-energy applications.