GigaOM » lithium air battery

There’s gold in them thar batteries

Katie Fehrenbacher — Tue, 24 Jul 2012 16:21:41 +0000

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The lithium air battery has long been over hyped — now add a pot of gold to the end of that rainbow. Scientific American reports that scientists at the University of Saint Andrews in Scotland have been using gold to make a prototype of a lithium air battery that has high energy density and lasts for a long time.

In a typical lithium ion battery, lithium ions travel from the cathode to the anode when you charge it (through the electrolyte), and the anode holds onto the lithium ions to store the energy. When you use a battery, the lithium ions move from the anode to the cathode and a resulting chemical reaction leads to the harvesting of the electrons. The anode and cathode are called the electrodes.

The scientists at Saint Andrews have been using gold to make a porous electrode that they say can create a lithium air battery that maintains almost all of its ability to hold a charge after 100 charging cycles. The battery also has high energy density, or amount of energy that the battery can hold for its size.

The problem with the life of batteries is that after a certain amount of charges — when ions are removed, sent over to the anode and then inserted back into the cathode — the structure of the battery starts to degrade. The crystal structure that holds the ions actually starts to change, as an ion from one spot doesn’t necessarily come back to that spot but could instead be inserted into another spot. In addition, traditional lithium ion batteries have a slurry made from an active material like lithium cobalt oxide held together with a glue-like binder. If the binder fails, the coating can peel off the current collector, and if the metal corrodes, it can’t move electrons as efficiently.

Lithium air batteries use air as the cathode and lithium metal as the anode. The scientists at University of Saint Andrews say using gold for part of the electrode provides a more stable substrate for the reaction between the air and the lithium. Their gold electrode also has tiny holes all over it — nano-porous — that provides room for the ions from the solid lithium peroxide. The electrolyte is made of an organic solvent called dimethyl sulfoxide.

The more energy dense a battery is, the less volume and weight is needed. For electric cars it is particularly important to have a high energy dense battery because electric cars need to be as lightweight as possible (any extra weight just drains the battery faster), and batteries that are smaller and use less materials can also be lower in cost.

The scientists at Saint Andrews say more work needs to be done to figure out why the experimental battery is providing such a high level of capacity and density. But they’re excited about the battery because it could provide a longer lasting electric car battery that has a bigger range than what’s currently available. In an electric car, air that passes over the battery as the car drives, could be used for the cathode.

Clearly using lots of gold in a battery would be prohibitively expensive. One way to get around this would be to coat carbon with a gold plating. Other companies are working on the lithium air battery including IBM, and PolyPlus.

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Why the lithium air battery is over hyped

Ucilia Wang — Wed, 06 Jun 2012 07:00:34 +0000

IBM has made a lot of noise about its lithium air battery, which it says can hold as much energy in a given volume as gasoline can. But General Motors isn’t all that convinced that lithium air battery technology is worth the investment.

“From General Motors’ perspective, we are not investing in this technology because it’s not providing a substantial benefit,” said Thomas Greszler, manager of the cell design group at GM’s electrochemical energy research lab, during a presentation at battery symposium hosted by the Lawrence Berkeley National Laboratory on Tuesday. Essentially making the lithium air technology work will require some big improvements and the end results may not turn out to be worth the trouble and costs, says Greszler.

The goal

PolyPlus Water

Bold claims have been made for years about the blend of battery chemistry that can use air as the cathode. Back in 2009, IBM said lithium air batteries could hold at least 10 times more energy than the lithium-ion batteries on the market then. Earlier this year, IBM re-stated this dramatic improvement potential and dangled the vision of a battery system that one day can prolong the drive range of an electric car to 500 miles per charge, or about five times the range of existing electric cars.

Lithium-air batteries are attractive to researchers because they can rely on air as the cathode and lithium metal as the anode. Oxygen, being and abundant and doesn’t require heavy casing to contain it inside a battery cell, also theoretically can achieve a high energy density, which extends the driving range of an EV. In a typical battery cell, lithium ions travel from the cathode to the anode when you charge it (through the electrolyte), and the anode holds onto the lithium ions to store the energy. When you use a battery, the lithium ions move from the anode to the cathode and a resulting chemical reaction leads to the harvesting of the electrons.

However, many improvements will need to be made to make a lithium air battery a good fit for an electric cars. Greszler noted that the need to pump oxygen into the battery system means an air compressor and blower will need to be built into the car. Adding more parts is generally not a good approach when a major goal is to reduce the weight of the car to improve its performance and fuel economy.

