Fabrication of Form-Stable Phase Change Materials Based on Mechanically Flexible SiO₂ Nanofibrous Mats for Thermal Energy Storage/Retrieval

For overcoming the fragility of inorganic supporting materials as form-stable phase change materials (FSPCMs), flexible and soft SiO₂ nanofibrous mats were applied as supporting materials of FSPCMs for storage/retrieval of thermal energy. Quaternary fatty acid eutectics were incorporated into SiO₂ nanofibrous mats as representative phase change materials. Flexible SiO₂ nanofibrous mats were prepared by electrospinning combined with annealing. The thermal energy storage capability, surface morphology and thermal energy storage/retrieval rate of FSPCMs were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and laboratorymade thermal performance measurement device. The results indicated that the resultant SiO₂ nanofibrous mats were soft and free-standing. Quaternary fatty acid eutectics were distributed uniformly in the three-dimensional (3D) network structure of the SiO₂ nanofibrous mats, thereby effectively preventing fatty acid leakage. The absorption capacities of five types of quaternary fatty acid eutectics varied from 85.1% to 88.9%. Moreover, after 20 cycles, the phase change temperature and enthalpy of FSPCMs did not change significantly, suggesting that ideal thermal stability was achieved. The time for thermal energy storage/retrieval taken by FSPCMs was shortened by 23.1% at minimum from that for pure quaternary fatty acid eutectics. Therefore, the fabricated FSPCMs offer promising application prospects in a wide variety of fields, including solar energy utilization, temperature-regulating textiles and air-conditioning systems.