Reintroduction of lithium into recycled battery materials

1. A method for making recycled positive-electrode material for a lithium-ion energy-storage device, the method comprising:

harvesting lithium-deficient positive-electrode material from a recycling or waste stream;

placing the lithium-deficient positive-electrode material in a pressure vessel containing an aqueous solution comprising lithium ions;

processing the lithium-deficient positive-electrode material in the pressure vessel to replenish at least some lithium in the lithium-deficient positive-electrode material by diffusing lithium into a lattice of the lithium-deficient positive-electrode material, wherein processing the lithium-deficient positive-electrode material comprises suspending the lithium-deficient positive-electrode material in the aqueous solution comprising lithium ions and hydrothermally reacting the lithium-deficient positive-electrode material with the aqueous solution comprising lithium ions in the pressure vessel at elevated temperature and pressure to form a hydrothermally reacted positive-electrode material, the elevated temperature being in a range of 100-300 degrees Celsius;

after forming the hydrothermally reacted positive-electrode material, removing the hydrothermally reacted positive-electrode material from the aqueous solution comprising lithium ions and then sintering the hydrothermally reacted positive-electrode material to form the recycled positive-electrode material.

2. The method of claim 1 , wherein harvesting the lithium-deficient positive-electrode material comprises separating an intact electrode from a spent battery.

3. The method of claim 1 , wherein harvesting the lithium-deficient positive-electrode material comprises separating the lithium-deficient positive-electrode material from a spent battery in pieces or in a finely divided state.

4. The method of claim 1 , wherein harvesting the lithium-deficient positive-electrode material comprises selecting the lithium-deficient positive-electrode material based on a grain size, a particle size, or a structure size of the lithium-deficient positive-electrode material.

5. The method of claim 1 , wherein the lithium-deficient positive-electrode material comprises lithium-deficient lithium cobalt oxide and a lithium-deficient form of one or more of lithium titanium oxide, lithium iron phosphate, lithium manganese oxide, and lithium nickel cobalt aluminum oxide, and wherein diffusing lithium into the lattice of the lithium-deficient positive-electrode material to form the recycled positive-electrode material comprises diffusing lithium into a lattice of each lithium-deficient material in the lithium-deficient positive-electrode material.

6. The method of claim 1 , wherein replenishing at least some lithium comprises photolyzing the lithium-deficient positive-electrode material in an environment comprising lithium ions.

7. The method of claim 1 , wherein replenishing at least some lithium comprises suspending the lithium-deficient positive-electrode material in a solution comprising one or more of a lithiating agent, a reducing agent, and lithium ions.

8. The method of claim 7 , wherein suspending the lithium-deficient positive-electrode material in a solution comprises suspending the lithium-deficient positive-electrode material in a solution comprising one or more of an ether and a hydrocarbon.

9. The method of claim 7 , wherein suspending the lithium-deficient positive-electrode material in a solution comprises suspending the lithium-deficient positive-electrode material in a solution comprising one or more of liquid and supercritical carbon dioxide.

10. The method of claim 1 , wherein replenishing at least some lithium comprises promoting a solid state reaction of the lithium-deficient positive-electrode material with a lithium compound intimately present in excess.

11. The method of claim 10 , wherein promoting the solid state reaction comprises heating an intimate mixture of the lithium-deficient positive-electrode material and the lithium compound to a sintering temperature of one or more components of the intimate mixture.

12. The method of claim 1 , wherein replenishing the lithium-deficient positive-electrode material yields a recycled electrode material, the method further comprising rinsing the recycled electrode material in a solvent to remove an excess reagent.

13. The method of claim 1 , wherein sintering the hydrothermally reacted positive-electrode material comprises heating the recycled hydrothermally reacted positive-electrode material to a sintering temperature of 500-800 degrees Celsius.

14. The method of claim 1 , wherein sintering the hydrothermally reacted positive-electrode material comprises heating a recycled hydrothermally reacted positive-electrode material to a sintering temperature without addition of lithium.