RESEARCHERS from Stanford have successfully used a pure lithium anode in a lithium ion battery.
The common lithium-ion batteries of today tend to use an anode made of graphite or silicon, with the lithium only used in the electrolyte.
While a lithium anode could boost the capacity by four fold and lower the weight of lithium ion batteries, researchers were unable to successfully implement it until now.
This is because lithium expands during charging, opening fissure on the surface that release lithium ions and form dendrites which eventually short circuit the battery.
Lithium anodes are also highly chemically reactive with the lithium electrolyte and can overheat to the point of fire or even explosion.
The Stanford researchers solved the problems with a protective layer of carbon nanospheres which form a flexible shield over the anode.
The nanosphere wall, just 20 nanometers thick, is strong and flexible enough to move up and down as the anode expands and contracts during the battery’s charge-discharge cycle.
The carbon nanosphere interface increases the recycling efficiency and also decreases the side chemical reaction of the electrolytes.
Light weight and with high energy density, lithium as a material could hold the future of high energy density batteries, even as graphite anodes start falling behind on capacity requirements.
Over the next few years, the team hopes to refine the battery design to both improve on the coulombic efficiency and sustain it for 500 to 1,000 cycles.
With next generation high density batteries, it might be possible to triple the battery life of mobile devices, and improve the range of electric cars while reducing their cost, making them competitive with internal combustion engines.
source: http://www.electronicsnews.com.au/news/pure-lithium-anode-could-quadruple-battery-capacit
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