Overview of aerogel materials
With its nano porous network structure, aerogel material has high porosity and extremely low density and thermal conductivity, making it an ultra light and thermal insulation material. It has been widely used in fields such as catalysis and thermal insulation.
◆ Thermal insulation performance
Aerogel performs well in thermal insulation, and its thermal conductivity at room temperature is as low as 0.013w/(m · k). This characteristic makes it a top-notch insulation material, which not only excels in the aerospace field such as spacesuits and fire insulation suits, but also demonstrates extensive and important value in daily life insulation bottles, automotive sound insulation, and other fields.
Characteristics of Super Insulation Materials
In 1992, American scholar HUNTAJ first proposed the concept of "super insulation material". This type of material has the following key characteristics: the majority of its pore characteristic sizes are below 100 nanometers, the bulk density is extremely low, and it can have a thermal conductivity lower than that of "no convective air" in specific usage environments. These characteristics make aerogel an excellent thermal insulation material.

Thermal insulation mechanism and materials
◆ Heat transfer mechanism
The thermal insulation mechanism of aerogel thermal insulation material can be revealed by its heat transfer formula. In this material, gas molecule thermal conductivity, convective thermal conductivity, solid-phase thermal conductivity, and radiative thermal conductivity are all significantly limited. Especially in aerogel composites, the gas flow is in the transition zone or free molecular zone, which makes the thermal conductivity of gas molecules, convection, solid thermal conductivity and radiant thermal conductivity approach 0, thus showing excellent thermal insulation performance.
◆ Oxide gas gel
Oxide aerogels have been extensively studied because of their high porosity and low thermal conductivity. These aerogels include tungsten oxide, ferric oxide, etc., but silica and alumina aerogels are most prominent in high-temperature applications.
◆ SiO2 and Al2O3 aerogels
Silica aerogel is one of the heat insulation materials with the longest research history. The use of sol - gel method makes its research in the field of high temperature insulation more mature. Alumina aerogels are famous for their excellent high temperature resistance, but they are prone to sintering. Their preparation process is quite similar to that of silica aerogels, but they have a higher melting point.
◆ Carbon aerogel gel and carbide aerogel gel
Carbon aerogels exhibit excellent performance at high temperatures, but are unstable in air. Its preparation process includes drying and carbonization of organic aerogel. In order to improve its stability, researchers are exploring the method of coating its surface with an antioxidant layer. Carbide aerogels stand out because of their excellent high temperature resistance and wear resistance. Although the carbide itself has a high thermal conductivity, its thermal insulation ability has been significantly improved after being made into aerogels with high porosity.

Summary and Outlook
Because of its excellent thermal insulation performance, aerogel ranks among the lightest solid materials in the world and meets the requirements of Class A fire protection. Although aerogels have broad application prospects in aerospace, military and civil fields, their low strength and high brittleness limit their use as thermal insulation materials alone. By introducing high-performance inorganic ceramic fiber cotton and shading agents, and optimizing process conditions, efficient insulation materials with better thermodynamic properties can be prepared.