The Incoming Graphene Age
How the lead in our pencils could power the next generation of tech
Since the 1960s, silicon has been widely used in a variety of tech. Its versatile electrical and thermal properties make it ideal for use in common technologies like phones, computers, and digital watches. The material can be found all around us. However, its advantages and properties barely compare to the silicon of the future: graphene.
What is Graphene?
Graphene is one of the strongest and most versatile materials on Earth. It is essentially carbon, but the difference is in the way the atoms are bonded. The atoms bond in interlocking hexagons, which makes the bond extremely strong. So strong, in fact, that a sheet of graphene as thick as saran wrap could withstand the weight of an elephant.
Another property of graphene is its thermal and electrical conductivity. The way the carbon atoms are structured and packed together allows ultra-stable bonds. The reason it conducts electricity and heat so well is because of its delocalized electrons (electrons not associated with a specific atom) that freely move along the surface of the graphene. Although graphene can be found in pencils, which is a common household item, mass-producing graphene isn’t the simplest.
How Graphene is Produced
Originally, graphene was made by pulling pieces of tape off of a particular kind of graphite so that flakes of graphene would stick to the tape. The tape would be dissolved from the graphene using chemicals, and voila: graphene flakes are produced.
Obviously, mass-producing graphene that way would be impossible because of the amount of time it would take up, so there are several different methods used for producing graphene. One of the methods used consists of adding sulfuric or nitric acid to the graphite, which forces oxygen atoms between the graphene sheets to separate. The acid used is then filtered out, and the sheets of graphene oxide are removed from the filter by dissolving the filter away with a solvent that doesn’t react with graphene oxide. Finally, the oxygen is removed with hydrazine, and a graphene coating is left behind.
Graphene and its properties are clearly very substantial, and these properties could potentially play a role in replacing silicon in some devices.
Why Graphene Instead of Silicon?
To start, silicon is used in computer chips in several computers and electronic devices today, most likely including the one you’re reading this article on right now. Silicon is a semiconductor, which means that it conducts electricity under some conditions and acts as an insulator in other conditions.
Naturally, graphene isn’t a semiconductor, so it can’t act as both a conductor and an insulator. However, Aarhus University in Denmark has developed something called bilayer graphene, where two graphene sheets are laid on top of one another leaving a small gap. This small gap encourages the transfer of energy between layers. Laser pulses boost electrons into the bilayer graphene and the movement of electrons in the small gap act as a semiconductor. This makes a faster and smaller electronic chip so that more transistors can put on one chip and more powerful processors can be used in computers.
Graphene does make for an amazing advance in technology with computers and processors, but its other properties allow it to be used for a large variety of things, some of which are currently on the market.
Products on the Market/in the Making using Graphene
Graphene Clothing
Ever wanted to know what it would be like to wear graphene? You can! The clothing company Vollebak has actually created wearable clothing made from graphene. Although it’s currently being released as an experimental prototype, the $695 graphene-coated jacket is strong and stretchy, as well as fully reversible. On cold days, the graphene side can be used to conduct heat and circulates it around your body. You would do this by placing it in front of a warm source before use and wearing the graphene side facing your skin.
The graphene side of the clothing is also waterproof and breathable. The tight bonds of the atoms cause the graphene clothing to be impermeable to almost all gases and liquids, other than water. The polyurethane membrane causes the material to be waterproof to 10,000 mm, and the breathable graphene allows your sweat to evaporate through the material.
There are many, many more details about the graphene jacket and their other products on their website, https://www.vollebak.com/product/graphene-jacket-1/.
Graphene-Powered Light Bulb
With graphene’s thermal properties, it can also be used to make light bulbs. Graphene light bulbs are essentially the “world’s thinnest lightbulb” because the material needed to make it (graphene) is incredibly thin.
The heat dissipation in graphene emits light, which is how the bulb is powered. To go more in-depth, passing a current through a filament with small strips of graphene reaches temperatures of over 2500°C (4532°F), which can produce visible light. The metal electrodes attached to the filaments don’t melt because when graphene is heated up at such a high temperature, the immense heat stays in the center of the filaments instead of spreading top to bottom. Micro-scale metal wires can’t withstand this heat, which is why carbon is the best material to use for lightbulbs this thin. A company that sells these lightbulbs is graphenelighting.co.
As amazing as this seems, this isn’t a new idea, but merely a rediscovered one. Thomas Edison actually initially used a carbon filament for his lightbulb. Now, we’ve rediscovered carbon and realized how well it works, but just with a different kind of carbon.
Vibration Energy Harvester
Imagine not ever having to charge your phone, laptop, or other electronic devices again. With vibration energy harvesters, this could be common in the future!
For the design to work, a negatively charged sheet of graphene is suspended between two metal electrodes. A section in the middle of the graphene sheet becomes concave when flipping up and down, and a charge is placed on the sheet of graphene. When the graphene section flips up, it induces a positive charge in the top electrode, and when flipped down a negative charge in the bottom electrode is induced. This creates an alternating current, and charge continuously flows between the electrodes, creating a battery lasting for years and years.
