Coolness, but don’t hold your breath.

A tenfold improvement in battery life? | CNET News.com:

Silicon anodes have the “the highest theoretical charge capacity” according to Cui’s paper, but they expand when charging and shrink during use: a cycle that causes the silicon to be pulverized, degrading the performance of the battery. For 30 years, this dead end stumped researchers, who poured their battery life-extending energy into improving graphite-based anodes. Now on News.com Live from Macworld 2008 Photos: Cracking open the Xbox 360 Elite Photos: Now, ads from your grocery cart? Extra: Today’s science, medieval Church Cui and his colleagues looked at this old problem and overcame it by constructing a new type of silicon nanowire anode. In Cui’s anode, the lithium is stored in a forest of tiny silicon nanowires, each with a diameter that is a thousandth of the thickness of a sheet of paper. The nanowires inflate to four times their normal size as they soak up lithium, but unlike previous silicon anodes, they do not fracture.

I’m always amazed by the way that very small materials get to behave differently because they don’t have the cracks and other defects of larger objects. Then I remember how, back in the late 80s some student at MIT had a new aerospace material that was going to revolutionize blah blah blah blah, made up of very thin (and hence defect-free) wires welded into immensely strong space-frame bricks. The only things holding him up were: 1) making sure that the welds were perfectly uniform and didn’t introduce any defects into the material or stress concentrations into the lattice 2) building a microscopic robot welder that could perform thousands of welds per second and 3) doing 1 and 2 at a price less than importing an equal weight of thionite from the gamma quadrant. Wonder whatever happened to that guy.

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