Superhydrophobic Shape-Stable Phase-Change Materials Based on Artificially Cultured Diatom Frustule-Derived Porous Ceramics

Abstract

Solid–liquid phase-change materials (PCMs) offer exciting potential for energy conservation, but they suffer from a vital drawback of significant leakage. To overcome this issue, we develop a new strategy to obtain high-performance leakage-proof shape-stable phase-change materials (ss-PCMs) by the combination of an inner porous frame and outer superhydrophobic covers. Paraffin wax as PCM was first trapped into artificially cultured diatom frustule-derived porous ceramics, which was then encapsulated using diatom frustule-based superhydrophobic coatings. The prepared ss-PCMs exhibit a wax loading of 52.28 wt % with a melting enthalpy of 117.5 J·g–1 and a high stability even after 500 thermal cycles as well as a 72.7% increase in thermal conductivity. In addition, the prepared ss-PCMs show a compressive strength of as high as 13.0 MPa. The superhydrophobic coatings provide ss-PCMs with superior chemical resistance and excellent mechanical robustness under long-distance abrasion, cyclic tape-peeling, and water jet impact. This porous ceramic-embedded, superhydrophobic coating-encapsulated strategy for obtaining high-performance ss-PCMs is expected to find potential applications in energy-efficient buildings, thermal management in electronic devices, self-cleaning materials, and so on.