Bifunctional wood-based phase change composites: Exceptional magnetothermal and photothermal conversion capabilities

Recently, wood-based phase change materials have broad research prospects in energy management materials, but their complex preparation process, low thermal conversion efficiency, and poor heat storage capacity still limit their application. This study successfully prepared magnetic wood-based phase change materials (MWPCM) composed of delignified wood (DW), magnetic ferrosoferric oxide (Fe 3 O 4 ) nanoparticles, and polyethylene glycol (PEG) through a two-step method. The incorporation of PEG significantly improved the thermal energy storage capabilities while mitigating the heat loss during the conversion process of the MWPCM. Consequently, the MWPCM could maintain about 90 °C after being exposed to sunlight for 10 min at a light intensity of 1 sun, and it could sustain a stable temperature of about 50 °C for approximately 500 s following the shutoff of the xenon lamp, indicating remarkable thermal storage efficiency. Moreover, the MWPCM demonstrated rapid heating capabilities when subjected to alternating magnetic fields. Additionally, the MWPCM maintained stability even at temperatures below 220 °C, exhibiting superior thermal stability. The MWPCM demonstrated outstanding magnetic properties, photothermal conversion, and magnetothermal conversion performance, rendering it an invaluable type of inductive heating and thermal energy storage material with substantial practical applications.