Patent EA-001504-B1 (EA)
Title: METHOD OF PREPARING Li1+xMn2-xO4 FOR USE AS SECONDARY BATTERY ELECTRODE
Inventor: SHEARGOLD STEPHEN W
IPC: H01M4/50
Filed: 1998-03-11
Abstract: 1. A continuous method of preparing a single phase lithiated manganese oxide intercalation compound of the formula Li1+XMn2-XO4 having a spinel-type structure comprising the steps of: (a) mixing intimately in amounts, based on said lithiated manganese oxide compound, a lithium hydroxide or a lithium salt and a manganese oxide or a manganese salt; b) feeding the intimately mixed compounds to a reactor; (c) continuously agitating the mixed compounds in the reactor; (d) heating the agitated mixed compounds in the reactor in the presence of air or an oxygen-enriched atmosphere at a temperature of from about 650 degree C to about 800 degree C for a time not in excess of about 4 hours; and (e) cooling the oxygen deficient product to less than about 200 degree C in less than about 2 hours; wherein x is from about 0.022 to about 0.125 and the a-axis lattice parameter is about 8.235 A. 2. The method according to claim 1 wherein further cooling the product to about 100 degree C. 3. The method according to claim 1 wherein further discharging the cooled product after step (c). 4. The method according to claim 1 wherein step (a) is performed using a drum-type mixer. 5. The method according to claim 1 wherein step (a) is performed using a ball mill. 6. The method according to claim 1 wherein step (a) is performed using a vibratory mill. 7. The method according to claim 1 wherein step (a) is performed using a jet mill. 8. The method according to claim 1 wherein step (b) is performed using a screw conveyor. 9. The method according to claim 1 wherein step (b) is performed using a pneumatic conveyor. 10. The method according to claim 1 wherein step (b) is performed using an air ejector. 11. The method according to claim 1 wherein the atmosphere is continuously purged with a flow of air, oxygen or oxygen-enriched air during step (c). 12. The method according to claim 1 wherein the atmosphere is continuously purged with a countercurrent flow of oxygen enriched atmosphere during step (c). 13. The method according to claim 1 wherein the reactor is a horizontal rotary tube with the exit end slightly lower than the entrance end. 14. The method according to claim 1 wherein the reactor is a horizontal burning kiln with a rotating screw. 15. The method according to claim 1 wherein the reaction is performed in a fluidized bed. 16. The method according to claim 1 wherein the reactor is a heated vibrating conveyor belt. 17. The method according to claim 1 wherein the reactor is a cascade of vertical rotating bottoms. 18. The method according to claim 1 wherein the heating step is performed in about 2 hours or less. 19. The method according to claim 1 wherein the cooling step is performed in about one and one-half hours or less. 20. The method according to claim 19 wherein the heating step temperature is from about 700 degree C to about 800 degree C. 21. The method according to claim 1 including continuous purging with a flow of air, oxygen or oxygen-enriched atmosphere during step (d). 22. The method according to claim 21 wherein the continuous purging is with a countercurrent flow of air. 23. The method according to claim 1 wherein the reactor is a horizontal burning kiln with a rotating screw. 24. The method according to claim 1 wherein the reaction is performed in a fluidized bed. 25. The method according to claim 1 wherein the cooling step is performed in a rotating kiln. 26. The method according to claim 1 wherein the cooling step is performed in a heated vibrating conveyor belt. 27. The method according to claim 1 wherein the cooling step is performed in a cascade of vertical rotating bottoms. 28. The method according to claim 1 wherein the cooling step is performed in about one and one-half hours or less. 29. The method according to claim 1 wherein the cooling step is performed in about less than one and one-half hours. 30. The method according to claim 1 wherein the cooling step is performed in zones of progressively cooler temperatures. 31. The method according to claim 30 wherein the cooling step is performed in at least two zones. 32. The method according to claim 31 wherein the temperature in each successive cooling zone is at least about 90 degree C lower than the immediately previous zone. 33. The method according to claim 32 wherein the temperature in the successive cooling zones is about 725 degree C, 625 degree C and 525 degree C. 34. The method according to claim 32 wherein the temperature in the successive cooling zones is about 800 degree C, 650 degree C and 500 degree C. 35. The method according to claim 32 wherein the temperature in the successive cooling zones is about 750 degree C, 600 degree C and 450 degree C. 36. The method according to claim 32 for preparing a spinel structure lithiated intercalation compound of the formula Li1+XMn2-XO4 wherein said cooled product is annealed by allowing the product to uptake oxygen. 