GRAPHENE LIVE: Still no “killer application” for graphene

By Emma Hughes
Published: Wednesday, 02 April 2014

Graphene is viewed as a wonder material that has the potential to revolutionise the technology industry, yet it still has some way to go before it can break through to full-scale commercialisation, according to speakers at Graphene Live! 2014 in Berlin.

While graphene has proven to be a nano-material with several desirable properties in the technology sphere, it is yet to find a “killer application” that will pull it firmly out of laboratories and into mainstream commercialisation.

This was the overarching sentiment of speakers during the first day of Graphene Live! 2014, which is taking place this week in Berlin, Germany.

Graphene is a two-dimensional, crystalline allotrope of carbon produced from either natural graphite, using an exfoliation route or synthetically, through processes such as chemical vapour deposition (CVD).

Graphene has hit the headlines over the past few years due to its exceptional properties, which include high intrinsic conductivity, high specific surface area, ultra thinness (one atom thick) and an inert basal surface.

These characteristics have granted graphene research and development airtime around the world, especially in relation to its potential use in energy storage and consumer technology applications.

However, while graphene exhibits properties that make it possible to improve the performance of technologies such as supercapacitors, batteries and solar cells, it has not yet found an application that will pull it firmly out of research and development, according to Dr Khasha Ghaffarzadeh, head of consulting at IDTechEx.

“Graphene clearly has significant potential,” he said, adding that “there is not yet a ‘killer application’ [for this material]”.

Ivan Buckley, project manager at the UK’s National Graphene Institute, used the same phraseology of “killer application” when describing the future outlook for graphene, commenting that while there are many areas of development that are being explored, it remains uncertain what is next for the nano material.

Energy storage

One area that holds a lot of possibilities for graphene is energy storage, according to Ghaffarzadeh, who outlined graphene technology, the market and its players in the Graphene Live! 2014 opening keynote.

According to his presentation, supercapacitors, or electric double-layer capacitors (EDLC) are one area where there is great potential for graphene.

This technology stores energy by separation of a charge in a so-called Helmholtz double layer at the interface between the surface of a conductive electrode and an electrolyte.

Dr Paolo Bondavali, head of nanomaterials group at France’s Thales Group, explained that graphene exhibits several characteristics that make it a viable supercapacitor material.

Such characteristics include very high rates of charge and discharge, high life cycle (>100,000), good reversibility, low toxicity of material used, high cycle efficiency, low internal resistance – making for a higher power output – and extremely low heating levels.

Several of these properties also mean graphene is being considered as an alternative in lithium-ion (Li-ion) batteries, which traditionally use graphite in anodes and cathodes.

Yet there are also drawbacks of using graphene in supercapacitors, including the low amount of energy this type of material can store and the fact that it requires sophisticated switching equipment, Bondavali explained.

Ghaffarzadeh also outlined that while graphene’s properties make it a suitable electrode material for electrochemical supercapacitors, the material faces stiff competition from indium tin oxide (ITO).

“The market is currently dominated by ITO, which is well established,” explained Ghaffarzadeh. “But graphene is positioning itself as an ITO alternative,” he added.