Synthesis and Characterization of Metal Oxide-Based Microcapsules Including Phase Change Materials for Energy Storage Applications

In this study, microcapsules based on Cu2O containing different phase change materials (PCM) were prepared and characterized. The elemental, structural and electronic properties of the Cu2O-based microcapsules were characterized using several techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy and Fourier-transform infrared spectroscopy. In addition, the thermal properties of the microcapsules prepared were characterized in order to analyse their possible application as a thermal energy storage medium. Heating/cooling cycles using a differential scanning calorimetry technique were performed, and the phase change temperature and enthalpy were estimated. We observed good stability after the cycles. Furthermore, the encapsulation efficiency was estimated from melting and crystallization enthalpy values, reaching a value of 14.8% for the paraffin wax-based microcapsules. Finally, isobaric specific heat was measured to evaluate the storage capability of the encapsulated PCMs with regard to pure Cu2O to evaluate their possible application as a thermal storage system. An increase of around 140% was found in the isobaric specific heat for the microcapsules based on paraffin wax with regard to pure Cu2O.