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. (C) 2016 Elsevier Ltd. All rights reserved.