Porous Titanium Dioxide Foams: A Promising Carrier Material for Medium- and High-Temperature Thermal Energy Storage

The packaging capability and thermal conductivity of medium- and high-temperature shape-stabilized composite phase change materials (ss-CPCMs) should be further improved to achieve more excellent properties by encapsulating them into a more promising encapsulation material. Porous TiO2 foam (PTF) with a unique three-dimensional interconnected adjustable porous structure was prepared by a particle-stabilized emulsion method, which was used as the package carrier material to overcome the leakage problem and low conductivity of phase change materials (PCMs). LiNO3 and Na2SO4 were selected as the medium- and high-temperature PCMs, respectively, and two kinds of novelty ss-CPCMs were fabricated by impregnation under medium- and high-temperature environments. Scanning electron microscopy results showed that the PCMs were evenly distributed into the pores of PTF, and the excellent chemical compatibility between PCMs and PTF was confirmed by X-ray diffraction and Fourier transform infrared tests. Moreover, differential scanning calorimetry tests showed that the latent heat of LiNO3-PTF and Na2SO4-PTF ss-CPCMs was 264.1 and 102.3 J g(-1), which indicated that ss-CPCMs had excellent heat storage performance and adapted the demand of the medium- and high-temperature application. The thermal conductivities of LiNO3-PTF and Na2SO4-PTF ss-CPCMs were 2.80 and 1.69 W m(-1) K-1 which increased by 100 and 50%, respectively. Thermogravimetric analysis showed the excellent thermal stability of ss-CPCMs within the different application temperature ranges. Hence, PTF was a promising carrier material for medium and high-temperature thermal energy storage.