Over the past decade or so, thanks to the hard work of electric car advocates, scientists and car companies like Tesla, Nissan and General Motors, electric cars have transitioned from a position in the public consciousness of ridicule to one of being a viable alternative to many internal combustion engine vehicles.
As Tesla Motors’ prized Model S P85D shows, electric cars can be fast, fun, and capable of covering fairly long distances on a single charge. They can even be recharged in the time it takes to grab a quick lunchtime bite at a nearby restaurant.
And while the latest-generation of lithium-ion battery technology is far superior to what it once was, it still represents the best compromise between energy density, cost, longevity and durability. Even Tesla’s battery technology — considered the best in the automotive world — is compromised by recharge time and will ultimately wear out.
Here at Transport Evolved, we’ve covered lots of next-generation battery technologies which claim to be the best battery since Alessandro Volta invented the voltaic pile. Some are incredibly energy dense. Others have an amazing shelf-life. Others offer rapid recharging, yet nearly all of them have the same problem: the scientists behind them have yet to figure out a way to reproduce their wonder battery on a mass-market, affordable scale.
The same is true of the supercapacitor — a device which takes the best bits of a capacitor (its rapid charging capabilities) and a battery (its energy density) and offers a storage medium which is both capable of storing large amounts of energy as well as offering super-fast recharge times. Make those supercapacitors with graphene — the wonder material of our generation which has a surface area of 2,675 square meters per gram and is essentially one-atom-thick layers of highly ordered carbon molecules — and you’re left with an electrical component whose energy density can rival the best lithium-ion batteries but recharge itself in super-quick time.
The problem? Like those wonder batteries, graphene-based supercapacitors are tough to make in large quantities because graphene itself is difficult to manufacture. Right now, the best way to make graphene is to take a graphite crystal and slowly peel back its layers one by one as if you were slicing an onion. Methods for doing that vary according to the quantity being made, but right now each of them is time-consuming and/or low in yield.
But now a team of scientists in South Korea led by Dr. Lu Wu of Gwangju Institute of Science and Technology think they’ve figured out a way to mass-produce graphene in large enough quantities that graphene-based supercapacitor production could now be commercially viable.
As TheEconomist detailed last month, Dr. Lu’s answer to producing large amounts of graphene was to essentially blow up graphite crystals in a controlled explosion. After first exposing powdered graphite to oxygen in a controlled environment to produce graphite oxide, his team then heated the resulting compound to 160 degrees celsius at a pressure of one tenth of an atmosphere.
As a consequence of being heated, the graphite oxide separated into carbon dioxide and steam, increasing internal pressures in the container and ultimately blowing the graphite apart into graphene sheets within the low-pressure container. After treating them further post-explosion to remove excess oxygen, these sheets were then ready to be used in a supercapacitor.
After incorporating the explosively-made graphene into supercapacitors, Dr. Lu and his team were able to produce supercapacitors capable of storing ‘as much energy per kilogram as a lithium-ion battery’ with recharge times of less than four minutes.
Sadly, the neither TheEconomist or any of our research into this technology has yielded a specific figure. And while we’ve reached out to Dr. Lu for more information, we’ve yet to hear from either him or his team about this particular breakthrough.
So why are we covering this? Regardless of how it is used — in an electrochemical battery or an electromechanical supercapacitor — graphene is the magical substance seen as a prerequisite for many next-generation energy storage technologies. If Dr. Lu and his team have truly found a way to mass-produce that graphene on an industrial scale, we could be on the brink of changing the way we charge plug-in vehicles and gadgets forever.
Like other heralded breakthroughs however, we’re going to have to see if this method of graphene production can make it out of the lab and into the factories first.
Watch this space.
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