AlN micro-honeycomb reinforced stearic acid-based phase-change composites with high thermal conductivity for solar-thermal-electric conversion

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2023-05, Vol.11 (2), p.1727-1737
• Main Authors: Hu, Jiabin, Wei, Zhilei, Ge, Bangzhi, Zhao, Lei, Peng, Kang, Shi, Zhongqi
• Format: Article
• Language: English
• Subjects: Aluminum; Aluminum nitride; Combustion synthesis; Composite materials; Electric contacts; Energy conversion; Energy harvesting; Energy storage; Heat conductivity; Heat transfer; Industrial wastes; Phase change materials; Photothermal conversion; Solar energy; Stearic acid; Thermal conductivity; Thermal energy; Thermal management; Thermal resistance; Thermoelectric generators; Waste heat recovery
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d2ta08748k

Phase-change materials (PCMs) for efficient thermal energy harvesting have promising prospects for thermal energy storage and thermal management. However, the low intrinsic thermal conductivity (TC) of PCMs is a long-standing drawback due to a lack of a thermally conductive network inside them. Herein, a cost-effective route for preparing thermal-conductive phase-change composites by freeze-casting and combustion synthesis to obtain micro-honeycomb aluminum nitride (MH-AlN) reinforcements followed by the impregnation with liquid stearic acid (SA) was presented. The as-prepared MH-AlN/SA composite at 44.46 vol% AlN loading exhibited a high TC of 13.95 W m −1 K −1 parallel to the pore channels, up to 53.49-fold higher compared with that of pure SA. The contact thermal resistance between AlN particles can be greatly lowered via constructing a three-dimensional MH-AlN network inside the SA matrix. Additionally, a typical solar thermoelectric generator was devised and photothermal-electric energy transformation was successfully realized. Real-time recorded maximum output voltage and current were 409.0 mV and 110.8 mA, respectively. The enhancement of the heat transfer gives MH-AlN/SA phase-change composites more application prospects in industrial waste heat utilization and effective solar energy harvesting. The designed solar-thermal-electric device using the as-prepared MH-AlN/SA composite presents a high output voltage and current of 409 mV and 110.8 mA, respectively. Its peak output power density is high up to 113.3 W m −2 .