In the laboratory, the reporter saw "carbon sponges" of different sizes: as big as tennis balls and as small as bottle stoppers. Under the electron microscope, carbon nanotubes and graphene support countless pores.
"Large space structures such as stadiums and gymnasiums are supported by steel bars and made of high-strength membranes. The overall material is light and strong. " Sun Haiyan, a doctoral student in the research group, said, "Here, carbon nanotubes are scaffolds and graphene is a wall."
Among the reported results, the "carbon sponge" prepared by Gao Chao's research team is still the lightest record holder-it can reach 0. 16 mg/cm3, which is lower than the density of helium. Related papers were published online in Advanced Materials on February, 2065438 18. However, the research team is not interested in applying for Guinness World Records. Lightness is not its biggest innovation. Superb explanation: its value lies in its simple preparation method and superior material properties.
According to scientists, the basic preparation principle of aerogels is to remove the solvent from the gel and keep its intact skeleton. In the past cases of preparing aerogels, scientists mainly used sol-gel method and template-oriented method. The former can be synthesized in batch, but its controllability is poor; The latter can produce an ordered structure, but it depends on the fine structure and size of the template and is difficult to prepare in large quantities. Gao Chao's research team found a new way to explore the template-free freeze-drying method: freeze-drying the aqueous solution in which graphene and carbon nanotubes were dissolved at low temperature to obtain a "carbon sponge", whose shape can be adjusted at will, making the production process more convenient and making it possible to manufacture and apply this ultra-light material on a large scale.
"Don't need a template, only related to the container. How big the container is, how big it can be prepared, which can be thousands of cubic centimeters or even larger. " Gao Chao said.