Marijuana could solve one of America’s biggest problems, without anyone smoking it
As Hemp makes a comeback in the US after a decades-long ban on its cultivation, scientists are reporting that fibers from the plant can pack as much energy and power as graphene, long-touted as the model material for super capacitors.
Marijuana (Hemp) can be used to store energy
At the American Chemical Society’s national meeting this week, researchers from the University of Alberta unveiled a way to create extremely efficient batteries called “super capacitors” using specially treated Hemp, a non-psychoactive variation of the Marijuana plant.
That means Hemp could be a low-cost, renewable raw material that revolutionizes energy storage.
How it works
Hemp fibers are heated over the course of 24 hrs, causing the material’s carbon atoms to align and form nanosheets, each of which are only one carbon atom thick, and which can be used as conductors in batteries.
The basic structure of a supercapacitor
One of the battery’s most impressive features is its ability to discharge energy very quickly, which could drastically cut down charging times.
You could recharge the device you’re reading this article on in seconds.
Why it’s a breakthrough
Prior to this finding, super capacitors used lab-created carbon nanosheets, a material called graphene.
Hemp is proving to be far more efficient.
According to a press release, “The hemp-based devices yielded energy densities as high as 12 watt-hours per kilogram, 2 to 3 times higher than commercial counterparts.”
That means we can charge up electronic devices faster and more efficiently than we currently do.
But, the storage capacity of a Hemp super capacitors is less than ones that use graphene.
Despite a smaller storage capacity, Hemp is a better choice, because graphene is far more expensive to synthesize, and Hemp is a sturdy, renewable resource that can flourish in a range of climates.
With this discovery, super capacitors could rely exclusively on Hemp rather than graphene, and the batteries would be inexpensive and easily replaceable.
At this point, it is a proof of concept, but it could challenge the current market for energy storage devices, which would struggle to compete with such a cheap alternative.
In 2004 two Russian-born scientists, Andre Geim and Konstantin Novoselov, along with others, published the first electronic measurements proving they had isolated graphene. They had removed carbon flakes from graphite using bits of sticky tape – which ultimately led to them winning a Nobel prize for physics in 2010.
“The theory only really held true for two dimensions, but in actual fact the crystal grows in a three-dimensional space and the small surface fluctuations, like waves, stabilize the crystal,” said Goerbig. Experiments rapidly confirmed the marvelous behavior of this new material, which can be explained by a kind of sea of electrons on the surface that nothing can stop and that do not interact with each other. It’s as though the electrons have no mass and move at a speed 300 times slower than light. The mathematical equation to describe them is closer to that for high-energy particles than for solid matter, hence this outstanding performance that suggests so many potential uses.
Being transparent as well as a good conductor, graphene could replace the electrodes in the indium used in touchscreens. Since it is light, graphene could be integrated into composite materials to eliminate the impact of lightning on aircraft fuselages. It is also waterproof and would be perfect to use in hydrogen reservoirs.
Since nothing can stop the electrons, graphene cannot be “switched off” so in theory it is of little use in transistors, which are the key components of modern electronic goods. However, research is being carried out into ways of creating an artificial band gap that would enable it to be switched off and therefore used for that purpose.
Graphene Super capacitor Breakthrough Offers Energy Density Comparable to NiMH Battery!
But With all the Advantages of Super capacitors.
As you can see above, graphene is a one-atom thick sheet of carbon atoms, very similar to carbon nanotubes, except for the “tube” part. This wonder-material has very interesting electrical properties that have allowed researchers to create a graphene-based super capacitor that exhibits a “specific energy density of 85.6 Wh/kg at room temperature and 136 Wh/kg at 80 °C.” This is similar to nickel-metal hydride batteries, the chemistry used in most current hybrid vehicles (like the Toyota Prius and Ford Fusion hybrid).The main difference is that super capacitors can be cycled an almost unlimited number of times (they don’t lose their ability to hold a charge like batteries), and they can be charged and discharged extremely quickly (as long as you have a “fat pipe” to supply the power). This would make them ideal for hybrids and electric cars iftheir power-density was high enough (so far it isn’t) and their cost went down.
This breakthrough is bringing closer the day when the power-density part of the equation is solved, and while the cost of graphene is still high, it should go down with volume production (after all, it’s only carbon).
Graphene: The Super-Material of the 21st Century
Graphene – a thin sheet of carbon atoms – along with its cousin, the carbon nanotube, is one of the most promising materials discovered in a long time. It has superlative properties when it comes to strength, thinness, conductivity, optics, etc. We know a lot about, but scientists and engineers are still finding new ways to use it. The latest discovery has to do with a property of graphene that makes it super permeable with respect to water.
When a metal container was sealed with such a film, even the most sensitive equipment was unable to detect air or any other gas, including helium, to leak through.
It came as a complete surprise that, when the researchers tried the same with ordinary water, they found that it evaporates without noticing the graphene seal. Water molecules diffused through the graphene-oxide membranes with such a great speed that the evaporation rate was the same independently whether the container was sealed or completely open.
Dr Rahul Nair, who was leading the experimental work, offers the following explanation: “Graphene oxide sheets arrange in such a way that between them there is room for exactly one layer of water molecules. They arrange themselves in one molecule thick sheets of ice which slide along the graphene surface with practically no friction.
“If another atom or molecule tries the same trick, it finds that graphene capillaries either shrink in low humidity or get clogged with water molecules.”
This should allow graphene to be used to purify water, removing everything else from it and thus making it drinkable.
There might be other technical or economic reasons why graphene won’t be used in water filtration any time soon, but economies of scale should make it cheaper to produce every year, and this super permeability could make it useful for at least some water filtration tasks (i.e. when you need to remove extremely toxic molecules from water and you need to be sure that you caught every last one of them).