Graphene At Play In New 300-Mile EV Battery
A research team from the Lawrence Berkeley National Laboratory has a 300-mile electric vehicle battery range in its sights, thanks to a unique combination of different electrochemical technologies including a new material called sulfur-graphene oxide (S-GO). CleanTechnica is one of the world’s leading fans of graphene so naturally we are most interested in (ok, so totally excited by) that. So, here goes.
Graphene To The Rescue
S-GO was developed in-house by Berkeley Lab, for use in next-generation EV batteries based on lithium-sulfur technology.
Sulfur has some key advantages over conventional lithium-ion battery technology in terms of storage capacity (far better), toxicity (none), cost (far less), and weight (ditto), but it is also very brittle.
The gist of the problem is that sulfur tends to be soluble in the organic solvents used in conventional batteries. That process forms polysulfide ions — I know, right? — which can get to the lithium anode and re-solidify as precipitates, forming a barrier that interferes with storage capacity.
The result is that typical lithium-sulfur prototypes can’t last more than a dozen or so charge-recharge cycles without losing it, “it” being their ability to store a charge.
The Berkeley solution was to develop a nanomaterial composed of small particles of graphene flakes coated with sulfur, namely S-GO. As described by Berkeley writer Allan Chen, S-GO is characterized by a large, cavity-speckled surface area, which allows for more “intimate electronic contact” with sulfur while minimizing loss of contact with the current collector of the electrode.
When used as a cathode material in a lithium-sulfur battery, S-GO binds with lithium during discharge and releases it back to the anode during recharge.
Meanwhile, S-GO resolves some other key issues, including the massive bloating that bedevils lithium-sulfur technology. The graphene lends an element of flexibility that enables S-GO to accommodate the volume increase of up to 76 percent that sulfur suffers through as it is converted to lithium sulfide during discharge.
Electrochemical Teamwork Better EV Battery Range
Now let’s take a look at how the S-GO cathode works together with other electrochemical technologies to extend EV battery range in a lithium-sulfur battery.
Aside from the vastly improved cathode performance, the new battery sports such goodies as an enhanced binder (elastomeric styrene butadiene rubber combined with a thickener) that increases power density.
To deal with the polysulfide issue, the team used a coating of cetyltrimethyl ammonium bromide (a surfactant commonly used in drug delivery systems) on the sulfur electrode.
Also helping out with the polysulfides thing was a new electrolyte based on an ionic liquid, developed in-house at Berkeley (ionic liquids are non-volatile and non-flammable btw).
The new ionic liquid also provides a huge boost in the rate of battery operation, while increasing the speed of charging and the delivery of power during discharge.
Here’s the result as reported by Chen:
The battery initially showed an estimated cell-specific energy of more than 500 Wh/kg and it maintained it at >300 Wh/kg after 1,000 cycles—much higher than that of currently available lithium-ion cells, which currently average about 200 Wh/kg.
That puts the new battery’s potential well within sight of a 300-mile EV battery range:
For electric vehicles to have a 300-mile range, the battery should provide a cell-level specific energy of 350 to 400 Watt-hours/kilogram (Wh/kg). This would require almost double the specific energy (about 200 Wh/kg) of current lithium-ion batteries. The batteries would also need to have at least 1,000, and preferably 1,500 charge-discharge cycles without showing a noticeable power or energy storage capacity loss.
The next steps include increasing the use of sulfur, maintaining performance in extreme conditions, and of course, scaling up to size.
If there are any private sector partners out there to pitch in with the funding, Berkeley would love to hear from you so give them a holler. Remember, graphene is the miracle material of the new millenium.
Meanwhile, considering that Berkeley Lab is a Department of Energy facility, yes we built this!
Follow me on Twitter and Google+.
Have a tip for CleanTechnica? Want to advertise? Want to suggest a guest for our CleanTech Talk podcast? Contact us here.
CleanTechnica Holiday Wish Book
Our Latest EVObsession Video
CleanTechnica uses affiliate links. See our policy here.
not only the car battery matters. combine car battery with induction charging cables
in the road, charging while driving and EV is on the road.
no limits.
The rate of progress on batteries is remarkable and cheering. A vote of thanks is due to former Energy Secretary Steven Chu, who made a big bet on battery research in the stimulus.
A 300-mile range would solve most range anxieties. A few decades ago, that was an acceptable range for a gasoline-fueled car.
We need also 200 kW fast charging.
what for? As soon as the range exceeds a 5 hour drive you gonna stop anyway to let the driver/passengers have a pause..
