The Battery 500 Project is part of IBM's Big Green Innovations program and has stated aims to develop rechargeable batteries for an all-electric vehicle that will boost the EV range from less than 100 miles today to as much as 500 miles.
To achieve the stated aims, clearly a step change improvement over existing energy storage technology is required. Indeed it is suggested that a 10-fold increase in energy density is necessary. This has necessitated some radical thinking - and clearly the development of battery systems way beyond simple iterative improvements over existing Li-ion technology.
According to IBM researchers the solution may lie in the development of commercial Lithium-air (Li-air) batteries. The theoretical performance of these batteries looks extremely compelling and Li-air technology has been researched at several institutions for many years.
Li-air batteries differ from Li-ion technology in that the discharge reaction depends on access to atmospheric oxygen - essentially harnessing the oxygen in air at the cathode. Since there is no requirement for a heavy and expensive cathode active material - simply a catalysed bi-functional air electrode - this feature creates an impressive advantage over Li-ion in both cost and performance.
Check out this website for a video describing IBM's Battery Project 500:
So what are the problems? There remain some very difficult technical challenges ahead. The use of metallic lithium at the anode will cause significant cycling and safety issues. Many of us can recall the problems experienced with the use of metallic Li electrodes during the development of rechargeable Li//V6O13 and Li//MoS2 cells in the 1980's and 1990's. Trying to make large format batteries for automotive applications will be particularly problematic. Quite rightly, the large autos companies are simply not interested in taking a risk with safety.
In addition, the properties of the bi-functional air electrode and the associated electrolyte will require significant innovation over the existing technology.
Still......the numbers do look impressive and us battery scientists do love a challenge!!
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