Stability enhancing additive for electrochemical devices

Abstract

Embodiments described herein relate generally to electric double layer capacitors having an electrolyte formulation that includes a quantity of a stabilizing additive such that the electrochemical double layer capacitors retain cell capacitance for longer periods of time, generate less gas during operation, and experience less long term ESR. In some embodiments, an electrolyte formulation includes an ionic species, a solvent, and a stabilizer. In some embodiments the stabilizer contains a moiety that promotes adsorption to a surface, such as a carbon surface, and a moiety that promotes polarity of the stabilizer. In some embodiments, the solvent can be a nitrile compound and the stabilizer can be a compound of the formula I: Such that R is H, saturated or unsaturated, linear or branched, acyclic carbon group, OH, halogen NH 2 , NO 2 , (SO) 2 CF 3 , or monocyclic or polycyclic aryl, and n is an integer from 0 to 5.

1 .- 45 . (canceled) 
     
     
         46 . An electrolyte formulation suitable for use in an energy storage device, said formulation comprising an ionic species, a solvent, and a stabilizer comprising a compound of formula I: 
       
         
           
           
               
               
           
         
         wherein: 
         R is H, or saturated or unsaturated carbon group, and n is an integer from 0 to 5. 
       
     
     
         47 . The formulation of  claim 46 , wherein R is an unsaturated cyclic carbon group. 
     
     
         48 . The formulation of  claim 47 , wherein R is a monocyclic or polycyclic aryl. 
     
     
         49 . The formulation of  claim 46 , wherein R is a saturated cyclic carbon group. 
     
     
         50 . The formulation of  claim 49 , wherein R is a monocyclic or polycyclic aryl. 
     
     
         51 . The formulation of  claim 46 , wherein the stabilizer is benzonitrile. 
     
     
         52 . The formulation of  claim 46 , wherein the stabilizer is a monomer. 
     
     
         53 . The formulation of  claim 46 , wherein the solvent is non-aqueous. 
     
     
         54 . The formulation of  claim 46 , wherein the solvent includes a nitrile compound. 
     
     
         55 . The formulation of  claim 54 , wherein the nitrile compound includes at least one of acetonitrile, propionitrile, and butyronitrile. 
     
     
         56 . The formulation of  claim 46 , wherein the solvent includes a carbonate compound. 
     
     
         57 . The formulation of  claim 56 , wherein the carbonate compound includes at least one of propylene carbonate, ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate. 
     
     
         58 . The formulation of  claim 46 , wherein the solvent includes a sulfone compound. 
     
     
         59 . The formulation of  claim 46 , wherein the energy storage device is an electric double layer capacitor. 
     
     
         60 . The formulation of  claim 59 , wherein the electric double layer capacitor has an operating voltage of greater than about 3 volts and/or an operating temperature of greater than about 50 degrees Celsius. 
     
     
         61 . The formulation of  59 , wherein the electric double layer capacitor has an operating voltage of greater than about 2.7 volts, and an operating temperature of greater than about 75 degrees Celsius. 
     
     
         62 . The formulation of  claim 59 , wherein the electric double layer capacitor has a capacitance of at least about 100 F. 
     
     
         63 . The formulation of  claim 46 , wherein the ionic species is a quaternary ammonium salt. 
     
     
         64 . The formulation of  claim 63 , wherein the quaternary ammonium salt includes at least one of spiro-bipyrrolidinium tetrafluoroborate (SBP BF4), tetraethylammonium tetrafluoroborate (TEA TFB), N-ethyl-N-methylpyrrolidinium tetafluoroborate, and triethyl(methyl)ammonium tetrafluoroborate. 
     
     
         65 . An electric double-layer capacitor comprising:
 an electrolyte formulation comprising an ionic species, a solvent, and a stabilizer comprising a compound of the formula I:   
       
         
           
           
               
               
           
         
         wherein: 
         R is H, or saturated or unsaturated carbon group, and n is an integer from 0 to 5. 
       
     
     
         66 . The electric double layer capacitor of  claim 65 , wherein R is an unsaturated cyclic carbon group. 
     
     
         67 . The electric double layer capacitor of  claim 66 , wherein R is a monocyclic or polycyclic aryl. 
     
