Solvents and novel electrolytic compositions having a large range of stability and high conductivity

Abstract

The present invention is concerned with novel polar solvents and novel electrolytic compositions comprising such solvents, and having a high range of stability, as required for applications in the field of electrochemistry. The present solvents have a highly polar amide function, and preferably combine with a salt soluble in the solvent and having an anion with a delocalized charge, and at least one polymer, to form an electrolytic composition.

What is claimed is:  
     
         1 . An aprotic polar compound having solvent properties, and of the general formula:  
       R 1 R 2 NX(Z)R 7    
       wherein 
 X═C or SO;  
 Z=O, NSO 2 NR 3 R 4  or NCN;  
 R 1  et R 2  are the same or different and are C 1-18 alkyl, C 1-18  oxaalkyl, C 1-18  alkylene or C 1-18 oxaalkylene;  
 R 3  à R 6  are the same or different and are C 1-18 alkyl or C 1-18  oxaalkyl;  
 R 7  is R F , R F CH 2 O—, (R F ) 2 CHO—, (R F CH 2 ) 2 N— or NR 5 R 6 ;  
 R F  is a fluorine atom, C 1-4 alkyl, C 1-4 oxaalkyl C 1-4 azaalkyl,  
 with the proviso that: 
 1) if Z=O, then R F  is not C 1-4 alkyl; and  
 2) if Z=O and X═SO, then R 5  or R 6  is not is not C 1-4 alkyl or C 1-4 oxaalkyl.  
 
 
     
     
         2 . An aprotic polar compound according to  claim 1  wherein the C 1-4 alkyle, C 1-4 oxaalkyle or C 1-4 azaalkyle in the definition of R F  is essentially fluorinated.  
     
     
         3 . An electrolytic composition comprising at least one polar compound according to  claim 1  or  2 , a salt soluble in said compound having an anion with a delocalized charge, and at least one polymer.  
     
     
         4 . An electrolytic composition according to  claim 3 , wherein the salt comprises I − , ClO 4   − , BF 4   − , PF 6   − , AsF 6   − , SbF 6   − , R F SO 3   − , XSO 2 NSO 2 X′ − , (XSO 2 )(X′SO 2 )(Y)C − , anionic derivatives of 4,5-dicyano-1,2,3-triazole, 3,5-bis(R F )-1,2,4-triazole, tricyanomethane, pentacyanocyclopentadiene and pentakis(trifluoromethyl)cyclopentadiene, R F SO 2 NCN − , C(CN) 3   − , R F SO 2 C(CN) 2   − , and mixtures thereof, wherein 
 X and X′ comprise R F , R F CH 2 O—, (R F )  2 CHO—, (R F CH 2 )  2 N—, R 8 , R 9 R 10 N—, with the proviso that at least one X or X′ is R F , R F CH 2 O—, (R F )  2 CHO—, or (R F CH 2 ) 2 N—;  
 Y═R F , R F SO 2  or CN;  
 R F  is as defined above and can be part of a macromolecular chain; and  
 R 8  to R 10  are the same or different, and are C 1-18 alkyl or C 1-18 oxaalkyl, and R 8  —R 10  can be part of a macromolecular chain.  
 
     
     
         5 . An electrolytic composition according to  claim 4 , wherein the cation includes derivatives of alkaline metals, alkaline earth metals, and organic cations of the “onium” type, comprising ammonium, imidazolium, sulfonium, phosphonium, oxomum or mixtures thereof.  
     
     
         6 . An electrolytic composition according to  claim 5 , wherein the cation is at least party lithium.  
     
     
         7 . An electrolytic composition according to  claim 3  further comprising a co-solvent.  
     
     
         8 . An electrolytic composition according to  claim 7 , wherein the co-solvent is aprotic and polar, and comprises dialkyl ethers of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycols; carbonic acid esters, γ-butyrolactone, nitriles, tricyanohexane, dimethyl formnamide, N-methylpyrrolidinone, or mixtures thereof.  
     
     
         9 . An electrolytic composition according to  claim 8 , wherein the polyethylene glycol mass is comprised between 400 and 2000.  
     
     
         10 . An electrolytic composition according to  claim 3 , wherein the polymer comprises monomer units derived from ethylene oxide, propylene oxide, epichlorohydrine, epifluorohydrine, trifluoroepoxypropane, acrylonitrile, methylmetacrylate, vinylidene fluoride, and N-vinylpyrolidinone, hexafluoropropene, either as homo- or copolymers, or mixtures thereof.  
     
     
         11 . An electrolytic composition according to  claim 8 , wherein the composition is plasticized or in the form of a gel.  
     
     
         12 . An electrolytic composition according to  claim 9 , wherein at least one polymer is a polyclectrolyte comprising a macromolecular woof similar to that of anions having a delocalized charge.  
     
     
         13 . An electrochemical generator comprising as an electrolyte an electrolytic composition according to  claim 3 .  
     
     
         14 . An electrochemical generator according to  claim 13 , wherein the negative electrode contains lithium metal, a lithium alloy, an carbon intercalation compound, an oxide having a low potential of intercalation, a double nitride of a transition metal in lithium, or mixtures thereof.  
     
     
         15 . An electrochemical generator according to  claim 14 , wherein the carbon intercalation compound is petroleum coke or graphite, and wherein the oxide having a low potential of intercalation is a titanium spinel.  
     
     
         16 . An electrochemical generator according to  claim 14 , wherein the positive electrode contains vanadium oxide, a mixed oxide of lithium and vanadium, an oxide of cobalt and lithium, a manganese spinel, a double phosphate of the olivine or Nasicon structure, a salt of rhodizonic acid, a polysidulfide derived from the oxidation of 2,5-dimercapto-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-oxadiazole, 1,2-dimercaptocyclobutene-3,4-dione, or mixtures thereof.  
     
     
         17 . An energy storage system of the supercapacitor type comprising as an electrolyte an electrolytic composition according to  claim 3.