Aramid Nanofiber‐Based Multifunctional Phase Change Film for Photo/Electro‐Thermal Energy Conversion, Harvesting and Storage

Phase change materials (PCMs) are extensively utilized in energy storage and thermal regulation due to their superior energy density, tunable response temperature, and environmental friendliness. However, the leakage susceptibility, inferior electrical conductivity, and solar harvesting ability significantly limit their practical application. To address these issues, we propose encapsulating PCMs with aramid nanofibers/MXene hybrid shells by Pickering emulsion templates to prevent leakage, and the obtained PCMs-loaded microcapsules are further processed into phase change films. Aramid nanofibers were chosen as stabilizers and film-forming substances due to their appropriate wettability and outstanding mechanical strength. Hexadecanol (HD), possessing high enthalpy, was employed as the PCM. MXene served as photothermal and electrothermal additives, endowing PCMs with enhanced thermal conductivity and the capacity to convert sunlight and electricity into heat. The obtained HD@ANF/MXene PCM films exhibited excellent shape stability, mechanical properties, high latent heat, and efficient heat uptake/release. Under the optimized conditions, the HD encapsulation content exceeded 68.6 wt.%, and the corresponding latent heat exceeded 110 J/g. After 50 heating-cooling cycles, the enthalpy of HD@ANF/MXene PCM films still remained stable, which is expected to significantly expand the application of PCMs in electric, thermal, solar energy storage, and thermal management.