Efficient recovery processes for the black mass from spent lithium-ion batteries

1. A method of recycling lithium-ion batteries, said method comprising:

isolating a composite electrode from a spent lithium-ion battery, the composite electrode comprising an electrode material adhered to a current collector with a polyvinylidene difluoride (PVDF) binder;

contacting the composite electrode with a polyol fluid capable of releasing the PVDF binder from the current collector, thereby forming a mixture;

delaminating the electrode material from the current collector to give a free electrode material and a free current collector; and

recovering each of the free electrode material and the free current collector from the mixture.

2. The method of claim 1 , wherein: (i) the polyol fluid comprises a glycol, a glycerol, or both; (ii) the electrode material and the current collector are delaminated at a temperature of from 20 to 198° C.; (iii) the electrode material and the current collector are fully delaminated within a time of from 2 seconds to 120 minutes after forming the mixture; or (iv) any combination of (i)-(iii).

3. The method of claim 1 , wherein: (i) the polyol fluid comprises an alkylene glycol; (ii) the electrode material and the current collector are delaminated at a temperature of from 100 to 198° C.; (iii) the electrode material and the current collector are fully delaminated within a time of from 2 to 120 seconds after forming the mixture; or (iv) any combination of (i)-(iii).

4. The method of claim 1 , wherein: (i) the polyol fluid is ethylene glycol; (ii) the electrode material and the current collector are delaminated at a temperature of from 160 to 198° C.; (iii) the electrode material and the current collector are fully delaminated within a time of from 2 to 6 seconds after forming the mixture; or (iv) any combination of (i)-(iii).

5. The method of claim 1 , wherein contacting the composite electrode with the polyol fluid comprises disposing the composite electrode in the polyol fluid, and wherein the polyol fluid: (i) is selected from ethylene glycol, diethylene glycol, glycerol, and combinations thereof; (ii) does not substantially dissolve the PVDF binder; (iii) remains substantially unreacted during the method; or (iv) any combination of (i)-(iii).

6. The method of claim 1 , further comprising:

collecting the polyol fluid after recovering the free electrode material and the free current collector;

optionally purifying the polyol fluid; and

reusing the polyol fluid in another round of the method to delaminate another composite electrode.

7. The method of claim 1 , wherein delaminating the electrode material from the current collector: (i) comprises peeling a film of the electrode material from the current collector; (ii) exhibits a peel-off efficiency of greater than 98%; or (iii) both (i) and (ii).

8. The method of claim 1 , wherein the composite electrode is further defined as a composite cathode, wherein the electrode material is further defined as a cathode active material.

9. The method of claim 8 , wherein in the composite cathode: (i) the cathode active material comprises a lithium-bearing metal oxide; (ii) the current collector comprises aluminum; or (iii) both (i) and (ii).

10. The method of claim 8 , wherein: (i) the cathode active material comprises a lithium nickel manganese cobalt oxide; (ii) the current collector is an aluminum sheet or foil; or (iii) both (i) and (ii).

11. The method of claim 1 , wherein the composite electrode is further defined as a composite anode, wherein the electrode material is further defined as an anode active material.

12. The method of claim 11 , wherein in the composite anode: (i) the anode active material comprises an electroconductive carbon compound; (ii) the current collector comprises copper; or (iii) both (i) and (ii).

13. The method of claim 11 , wherein in the composite anode: (i) the anode active material comprises graphite and/or carbon black; (ii) the current collector is a copper sheet or foil; or (iii) both (i) and (ii).

14. The method of claim 1 , wherein isolating the composite electrode comprises: (i) separating the composite electrode from one or more other components of the spent lithium-ion battery; (ii) washing the composite electrode with a solvent to remove a residual electrolyte therefrom; or (iii) both (i) and (ii).

15. The method of claim 1 , wherein: (i) the mixture comprises a solid-to-liquid ratio of about 1:10 wt./wt., based on the weights of the composite electrode and the polyol fluid; (ii) delaminating the electrode material from the current collector comprises mechanically agitating the mixture; or (iii) both (i) and (ii).

16. The method of claim 1 , wherein recovering each of the free electrode material and the free current collector from the mixture comprises: (i) filtering the mixture to extract at least one of the free electrode material and the free current collector; (ii) sizing the free electrode material; (iii) rinsing the at least one of the free electrode material and the free current collector with a solvent to remove a residual amount of the polyol fluid therefrom; or (iv) any combination of (i)-(iii).

17. The method of claim 1 , wherein the free electrode material recovered from the mixture: (i) comprises substantially the same morphology as the electrode material; (ii) comprises substantially the same chemical composition as the electrode material; (iii) comprises substantially the same electrochemical performance as the electrode material; (iv) is directly reusable in the preparation of a new composite electrode; or (v) any combination of (i)-(iv).

18. The method of claim 1 , wherein the free current collector recovered from the mixture is substantially free from: (i) corrosion; (ii) residual electrode material; or (iii) both (i) and (ii).

19. The method of claim 1 , further comprising preparing a new composite electrode using the free electrode material.

20. The method of claim 19 , further comprising preparing a new lithium-ion battery using the new composite electrode.