Method and apparatus for recycling electrode material of lithium secondary battery
Lithium cobaltate forming the positive electrode of a lithium secondary battery is subjected together with lithium metal to reducing reaction in molten lithium chloride to produce lithium oxide and to precipitate and separate cobalt or cobalt oxide. The lithium oxide is subjected to electro-deposition in molten lithium chloride contained in a lithium electro-deposition tank provided with an anode and a cathode to recover lithium metal deposited on the cathode.
1. A method of recycling an electrode material of a lithium secondary battery, comprising:
subjecting a lithium cobaltate contained in the electrode material of a positive electrode of the lithium secondary battery together with a lithium metal to a reducing reaction in a molten lithium chloride to produce a lithium oxide and separate a cobalt or a cobalt oxide by a precipitation; and
subjecting the lithium oxide to an electrolysis in a molten lithium chloride so as to deposit a lithium metal on a cathode for recovering the lithium metal.
2. The recycling method according to claim 1 , wherein the lithium metal having a quantity at least three times a quantity of the lithium cobaltate contained in the electrode material forming the positive electrode is added for the reducing reaction to precipitate and separate mainly the cobalt.
3. The recycling method according to claim 1 , wherein the lithium metal having a quantity equal to a quantity of the lithium cobaltate contained in the electrode material forming the positive electrode is added for the reducing reaction to precipitate and separate mainly the cobalt oxide.
4. The recycling method according to claim 1 , wherein a voltage for the electrolysis is in a range of 2.47 to 3.46 V.
5. An apparatus for recycling an electrode material of a lithium secondary battery, comprising:
a reducing reaction tank; and
a lithium electro-deposition tank in which a liquid processed in the reducing reaction tank is processed;
wherein the reducing reaction tank is configured to receive a lithium cobaltate contained in the electrode material of a positive electrode of the lithium secondary battery into a molten lithium chloride contained in the reducing reaction tank, a lithium metal being added to the molten lithium chloride in the reducing reaction tank, the molten lithium chloride being stirred to produce a lithium oxide and separate a cobalt or a cobalt oxide by a precipitation,
wherein the electro-deposition tank is configured to receive the liquid processed by the reducing reaction in the reducing reaction tank so that the liquid is subjected to an electrolysis to deposit a lithium metal on a cathode and recover the lithium metal.
6. The recycling apparatus according to claim 5 , wherein the lithium metal having a quantity at least three times a quantity of the lithium cobaltate contained in the electrode material of the positive electrode is added in the reducing reaction tank for the reducing reaction to precipitate and separate mainly the cobalt.
7. The recycling apparatus according to claim 5 , wherein the lithium metal having a quantity equal to a quantity of the lithium cobaltate contained in the electrode material of the positive electrode is added in the reducing reaction tank to precipitate and separate mainly the cobalt oxide.
8. The recycling apparatus according to claim 5 , wherein a voltage for the electrolysis in the lithium electro-deposition tank is in a range of 2.47 to 3.46 V.
9. The recycling apparatus according to claim 5 , wherein the reducing reaction tank also functions as the lithium electro-deposition tank so that an electro-deposition of lithium can be carried out without carrying the liquid in the reducing reaction tank after the reducing reaction.