Increasing Discharge Capacities of Li-(CF)(sub n) Cells

Whitacre, Jay; West, William

An electrolyte additive has shown promise as a means of increasing the sustainable rates of discharge and, hence, the discharge capacities, of lithiumpoly(carbon monofluoride) electrochemical power cells. Lithium-poly(carbon monofluoride) [Li-(CF)n] cells and batteries offer very high specific energies practical values of about 600 W.h/g and a theoretical maximum value of 2,180 W.h/kg. However, because Li-(CF)n cells and batteries cannot withstand discharge at high rates, they have been relegated to niche applications that involve very low discharge currents over times of the order of hundreds to thousands of hours. Increasing the discharge capacities of Li- (CF)n batteries while maintaining high practical levels of specific energy would open new applications for these batteries. During the discharge of a Li-(CF)n cell, one of the electrochemical reactions causes LiF to precipitate at the cathode. LiF is almost completely insoluble in most non-aqueous solvents, including those used in the electrolyte solutions of Li-(CF)n cells. LiF is electrochemically inactive and can block the desired transport of ions at the cathode, and, hence, the precipitation of LiF can form an ever-thickening film on the cathode that limits the rate of discharge.

Document ID

20090020527

Acquisition Source

Jet Propulsion Laboratory

Document Type

Other - NASA Tech Brief

External Source(s)

http://www.techbriefs.com/component/content/article/2608

Authors

Date Acquired

August 24, 2013

Publication Date

February 1, 2008

Publication Information

Publication: NASA Tech Briefs, February 2008

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Report/Patent Number

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Public

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