Method for producing positive electrode material of Li-ion secondary battery
A method for producing a positive electrode material adapted to the Li-ion secondary batteries is disclosed. The produced material has the following formula (I), Li 1+x Mn 2−y M y O 4 (I) wherein M is Mg, Al, Cr, Fe, Co, or Ni; 0≦x≦0.4, and 0≦y≦0.2. The method is achieved by co-precipitating a gel salts with an organic acid. First, salts of Li, Mn and M are mixed with at least a solvent to form an initial solution. The mole ratio of Li, Mn and M ions in their respective salts is (1+x):(2−y):y. Next, at least a chelate is added into the initial solution to form a suspension, which is then filtered to obtain a co-precipitate. Finally, the co-precipitate is calcined and heated to obtain the final product.
1. A method for producing a positive electrode material of the formula (I),
Li 1+X Mn 2−y M y O 4 (I)
wherein M is Mg, Al, Cr, Fe, Co, or Ni, 0≦x≦0.4, and 0≦y≦0.2 comprising steps of:
(A) mixing salts of Li, Mn and M with at least a solvent to form an initial solution, wherein the mole ratio of Li, Mn, and M ions contained in their respective salts is (1+x):(2−y):y;
(B) adding at least a chelate into said initial solution to form a suspension, wherein the mole ratio of said chelate to Li ion in said Li salt ranges from 1:1 to 5:1;
(C) filtering said suspension to obtain a co-precipitate; and
(D) calcining and heating said co-precipitate.
2. The method as claimed in claim 1 , wherein said Li salt is selected from the group consisting of nitrate, chloride, hydroxide, carbonate and acetate.
3. The method as claimed in claim 1 , wherein said Mn salt is selected from the group consisting of nitrate, chloride, hydroxide, carbonate and acetate.
4. The method as claimed in claim 1 , wherein said M salt is selected from the group consisting of nitrate, chloride, hydroxide, carbonate and acetate.
5. The method as claimed in claim 1 , wherein said solvent is selected from the group consisting of water, methanol, ethanol, propanol, butanol and combinations thereof.
6. The method as claimed in claim 1 , wherein said chelate is selected from the groups consisting of citric acid, oxalic acid, tartaric acid, and combinations thereof.
7. The method as claimed in claim 1 , wherein the mole ratio of said chelate to Li ion in said Li salt ranges from 1:1 to 5:1.
8. The method as claimed in claim 1 , wherein said co-precipitates is calcined at 200° C.–900° C.
9. The method as claimed in claim 1 , wherein said co-precipitate is calcined for 1 to 4 hours.
10. The method as claimed in claim 1 , wherein said co-precipitates is calcined at 600° C.–900° C.
11. The method as claimed in claim 1 , wherein said co-precipitate is calcined for 1 to 8 hours.