Hard carbon nanofiber aerogel becomes superelastic

Conductive and compressible carbon aerogels are admirable in a variety of applications. In recent decades, carbon aerogels have been widely explored by using graphitic carbons and soft carbons, which show advantages in superelasticity. These elastic aerogels usually have delicate microstructures with good fatigue resistance but ultralow strength. Hard carbons show great advantages in mechanical strength and structural stability due to the sp3 C-induced turbostratic “house-of-cards” structure. However, the stiffness and fragility clearly get in the way of achieving superelasticity with hard carbons. Up to now, it is still a challenge to fabricate superelastic hard carbon-based aerogels.

Recently, inspired by the flexibility and rigidity of natural spider silks webs, a research team led by Shu-Hong Yu from the University of Science and Technology of China developed a simple and general method to fabricate superelastic and fatigue resistant hard carbon aerogels with nanofibrous network structure by using resorcinol-formaldehyde resin as a hard carbon source. This work was published on Advanced Materials entitled as “Superelastic hard carbon nanofiber aerogels” on April 15th as a back cover (Advanced Materials 2019, 1900651).

The polymerization of resin monomers was initiated in the presence of nanofibers as structural templates to prepare a hydrogel with nanofibrous networks, followed by the drying and pyrolysis to get hard carbon aerogel. During polymerization, the monomers deposit on templates and weld the fiber-fiber joints, leaving a random network structure with massive robust joints. Moreover, physical properties (such as diameters of nanofiber, densities of aerogels, and mechanical properties) can be controlled by simply tuning templates and the amount of raw materials.

Due to the hard carbon nanofibers and abundant welded joints among the nanofibers, the hard carbon aerogels display robust and stable mechanical performances, including super-elasticity, high strength, extremely fast recovery speed (860 mm s-1) and low energy loss coefficient (

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See the article:

Super-Elastic Hard Carbon Nanofiber Aerogels,

Adv. Mater. 2019, 1900651.

https://onlinelibrary.wiley.com/doi/full/10.1002/adma.201900651