Creating a watertight design is also critical because lithium metal is highly flammable and can ignite and burn when exposed to water. So removing water vapor from the air is a must.

As a result of some of these issues, a lithium air battery could be heavier than the advanced lithium-ion batteries under development now, and Greszler said it’s “highly unlikely that lithium-air will provide any cost savings.”

The hype

The promise of lithium air battery has also led to a level of hype, many researchers agree. One of the hypes is the belief that lithium air batteries could deliver about 1,300 watt hours per kilogram of energy, said Stan Whittingham, professor of chemistry and material science at the State University New York, in a talk that he titled, “Beyond Lithium Ion: A Reality Check.”

A more realistic estimate is the 800 watt hours per kilogram that startup PolyPlus is hoping to achieve. PolyPlus received a Department of Energy grant to work on encapsulating the lithium electrode to create a more stable battery system. In comparison, lithium-ion batteries used in cell phones today are in the 200 watt hours per kilogram range.

Whittingham said lithium air batteries might find good uses elsewhere, just not in cars. Whittingham also looked to “IBM is one of the culprits for hyping,” lithium air battery technology for electric cars.

Even if IBM delivers on this technology, everyone agrees that commercializing lithium air batteries will take a long time. IBM said its project won’t likely lead to a commercial product until 2020 or 2030.

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Introducing an air-breathing battery that could power a breakout electric car

Katie Fehrenbacher — Fri, 20 Apr 2012 06:45:54 +0000

Darn those batteries — they continue to be the bugaboo for both the unplugged, always-on lifestyle and the dream of the mainstream electric car. But if a breakthrough air-breathing battery design, created by none other than IBM, ever makes it out of the lab, the world could one day see an electric car with a whopping 500-mile range — about five times what the current electric cars on the market today are offering.

On Friday IBM is unveiling progress and new partners for its lithium air battery technology, which it started working on back in the Summer of 2009 and which could one day be a commercial product perhaps in the 2020/2030 timeframe (yeah, not real soon). Big Blue says to move its battery research forward it has teamed up with Japanese chemical companies Asahi Kasei and Central Glass.

To put this innovation in perspective, scientists have been working on the lithium air battery for years. It’s considered to be one of the only types of batteries that could get close to the kind of energy density (the amount of energy stored for a set volume) that gasoline has, and so it could be a breakthrough for the electric car specifically. Electric cars need to have batteries that are as lightweight as possible — extra weight just drains the battery faster, and batteries that are smaller and use less materials can also be lower in cost.

IBM says its lithium air battery could have an energy density of 1,000 watt hours per kilogram, which is more than double the energy density of some of the most cutting edge lithium ion batteries out there being made by Envia. It’s also five to ten times more energy dense than the basic lithium ion batteries on the market.

Now let’s get back to battery 101 basics. A battery is made up of an anode and a cathode and electrolyte in between. For a lithium ion battery, lithium ions travel from the anode to the cathode through the electrolyte, creating a chemical reaction that allows electrons to be harvested along the way.

For IBM’s lithium air battery, the anode is made of metallic lithium, and the cathode is essentially a meeting ground for oxygen from the air and lithium ions that have come across the electrolyte from the anode. The electrolyte is made up of an organic liquid.

The battery can have such a high energy density partly because you’re doing away with the cathode — and pulling in ambient air — so it can be light weight as well as low cost. The battery would pull in and use oxygen in a similar way to how an internal combustion engine draws in oxygen.

Of course, this research is essentially being produced in a lab setting right now, so whether or not it will make it into a commercial battery, remains to be seen. IBM’s Principle Investigator Winfried Wilcke told me in an interview this week that the project is his “Mt. Everest” — ie. very difficult to climb — and, he says, they’ve just left Base Camp.

I know what you’re thinking next: IBM isn’t a battery maker. And Wilcke tells me that IBM has no plans to manufacture the battery. But with IBM’s partners, the group could one day license the technology to a battery manufacturer (much the way 3M would license its battery tech). Asahi Kasei is developing the membrane technology for the battery and Central Glass is developing a new kind of electrolyte for the battery.

IBM is more commonly associated with computer modelling, and IBM used sophisticated computer models on its Blue Gene/P supercomputers to study the simulations of the interactions for the electrolyte. IBM also has a history in nanotech, which led to the development of nanostructures.

One of the more important aspects of the lithium air technology is the membranes and nanostructures that can keep water out and let oxygen in to the battery. Why? Lithium metal is highly flammable and reacts with water. Search lithium and water on YouTube to see some of the explosive videos.

Images, video courtesy of IBM Research.

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