An aerogel is a low-density solid gel in which a liquid has been replaced by a gas or air and is the world's least dense solid. There are many types of aerogel, silica aerogel, all carbon aerogel, metal oxide aerogel, metal aerogel and so on, of which silica aerogel is the most common.

The internal structure of aerogel is a tiny cavity, three-dimensional, interwoven structure, the material accounts for only 3% of the total volume of aerogel, and the gas accounts for the remaining 97% of the volume of aerogel. Therefore, regardless of the material used, the appearance of aerogel is usually almost transparent. In addition, the space for the internal flow of the gas is very small, which can inhibit both convection and gaseous conduction. These properties make aerogel the world's lowest density solid and the most effective insulation material. At the same time, aerogel also has the following characteristics:
1, low density and low thermal conductivity
Aerogels are translucent because they are mostly air inside, which explains their low density, and silica aerogels have a density of between 0.1 g/cm3 and 0.5 g/cm3, which is only three times heavier than air. The aerogel has a low thermal conductivity of 0.017(w/m.k)/25 ° C, thus greatly reducing heat loss.
2, high insulation resistance
Aerogel can maintain its shape at high temperatures without clumping, pitting or cracking like other thermal insulation materials, and also has excellent thermal insulation (0.023w/mm, 100 ° C). Aerogel therefore effectively improves the energy efficiency of equipment when used for high-temperature insulation, which also helps to reduce emissions and energy costs.
3. Hydrophobic
Aerogel has a high hydrophobicity of up to 99.5%, so it protects insulated parts from corrosion and humidity damage.
4, long service life
Aerogel is chemically stable, does not react with other substances, and has a service life of up to 20 years.
5. Acoustic performance
Aerogel has excellent acoustic properties, providing better sound insulation than polyurethane.
Aerogel has low density and low thermal conductivity, high insulation resistance, hydrophobicity, long service life, sound insulation properties, etc., making it a good insulation material. Despite rapid advances in production technology, aerogel is still difficult to make and therefore relatively expensive. However, with the support of national policies and the continuous progress of scientific research and technology, aerogels will gradually be commercialized.