Although this news broke last week, it's particularly interesting in light of yesterday's discussion of the innovations IBM thinks will emerge in the next five years. A tenfold increase in battery life was on that list, and researchers have made a new discovery that could improve the longevity of lithium ion cells. Scientists from the Pacific Northwest and Sandia National Laboratories used an transmission electron microscope to look inside a custom-built lithium ion battery. They found that the thin wires of tin oxide that typically make up a battery's electrode twist and deform as electrons flow through them. The wires became longer and fatter as they twisted, increasing in volume by about 250%. In addition to deforming, the internal structure of the wires changed from a crystalline form to a glassy material whose atoms were arranged more randomly.
The bulk tin oxide typically used to make electrode wires is described as a "brittle ceramic." Researchers believe that the deformation they observed can create small defects that will only accumulate over time. Those defects could affect the overall efficiency and longevity of a battery.
In an attempt to combat deformation, the researchers experimented with electrodes crafted from tin oxide nanowires. As materials scientist Chongmin Wang explains, the approach is like "making a rope from steel — you wind together thinner wires rather than making one thick rope." The custom-wound nanowires withstood deformation much better than the standard tin oxide wires, although it's unclear whether the nanowires managed to maintain their crystalline form.
Either way, the researchers see this discovery as an important one on the road to creating better batteries. It might not improve the storage capacity of rechargeable cells, but it could allow them endure more charge/discharge cycles without any loss in performance. Thanks to Engadget for the tip.