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Graphene is a material that has been touted for several market sectors and applications. Graphene has many excellent properties, such as its electrical conductivity and tensile strength. While these are important reasons for using graphene in different applications, how we produce and integrate graphene could play a key role in its future market success.
Graphene has a huge potential for being a highly sustainable material and improving the sustainability of different industries.
In recent years, it has emerged that graphene can be integrated into different materials to make them more environmentally friendly. However, there are also green graphene production methods available. While graphene has a lot of potential and shows improved properties over many of the materials currently in use, some industries have been slow to adopt it. The added sustainability bonus that graphene could bring to different industry sectors could help graphene become more readily and widely adopted.
Here, we look at how graphene can create more sustainable materials and how companies are now developing methods that can manufacture graphene in a green and sustainable way.
Creating Sustainable Materials
The direct integration of graphene into different materials highlights the sustainability potential for graphene. When used as an additive, the various physical properties that graphene possesses reduce the application's material. This is because the incorporation of graphene increases the host material's physical properties, so less material is needed to perform the same function. This creates a more sustainable material, as less of it is used, so the carbon footprint required to manufacture and integrate the material into its intended application is lower.
A key example of this is cement and concrete. Cement is added into concrete to hold the material together, but graphene can be added into cement (and concrete) to reduce the overall amount of material required to perform the same structural functions.
Concrete is responsible for around 8% of the world’s CO2 emissions. However, adding approximately 0.03 weight percent (wt%) of graphene into concrete reduces the carbon footprint by 25-33% and the global carbon emissions by 2%. Several graphene companies are working on graphene-enhanced cement and concrete around the world.
Graphene can also be added to asphalt – the material used to construct roads - to reduce the amount of material needed during production. Moreover, the asphalt's improved physical properties mean that it is more wear-resistant. Graphene-enhanced asphalt not only requires less material, but it also needs to be replaced less frequently, so the worldwide carbon footprint is greatly improved. This has been trialed on roads and is likely to be rolled out in more places.
Plastics is another area that graphene can make more sustainable. Recycling is in place for renewing plastics worldwide, but there are sometimes significant issues, as recycled plastics tend to have worse mechanical properties than the original plastic, limiting their use.
A number of companies (such as TLC Products) are integrating graphene into various plastics to create composites with very strong mechanical properties. The use of graphene in this area has the potential to improve the sustainability of the plastics industry by creating more durable plastics (without significantly increasing the cost), so fewer plastics will need to enter the landfill (and, in turn, the oceans and local ecosystems) compared to the current situation.
Sustainable Graphene Manufacturing Processes
Aside from making other materials sustainable, some highly green processes can be used to manufacture graphene. The first method ties into one of the issues mentioned about surrounding plastics. This first method is the ‘flash graphene’ process created by James Tour and commercialized by Universal Matter. This method takes all organic waste, whether plastics, household waste, or other carbon-based materials, and turns it into contaminant-free graphene.
The ‘flash method’, known as Flash Joule Heating (FJH), uses a high voltage pulse to raise the materials' temperature, subliming everything other than carbon. The excess carbon then naturally forms graphene sheets. This method offers a lot of potential for significantly reducing household waste while producing a large amount of graphene (as the process is highly scalable).
This graphene could then be used in some of the construction materials used above, creating a very green process from everyday waste to sustainable end products (and then possibly back into graphene again when the product is spent, creating a circular process).
GrapheneCR (GCR) also creates graphene from biochar, and the process itself is carbon negative. Using biochar over other materials (such as graphite) means that the process is much more sustainable in the long run, as there is no need for mining (and the environmental impacts that it brings).
Using biochar to create graphene also produces a lot of water (held in the biochar) that can be used in other products. Biochar by-products not converted into graphene can be used in agricultural settings and fed back into the land.
Almost everything in the GCR process, including green energy being used to power the facilities, the use of biochar materials, by-products going back into the land, to the end-use graphene in now-greener products, has created an almost circular process.
The Future of Sustainable Graphene
Graphene has a lot of potential as a sustainable material. This includes sustainable ways of making graphene from either natural sources or waste to utilizing graphene to reduce material usage (and reducing the carbon footprint of these materials in the process). Many people talk about graphene in high-tech applications, but it is these fundamental applications where graphene can be used as an additive that will drive the graphene market forward.
Graphene can be used as an additive for physical properties and for improving the green characteristics of materials. This will likely mean that focusing on its sustainable aspects will help with its worldwide growth and market penetration in a more green-focused society.
References and Further Reading
PR News Wire (2021) IDTechEx Explores Sustainability as a Potential Key Driver for Emerging Graphene Markets [Online]. Available at: https://www.prnewswire.com/news-releases/idtechex-explores-sustainability-as-a-potential-key-driver-for-emerging-graphene-markets-301215355.html
National Graphene Association/YouTube (2020) NGA2D Interview: Inside the Industry: Dr. James M. Tour [Online]. Available at: https://www.youtube.com/watch?v=wYWmoFxR40M
National Graphene Association/YouTube (2020) NGA2D Interview: When graphene goes green [Online]. Available at: https://www.youtube.com/watch?v=1F8AeQuiK5Y