By Andrew Nusca
Posting in Energy
A lithium-air cell is more than 1,000 times denser than conventional lithium-ion versions used in electric cars. IBM researchers hope the technology will cure EV range anxiety.
Aside from cost, the biggest concern most people have about electric vehicles is range. Simply, no one wants to find themselves 100 miles from home with no electrical outlet in sight.
With more than 1,000 times the energy density of conventional lithium-ion batteries, IBM's lithium-air version holds promise, allowing for a 500-mile (800 km) range that keeps EVs in competition with their gasoline-powered cousins.
The range of lithium-ion batteries on the market today maxes out at around 100 miles (160 km).
Instead of employing metal oxides in the positive electrode, lithium-air cells use carbon. The material is lighter and reacts with oxygen in the air around it to produce a current -- hence the "-air" part of its name.
There's a huge catch, however: the cell's chemical instability severely limits its recharging ability.
Researchers in IBM's Almaden lab in San Jose, Calif. are a step closer to leaping that hurdle. Physicist Winfried Wilcke used a mass spectrometer to better understand the electrochemistry of the battery and discovered that the oxygen was reacting both with the carbon electrode and the electrolytic solvent around it, depleting its ability to carry lithium ions between electrodes.
With help from colleague Alessandro Curioni and a Blue Gene supercomputer, Wilcke ran detailed models -- down to the atoms -- of the reactions in search of alternative electrolytes. One secret material held promise.
The team -- which has been working on the technology for more than three years -- has built several research prototypes and are now working to produce a full-scale version by 2013. A tentative commercial production date is 2020.
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Jan 12, 2012