A new type of nanomaterial developed by researchers at Rensselaer Polytechnic Institute could possibly enable the next generation of high-power rechargeable lithium (Li)-ion batteries for electric automobiles, as well as batteries for other portable devices. Led by Professor Nikhil Koratkar, the research team demonstrated how a nanoscoop (called so because it resembles an ice cream cone) electrode could be charged and discharged at a rate 40 to 60 times faster than conventional battery anodes, while maintaining a comparable energy density. The anode structure of a Li-ion battery physically grows and shrinks as the battery charges or discharges. When charging, the addition of Li ions increases the volume of the anode, while discharging has the opposite effect. These volume changes result in a buildup of stress in the anode. Too great a stress that builds up too quickly, as in the case of a battery charging or discharging at high speeds, can cause the battery to fail prematurely. This is why most batteries in today’s portable electronic devices like cell phones and laptops charge very slowly – the slow charge rate is intentional and designed to protect the battery from stress-induced damage. The Rensselaer team’s nanoscoop, however, was engineered to withstand this buildup of stress. Made from a carbon (C) nanorod base topped with a thin layer of nanoscale aluminium (Al) and a “scoop” of nanoscale silicon (Si), the structures are flexible and able to quickly accept and discharge Li ions at extremely fast rates without sustaining significant damage. The segmented structure of the nanoscoop allows the strain to be gradually transferred from the C base to the Al layer, and finally to the Si scoop. This natural strain gradation provides for a less abrupt transition in stress across the material interfaces, leading to improved structural integrity of the electrode. For more information please visit: http://news.rpi.edu/update.do
I've been hear about so many different new battery technologies, why isn't one out yet?
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