All You Need to Know About Graphene Power
The concept of storing energy cuts across most modern technologies or inventions. For instance, your phone, tablet, the fitness watch on your wrist and the electric car in your garage all rely on batteries to function. However, it seems that we have never fully reached the potentials that a current battery can achieve.
There has been a lot of attention on graphene, the latest wonder material in industrial circles. One application of graphene is in batteries or energy storage.
Almost every electronic device runs on batteries and these traditional batteries work on the principle of two terminals of the battery being separated by electrolytes, that allows charge flow between the terminals. When you connect these batteries to an external circuit board, the electrolytes move as ions, allowing the chemical reactions to be completed at the terminals and thereby delivering energy to the external circuit. It is the movement of the ions within a battery that allows current to flow out of the battery.
Now, there is another form of energy storage known as ultracapacitors. Ultracapacitors aka as supercapacitors are a monumental breakthrough in capacitor technology and are source of electrical energy.
Ultracapacitors are double layer capacitors that offer significantly high energy density, meaning they are able to hold hundreds of times more electrical charge compared to standard capacitors. Ultracapacitors are bigger capacitors that are inherently better energy storage devices that are able to store a large amount of electrical charge than chemical batteries. Compared to similarly-sized batteries, ultracapacitors have a high power density, quick charge-discharge rate and a longer life cycle. They can be used wherever a large amount of power is required for a short period of time.
Unlike standard capacitors, ultracapacitors have an electrolyte between the plates rather than a dielectric, meaning they store energy in an electric field rather than in a chemical reaction. Unlike batteries, they are resilient to high temperatures and charge much faster.
Ultracapacitors benefit from this new wonder material, graphene. Graphene has emerged as one of the most promising nanomaterials because of its unique combination of exceptional properties: it is not only the thinnest but also one of the most robust materials because it conducts heat better than all other materials and is optically transparent, yet so dense that it is impermeable to gases. It has high electron mobility (roughly a 100x faster than Silicon!), conducts heat 2x better than diamond and 13x more electrically conductive than copper!
Ultracapacitors and Graphene
Graphene provides the next generation of supercapacitors with an interesting array of improvements. In particular, graphene offers substantially more surface area, giving supercapacitors even more capacity for energy storage. In addition to that, graphene is ultralight, has unique elasticity and is incredibly strong.
To answer the question ‘Why a Graphene supercapacitor?’ we need to know what graphene is, essentially.
Graphene is fundamentally, a single layer of graphite- the material that makes pencils useful. Instead of having a 3 dimensional crystalline structure like graphite, graphene is basically 2 dimensional, meaning it’s just one atom thick with the atoms arranged in hexagonal lattice or a honeycomb arrangement. This structure is important because it allows each carbon atom to be covalently bonded, that is, sharing an electron pair to three or more around it. It is the strength of these bonds that makes graphene more strong and stable. Not to mention, atoms in the monolayer can move more freely- and this is what makes graphene really good at heat and electric conduction.
The Challenges of the Graphene Ultracapacitor
What normally happens with technologies that use graphene, is that it works really well in a lab. When you move from synthesising one gram to a hundred, you don’t get the same material you think you’d get. The synthesis doesn’t seem to work anymore. Moving from the first gram to the first kilogram is the hardest part. It takes a very long time for a technology to go from lab to mass market production.
The most difficult part isn’t figuring out IF something will work, but HOW to produce it at scale. What really is strenuous, is coming up with concepts that make any technology better that are commercially and industrially feasible.
So really, you can come up with a thousand ways to make ultracapacitors and batteries better, but to find that one way to make it better that is cheap, effective and scalable is the hard part.
The Future!
Having discussed these challenges, we’re probably not going to see these ultracapacitors replacing Li-ion batteries in your cars. Their specific energy (Volumetric energy density) is dramatically lower than a battery, but the power capacity and how much power it can deliver at once is where it shines.
What we’ve seen, is that they pair nicely with Li-ion batteries. Ultracapacitors can help a lot to make the energy storage that is used in these Li-ion modules, smaller, lighter and safer. Here is an opportunity where we can use curved graphene ultracapacitors because they are already much smaller and they carry much more juice in this form factor. So you can make the whole application cheaper and lighter. The higher capacity of new curved graphene products can help save space and weight.
One specific application that we have is on top of trains or light rail trains, where you have ultracapacitors that store the energy when the train breaks and release it when the train accelerates which can save a lot of energy.
When it comes to renewables, ultracapacitors play a big role. We’re already using ultracapacitor modules in wind turbines to help manage the blade pitch control(adjusting the rotation speed and the generated power). The graphene versions of ultracapacitors can provide the same amount of power and control in fewer modules which means reduced space, weight and cost.
Ultracapacitors also play a big role in grid scale energy storage systems.
Now, a lot of energy is good and its essential, but its almost like candy. If you have too much of it, it might be bad because that actually destabilises the grids. If we have too much solar or too much wind and what we’re striving for is to get 100%, and we have no energy storage, we lack the foundation. Ultracapacitors are able to deal with short power peaks that are normally dealt with by huge rotating turbines that we have stationed in coal and nuclear power plants. The more you take these out and bring renewable energy in, the more reactive power storage you need, and that’s where ultracapacitors can actually help out.
Its really exciting to see where innovative companies take their curved graphene products, and how other products like them will help benefit renewables and other sustainable technologies. With new materials like Borophene, the possibilities of what the future of energy storage holds is exponential.
