Aerogel: The Multifunctional Wonder Material Revolutionizing Industries

Aerogel, a revolutionary material, is taking the world by storm with its unique properties and diverse applications. With a high specific surface area, high porosity, and a special microstructure, aerogel is chemically stable, has an extremely low thermal conductivity, can withstand high temperatures, operates across a wide temperature range, and boasts a long lifespan. In recent years, researchers from China, the United States, Europe, and other regions have developed various new types of aerogels, such as biomass - based aerogels, through improved preparation processes.

## The Lightweight Marvel

Aerogel is a type of super - material that is incredibly light. It is so light that placing a piece of it on a flower stamen won't even bend the stamen. Today, a wide variety of aerogels have been developed, with properties ranging from soft to hard, conductive to insulating, making them applicable in numerous fields.

## Superior Thermal Insulation

As the solid material with the lowest known thermal conductivity and the smallest density, aerogel is the "thermal insulation king" in the material field. It has been widely used in aerospace, petrochemical, and other industries. For instance, it was applied in the engine of the "Tianwen - 1" probe and the surface of the Mars rover, the high - temperature gas system of the "Long March 5" Y4 carrier rocket engine, and the thermal battery protection of the "Chang'e - 4" probe. After China proposed the "dual - carbon" goal, with continuous technological innovation, the application scenarios of aerogel have further expanded.

In the Xinxiang Steam Pipeline Project in Henan Province, where high - level anti - corrosion and thermal insulation are required for steam pipe networks, high - temperature centrifugal glass wool and nano - aerogel composite insulation materials were selected. According to Wang Xing, the project's technical director, the thermal insulation effect of nano - aerogel is 2 - 5 times that of traditional insulation materials. This not only significantly improves construction quality and efficiency but also reduces construction costs.

## Diverse Properties

Aerogel, a nano - level porous solid new material, has pores that can account for up to 99% of its total volume. It features a high specific surface area, high porosity, nano - sized pores, and low density. Besides excellent thermal insulation, it also has high elasticity, strong adsorption, good waterproofing, and can be used in a wide temperature range.

As Wang Beier, a technical expert in the aerogel field, put it, "Aerogel can be understood as a nano - version of a porous sponge." With pore diameters between 20 and 50 nanometers, smaller than the size of air molecules (about 70 nanometers), air flow on aerogel is highly inefficient. Coupled with its high specific heat capacity, heat radiation transfer is minimized.

## Types of Aerogel

Aerogels are mainly classified into three categories: inorganic aerogels, organic aerogels, and organic - inorganic hybrid aerogels. Inorganic aerogels have inorganic substances as the main component, including elemental aerogels, oxide aerogels, and sulfide aerogels. Organic aerogels are based on organic substances, such as phenolic aerogels, cellulose aerogels, polyimide aerogels, chitosan aerogels, and chitosan - cellulose aerogels. Organic - inorganic hybrid aerogels can leverage the respective advantages of organic and inorganic substances to achieve special functionalizations.

In 2021, *Science* magazine listed aerogel as one of the top ten popular scientific and technological achievements, calling it a "multifunctional new material that can change the world." Among the top ten new materials selected by *Science*, aerogel is the only one that has been widely implemented in actual commercial scenarios.

## Preparation and Cost

The preparation process of aerogel mainly consists of two steps: preparing the gel through the sol - gel process and then replacing the liquid substances in the gel with gaseous substances using a certain drying method.

Data shows that in the cost structure of the aerogel industry, manufacturing costs account for approximately 45%. Zheng Song, the assistant to the chairman of Suzhou Jinfu Technology Co., Ltd., said that reducing aerogel costs is an ongoing effort in the industry. One of the main approaches is the implementation of automated production lines, which, when achieved, will open up more application scenarios.