Here in Europe we are used to drive 160–200 km/h on highways. With 200 km/h driving speed, you need stop charging every 50 minutes.
Where else but Germany? France: 130 km/hr. Belgium, Spain, Sweden, Switzerland: 120 km/hr. Britain: 113 km/hr. Etc. Only lunatics try to drive at 160 km/hr, let alone 200 km/hr: the other traffic won’t permit it.
Is it not the case that one can drive at high speeds for only short distances on the Autobahn?
It’s not like one can drive non-stop from Seattle to San Diego at 100 MPH. More like Lodi to Stockton.
You can drive high speeds until Autobahn ends.
Most of EU countries have around 120-130km/h. Italy has some parts with 160km/h.
So the competitive price to shoot for should be less than $125/kWh. And graphene is not cheap to manufacture at the moment, but that is another problem. It is good to see various alternative battery chemistries solve some of their problems or limitations.
BS this article. There are dozens of more promising battery lab prototypes available. Having a lab prototype, does not mean that it is ready for production. Typically it takes at least a dacade to advance from early lab prototype to commercial product.
Also Tesla already has affordable 300 mile range battery. The cost of 300 mile battery is just $25k.
Envia already has the 300-mile battery, just waiting for investors to build a scaled-up factory. Envia’s projection is that the 300 mile battery would cost only $20K, including the car that houses it, while Tesla’s $25K is just the battery.
Although Envia claims that they are much further than mere lab prototype, I would still classify Envia as vaporware before they have real prototype up and running. It should not be hard to convert ICE vehicle to 300 mile range EV, if Envia batteries are as good as they claim.
GM owns part of Envia. A few months back a GM exec let slip that GM was testing a new high capacity battery on their test tracks. One would assume he was talking about the Envia battery.
I hope that Envia is real and not vaporware.
Envia has been very silent as of late. Their last official news was on March 13, 2012. Maybe something is brewing up, let us hope that GM is developing and testing mule cars based on Envia’s battery, perhaps selling 200-mile to 300-mile range EV cars in the $20K-$35K range by 2015.
So why would you be against Envia? AFAIK, the EV battery industry is not in the teradollar level. I truly would love to use cheaper long lasting batteries coupled with solar PV. That would be the next revolution in solar. You will have free fuel for daily commute.
cheap Envia batteries would effectively kill oil and ICE car industry. Also aviation could be electrified and this would mean the end for Boeing and Airbus. Also coal, natural gas would suffer enormously and nuclear industry would die completely. This is why Envia batteries would be the biggest technological disruption in history and the economic impact would be teradollar level per year.
Oh I See, I misinterpreted your earlier response.
latest update from Envia:
Rumor:
http://evobsession.com/long-range-ev-from-gm-envia-rumors/
Interview:
http://www.mercurynews.com/ci_22312503/mercury-news-interview-atul-kapadia-battery-maker-envia-systems
Q: What do you think of Tesla Motors (TSLA) and their battery?
A: Tesla has done a brilliant job of managing the manufacturing problem. But fundamentally, they are still using the wrong chemistry. They cannot bring the battery cost down with the chemistry they are using.
Envia it does look very promising in terms of the energy density however it’s cycle life doesn’t appear to be that good. It looks to me like the 45 ah cell loses almost half its capacity after only 500 cycles but i may be interpreting the graph wrong
It is good development. But do make another announcement when they start selling these batteries, 5 years from now?
Why not be a little bold and license out Envia technology for literally $100 to all the automobile companies out there?
This would be good for the planet and no elites would be able to lock down the technology. If Envia has that much potential, they must realize their responsibility that comes with vast knowledge and the resulting power from it. They will have a very proud place in history, more respectful than any other capitalist out there.
i hope the price tag wont be as high as the current battery prices given graphene is low cost.
mreddie You had to throw in. yes, we built it. The Berkley Lab is a research center that is given research money by the U. S. Government. An absolute correct thing for our tax money. Ask any conservative. Please note their request for private money. It will be private money that bullds factorys, hires the workers, markets the product and takes all the risks. I would appreciate if you would leave your personal political opions to yourself. It mocks serious people.
Higher speed causes a reduced milage in the car due to higher drag levels. My Prius gets 48-50 in town at lower speeds, 44 on the highway with speeds in the 60s and back and forth Phoenix to LA with 75mph speed limits in achieves less than 44. More work on streamlining would help but there will be a practical limit there at some speed.
– Dan in phoenix
“So considering that Berkeley Lab is a Department of Energy facility, yes we built this!”
So, the only people that “build this” are government facilities? Go f*ck yourself, Casey.