WE CLAIM:
1. A hybrid lithium ion capacitor (100), comprising:
a positive electrode (102) composed of three active materials, wherein a first active
material is a reversible Electrochemical Double-Layer Capacitance (EDLC) material, a
second active material is a reversible redox active material, and a third active material is an
irreversible redox active material; and
a negative electrode (104) composed of a fourth active material providing a surface for
reversible intercalation of lithium ions,
wherein the third active material is capable of providing irreversible in-situ prelithiation of the negative electrode (104) during a formation cycle of a Solid Electrolyte
Interphase (SEI) film (112) in the hybrid lithium ion capacitor (100).
2. The hybrid lithium ion capacitor (100) as claimed in claim 1, wherein the third active
material decomposes to generate lithium (Li+
) ions and an inert gas, during the formation
cycle.
3. The hybrid lithium ion capacitor (100) as claimed in claim 1, wherein a redox potential
of the second active material of the positive electrode (102) is higher than a redox voltage
of the negative electrode (104).
4. The hybrid lithium ion capacitor (100) as claimed in claim 1, wherein a working
potential of the first active material of the positive electrode (102) is higher than a redox
potential of the second active material.
5. The hybrid lithium ion capacitor (100) as claimed in claim 1, wherein a redox potential
of the third active material of the positive electrode (102) is higher than a redox potential of
the second active material.
6. The hybrid lithium ion capacitor (100) as claimed in claim 1, wherein a redox potential
of the second active material of the positive electrode (102) is less than a desired nominal
voltage of the hybrid lithium ion capacitor (100).
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7. The hybrid lithium ion capacitor (100) as claimed in claim 1, further comprising an
electrolyte (108) having a redox potential higher than a redox potential of the third active
material.
8. The hybrid lithium ion capacitor (100) as claimed in claim 1, wherein the first active
material is selected from a group consisting of activated carbon, graphene, hard carbon, and
carbon nitride.
9. The hybrid lithium ion capacitor (100) as claimed in claim 1, wherein the second active
material is selected from a group consisting of carbon coated Lithium Iron Phosphate (LFP),
lithium nickel-manganese-cobalt oxide, Lithium Iron Manganese Phosphate (LMFP or
LiFexMn1-x PO4), and lithium cobalt oxide.
10. The hybrid lithium ion capacitor (100) as claimed in claim 1, wherein the third active
material is selected from a group consisting of lithium oxalate, lithium nitride, and lithium
succinate.
11. The hybrid lithium ion capacitor (100) as claimed in claim 1, wherein the fourth active
material of the negative electrode is selected from a group consisting of graphite, graphene,
hard carbon, and a mixture of graphite and hard carbon or graphene.
12. A method of fabrication of a positive electrode (102) for use in a hybrid Lithium-ion
capacitor (100), the method comprising:
dry mixing a first active material with a second active material for a first time period to
obtain a first mixture, wherein the first active material is a reversible Electrochemical
Double-Layer Capacitance (EDLC) material and the second active material is a reversible
redox active material;
dry mixing a third active material with the first mixture for a second time period to
obtain a second mixture, wherein the third active material is an irreversible redox active
material;
mixing a solution of a binder and a conductive additive into the second mixture for a
third time period to obtain a slurry; and
coating the slurry on a current collector to obtain the positive electrode (102).
13. The method as claimed in claim 11, wherein the positive electrode (102) along with a
negative electrode (104) and an electrolyte (108) are used to form the hybrid lithium-ion
capacitor (100).
14. The method as claimed in claim 12, wherein the hybrid lithium-ion capacitor (100) is
charged for initiation of a formation cycle of a Solid Electrolyte Interphase (SEI) film (112),
and wherein the third active material irreversibly decomposes to generate lithium ions and
an inert gas, the lithium ions compensate for loss of lithium at the negative electrode (104)
during the formation cycle.
15. The method as claimed in claim 13, wherein the inert gas is released after formation of
the SEI film (112) and before packaging of the hybrid lithium-ion capacitor (100).
16. The method as claimed in claim 11, wherein the first active material is selected from a
group consisting of activated carbon, graphene, hard carbon, and carbon nitride.
17. The method as claimed in claim 11, wherein the second active material is selected from
a group consisting of carbon coated Lithium Iron Phosphate (LFP), lithium nickelmanganese-cobalt oxide, Lithium Iron Manganese Phosphate (LMFP or LiFexMn1-x PO4),
and lithium cobalt oxide.
18. The method as claimed in claim 11, wherein the third active material is selected from a
group consisting of lithium oxalate, lithium nitride, and lithium succinate.
19. The method as claimed in claim 12, wherein the fourth active material of the negative
electrode (104) is selected from a group consisting of graphite, graphene, hard carbon, and
mixture of graphite and hard carbon or graphene.
20. The method as claimed in claim 11, wherein the binder is one of Polyvinylidene fluoride
or Polyvinylidene Difluoride (PVDF), and Fluorine Acrylate (FAA), and the conductive
additive is SuperP.
21. The method as claimed in claim 11, wherein the first time period ranges from 2 to 3
hours the second time period ranges from 2 to 3 hours, and the third time period ranges from
12 to 16 hours.