Low-density graphene/carbon composite aerogels prepared at ambient pressure with high mechanical strength and low thermal conductivity

Low-density graphene/carbon composite aerogels were prepared by sol-gel polymerization, ambient pressure drying and carbonization in an inert gas atmosphere. The preparation conditions, including the initial pH, solid concentration of the precursor solution, and the GO loading content, were investigated in detail. The dispersed graphene nanosheets in the carbon aerogel (CA) matrix made significant contributions to the decreased densities (as low as 0.11 g cm −3 ) of the CAs. The resultant composite CAs exhibited high specific surface area (>400 m 2 g −1 ), high compression strength (19.9 MPa at a density of 0.404 g cm −3 ), and extremely low thermal conductivity of 0.028 W m −1 K −1 , equal to one fifth of the value of the pristine carbon aerogel. SEM and TEM pictures show that GNSs can be well-dispersed in a carbon matrix. The resultant composite CAs exhibited high compression strength and extremely low thermal conductivity of 0.028 W m −1 K −1 .