Synergistically enhanced NF/CNTs@ PDA/PEG composite phase change materials for high-efficiency solar-thermal energy storage and conversion

In order to solve the low thermal conductivity and leakage challenges of phase change materials (PCMs), a high-performance composite phase change material (CPCM) by integrating nickel foam (NF), carbon nanotubes (CNTs), and polydopamine (PDA) is developed. A three-dimensional (3D) porous NF/CNTs@PDA framework was constructed through oxidative self-polymerization of PDA on NF surfaces, followed by ultrasonic-assisted CNTs impregnation. CNTs-NF interfacial bonding was strengthened and interfacial thermal resistance was reduced by the PDA coating, as demonstrated in experimental results, leading to enhanced thermal conductivity. Light absorption and heat conduction were further optimized by CNTs. The optimized CPNF-9/PEG composite exhibited a thermal conductivity of 0.899 W m −1  K −1 , representing an 565.93 % enhancement over pure PEG (0.135 W m −1  K −1 ). The melting and crystallization enthalpies of the material were 121.13 J g −1 and 113.44 J g −1 respectively, and solar-thermal tests indicated a 95.37 % conversion efficiency. After 200 thermal cycles, the composite maintained stable phase change latent heat (loss rate <3 %) and structural integrity, indicating excellent cyclic durability. Furthermore, leakage resistance tests at 80 °C revealed minimal mass loss (2 % over 100 min), highlighting its suitability for high-temperature applications. The work provides a novel strategy for designing efficient solar-thermal energy storage systems, with potential applications in solar-thermal management and renewable energy conversion technologies.