What is a foam?
A foam is a substance in which gas is trapped in a liquid or a solid in pockets. There are many types of foams - for example, those used by firefighters (mostly to combat burning oils). A bread is also, at least formally, a type of foam.
Graphene foams are usually made by growing graphene using a CVD process on a 3D metal foam (structure). The metal is then removed which leaves the graphene 3D foam.
Graphene foams are somewhat similar to graphene aerogels, in which the liquid part of the gel is replaced by a gas (usually air).
Graphene foams are now available commercially, contact us for details.
The latest graphene foam news:
Researchers at the University of Aveiro in Portugal designed unique "tea bags" using a porous graphene oxide foam, which they say can help purify water by removing dissolved mercury. These foams demonstrate several significant advantages over existing water purification systems: they are reusable, simple to synthesize and should be easy to produce in bulk at a relatively low cost. The scientists add that they are also not affected by pH, which is beneficial since other sorbents often need the pH to be optimized, which drives up costs.
The scientists heated graphene oxide with ammonia to create a porous 3D material with a high surface area. After screening their materials for their ability to adsorb various toxic pollutants, the team chose to focus on mercury, one of the top three on the EU’s priority list of hazardous substances in water. The "tea bag" form was chosen due to the fact that the foam sometimes broke apart, and also to optimize contact with water.
Researchers at the Harbin Institute of Technology in China and the University of Michigan in the US demonstrated improved LFP battery cathode, augmented by reduced graphene oxide. The scientists used reduced graphene oxide (rGO) in LFP battery cathodes to create a new high surface area 3D composite.
LFP (or LiFePO4) is a kind of Li-Ion rechargeable battery for high power applications, such as electric vehicls, Power Tools and more. LFP cells feature high discharging current, non explosive nature and long cycle life, but its energy density is lower than normal Li-Ion cell. In this study, the researchers created the composite using a nickel foam template that was coated with layers of graphene oxide. The graphene oxide reduced as the LFP nanoparticles were synthesized in a simple technique that allows larger amounts of the LFP to be loaded into the carbon material.
Researchers at Stanford University developed a new battery technology based on graphene and aluminum. The stanford team claims that their aluminum battery has a number of advantages over lithium: it's flexible, can be charged in a minute instead of hours and is very durable. it's also cheaper and non-reactive (meaning compromising it will not result in sparks like lithium batteries).
The scientists used graphene foam (made by creating a metal foam, then catalyzing graphene formation on its surface) as cathode material and aluminum foil as the anode. The electrolyte the researchers used was a solution of aluminum trichloride dissolved in an organic solvent that also contained chlorine. While this granted better performance (7,500 cycles, much more than the 1,000 expected from a Li-ion battery), the voltage provided by an aluminum-ion battery is only about half of that what you'd get from a lithium-ion cell. Also, the overall power density (the amount of power you can store in a battery in relation to its size) is still insufficient.
Researchers at the Rice University have devised a process in which a computer-controlled laser burns through a polymer to create flexible, patterned sheets of multilayer graphene that may be suitable for electronics or energy storage. The process works in air at room temperature, cancelling the need for hot furnaces and controlled environments.
The product of this process is not a 2D piece of graphene but a porous foam of interconnected flakes about 20 microns thick. The laser doesn't cut all the way through the base material, so the foam remains attached to a flexible plastic base.
An annual photo competition held by faculty of engineering at the University of Cambridge aims to present the wide variety of engineering research at the university. This year, the winner of this competition was an incredible electron micrograph photo of free-standing graphene foam.
The graphene foam was made by growing a few layers of graphene on the surface of a porous metal foam skeleton (by CVD), then removing it by dissolving it in etching solution. The photo, by Adrianus Indrat Aria, was called Asteroidea Electrica.