     
         68 . The electric double layer capacitor of  claim 65 , wherein R is a saturated cyclic carbon group. 
     
     
         69 . The electric double layer capacitor of  claim 68 , wherein R is a monocyclic or polycyclic aryl. 
     
     
         70 . The electric double layer capacitor of  claim 65 , wherein the stabilizer is benzonitrile. 
     
     
         71 . The electric double layer capacitor of  claim 65 , wherein the stabilizer is a monomer. 
     
     
         72 . The electric double-layer capacitor of  claim 65 , wherein the solvent is a nitrile compound. 
     
     
         73 . The electric double-layer capacitor of  claim 72 , wherein the nitrile compound includes at least one of acetonitrile, propionitrile, and butyronitrile. 
     
     
         74 . The electric double layer capacitor of  claim 65 , wherein the ionic species is a quaternary ammonium salt. 
     
     
         75 . The electric double layer capacitor of  claim 74 , wherein the quaternary ammonium salt includes at least one of spiro-bipyrrolidinium tetrafluoroborate (SBP BF 4 ), tetraethylammonium tetrafluoroborate (TEA TFB), N-ethyl-N-methylpyrrolidinium tetafluoroborate, and triethyl(methyl)ammonium tetrafluoroborate. 
     
     
         76 . The electric double layer capacitor of  claim 65 , having a capacitance of at least about 100 F. 
     
     
         77 . The electric double layer capacitor of  claim 65 , having an operating voltage of g greater than about 3 volts and/or an operating temperature of greater than about 50 degrees Celsius. 
     
     
         78 . The electric double layer capacitor of  claim 65 , having an operating voltage of greater than about 2.7 volts and an operating temperature of greater than about 75 degrees Celsius. 
     
     
         79 . A method of manufacturing an electric double layer capacitor cell, the method comprising;
 disposing a cathode on a positive current collector;   disposing an anode on a negative current collector;   disposing a separator between the positive current collector and the negative current collector to form the electric double layer capacitor cell;   disposing the electric double layer capacitor cell in a container; and   infiltrating the electric double layer capacitor cell with an electrolyte formulation, the electrolyte formulation comprising an ionic species, a solvent, and a stabilizer comprising the compound of formula I:   
       
         
           
           
               
               
           
         
         wherein: 
         R is H, or saturated or unsaturated carbon group, and n is an integer from 0 to 5. 
       
     
     
         80 . The method of  claim 79 , wherein R is an unsaturated cyclic carbon group. 
     
     
         81 . The method of  claim 80 , wherein R is a monocyclic or polycyclic aryl. 
     
     
         82 . The method of  claim 79 , wherein R is a saturated cyclic carbon group. 
     
     
         83 . The formulation of  claim 82 , wherein R is a monocyclic or polycyclic aryl. 
     
     
         84 . The method of  claim 79 , wherein the stabilizer is benzonitrile. 
     
     
         85 . The method of  claim 79 , wherein the stabilizer is a monomer. 
     
     
         86 . The method of  claim 85 , further comprising:
 polymerizing the monomer to form a protective layer at the cathode surface and/or anode surface.   
     
     
         87 . The method of  claim 79 , wherein the solvent includes at least one of acetonitrile, propionitrile, and butyronitrile. 
     
     
         88 . The method of  claim 79 , wherein the ionic species is a quaternary ammonium salt. 
     
     
         89 . The method of  claim 88 , wherein the ionic species is at least one of spiro-bipyrrolidinium tetrafluoroborate (SBP BF4), tetraethylammonium tetrafluoroborate (TEA TFB), N-ethyl-N-methylpyrrolidinium tetafluoroborate, and triethyl(methyl)ammonium tetrafluoroborate. 
     
     
         90 . The method of  claim 79 , wherein the electric double layer capacitor cell has a capacitance of at least about 100 F. 
     
     
         91 . The method of  claim 79 , wherein the energy storage device has an operating voltage of greater than about 3 volts and/or an operating temperature of greater than about 50 degrees Celsius. 
     
     
         92 . The method of  claim 79 , wherein the electric double layer capacitor cell has an operating voltage of greater than about 2.7 volts and an operating temperature of greater than about 75 degrees Celsius.