Graphene is strong, possibly even the most durable material in the world. But that’s not its sole attribute. The two-dimensional carbon allotrope is also remarkably light and thin, has very high thermal conductivity, can conduct electricity well, and it’s transparent. These one-of-a-kind qualities make graphene a prized material in many products, and it is an ideal component for others in which its use has only been hypothesized. Some formerly-potential applications of graphene, however, are finding realization through scientific innovation.
Advanced Lithium Ion Battery
One of these is the use of graphene as an alternative to conventional batteries. Currently, rechargeable lithium-ion batteries are the industry standard for mobile phones, tablets, laptops, computers, and electric cars, along with non-consumer devices, such as electronic medical devices. While the Li-ion battery is, in many ways, a marvel of modern technology, it is still restricted by its limited power density and inability to quickly accept or discharge large amounts of energy. This inspired a team of engineering researchers at Rensselaer Polytechnic Institute, led by nanomaterials expert Nikhil Koratkar, to incorporate graphene into the traditional design.
By exposing a large sheet of graphene oxide paper to a laser or a flash from a digital camera, the Rensselaer team was able to create an anode for a Li-ion battery. This resulted from the laser or photoflash literally causing mini-explosions throughout the paper, as the oxygen atoms were violently expelled from the structure. The end product was graphene paper, five-fold in thickness as compared to the original sample, with large voids, cracks, pores, and other blemishes between the individual sheets.
With the graphene paper anode, the battery’s ions were able to use the cracks and pores as shortcuts to move quickly into or out of the graphene—greatly increasing the battery’s overall power density. This experimental anode material is, as expected with graphene, incredibly robust, and could charge or discharge ten times faster than conventional anodes in Li-ion batteries. The researchers have also stated that process of making these graphene anodes can easily be scaled up to fit the needs of the industry.
If you’d like to learn more, please refer to the original research paper here: Photothermally Reduced Graphene as High-Power Anodes for Lithium-Ion Batteries
Another potential use of graphene became reality from the work conducted by a research team, led by Professor Monica Craciun, from the University of Exeter. This team discovered a new technique, which involved growing graphene in an industrial cold wall chemical vapor deposition (CVD) system, a state-of-the-art piece of equipment recently developed by UK graphene company Moorfield, to create the first transparent and flexible touch-sensor.
The applications of this graphene-based sensor are numerous, and, since the nanoCVD system can grow graphene 100 times faster than conventional methods and reduce costs by 99 percent, it is highly desirable for creating more flexible electronics. In fact, it is even possible for the material to be used as a flexible skin for robots. As noted by Professor Craciun, this electronic skin could even be seen as part of the vision for a “graphene-driven industrial revolution”.
Graphene Temporary Tattoo for Tracking Vital Signs
Another graphene-based innovation also closely related to skin was discussed in IEEE Spectrum. This is a graphene health sensor, which appears much like a small temporary tattoo on an individual’s skin and was presented in December 2016 at the International Electron Devices Meeting in San Francisco.
This graphene sensor was created by researchers at the University of Texas at Austin, who engaged in the following process: they grew a single-layer graphene on a sheet of copper, coated the 2D carbon sheet in in a stretchy support polymer, etched off the copper, placed the polymer-graphene sheet on temporary tattoo paper, carved the graphene to make electrodes with stretchy spiral-shaped connections between them, and lastly, removed the excess graphene. The result is the thinnest epidermal electronic ever made.
This graphene health sensor is unobtrusive, durable, highly conformable to the unique surfaces of human skin, and, most importantly, able to measure electrical signals from the heart, muscles, and brain, as well as skin temperature and hydration, with the same precision as conventional devices.
Standardized Use of Graphene: Electronics
These research achievements are miraculous, but they shouldn’t overshadow the standardization of graphene in electronics. Currently, IEC/TS 62607-6-4 Ed. 1.0 en:2016 – Nanomanufacturing – Key control characteristics – Part 6-4: Graphene – Surface conductance measurement using resonant cavity (a technical specification, not a standard) establishes a method for determining the surface conductance of layers of nano-carbon graphene structures. The measurements that can be derived from this method are essential for incorporating graphene into electronics.
The actual incorporation of graphene into electronics is covered by IEC/IEEE 62659 Ed. 1.0 en:2015 – Nanomanufacturing – Large scale manufacturing for nanoelectronics, which provides a framework for introducing nanoelectronics into semiconductor manufacturing facilities.
While the manufacturing of electronics will likely serve as an early commercial use for the robust material, it is not yet a common practice in industry. However, with growing corporate research, such as the announcement in 2014 that IBM would invest $3 billion in graphene semiconductor research, it’s understandable to assume that graphene will be a part of the future.