Solar Cells
Solar panels are marvelous. They literally turn energy all around us from the sun into useable electricity for our homes and electronics. However, they could be a lot more powerful if they used more of the energy they conducted and didn’t waste it. With carbon nanotubes, which are essentially a hollow cylindrical structure made from rolled-up graphene sheets, more energy can be used from solar panels.
Normally, solar cells are made from a semi-conductor (like silicon), where a positive charge and negative charge are added on the top and bottom of the inside of the solar cell, creating an electric field. Photons from the sun bounce off the surface of the solar cell, which knocks electrons off the silicon atoms on the surface to a regulator, which makes electricity. This method works but doesn’t catch all forms of solar energy due to there being different kinds of solar rays. Around 70% of solar energy is lost with this method.
Scientists found a way to resolve the waste energy by realizing that the heat bouncing off the solar panels can be used as electricity. Here, carbon nanotubes are used in the solar panels to absorb the heat instead of allowing it to reflect off. The waste heat is channeled into narrow bandwidth photons, which are then converted to electricity. Carbon nanotubes also absorb heat very well and can withstand high temperatures, which makes them ideal for solar panels. This could increase the efficiency of solar panels from 29% to 80%.
Samsung Graphene Batteries
Earlier in 2017, Samsung announced that one of their upcoming androids would use graphene batteries that they hope will come out by 2021. The ball-shaped graphene battery is said to enable a 45% increase in capacity and charging speeds five times faster than standard lithium-ion batteries.
The graphene would be shaped into a 3D popcorn-like form using silica and would be used to enhance the properties of lithium-ion batteries. The “graphene ball” is said to be utilized for both the anode protective layer (a layer used to exert mechanical force onto positively charged electrodes leaving the battery), and for cathode materials in the battery (negatively charged electrode materials). The graphene ball ensures less charging time, an increase in charging capacity, and balanced temperatures.
Graphene-Powered Cars
Graphene can also be used in the automotive industry! Because graphene is a conductive material as strong and light, it can be used for more than one part of the car.
The lightweight yet strong qualities of graphene allow it to be used for the bumper of the car, which means less weight and less energy used. To accomplish this, graphene would be combined with carbon-fiber-reinforced epoxy resin. The battery of the car can also be made with graphene, although this could be faulty due to the electricity grid’s load-balancing issues and other problems that may come up. The transparency and conductivity of graphene can also be implemented in a touch-screen display on the dashboard. Because of graphene’s flexibility, a curved touchscreen can be designed that can stretch over larger areas of the car.
These are only a few areas in which graphene can be implemented in cars. Other applications that can be used include graphene-heated car seats and even graphene-based pollutant detectors!
Graphene Touch Screen
Completely foldable touch screens can also be made from graphene. And not the ones that can be folded in half made by Samsung — graphene touch screens are entirely bendable.
Today, most mobile devices use a material called indium tin oxide. These screens crack easily and can be expensive to repair. Graphene screens, however, are much more flexible and a lot cheaper than indium tin oxide screens.
To make these, a layer of graphene is grown on copper foil using chemical vapor deposition. The graphene face is then pressed against adhesive polymer support using a roller and the copper is etched away, isolating the graphene film with the polymer. The graphene is finally pressed against an underlying substance or layer, and the polymer adhesive is released with heat. This creates a flexible, transparent, and functional touch screen that is tougher and cheaper than ITO touchscreens.
These aren’t currently on the market due to a lack of better production methods, but expect to see these in the future!
Blocking COVID-19
With the ongoing virus, COVID-19 can be easy to catch when people reuse masks. Masks also don’t completely block out the virus, and there’s no sure-fire way to prevent catching it. To take precautionary measures an extra step, graphene can be used in masks!
Laser-induced graphene that would be used in the masks is made from directly writing on carbon-containing polyimide films(a plastic material with high thermal stability) using a CO2 infrared laser system. The reusable graphene masks also have an antibacterial efficiency of 82% when tested with E. coli, compared to carbon fiber and melt-blown fabrics, which are materials commonly used in masks, having a 2% and 9% efficiency.
Previous studies also suggest that COVID-19 loses its infectivity at high temperatures. After experimenting with the material’s photothermal effect, it was shown that the graphene material’s efficiency improved 99.998% within 10 minutes under sunlight compared to carbon fiber and melt-blown fabrics showing an improvement of 67% and 85%.
Conclusion
Graphene is such an amazing material that can be utilized in so many forms of tech in the future, most of which weren’t even put into this article. One day, graphene could be found in almost every one of our devices, and even in most of our clothing. So next time you pick a pencil up, remember that the biggest and most climactic invention of the century could be made with carbon similar to the one in that very pencil.
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