## Biomass - based Aerogels: The New Hotspot

According to the evaluation of the China Petroleum Pipeline Science and Technology Research Center, for the thermal insulation application of 350 - degree Celsius steam pipelines, compared with traditional insulation materials, the thickness of the aerogel insulation layer can be reduced by 2/3, energy consumption can be saved by over 40%, and each kilometer of pipeline can reduce carbon dioxide emissions by 125 tons per year.

In 2021, the demand for aerogels in the oil and gas field accounted for 56% of the total demand, with 18% for industrial insulation, 9% for construction, and 8% for transportation. The National Advisory Committee for the Development of New Materials pointed out in the "2022 Aerogel Industry Research Report" that using aerogel flame - retardant materials in the battery core modules of new energy vehicles can increase the high - temperature tolerance of the battery pack to over 800 degrees Celsius. With the development of the new energy vehicle industry, the application scenarios of aerogels in the new energy vehicle and energy storage industries are extensive, and the demand is expected to continue to rise.

Biomass - based aerogels have become a research hotspot. Biomass raw materials are widely available, low - cost, and rich in carbon sources. Preparing environmentally friendly porous carbon fiber aerogels from biomass raw materials is an economic and sustainable production method. For example, the research team of Academician Yu Shuhong from the University of Science and Technology of China developed a super - elastic cellulose aerogel. This cellulose aerogel exhibits super - elasticity that does not change with temperature from room temperature to minus 196 degrees Celsius, as well as excellent fatigue resistance, showing great thermal insulation potential in harsh environments. Moreover, the materials used in its preparation are all biomass raw materials, which is expected to solve the environmental pollution problems caused by energy - intensive technologies and petrochemical materials, and is an ideal substitute for traditional non - renewable aerogels.

The research team of Researcher Lu Yun from the Institute of Wood Industry of the Chinese Academy of Forestry Sciences used wood as the matrix to combine inorganic and organic aerogels with the wood skeleton matrix, creating the third - generation lignocellulose aerogel. By regulating the cellulose of wood and biomass waste, the specific surface area of cellulose was increased by 7 orders of magnitude. It has an oil - absorption capacity of 75 - 300 times its own mass, reduces volume usage by 50% - 75%, and is biodegradable and renewable.

## Policy - driven Growth and Challenges

The development of aerogel has received continuous support from national policies. In 2014 and 2015, the National Development and Reform Commission listed aerogel in the "National Key Energy - Saving and Low - Carbon Technology Promotion Catalogue" for two consecutive years, initially promoting its application. In June 2018, aerogel was included in the emerging building materials industry. In September of the same year, the first national standard for aerogel, "Nanoporous Aerogel Composite Insulation Products," was released. In 2020, the "Technical Standard for Aerogel Thermal Insulation Coating Systems" came into use. In 2021, the "Opinions of the Central Committee of the Communist Party of China and the State Council on Comprehensively and Accurately Implementing the New Development Concept and Doing a Good Job in Carbon Peaking and Carbon Neutrality" proposed promoting the research and application of aerogel and other new materials.

However, there are still some problems in aerogel research. For example, its thermal conductivity increases rapidly at high temperatures, its adhesion to reinforcing matrix materials such as fibers is poor, many organic solvents are used in the production process, causing environmental pollution, and it is difficult to recycle, which is not conducive to sustainable development. In addition, the production cost of aerogel is high, and the product price is expensive. The "2022 Aerogel Industry Research Report" pointed out that the production cost of aerogel is mainly concentrated on raw material silicon sources, equipment depreciation, and energy consumption. Reducing costs effectively depends on breakthroughs in preparation processes and the large - scale industrialization of low - cost raw materials.

Despite these challenges, aerogel is a rare material that can simultaneously meet multiple needs such as fire - resistance, waterproofing, thermal insulation, and sound insulation. The future research of aerogel will mainly focus on developing new types of aerogels, including cellulose aerogels, graphene aerogels, perovskite - structured aerogels, and non - metallic elemental aerogels. As the technology continues to evolve, aerogel is set to play an even more significant role in various industries around the world.