Electrolyte for three-volt ultracapacitor
View Patent ↗An electric double-layer ultracapacitor configured to maintain desired operation at an operating voltage of three volts, where the capacitor includes a housing component, a first and a second current collector, a positive and a negative electrode electrically coupled to one of the first and second current collectors, and a separator positioned between the positive and the negative electrode. The capacitor may also include an electrolyte in ionic contact with the electrodes and the separator, the electrolyte having acetonitrile and a quaternary ammonium salt with a molarity of less than one.
1. An ultracapacitor, comprising:
a first current collector and a second current collector;
a positive electrode electrically coupled to the first current collector;
a negative electrode electrically coupled to the second current collector;
a separator positioned between the positive electrode and the negative electrode;
an electrolyte comprising a quaternary ammonium salt in ionic contact with the positive electrode and the negative electrode, wherein the electrolyte comprises less than 1M salt; and
a housing component to retain the positive electrode, the negative electrode, the separator and the electrolyte, wherein the ultracapacitor is configured to operate between about 2.8 volts to about 3 volts, and
wherein the ultracapacitor is further configured to operate at 65° C. with a cycle life of greater than 500k cycles.
2. The ultracapacitor of claim 1 , wherein the quaternary ammonium salt comprises a cation selected from the group consisting of spiro-(1,1′)-bipyrrolidinium, triethylmethyl ammonium and tetraethyl ammonium.
3. The ultracapacitor of claim 1 , wherein the quaternary ammonium salt comprises an anion selected from the group consisting of tetrafluoroborate and iodide.
4. The ultracapacitor of claim 1 , wherein the electrolyte further comprises acetonitrile.
5. The ultracapacitor of claim 1 , wherein the salt concentration of the electrolyte is about 0.8M.
6. The ultracapacitor of claim 1 , wherein the positive electrode and negative electrode each independently comprise a dry electrode film comprising carbon and binder.
7. An ultracapacitor comprising:
a first current collector and a second current collector;
a positive electrode electrically coupled to the first current collector;
a negative electrode electrically coupled to the second current collector;
a separator positioned between the positive electrode and the negative electrode;
an electrolyte comprising a quaternary ammonium salt in ionic contact with the positive electrode and the negative electrode, wherein the electrolyte comprises less than 1M salt; and
a housing component to retain the positive electrode, the negative electrode, the separator and the electrolyte;
wherein the ultracapacitor is configured to operate at 3 volts or greater at 65° C. and maintain greater than 80% of its initial capacitance for over 1500 hours.
8. The ultracapacitor of claim 7 , wherein the quaternary ammonium salt comprises a cation selected from the group consisting of spiro-(1,1′)-bipyrrolidinium, triethylmethyl ammonium and tetraethyl ammonium.
9. The ultracapacitor of claim 7 , wherein the quaternary ammonium salt comprises an anion selected from the group consisting of tetrafluoroborate and iodide.
10. The ultracapacitor of claim 7 , wherein the electrolyte further comprises acetonitrile.
11. The ultracapacitor of claim 7 , wherein the salt concentration of the electrolyte is about 0.8M.
12. The ultracapacitor of claim 7 , wherein the positive electrode and negative electrode each independently comprise a dry electrode film comprising carbon and binder.
13. An ultracapacitor, comprising:
a first current collector and a second current collector;
a positive electrode electrically coupled to the first current collector;
a negative electrode electrically coupled to the second current collector;
a separator positioned between the positive electrode and the negative electrode;
an electrolyte comprising a quaternary ammonium salt in ionic contact with the positive electrode and the negative electrode, wherein the electrolyte comprises less than 1M salt; and
a housing component to retain the positive electrode, the negative electrode, the separator and the electrolyte;
wherein the ultracapacitor is configured to operate at 3 volts or greater at 65° C. and maintain less than 200% of its initial equivalent series resistance for over 1500 hours.
14. The ultracapacitor of claim 13 , wherein the quaternary ammonium salt comprises a cation selected from the group consisting of spiro-(1,1′)-bipyrrolidinium, triethylmethyl ammonium and tetraethyl ammonium.
15. The ultracapacitor of claim 13 , wherein the quaternary ammonium salt comprises an anion selected from the group consisting of tetrafluoroborate and iodide.
16. The ultracapacitor of claim 13 , wherein the electrolyte further comprises acetonitrile.
17. The ultracapacitor of claim 13 , wherein the salt concentration of the electrolyte is about 0.8M.
18. The ultracapacitor of claim 13 , wherein the positive electrode and negative electrode each independently comprise a dry electrode film comprising carbon and binder.