Multifunctional lamellar aerogel phase-change composites for integrated thermal management, electromagnetic shielding and photothermal conversion

Efficient thermal management materials are required for electronics and energy systems where heat accumulation, electromagnetic interference and intermittent solar input coexist. Polyethylene glycol (PEG) phase-change materials offer latent heat storage, but their practical application is limited by leakage, low thermal conductivity, weak light absorption and insufficient electromagnetic attenuation. Herein, a lamellar aerogel-confined PEG composite was prepared by directional freeze-casting of reduced graphene oxide (rGO), carboxylated multiwalled carbon nanotubes (MWCNT-COOH) and sodium carboxymethyl cellulose (CMC), followed by carbonization and vacuum impregnation with PEG. The resulting PEG@((MWCNT-COOH)-CMC-rGO) preserves the crystalline phase of PEG and provides oriented channels, carbon-based heat-transfer pathways and capillary confinement. The composite delivers a melting enthalpy of 180.90 J g −1 and a crystallization enthalpy of 170.25 J g −1 . Its thermal conductivity reaches 0.449 W m −1 K −1 , 30.9% higher than pure PEG, with good shape stability and leakage resistance. It also achieves absorption-dominated electromagnetic shielding effectiveness of 21.20 dB at 12–18 GHz and a repeatable photothermal response over three irradiation cycles. This work demonstrates a multifunctional phase-change composite integrating heat storage, thermal conduction, electromagnetic shielding and photothermal conversion.