Innovative technique to synthesise advanced graphene-based nanocomposites

(Nanowerk News) Inspiring a 2010 Physics Nobel Prize, the recently discovered carbon form known as graphene, is predicted to launch the next tech revolution. But only if it can be efficiently manufactured. Looking at electrical energy storage (EES), one project points the way forward.
Graphene uniquely combines great mechanical and tensile strength, a large surface area, high chemical stability, with superior thermal and electrical conductivity. Properties which give the material extraordinary potential. Additionally, as it is one of the earth’s most abundant elements it is also exciting economically (check out this graphene infographic).
One area where graphene and graphene-based composites currently hold out much promise is as replacement materials for electrodes in energy storage devices. To date, graphene has significantly increased the capacity and efficiency of Li-ion batteries and supercapacitors.
However, barriers to widespread implementation across industrial applications remain. There is a lack of viable methods to produce advanced graphene-based nanocomposites on an industrial scale and cost-effectively, owing largely to the multiple chemical transformations that must be undertaken.
To overcome this, Gnanomat, under the EU-supported GRAPHEEN project, used a patented technique to build a pilot plant to scale up electrode materials for energy storage devices. The team also implemented a quality control system and commercialisation is already underway.

From lab testing to pilot plant and beyond

The project initially used different lab-based characterisation techniques to better understand the synthesis process undergone by nanomaterials during production. “Understanding the synthesis mechanism and problems with the cycling stability of metal oxides – used to improve the electrochemical properties of carbon – was challenging. It is complicated to control all the synthesis parameters, such as reduction–oxidation (Redox) for short reactions,” says project coordinator Dr Alejandra García.
The nanomaterials were then evaluated for their suitability for electrodes in energy storage devices, with the most promising chosen for the pilot plant.
The principal challenge for energy storage device manufacturing is to improve the electrochemical parameters of energy density, (the amount of charge a device can store and then deliver), power density (how quickly the device can deliver power), and device lifecycle, while decreasing the cost per kWh generated.
The GRAPHEEN pilot plant used the Gnanomat patented, environmentally-friendly and safe-single step technique for the production of advanced graphene-based nanocomposites. The scale-up process is conducted in a liquid medium. Where the properties of the products can be determined, by controlling the synthesis parameters, it is possible to use a procedure that does not require high pressures or temperatures. The solvents used are common in the industry and do not present any danger related to toxicity or volatility.
Quality control measurements were also applied to the plant’s production cycles to ensure that these optimised nanomaterials reached the expected market standards.
“This relatively simple, scalable and cost-effective way to produce advanced graphene-based nanocomposites has the potential to become the gold-standard,” says Dr García. “At the end of the project, we were developing advanced nanomaterials with good electrochemical responses.”

Disruptive potential

With so many human activities dependent on energy production and storage devices, any material offering more efficiency, and at reduced price, has huge positive disruptive potential. Crucially, nanocomposites could also contribute to the reduction of greenhouse gas emissions by improving the capacities of renewable energies, electric vehicles or electronic devices.
Currently, the technology remains at the pre-industrial scale stage. To progress to market-ready, large scale provision for manufacturers and assemblers, Gnanomat is developing a strategic partnership with the engineering materials group, Versarien.
Source: European Commission
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