Electromagnetic wave absorption in graphene nanoribbon nanocomposite foam by multiscale electron dissipation of atomic defects, interfacial polarization and impedance match

For carbon-based nanocomposites, enhanced conduction loss, polarization loss and impedance match are beneficial for enhancing electromagnetic wave (EMW) absorption property. In this work, graphene nanoribbon (GNR) nanocomposite foam system with regulated atomic defects, enhanced interfacial polarization and suitable impedance match were combined to achieve high-efficient EMW absorption: (1) Tubular carbon nanotube (CNT) is unzipped via chemical oxidation to obtain GNR with unique structure of long strip; (2) Oxidation and reduction of GNR enables the regulation of in-plane atomic defects; (3) a suitable electrical conduction of GNR renders its nanocomposite a better impedance match than CNT or graphene nanoplatelet (GNP) nanocomposites; (4) cellular structure in GNR nanocomposite further improves the impedance match compared with air; (5) the long-strip characteristic of GNR features the high-efficient interfacial polarization even in cell walls which undergo stretching, while tubular CNTs have weak interfacial polarization and platelet GNPs have deteriorated interfacial polarization after cell wall stretching. Owing to the above specific tailored multiscale electron dissipation strategy, GNR nanocomposite presents better EMW absorption property of −42.6 dB than CNT nanocomposite of −21.8 dB and GNP nanocomposite of −25.6 dB. Furthermore, supercritical carbon dioxide (scCO2) foaming improves the impedance match and enhances GNR interfacial polarization. The EMW absorption property of GNR nanocomposite foam further increased to −54.1 dB after selectively and restrictively locating GNR in cell walls.