Block aerogel composite material and preparation method thereof

The invention discloses a block aerogel composite material and a preparation method thereof. The block aerogel composite material consists of reticular cellulose nano fiber skeletons and sol in a combining way, wherein the porosity of the aerogel composite material is 80-99.5 percent, the density is 0.015-0.680g/cm , the BET specific surface area is 150-1200m /g, the coefficient of heat conductivity is 0.015-0.045Wm k and the modulus of elasticity is 0.5-150MPa. The block aerogel composite material provided by the embodiment of the invention has the advantages that since the material consists of the reticular cellulose nano fiber skeletons and the sol in the combining way, the mechanical property of the block aerogel composite material can be obviously improved, the heat conductivity is low, the density is small and the specific surface area is large; and besides, the equipment cost can be decreased by adopting a relatively low and safe freeze-drying method to replace the traditional supercritical drying method.