Dual-drive mica-based magnetic composite phase-change materials for photothermal and magnetothermal conversion

To extend the applications of phase-change materials to multiple scenarios, Fe₃O₄ nanoparticles were deposited on the surface of mica with a layer-like structure using a simple method, and composite phase-change materials (CPCMs) with dual-driven energy conversion performance were subsequently obtained via vacuum impregnation. The addition of boron nitride (BN) and cellulose nanofibers (CNFs) endowed the CPCMs with higher thermal conductivity (0.85 W m⁻¹ K⁻¹) and lower specific heat capacity (1.42 MJ m⁻² K⁻¹), thereby constructing an effective heat transfer channel. The photothermal conversion efficiency of the CPCMs reached up to 88.36%. The magnetic Fe₃O₄ nanoparticles endowed the CPCMs with magnetic responsiveness, enabling the phase transition process to complete within just 112 s under a magnetic field. With a high phase-change material loading (82.65%), the CPCMs maintained excellent thermal stability during the energy conversion process. These results provide guidance for the preparation of CPCMs with multiple types of efficient energy conversion.