Fluorinated Electrolyte Enhances Voltage, Safety of Li-ion

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New Fluorinated Electrolyte Enhances Voltage, Safety of Li-ion Batteries
Apr 2, 2010 10:26
Motohiko Hamada, Nikkei Automotive Technology

Daikin Industries Ltd and Kansai University developed a fluorinated electrolyte that can realize a lithium-ion (Li-ion) rechargeable battery with a high voltage and safety.

They confirmed that, when the electrolyte is combined with a battery using a positive electrode material suited for high-voltage applications, it is possible to stably charge and discharge the battery at a voltage as high as 4.7V (they tested 30 cycles).

Also, even when the electrolyte was combined with a battery using a normal positive electrode material, the battery stably operated at a voltage as high as 4.5V. Because the new electrolyte prevents phase transition from occurring at electrodes, it became possible to exploit the electromotive force of positive electrodes.

By enhancing the upper limit of voltage from 4 to 4.7V, the energy density was improved (Commercially-available Li-ion rechargeable batteries have an average voltage of 3.6 to 3.7V). Moreover, because the electrolyte can withstand such a high voltage, it probably became possible to use a new electrode material, paving a road to an electric vehicle that can travel longer.

Because fluorine compounds are very stable, they improve cycle characteristics at high temperatures and storage properties. They are less likely to cause a decomposition reaction at electrodes and can be made so that they do not have a firing point, enhancing the safety of Li-ion rechargeable batteries.

Original URL:
http://techon.nikkeibp.co.jp/english/NEWS_EN/20100402/181586/

tks
lloK
 
this makes sense since the current electrolytes are carbonates i think. so the flourine has a stronger bond than the oxygen in the carbonate, and would not be released if overcharged to the higher voltage.
 
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