Research progress of mesoporous silica-based composite phase change materials

Increasing concerns surrounding the rising global energy demand has forced humans to look for alternative energy sources such as the development and utilization of natural gas and nuclear energy, or to increase the efficiency of energy use, thereby optimizing the use of energy. Improving energy efficiency is an effective method that can quickly and efficiently reduce the energy demand and supply gap. Furthermore, developing new technologies for energy storage and energy saving is an effective way to solve the energy crisis, which is of great significance for the sustainable development of energy. Latent heat storage has become a popular research topic owing to its large energy storage density and small temperature changes during energy storage and its excellent thermal stability and high safety. Currently, phase-change materials have been widely used in solar heating systems, air conditioning systems, thermally regulated textiles, energy-efficient building construction, temperature-controlled greenhouses and other fields. The development of phase-change energy storage technology is significant for promoting the development of alternative energy sources and improving energy efficiency. However, phase change materials are prone to liquid leakage during the solid-liquid phase transition, which limits their application. To solve this problem, researchers have started introducing porous support materials to phase-change materials. Porous support materials have attracted extensive research attention in recent years owing to their outstanding properties such as high specific surface area, large pore volume, and low density. Porous support materials can absorb phase-change materials in their pores through the physical adsorption phenomena such as capillary action and interfacial tension, and thereby gradually develop into important substrates for phase-change material encapsulation. Inorganic materials are used as carriers for phase change energy storage materials. Compared with organic carrier materials, inorganic carrier materials have higher mechanical strength, flame retardancy and thermal conductivity, which can reduce the production cost of phase-change energy storage materials, and have a high research value. Mesoporous silica materials have good physical and chemical stability, biocompatibility, flame retardancy, low toxicity, corrosion resistance, controllable size, adjustable surface morphology and high specific surface area. They can comprehensively improve the performance of various aspects of phase change composites and broaden the application space of phase change energy storage materials. In this review, the effects of pore size, pore structure, and pore surface properties on the crystallization behavior of phase change materials in mesoporous silica carriers developed in recent years were comprehensively analyzed, and prospects of research methods for heat storage efficiency were explored.