Highly anisotropic graphene/boron nitride hybrid aerogels with long-range ordered architecture and moderate density for highly thermally conductive composites

Although graphene aerogels have great potentials in preparing heat dissipation composites on the basis of their continuous thermally conducting networks, their low density and isotropic architecture hinder further improvement of the thermal conductivity of their composites. Herein, highly anisotropic graphene/boron nitride (BN) hybrid aerogels with a long-range ordered architecture and moderate density are prepared for the first time by hydrothermally treating the suspension of graphene oxide sheets and BN nanoplatelets, air-drying the resultant hydrogels, and thermally annealing the highly anisotropic aerogels at 2000 °C. During the hydrothermal treatment, the chemically reduced graphene oxide (RGO) sheets are self-assembled into the highly anisotropic and long-range ordered network, while the BN nanoplatelets are distributed between the aligned RGO sheets to prevent the excessive volume shrinkage of the aerogel and retain its anisotropic porous structure with high porosity during the air-drying. Furthermore, the RGO/BN hybrid aerogel is thermally annealed at 2000 °C to fully remove the residual oxygen-containing groups and heal the defects on its RGO component. The thermally annealed hybrid aerogel is highly efficient in enhancing the thermal conductivity of epoxy resin, and the resultant composite exhibits an ultrahigh through-plane thermal conductivity of 11.01 W/(mK) with an excellent thermal conductivity enhancement of 277%.