Capacitor electrodes for lead-acid battery with surface-modified additives
View Patent ↗Electrodes, which may be composite capacitor electrodes, include carbon fibers, illustratively chopped carbon fibers having an aspect ratio of from about 100-5000, have been treated with a non-ionic surfactant, specifically the polyoxyethyleneglycol octophenyl ether, Triton X-100, to increase the hydrophilicity of the fibers. The capacitive electrodes prepared with the surface-modified carbon fibers exhibit increased charge acceptance.
1. A lead-acid battery, comprising:
a capacitor electrode, comprising:
a lead-based current collector; and
capacitor active material disposed on the current collector, wherein the capacitor active material comprises:
a carbon capacitive material,
a conductive carbon material having a lower surface area than the carbon capacitive material, and
carbon fibers treated with polyethylene glycol-based surfactant which is adsorbed onto the carbon fibers to produce surface modified carbon fibers.
2. The lead-acid battery of claim 1 , wherein the carbon capacitive material is activated carbon.
3. The lead-acid battery of claim 1 , wherein the conductive carbon material is carbon black.
4. The lead-acid battery of claim 1 , wherein the surface modified carbon fibers have an aspect ratio of between approximately 100 and approximately 5000.
5. The lead-acid battery of claim 4 , wherein the polyethylene glycol-based surfactant is a polyoxyethyleneglycol octophenyl ether.
6. The lead-acid battery of claim 1 , wherein the capacitor electrode comprises a polymer binder.
7. The lead-acid battery of claim 6 , wherein the polymer binder is selected from the group consisting of carboxymethylcellulose, polytetrafluoroethylene, and styrene-butadiene rubber.
8. The lead-acid battery of claim 7 , wherein the polymer is polytetrafluoroethylene.
9. The lead-acid battery of claim 1 , wherein the capacitor active material is negative.
10. A lead-acid battery, comprising:
at least one PbO 2 positive electrode;
at least one Pb-based negative electrode;
a capacitor electrode electronically connected in parallel to the at least one Pb-based negative electrode, wherein the capacitor electrode comprises:
a lead-based current collector,
a capacitor active material disposed on the current collector, wherein the capacitor active material comprises:
a carbon capacitive material,
a conductive carbon material having a lower surface area than the carbon capacitive material, and
carbon fibers treated with a polyethylene glycol-based surfactant which is adsorbed onto the carbon fibers to produce surface modified carbon fibers; and
an electrolyte in communication with the at least one positive electrode and the at least one negative electrode.
11. The lead-acid battery of claim 10 , wherein the surface modified carbon fibers have an aspect ratio of between approximately 100 and approximately 5000.
12. The lead-acid battery of claim 10 , wherein the polyethylene glycol-based surfactant is a polyoxyethyleneglycol octophenyl ether.
13. The lead-acid battery of claim 10 , wherein the carbon capacitive material has a surface area greater than about 2000 m 2 /g.
14. The lead-acid battery of claim 10 , wherein the carbon capacitive material has a surface area greater than about 3000 m 2 /g.
15. The lead-acid battery of claim 10 , wherein the carbon capacitive material comprises between 10 wt % and 20 wt % of the capacitor active material.
16. The lead-acid battery of claim 10 , wherein the conductive carbon material has a surface area of approximately 100 m 2 /g or less.
17. The lead-acid battery of claim 10 , wherein the conductive carbon material comprises between 3 wt % and 5 wt % of the capacitor active material.
18. The lead-acid battery of claim 10 , wherein the surface modified carbon fibers comprise between 5 wt % and 15 wt % of the capacitor active material.
19. The lead-acid battery of claim 10 , wherein the capacitor electrode comprises an aqueous solvent.
20. The lead-acid battery of claim 1 , comprising at least one Pb-based negative electrode, wherein the at least one Pb-based negative electrode is electrically connected in parallel to the capacitor electrode.
21. The lead-acid battery of claim 20 , comprising:
at least one PbO 2 positive electrode, and
an electrolyte in communication with the at least one positive electrode and the at least one negative electrode.