{"id":7470,"date":"2013-02-15T10:35:49","date_gmt":"2013-02-15T17:35:49","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=7470"},"modified":"2013-02-15T10:35:49","modified_gmt":"2013-02-15T17:35:49","slug":"cheaper-lighter-stronger-but-when","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/cheaper-lighter-stronger-but-when\/","title":{"rendered":"Cheaper, Lighter, Stronger \u2013 But When?"},"content":{"rendered":"

We\u2019d all love to see the battery that\u2019s lighter, stronger, charges like a capacitor and costs next to nothing.\u00a0 We\u2019d all be driving electric cars and those of us who wanted battery-powered airplanes would be designing the next new wave of flight.<\/p>\n

Usually, these things are a decade or more away, following excruciating intervals of study, commercialization and usually, much-delayed or postponed production.<\/p>\n

Dr.\u00a0Chongwu Zhou<\/a>, a professor at the University of Southern California\u2019s (USC\u2019s) Viterbi School of Engineering, claims to have such a battery under provisional patent, and potentially available commercially within \u201ctwo or three years,\u201d according to school press releases.<\/p>\n

The battery uses porous silicon nanoparticles to replace traditional graphite anodes and provide superior performance \u2013 three times as much energy as a graphite-based lithium battery and capable of being recharged within only 10 minutes.<\/p>\n

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Nanoparticles are incredibly small. Imagine etching them with even tinier holes<\/p><\/div>\n

Zhou says, “It’s an exciting research. It opens the door for the design of the next generation lithium-ion batteries.” Zhou worked with USC graduate students Mingyuan Ge, Jipeng Rong, Xin Fang and Anyi Zhang, as well as Yunhao Lu of Zhejiang University in China. Their research was published in\u00a0Nano Research<\/em>\u00a0in January.<\/p>\n

Other attempts to use silicon in battery anodes have met with disappointment because the material expands and contracts on charging and discharging, causing eventual dismantling of the anodes.<\/p>\n

Zhou and his team tried a subtle difference, using porous silicon nanowire less than 100 nanometers in diameter and a few microns long.\u00a0 The tiny pores allow expansion and contraction without breaking while increasing the surface area available for reaction with lithium ions, which can move about the internals of the battery freely.<\/p>\n

A downside was that mass production of these nanowires proved difficult.\u00a0 In a great workaround, Zhou\u2019s team etched commercially available nanoparticles with the same pores as the nanowires.\u00a0 (Think of stories of people who\u2019d engraved a favorite poem on a grain of rice \u2013 only at a sub-microscopic level.)\u00a0 According to USC, \u00a0the particles function similarly and can be made in any quantity desired.<\/p>\n

In another downside, the silicon nanoparticle batteries currently last for just 200 recharge cycles (compared to an average of 500 for graphite-based designs).\u00a0 Hope still reigns, though. The original silicon nanowire-based design lasted for up to 2,000 cycles, as reported in Nano Letters<\/em> last April and available in Nano Research as a \u201cJust Accepted\u201d paper<\/a>. Further development of the nanoparticle design should boost the battery’s lifespan, Zhou said.<\/p>\n

Zhou hopes for a \u201creal impact on battery applications in the near future,” and is driving his team to develop a high-capacity cathode material to complement their new anode.\u00a0 Such a battery would be a great contribution to the future of the electric vehicle.<\/p>\n