Recovery of materials from electrode scraps and spent lithium-ion batteries via a green solvent-based separation process

1. A method of recycling lithium-ion battery materials, the method comprising:

isolating a composite electrode, the composite electrode comprising an electrode material adhered to a current collector with a polyvinylidene difluoride (PVDF) binder;

combining the composite electrode with triethyl phosphate (TEP) as a solvent to form a mixture, wherein the mixture comprises a solid-to-liquid ratio ranging from 1:10 to 1:2 based on the weights of the composite electrode and the TEP solvent;

delaminating the electrode material from the current collector in the mixture 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 the composite electrode is further defined as a composite cathode, and the electrode material is further defined as a cathode active material.

3. The method of claim 2 , 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).

4. The method of claim 2 , wherein the composite cathode is one or both of a spent cathode from a spent lithium-ion battery and cathode scrap from a cathode manufacturing process.

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

6. The method of claim 5 , wherein the composite electrodes are washed with an organic solvent.

7. The method of claim 1 , further comprising the step of shredding the composite electrode into a collection of smaller composite electrode fragments before the step of combining the composite electrode with TEP.

8. The method of claim 1 , wherein the step of delaminating the electrode material from the current collector includes heating the mixture to a temperature in the range of 20° C. to 215° C. and stirring the mixture.

9. The method of claim 8 , wherein the stirring is conducted for a time of 5 to 300 minutes.

10. The method of claim 1 , wherein the step of delaminating the electrode material from the current collector includes heating the mixture to a temperature of in the range of 20° C. to 215° C. and stirring the mixture, and subsequently subjecting the mixture to sonication.

11. The method of claim 10 , wherein the stirring is conducted for a time of at least 30 minutes, and the sonication is conducted for a time of at least 30 minutes.

12. The method of claim 1 , wherein recovering each of the free electrode material and the free current collector from the mixture comprises one or more of: (i) sieving the mixture; (ii) subjecting the mixture to filtration and centrifugation; (iii) rinsing at least one of the free electrode material and the free current collector; and (iv) drying at least one of the free electrode material and the free current collector.

13. The method of claim 1 , wherein the free electrode material recovered from the mixture: (i) comprises the same morphology as the electrode material; (ii) comprises the same chemical composition as the electrode material; (iii) comprises 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).

14. 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).

15. The method of claim 1 , further comprising the step of recovering the PVDF binder from the mixture.

16. The method of claim 15 , wherein the PVDF binder is recovered by non-solvent induced phase separation (NIPS).

17. The method of claim 1 , further comprising preparing a new composite electrode by coating the free electrode material on a current collector.

18. The method of claim 17 , further comprising preparing a new lithium-ion battery by including the new composite electrode in the lithium-ion battery.