Fluoride Ion Electrochemical Cell

Abstract

Electrochemical cells of the present invention are versatile and include primary and secondary cells useful for a range of important applications including use in portable electronic devices. Electrochemical cells of the present invention also exhibit enhanced safety and stability relative to conventional state of the art primary lithium batteries and lithium ion secondary batteries. For example, electrochemical cells of the present invention include secondary electrochemical cells using anion charge carriers capable of accommodation by positive and negative electrodes comprising anion host materials, which entirely eliminate the need for metallic lithium or dissolved lithium ion in these systems.

1 . An electrochemical cell comprising:
 a positive electrode;   a negative electrode; and   liquid phase electrolyte provided between said positive electrode and said negative electrode; said electrolyte capable of conducting anion charge carriers; said liquid phase electrolyte comprising a source of fluoride ions (F − ) dissolved in a solvent.   wherein said positive electrode and negative electrode reversibly exchange said anion charge carriers with said electrolyte during charging or discharging of said electrochemical cell;   wherein said anion charge carriers are said fluoride ions.   
     
     
         2 . (canceled) 
     
     
         3 . The electrochemical cell of  claim 1  wherein said electrolyte comprises a solvent and a fluoride salt, wherein said fluoride salt is at least partially present in a dissolved state in said electrolyte, thereby generating said fluoride ions in said electrolyte. 
     
     
         4 . The electrochemical cell of  claim 3  wherein said fluoride salt has the formula MF n , wherein M is a metal, and n is an integer greater than 0. 
     
     
         5 . The electrochemical cell of  claim 4  wherein M is an alkali metal or an alkaline earth metal. 
     
     
         6 . The electrochemical cell of  claim 4  wherein M is a metal other than lithium. 
     
     
         7 . The electrochemical cell of  claim 4  wherein M is Na, K, or Rb. 
     
     
         8 . The electrochemical cell of  claim 1  wherein said anion charge carriers are selected from the group consisting of:
 BF 4   − , PF 6   − , AsF 6   − , SbF 6   − , BiF 6   − , AlF 4   − , GaF 4   − , InF 4   − , TlF 4   − , SiF 5   − , GeF 5   − , SnF 5   − , PbF 5   − , SF 7   − , IF 6   − , ClO 4   − , CF 3 SO 3   − , (CF 3 SO 2 ) 2 N −  and C 4 F 9 SO 3   −   
 
     
     
         9 . (canceled) 
     
     
         10 . The electrochemical cell of  claim 1  wherein said electrolyte further comprises an anion receptor. 
     
     
         11 . The electrochemical cell of  claim 3  wherein said electrolyte further comprises a fluoride ion anion receptor capable of coordinating fluoride ions from said fluoride salt. 
     
     
         12 . The electrochemical cell of  claim 1  wherein said electrolyte further comprises a cation receptor capable of coordinating metal ions from said fluoride salt. 
     
     
         13 . The electrochemical cell of  claim 1  wherein said electrolyte is an aqueous electrolyte. 
     
     
         14 . The electrochemical cell of  claim 1  wherein said electrolyte is a nonaqueous electrolyte. 
     
     
         15 . The electrochemical cell of  claim 1  wherein said negative electrode is a fluoride ion host material. 
     
     
         16 . The electrochemical cell of  claim 15  wherein said fluoride ion host material of said negative electrode is a fluoride compound. 
     
     
         17 . The electrochemical cell of  claim 15  wherein said fluoride ion host material of said negative electrode is selected from the group consisting of: LaF x , CaF x , AlF x , EuF x , LiC 6 , Li x Si, Li x Ge, Li x (CoTiSn), SnF x , InF x , VF x , CdF x , CrF x , FeF x , ZnF x , GaF x , TiF x , NbF x , MnF x , YbF x , ZrF x , SmF x , LaF x  and CeF x , 
     
     
         18 . The electrochemical cell of  claim 15  wherein said fluoride ion host material of said negative electrode is a polymer selected from the group consisting of: polyacetylene, polyaniline, polypyrrol, polythiophene and polyparaphenylene. 
     
     
         19 . The electrochemical cell of  claim 15  wherein said negative electrode has a standard electrode potential less than or equal to −1 V. 
     
     
         20 . The electrochemical cell of  claim 15  wherein said negative electrode has a standard electrode potential less than or equal to −2 V. 
     
     
         21 . The electrochemical cell of  claim 1  wherein said electrolyte does not comprise lithium ions. 
     
     
         22 . The electrochemical cell of  claim 1  wherein said electrolyte comprises a fluoride salt dissolved in said solvent. 
     
     
         23 . The electrochemical cell of  claim 1  wherein said positive electrode is a fluoride ion host material. 
     
     
         24 . The electrochemical cell of  claim 23  wherein said fluoride ion host material of said positive electrode is an intercalation host material capable of accommodating said fluoride ions so as to generate a fluoride ion intercalation compound. 
     
     
         25 . The electrochemical cell of  claim 23  wherein said fluoride ion host material of said positive electrode is a fluoride compound. 
     
     
         26 . The electrochemical cell of  claim 25  wherein said fluoride ion host material of said positive electrode is a subfluorinated carbonaceous material having a formula CF x , wherein x is the average atomic ratio of fluorine atoms to carbon atoms and is selected from the range of 0.3 to 1.0; and wherein said carbonaceous material is selected from the group consisting of graphite, coke, multiwalled carbon nanotubes, multi-layered carbon nanofibers, multi-layered carbon nanoparticles, carbon nanowhiskers and carbon nanorods.