October 14, 2009 | Leave a Comment
IBM has made a major splash in the battery industry with their announcement that the company is going to research lithium air battery technology. They are a little further along than the press and media are allowing. IBM plans to get a jump on the process by using its nano membrane technology developed for water-purification systems to separate water and other elements from the oxygen in air. They will use their nano-structure expertise developed for the semiconductor industry to help distribute oxygen evenly around the interior of the battery cells – preventing blockages. Supercomputing will be used to model techniques for moving individual atoms through the membranes.
The race is on because lithium air batteries approach the energy density of fuel cells without the plumbing and carrying the fuel needed for these devices; in theory, the maximum energy density is more than 5,000 watt-hours per kilogram, or more than 10 times that of today’s lithium-ion batteries. Lithium air batteries are also very lightweight because it’s not necessary to carry a second reactant.
Lithium Air Battery Activity Flow Chart. Click image for the largest view.
The main problem with using lithium metal as a battery electrode is the material reacts rapidly and violently with water. Lithium air batteries have been considered for decades, but there’s always water in the air. Exposure to even traces of water rapidly degrades the material. Lithium air batteries are unique in that instead of being a sealed system, they use atmospheric oxygen, essentially harnessing the oxygen in the air as the cathode of the battery. Since oxygen enters the battery on demand, it offers an essentially unlimited amount of reactant, metered only by the surface area of its electrodes.
That violent reaction with water has consequences. About 20 years ago the Canadian company Moli Energy recalled its rechargeable lithium-metal batteries, which used not air but a more traditional cathode, after one caught fire; the incident led to legal action, and the company declared bankruptcy. That was a very cold water splash.
Until the IBM announcement only a handful of labs around the world, including those at PolyPlus Battery in Berkeley, CA, Japan’s AIST and St. Andrews University, in Scotland, have been working on lithium air batteries. Since the IBM announcement news leaked that Toyota recently began looking into lithium air technology. Its not any kind of secret that General Electric is investing $150 million over five years to develop massive sodium batteries for use in locomotives and electrical grids. It has also made an equity investment in A123, a small company that supplies lithium-ion batteries for plug-in electric vehicles.
But IBM will partner with Oak Ridge, Lawrence Berkeley, Lawrence Livermore, Argonne, and Pacific Northwest national labs. The company and its collaborators are currently working on a proposal for funding from the U.S. Department of Energy under the Advanced Research Projects Agency-Energy bringing a very large and diverse set of intellects to the race.
Along with the water plus lithium violence potential there are two other problems. First, the design of the cathode needs to be optimized so that the lithium oxide that forms when oxygen is pulled inside the battery won’t block the oxygen intake channels. Second, better catalysts are needed to drive the reverse reaction that recharges the battery.
Recharging also has safety issues. When lithium air batteries are charged and discharged, there is an electroplating and then stripping of the metal over and over again in each cycle. Over time, just as in a lithium ion battery, the lithium air surface becomes rough, which can lead to thermal runaway, when the battery literally burns until all the reactants inside are used up. The savior in that is the lithium air construction would limit incoming air making such a heat buildup impossible without cracking open the battery case.
IBM is pursuing the risky technology attempt instead of lithium-ion batteries because it has the potential to reach high enough energy densities to change the transportation system. IBM Almaden Research Center’s manager of science and technology Chandrasekhar Narayan said, “With all foreseeable developments, lithium-ion batteries are only going to get about two times better than they are today. To really make an impact on transportation and on the grid, you need higher energy density than that.”
The motivator is a goal, a lightweight 500-mile battery for a family car. The Chevy Volt has only 40 miles on board and the Tesla can get to 300 miles before recharging. The room for growth is virtually the entire personal transport market, worldwide.
The U.S. also has another concern. IBM is also eager to reclaim U.S. leadership in battery tech from Asia. While many of the original breakthroughs for the batteries that power today’s laptop computers and cell phones happened in the U.S., those batteries now come primarily from Japan and Korea.
Industry leaders have called for just this kind of concerted effort amid concern that the U.S. will miss out on one of the most important technology shifts in history—the switch from gasoline to electricity as the primary power source for light vehicles. The worry is that the U.S. will trade its current dependency on the Middle East for oil with a new dependency on Asia for vehicle batteries. “We lost control of battery technology in the 1970s,” laments Andy Grove, former chairman of chip giant Intel. “Battery technology will define the future, and if we don’t act quickly it will go to China and Japan.”
The race is on. Major players in industry and science are on board. The problems to start with are well known. Experience in other fields might bring solutions. That electric drive for personal transport looks more likely each time the news is checked. Storage for intermittent grid generation is getting answered as well. Batteries are getting more interesting than seen in decades with idled ideas getting new life from connections with other technologies. It’s a major race, indeed.