Ultralight, flexible carbon hybrid aerogels from bacterial cellulose for strong microwave absorption

Carbon-based aerogels have demonstrated to have a great promise as advanced microwave absorption materials due to their ultralow volumetric density, unique pore structure, and high electrical conductivity. However, the comparatively complex fabrication process, weak machinability and difficulty in regulation of electromagnetic properties still hinder their large-scale application. Here, we reported a facile and scalable fabrication of novel carbon hybrid aerogels with adjustable electromagnetic properties from naturally abundant bacterial cellulose. Composed of robust network of ultrahigh-aspect-ratio metal/carbon nanofibers, the carbon hybrid aerogels exhibited combined characteristics of highly porous structure, ultralow density, physical flexibility and electromagnetic properties. As fillers of microwave absorption materials, the fabricated hybrid aerogels delivered strong microwave-absorbing ability with the minimum reflection loss of similar to 70.1 dB even at the filler loading as low as 0.8 wt%, superior to previously reported carbon-based aerogels. Especially, the naturally unique surface chemistry and physical properties of bacterial cellulose provided the possibility of manipulating the microstructure and morphology of carbon hybrid aerogels in easy ways as demonstrated in this work, which can be utilized to optimize microwave absorption property and absorption band. Thus, biocarbon materials exhibit promising potential for meeting the increasing demand for scalable, high-efficiency and requirement-guided microwave absorption materials. (c) 2020 Elsevier Ltd. All rights reserved.