37. The method according to claim 36 wherein said cooled product is annealed by allowing the product to uptake maximum amount of oxygen. 38. The method according to claim 1 wherein the atmosphere is continuously purged with a flow of air, oxygen or an oxygen-enriched atmosphere during the cooling step. 39. The method according to claim 38 wherein the continuous purging is with a countercurrent flow of air is performed during the cooling step. 40. The method according to claim 1 wherein the manganese oxide or manganese salt is selected from the group consisting of MnO2 (electrolytically or chemically produced), MnCO3, Mn2O3, Mn3O4, MnO, manganese acetate and mixtures thereof. 41. The method according to claim 1 wherein the manganese oxide has been heat treated prior to step (a). 42. The method according to claim 1 wherein the lithium hydroxide or lithium salt is selected from the group consisting of LiOH, Li2CO3, LiNO3 and mixtures and hydrates thereof. 43. The method of claim 41 wherein the MnO2 is electrolytically produced and is neutralized by LiOH or NH4OH during its synthesis. 44. A method of synthesizing a lithium manganese oxide having a spinel-type crystal structure with an a-axis lattice parameter of not more than 8.235 A, comprising forming an intimate mixture in finely divided solid form of at least one lithium hydroxide or lithium salt reactant selected from the group consisting of LiOH, Li2CO3, LiNO3 and mixtures thereof and at least one manganese oxide or manganese salt reactant selected from the group consisting of MnO2, Mn2O3, MnCO3, Mn3O4, MnO, manganese acetate and mixtures thereof, continuously agitating and heating the mixture in a reactor under a continuous purge of countercurrent air at a temperature in the range of from about 650 degree C to about 800 degree C for a period not in excess of about 4 hours to cause said reactants to react with each other. 45. The method according to claim 44 wherein the heating of the mixture is in air at a temperature of from about 700 degree C to about 800 degree C, the mixture being held at the maximum temperature for a period of less than about 2 hours. 46. The method according to claim 44 wherein the manganese oxide has been heat treated prior to forming the mixture. 47. A lithium manganese oxide having a spinel crystal structure, synthesized by the method of claim 44. 48. A method according to claim 1 wherein prior to the cooling step further steps are performed: (i) removing the product from the reactor and (ii) transferring the reaction product to a separate vessel. 49. A method of preparing a single phase lithiated manganese oxide intercalation compound of the formula Li1+XMn2-XO4 by a batch process comprising the steps of: (a) mixing intimately in stoichiometric amounts, based on said lithiated manganese oxide compound, a lithium hydroxide or a lithium salt and a manganese oxide or a manganese salt; (b) feeding the intimately mixed compounds to a reactor; (c) agitating the mixed compounds in the reactor; (d) heating the agitated mixed compounds in the reactor in the presence of air or an oxygen-enriched atmosphere at a temperature of from about 650 degree C to about 800 degree C for a time not in excess of about 4 hours; and (e) cooling the oxygen deficient product to less than about 100 degree C in about 2 hours or less, wherein x is from about 0.022 to about 0.200 and the a-axis lattice parameter is about 8.235A. 50. The method according to claim 49 wherein the cooling vessel is a burning kiln with a rotating screw. 51. The method according to claim 49 wherein the cooling step is performed in a fluidized bed. 52. The method according to claim 49 wherein the cooling step is performed on a heated vibrating conveyor belt. 53. The method according to claim 49 wherein the cooling step is performed on a cascade of vertical rotating bottoms. 54. The method according to claim 49 wherein the cooling step is performed in a rotating kiln. 55. The method according to claim 49 wherein the cooling is performed in about one and one-half hours or less. 56. The method according to claim 49 wherein the cooling is performed in less than about one hour. 57. The method according to claim 1 wherein heating step (d) is performed in zones of progressively warmer temperatures. 58. . The method according to claim 57 wherein the heating step is performed in at least four zones. 59. The method according to claim 58 wherein the temperature in each successive heating zone is at least 25 degree  higher than the immediately previous zone. 60. The method according to claim 25 wherein the agitated mixed compounds remain in each zone at least about 30 minutes.