Highly compressible anisotropic graphene aerogels fabricated by directional freezing for efficient absorption of organic liquids

Highly compressible three-dimensional graphene aerogels with anisotropic porous structure are fabricated by directional freezing of graphene hydrogel using anisotropically grown ice crystals as templates followed by freeze–drying. The directional freezing approach endows the graphene aerogel with a high compressive strength in the axial direction and good compressibility in both axial and radial directions. The anisotropic graphene aerogel also exhibits ultralow density, excellent flexibility in liquids, satisfactory fire-resistance, and strain-sensitive electrical conductivity. After absorbing organic liquids, the aerogel can be well recycled by burning, distilling, or squeezing, which makes it promising for oil absorption with a good recyclability.