Major breakthrough in lithium battery technology reported
May 18, 2009An NSERC-funded lab at the University Of Waterloo has laid the groundwork for a lithium battery that can store and deliver more than three times the power of conventional lithium ion batteries.
The research team of professor Linda Nazar, graduate student David Xiulei Ji and postdoctoral fellow Kyu Tae Lee are one of the first to demonstrate robust electrochemical performance for a lithium-sulphur battery. The finding is reported today in the on-line issue of Nature Materials.
The prospect of lithium-sulphur batteries has tantalized chemists for two decades, and not just because successfully combining the two chemistries delivers much higher energy densities. Sulphur is cheaper than many other materials currently used in lithium batteries. It has always showed great promise as the ideal partner for a safe, low cost, long lasting rechargeable battery, exactly the kind of battery needed for energy storage and transportation in a low carbon emission energy economy.
"The difficult challenge was always the cathode, the part of the battery that stores and releases electrons in the charge and recharge cycles," said Dr. Nazar. "To enable a reversible electrochemical reaction at high current rates, the electrically-active sulphur needs to remain in the most intimate contact with a conductor, such as carbon."
The Canadian research team leap-frogged the performance of other carbon-sulphur combinations by tackling the contact issue at the nanoscale level. Although they say the same approach could be used with other materials, for their proof of concept study they chose a member of a highly structured and porous carbon family called mesoporous carbon. At the nanoscale level, this type of carbon has a very uniform pore diameter and pore volume.
Using a nanocasting method, the team assembled a structure of 6.5 nanometre thick carbon rods separated by empty three to four nanometre wide channels. Carbon microfibres spanning the empty channels kept the voids open and prevented collapse of the architecture.
Filling the tiny voids proved simple. Sulphur was heated and melted. Once in contact with the carbon, it was drawn or imbibed into the channels by capillary forces, where it solidified and shrunk to form sulphur nanofibres. Scanning electron microscope sections revealed that all the spaces were uniformly filled with sulphur, exposing an enormous surface area of the active element to carbon and driving the exceptional test results of the new battery.
"This composite material can supply up to nearly 80 percent of the theoretical capacity of sulphur, which is three times the energy density of lithium transition metal oxide cathodes, at reasonable rates with good cycling stability," said Dr. Nazar.
What is more, the researchers say, the high capacity of the carbon to incorporate active material opens the door for similar "imbibed" composites that could have applications in many areas of materials science.
The research team continues to study the material to work out remaining challenges and refine the cathode's architecture and performance.
Dr. Nazar said a patent has been filed, and she is reviewing options for commercialization and practical applications.
Source: Natural Sciences and Engineering Research Council
Feb 15, 2005 |
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Really?
How are you going to recharge that electric vehicle of yours when it runs out of juice on the side of the road(middle of the desert,out in the woods, fill in your own remote location here)?
Great work here and a much needed improvement over existing technology, how expensive are these batteries going to be, how intricate is the manufacturing process, how durable to bumps and thumps is the new battery?
Wow, we should just stop researching electric cars because someone might get stuck in a remote location. You know the same remote location that gas powered car can get stuck in.
Here some information for you 75-80% of american drive less then 40 miles a day. GM killed a electric car that got 70miles to a charge in 1996 without even using the latest generation batteries.
No, we don't need hydrogen.
Telsa sells a car that can get over 235 miles to a charge if the big 3 had the political will to do it they can do the same.
You can't fill your gasoline car either. With a battery you could actually carry a photovoltaic cell on your roof. In the desert this might give you enough charge to make it out of it if you can wait a while.
Why not just add a bike-pedal under the floor, so you could pedal your way outta there...just pray you don't get any big hills -:)
Sheldon buzzes in and says, "The answer is, of course, a right triangle the hypotenuse of which is equal to the sum of the power ratio and the drag rating of the wheel bearings, divided by the barometric pressure....."
How is this a problem?
If you're so completely daft as to get stuck in the middle of nowhere, do what you'd do with hydrogen or gasoline vehicles and call emegency services; get your dumb ass towed out of there.
probably the same way we do it now: hike back to the charging station and then lug an emergency back-up battery, good for a few miles, enough miles to get you back to the charging station. No different than now. You know, horse owners were using the same augument against gasoline cars 100 years ago!
Ahh, if they could only make cars run on water, grass, and oats...
Over the last few years, to my recollection the longest auto trip was 400miles round trip with an overnight at a hotel on the halfway other end. Topp off the Gasoline on both ends. So, it really would not have been much different with the employment of a plugin electric like a Tesla roadster. The Hilton had a quick charging station so a "fill up" would have only taken less time than it took to get checked into a suite at the hotel. With the proper tax incentive every hotel, motel, notell coast to coast would be thrilled to add in features attractive to plugin electric and plugin hybrids such as the new competitor to Tesla the Fisker autos.
Perhaps Hydrogen has a place. But, it is still 20 years down the road.