Partially surface-mediated lithium ion-exchanging cells and method for operating same
View Patent ↗A lithium super-battery cell comprising: (a) A cathode comprising a cathode active material having a surface area to capture or store lithium thereon, wherein the cathode active material is not a functionalized material and does not bear a functional group; (b) An anode comprising an anode current collector; (c) A porous separator disposed between the two electrodes; (d) A lithium-containing electrolyte in physical contact with the two electrodes, wherein the cathode active material has a specific surface area of no less than 100 m 2 /g being in direct physical contact with the electrolyte to receive lithium ions therefrom or to provide lithium ions thereto; and (e) A lithium source implemented at one or both of the two electrodes prior to a first charge or a first discharge cycle of the cell. This new generation of energy storage device exhibits the best properties of both the lithium ion battery and the supercapacitor.
1. A partially surface-mediated lithium ion-exchanging cell comprising:
(a) A positive electrode (cathode) consisting essentially of a binder, a conductive additive, and a cathode active material selected from the group consisting of (A) a porous disordered carbon material selected from an activated soft carbon, activated hard carbon, activated polymeric carbon or carbonized resin, activated meso-phase carbon, activated coke, activated carbonized pitch, activated carbon black, or activated partially graphitized carbon that contain electrolyte-accessible pores; (B) a graphene material selected from a single-layer sheet or multi-layer platelet of hydrogenated graphene, nitrogenated graphene, boron-doped graphene, or nitrogen-doped graphene, forming a meso-porous structure; (C) exfoliated graphite; (D) meso-porous carbon; and (E) combinations thereof, wherein said cathode active material has surface area to capture or store lithium thereon, wherein the cathode contains no functionalized material that has a functional group to capture a lithium ion, wherein said cathode has interconnected pores each having a size ranging from 2 nm to 50 nm;
(b) A negative electrode (anode) being composed of an anode current collector and a lithium source implemented at the anode prior to a first discharge of the cell, wherein said lithium source is selected from a lithium chip, lithium alloy chip, lithium foil, lithium alloy foil, lithium powder, lithium alloy powder, surface stabilized lithium particles, or a combination thereof;
(c) A porous separator disposed between the two electrodes; and
(d) A lithium-containing electrolyte in physical contact with the two electrodes;
wherein said cathode active material has a specific surface area of no less than 100 m 2 /g being in direct physical contact with said electrolyte to receive lithium ions therefrom and storing said lithium atoms on surface active sites that are immersed in said electrolyte or to provide lithium ions thereto without lithium intercalation or de-intercalation, wherein said partially surface-mediated lithium ion-exchanging cell is not a supercapacitor and wherein a charge or discharge operation of said partially surface-mediated lithium ion-exchanging cell involves an exchange of lithium ions between said negative electrode and said positive electrode.
2. The cell of claim 1 , wherein said cell has an open-circuit voltage of at least 1.2 volts.
3. The cell of claim 1 , wherein said cell has an open-circuit voltage of at least 1.5 volts.
4. The cell of claim 1 , wherein at least 90% of the lithium is stored on surfaces of said cathode active material, with said lithium being in direct physical contact with said cathode surfaces, when the cell is in a discharged state.
5. The cell of claim 1 , wherein the electrolyte is liquid electrolyte or gel electrolyte containing a first amount of lithium ions.
6. The cell of claim 1 , wherein a charge or discharge operation of the cell does not involve lithium intercalation or solid state diffusion.
7. The cell of claim 5 , wherein an operation of said cell involves an exchange of a second amount of lithium ions between said cathode and said anode and said second amount of lithium is greater than said first amount.
8. The cell of claim 1 , wherein said cell operates in a voltage range of from 1.5 volts to 4.5 volts.
9. The cell of claim 1 , wherein said cell operates in a voltage range of from 1.5 volts to 4.0 volts.
10. The cell of claim 1 , wherein said cell containing a liquid organic electrolyte operates in a voltage range above 3.8 volts.
11. The cell of claim 1 , wherein said cathode active material has a specific surface area of no less than 500 m 2 /g that is in direct contact with said electrolyte.
12. The cell of claim 1 , wherein said cathode active material has a specific surface area of no less than 1,000 m 2 /g that is in direct contact with said electrolyte.
13. The cell of claim 1 , wherein said cathode active material has a specific surface area of no less than 1,500 m 2 /g that is in direct contact with said electrolyte.
14. The cell of claim 1 , wherein said cathode active material has a specific surface area of no less than 2,000 m 2 /g that is in direct contact with said electrolyte.
15. The cell of claim 1 , wherein no more than 10% of the lithium is stored in the bulk of said cathode active material when the cell is in a discharged state.
16. The cell of claim 1 wherein said cathode active material is a graphene material containing no functional group.
17. The cell of claim 1 wherein said disordered carbon material is formed of two phases with a first phase being graphite crystals or stacks of graphene planes and a second phase being non-crystalline carbon, and wherein the first phase is dispersed in the second phase or bonded by the second phase.
18. The cell of claim 1 wherein said electrolyte comprises a lithium salt-doped ionic liquid.
19. The cell of claim 1 wherein said positive electrode has a thickness greater than 100 μm.
20. A method of operating the cell of claim 1 , said method including implementing a lithium source at the anode and ionizing said lithium source to release lithium ions into said electrolyte during the first discharge cycle of said cell.
21. A method of operating the cell of claim 1 , said method including implementing a lithium source at the cathode and operating said lithium source to release lithium ions into said electrolyte during the first charge cycle of said cell.
22. A method of operating the cell of claim 1 , said method including implementing a lithium source at the anode, ionizing said lithium source to release lithium ions into said electrolyte during the first discharge cycle of said cell, and electrochemically driving said released lithium ions to said cathode where said released lithium ions are captured by said cathode active material surfaces.
23. The method of claim 22 , further comprising a step of releasing lithium ions from said cathode surfaces during a re-charge cycle of said device, electrically driving said released lithium ions to an anode current collector surface or said lithium source using an external battery charging device.