Facile preparation and adjustable thermal property of stearic acid–graphene oxide composite as shape-stabilized phase change material

Abstract

In spite of the well-known desirable properties of organic PCMs like stearic acid (SA) for thermal energy storage, the leakage, high phase change temperature and poor thermal conductivity limit their direct applications. In this study, a novel shape-stabilized phase change material of stearic acid–graphene oxide (SA–GO) was fabricated by imprisoning SA in the interlayer spaces of the multilayer GO, based on the capillary action and interfacial interaction. The as-prepared SA–GO composites were characterized by the X-ray diffractometer, scanning electronic microscope, Fourier transformation infrared spectroscope, thermogravimetry analyzer and differential scanning calorimeter. The thermal properties of SA–GO composite could be tailored by adjusting SA/GO mass ratio. The SA–GO composite prepared from SA/GO mass ratio of 1 exhibited greatly decreased melting point (Tm) and freezing point (Tf) relative to those of the pristine SA, and the melting latent heat is 55.7J/g, corresponding to the thermal storage capability rate of 82.4%. The thermal behaviors of SA–GO composites with different SA/GO mass ratios were explained from the point of confinement effect, which were further confirmed by comparison with those of SA–graphite and SA–active carbon composites. The present research provides a novel shape-stabilized composite PCM for the thermal energy storage as well as some new insights into phase change behavior of organic PCMs in nanoconfined geometries.