Aerogel has the characteristics of extremely low density, ultra-high porosity, low refractive index, low thermal conductivity and low impedance, which are not possessed by general solid materials. These characteristics make it have great application prospects in thermal insulation, biomedicine, sound insulation, adsorption and other fields.
     (1) The field of thermal insulation
The thermal conductivity of aerogel material is very low, and it is the best material with thermal insulation and thermal insulation performance known at present. NASA has made a comprehensive comparison on the thermal insulation effect, quality, material flexibility, mechanical strength, thickness and other properties of porous materials, foam materials, phase change materials, aerogel materials and other materials, and found that aerogel not only has good comprehensive performance, but also has more excellent thermal insulation performance, and can be used as a candidate material for space suits. In addition, aerogel materials are also widely used in civil fields such as energy-saving Windows, roof solar collectors, thermal insulation coatings, and military fields such as aircraft black boxes and aircraft cabin insulation.
     (2) Biomedical field
Aerogel materials have biocompatibility, suitable mechanical properties, biodegradability and other properties, and have been applied in implantable medical devices, non-invasive imaging, bone grafting and biosensors. In addition, aerogel materials can also be prepared into microspheres for drug sustained release, so as to achieve the function of controlling drug release to target cells, which has potential application value.
     (3) The field of sound insulation
Aerogel materials not only have a large internal surface area, which can attenuate sound waves by repeated reflection on its internal surface, but also have a very high porosity. Nano-scale pores on its surface make the air viscous flow speed close to the Knudsen diffusion speed of air molecules, so as to consume part of the sound energy transmitted through the air and achieve good sound insulation effect.
    (4) Adsorption field
Aerogel materials have extremely high porosity, which can effectively adsorb organic matter, and can also be used to remove metal ions. Compared with the traditional method, the electroadsorption of carbon aerogel to remove metal ions in solution has the advantages of reducing secondary pollution, saving energy and being renewable. In addition, the modified aerogels can also selectively adsorb specific substances, such as tetraethylenepentamine loaded in silica aerogels, which can efficiently adsorb carbon dioxide.

       Future research directions of aerogel materials
There are various kinds of aerogel materials, and the synthesis process has gradually formed a system, but there are still some problems in the current research on aerogel: the thermal conductivity of aerogel increases rapidly under high temperature conditions; Compared with metal materials, the overall mechanical strength of aerogel is still weak. The adhesion of aerogel and fiber reinforced matrix materials is poor. Many organic solvents are used in the production process of aerogel, which causes environmental pollution and is not conducive to large-scale production. Aerogel is difficult to recycle and is not conducive to sustainable development.

     The future research direction and development trend of aerogel mainly focus on the development of cellulose aerogel, graphene aerogel, perovskite structure aerogel, non-metallic aerogel and other new aerogel materials; The aerogel structure was regulated by using different precursors, optimizing synthesis methods and changing reinforcing bodies. Expand the aerogels application field.

     The development and application of aerogel materials is still in the process of continuous exploration, although research progress has been made in some areas, but still need to solve the problem of inadequate utilization of resources, high manufacturing costs, technical defects and other problems, major countries will also be fierce competition in this field. China's research level in the field of aerogel materials is in the forefront of the world, should continue to carry out research on the preparation of aerogel materials and large-scale production technology, expand the application field of aerogel materials, and maintain a leading position in the field.