USA: Si nanocomposites better Li-ion battery performance

Researchers at the Gerorgia Institute of Technology have scaled up the capacity of Li-ion batteries 5x by hanging nanometre-sized silicon particles on trees of carbon black that self-assemble into porous micron-sized spheres, which increase an electrode’s surface area with interconnected internal channels.

High-performance Li-ion batteries today use anodes made from carbon (graphite). Silicon has been proposed as a substitute for graphite since it offers a theoretical improvement of 10x in capacity over graphite, but so far prototypes have proven too unstable for creating lithium batteries with a long lifetime, according to professor Gleb Yushin at the Georgia Institute of Technology.

The problem, according to Yushin, is that silicon particles crack when they are formed at the same granularity of graphite particles—about 15- to 20µm. The new nanocomposite material solves that problem by hanging 30nm-sized silicon particles on trees of carbon black which then self-assemble into porous spheres about 10- to 30µm in diameter. The resulting electrode remains stable due to the durable carbon-superstructure that prevents cracking, but benefits from the increased surface area afforded by the smaller silicon nanoparticles
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Source: eetinndia.co.in