Dynamic ionic bond-enabled MXene-cellulose nanofiber composite phase change materials: Local bonding in molten state, global crosslinking in solid state

The dynamic ionic bonds effectively address the leakage issue of phase change materials through the reversible breaking and reformation of chemical bonds, offering an efficient and green preparation method. In this study, we successfully fabricated MXene-CNFs-PEG composite PCMs using an ultrasonic-assisted and ion-crosslinking method. This strategy leverages the strong intermolecular hydrogen bonding between one-dimensional cellulose nanofibers (CNFs) and two-dimensional Ti 3 C 2 T x (MXene) nanosheets, combined with metal ion crosslinking, to form a continuous three-dimensional network that effectively anchors organic phase change materials. It significantly reduces MXene agglomeration, delays oxidation and enhances the overall structural integrity. The non-rigid network structure imparts outstanding plasticity in the solid state, making the composite an ideal precursor for 3D printing and enabling the precise construction of complex architectures. MXene confers superior photothermal conversion efficiency, enabling integrated conversion of “photo-thermal-electric” energy conversion, successfully driving common electronic device. The composite PCMs have significant application value in fields such as 3D printing and multilevel energy conversion system.