Fabrication of anisotropic carbon aerogels from cellulose nanofiber/graphene oxide composites for electromagnetic interference shielding

Aerogels have been considered as a promising electromagnetic interference (EMI) shielding materials due to their lightweight, compressibility, high elasticity and electrical conductivity. In order to improve their EMI shielding effectiveness (EMI SE), developing carbon aerogel with adjustable microstructure is still an urgent problem. Herein, carbon aerogels were fabricated from bamboo cellulose nanofiber (CNF)/graphene oxide (GO) composites with the layered interconnected structure via bidirectional freezing and carbonization. The prepared aerogels exhibited high mechanical strength in the parallel lamellar direction and excellent compression flexibility in the vertical lamellar direction. After 300 cycles of compression in the vertical lamellar direction, 97% of its original height can be recovered. The absolute shielding effectiveness of anisotropic carbon aerogels could achieve 23628 dB·cm2·g-1 with an ultralow density (3 mg·cm-3). This study explores the correlation between the structure of carbon aerogels and their EMI shielding properties, offering an eco-friendly approach to produce lightweight anisotropic carbon aerogels for EMI shielding.