Patent ID: 6743947
Filing Date: 2004-06-01
Classification: C07D,C07F,H01G,Y02E

Abstract:
An electrochemical capacitor, comprising a pair of high surface area electrodes, a separator, and an electrolyte, wherein said electrolyte comprises an asymmetric onium salt further comprisingan onium cation and an anion, and wherein said onium cation is selected from an onium cation having the structure (III): wherein Z is a nitrogen atom bearing the charge and R5, R6, R7 and R8 are selected from the groups consisting of (a) C1ËœC10 normal alkyl, (b) C3ËœC10 branched alkyl, (c) C6ËœC12 aryl, (d) C7ËœC15 aralkyl, and (e) C1ËœC10 normal or branched alkyls having functional groups selected from the groups consisting of (i) 0Ëœ2n+1 halogens, wherein n is the number of carbon atoms in the substituent, (ii) sulfone, (iii) ether linkage, and (iv) carbonic diester; and wherein said anion comprises an organic or inorganic anion which is selected from the group consisting of polyhaloaluminate (AlX4âˆ’, X=F, Cl, Br and I), triflate (CF3SO3âˆ’, Tfâˆ’), bis(trifluoromethane sulfonyl)imide ((CF3SO2)2Nâˆ’, Imâˆ’, bis(penta fluoroethane sulfonyl)imide ((C2F5SO2)2Nâˆ’), perchlorate (ClO4âˆ’), tetrafluoroborate (BF4âˆ’), tris(trifluoromethanesulfonyl)methide ((CF3SO2)3Câˆ’, Meâˆ’), hexafluoroarsenate (AsF6âˆ’), hexafluorophosphate (PF6âˆ’), and mixtures thereof;or a mixture of such salts dissolved in an aprotic, non-aqueous solvent or mixture of such solvents.