Multifunctional wood based composite phase change materials for magnetic-thermal and solar-thermal energy conversion and storage

Highlights: • Balsa wood as supporting material has high loading content of PCMs over 80%. • The composites have high energy storage capacity and good thermal reliability. • The composites exhibit excellent magnetic property and magnetothermal effect. • The addition of Fe₃O₄ improves the solar-to-thermal conversion efficiency. -- Abstract: In recent years, multifunctional form-stable composite phase change materials have been the research focus in the field of thermal energy storage. In this work, magnetic wood-based composite phase change materials are prepared via the impregnation of a compound of 1-tetradecanol and Fe₃O₄ nanoparticles into delignified balsa wood. Delignified balsa wood, which has porous structure with low density and high loading content of over 80%, was used as a supporting material. The addition of Fe₃O₄ nanoparticles provides an excellent magnetic property and improves the solar-to-thermal conversion efficiency of the composite. Benefiting from the magnetothermal effect, the magnetic wood-based composite phase change materials can be heated under an alternating magnetic field. Also, the magnetic wood-based composite phase change materials exhibit large latent heat (179 J/g), excellent thermal reliability after 100 heating-cooling cycles, and outstanding shape stability. And they have good thermal stability below 112 ℃. Considering the easy processing and excellent property, the magnetic wood-based composite phase change materials have great prospect in multifunctional thermal energy storage in practical applications.