Carbon aerogel evolution: Allotrope, graphene-inspired, and 3D-printed aerogels

Abstract

Carbon aerogels (CAs) are a unique class of high surface area materials derived by sol-gel chemistry. Their high mass-specific surface area and electrical conductivity, environmental compatibility, and chemical inertness make them very promising materials for many applications, such as energy storage, catalysis, sorbents, and desalination. Since the first CAs were made via pyrolysis of resorcinol-formaldehyde (RF)-based organic aerogels in the late 1980s, the field has really grown. Recently, in addition to RF-derived amorphous CAs, several other carbon allotropes have been realized in aerogel form: carbon nanotubes (CNTs), graphene, graphite, and diamond. Furthermore, the popularity of graphene aerogels has inspired research into aerogels made of a host of graphene analog materials (e.g., boron nitride, transition metal dichalcogenides, etc.), with potential for an even wider array of applications. Finally, the development of threedimensional-printed aerogels provides the potential for CAs to have an even broader impact on energy-related technologies. Here, we will present recent work covering the novel synthesis of

Electromagnetic and microwave absorption characteristics of PMMA composites filled with a nanoporous resorcinol formaldehyde based carbon aerogel

“…The two broad peaks positioned at 2q ¼ 24 and 42 correspond to the reections of (002) and (100) planes of graphite, respectively. 22,29,35 Since the peak intensity of d 002 plane in CAs is weak, it is concluded that the CAs structure consists of low degree of crystallinity.…”

Interaction of Multiwalled Carbon Nanotube Aerogels with Quasi‐Optical Terahertz Beams

“…Nanomaterials based on different forms of carbon (carbon black, activated carbon, carbon fibers, nanotubes, graphene) are the most important components in the development of EMM due to the successful combination of their properties (electrical conductivity, chemical stability, and lightness) . Among these materials, aerogels of multiwalled carbon nanotubes (MWCNTs) combine the unique mechanical, thermal, and electrical properties of nanotubes with specific characteristics of aerogels (low density, high porosity, and large surface area) . Due to the absence of a binder polymer, aerogels have the lowest density combined with high conductivity, which are unattainable for other classes of composites.…”

“…[6][7][8][9][10] Among these materials, aerogels of multiwalled carbon nanotubes (MWCNTs) combine the unique mechanical, thermal, and electrical properties of nanotubes with specific characteristics of aerogels (low density, high porosity, and large surface area). [11] Due to the absence of a binder polymer, aerogels have the lowest density combined with high conductivity, which are unattainable for other classes of composites. These media can possess specific electromagnetic properties due to the superior properties of CNTs themselves.…”

“…This model is semi-empirical since the experimentally determined polarizability of a spherical sample is used to estimate the electrophysical parameters of the aerogel environment. An experimental study of spherical aerogels in the gigahertz range (8)(9)(10)(11)(12) [30,31] showed that, despite the high conductivity of CNTs in the aerogel media and high density of their packages compared to the wavelength, effective parameters of aerogels noticeably differ from those of metals.…”

Sensing up to 40 atm Using Pressure‐Sensitive Aero‐GaN

“…Aeromaterials, such as aerogels, represent three‐dimensional ultra‐lightweight extra‐porous materials formed by randomly distributed networks of nanostructures having different sizes and shapes, such as nanowires, nanotubes, or nanosheets . There is a rather limited number of materials that can be prepared as aeromaterials, but this number is continuously increasing, especially for carbon‐based nanomaterials, such as carbon nanotubes, graphene, aerographite, etc . This tremendous development of aeromaterials is related to an impressive number of applications in energy storage and conversion (e.g., supercapacitors and solar cells), environmental protection (e.g., large absorption of crude oil, sensors), biological applications (e.g., drug delivery, tissue engineering, implantable devices, and biosensing) .…”