Method for recycling and refreshing cathode material, refreshed cathode material and lithium ion battery
Provided is a method for recycling and refreshing a cathode material, a refreshed cathode material and a lithium ion battery. The method for recycling and refreshing the cathode material includes: 1) a cathode material recycled from a waste battery is mixed with a manganiferous salt solution; 2) an alkali aqueous solution is added to the mixture to react to obtain a manganese hydroxide coating cathode material; and 3) the manganese hydroxide coating cathode material is sintered with a lithium resource to obtain a refreshed cathode material. The refreshed cathode material has no obvious impurity phase and has good crystallinity, high initial charge-discharge efficiency and good cycling performance.
1. A method for recycling and refreshing a cathode material, comprising:
1) mixing a cathode material recycled from a waste battery with a manganiferous inorganic aqueous solution to obtain a mixture, while the cathode material is lithium nickel-cobalt-manganese oxide, lithium manganate, or a mixture of lithium nickel-cobalt-manganese oxide and lithium manganate;
2) adding an alkali aqueous solution into the mixture to react to obtain a manganese hydroxide coating cathode material; and
3) sintering the manganese hydroxide coating cathode material with a lithium resource to obtain a refreshed cathode material.
2. The method as claimed in claim 1 , wherein a step for recycling the cathode material from the waste battery comprises: disassembling the waste battery to obtain a positive electrode; then, soaking the positive electrode by a solvent to obtain cathode powder; and then, calcining the cathode powder.
3. The method as claimed in claim 1 , wherein a concentration of manganese ions in the manganiferous inorganic aqueous solution in the step 1) is 0.1 mol/L-2.0 mol/L.
4. The method as claimed in claim 1 , wherein a molar ratio of the cathode material to the manganese element in the step 1) is 1:0.01-1:0.10.
5. The method as claimed in claim 1 , wherein in the step 2), the alkali aqueous solution is dripped to the mixture to react and a pH value of a reaction system is adjusted to 10-13 to obtain the manganese hydroxide coating cathode material.
6. The method as claimed in claim 1 , wherein in the step 2), the alkali aqueous solution is dripped to the mixture to react, and after the reaction, aging is performed to obtain the manganese hydroxide coating cathode material.
7. The method as claimed in claim 1 , wherein in the step 2), a concentration of the alkali aqueous solution is 0.01 mol/L-2.00 mol/L.
8. The method as claimed in claim 1 , wherein in the step 2), a reaction time is 2 h-8 h.
9. The method as claimed in claim 1 , wherein a mass ratio of the manganese hydroxide coating cathode material to the lithium resource is 1:0.04-1:0.30.
10. The method as claimed in claim 1 , wherein in the step 3), the manganese hydroxide coating cathode material and the lithium resource are mixed for ball milling and are sintered to obtain the refreshed cathode material.
11. The method as claimed in claim 1 , wherein in the step 3), a sintering temperature is 700° C.-1000° C.
12. The method as claimed in claim 1 , wherein in the step 3), a sintering time is 6 h-20 h.
13. The method as claimed in claim 1 , wherein the cathode material is lithium nickel-cobalt-manganese oxide, lithium manganate, or a mixture of lithium nickel-cobalt-manganese oxide and lithium manganate.
14. The method as claimed in claim 2 , wherein the solvent is selected from a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, a lithium hydroxide aqueous solution or an N-methyl-2-pyrrolidone.
15. The method as claimed in claim 14 , wherein a concentration of the sodium hydroxide aqueous solution is 0.1 mol/L-2.0 mol/L; a concentration of the potassium hydroxide aqueous solution is 0.1 mol/L-2.0 mol/L; and a concentration of the lithium hydroxide aqueous solution is 0.1 mol/L-2.0 mol/L.
16. The method as claimed in claim 14 , wherein the positive electrode is soaked by the sodium hydroxide aqueous solution for 5 s-60 s, and the positive electrode is soaked by the N-methyl-2-pyrrolidone for 0.5 h-6.0 h.
17. The method as claimed in claim 14 , wherein a mass ratio of the sodium hydroxide aqueous solution to the positive electrode is 20:1-1:1; and a mass ratio of the N-methyl-2-pyrrolidone to the positive electrode is 200:1-3:1.
18. The method as claimed in claim 2 , wherein a calcination temperature is 400° C.-650° C.