Co/C@cellulose nanofiber aerogel derived from metal-organic frameworks for highly efficient electromagnetic interference shielding

A three-dimensional (3D) ultralight Co/C@CNF aerogel is fabricated by directional freeze-casting of cellulose nanofiber (CNF) anchored Zeolitic Imidazolate Framework-67 (ZIF-67) and subsequently annealing process of ZIF-67/CNF aerogel at different temperature from 700 degrees C to 900 degrees C. The resultant Co/C@CNF aerogels are interconnected carbon sheet networks inlaid with Co/C nanoparticles, and the corresponding EMI shielding properties are proved to be dependent on the annealing temperature. Remarkably, the Co/C@CNF aerogel at 900 degrees C displays high EMI shielding effectiveness of 35.1 dB at a density of only 1.74 mg cm(-3), corresponding to the highest specific SE reaching 20172.4 dB cm(3) g(-1), and an extremely high absorption characteristic. This good performance is benefiting from magnetic nanoparticles of Co embedded in carbon sheet and 3D interconnected networks, enhancing magnetic loss and dielectric loss ability. This study offers a facile approach to design novel aerogels with ultra-high absorption for highly efficient EMI shielding application in aerospace, portable electronics, and so on.