Two-phase positive electrode material for a lithium battery and method for the synthesis of same
A two-phase positive electrode material for a lithium battery in which particles of lithium-enriched layered oxide of formula Li 1+x (Mn a Ni b M c ) 1−x O 2 are at least partially coated on the surface with a metal oxide of formula Li y VO z . Such a material is advantageously produced by mixing the lithium-enriched lamellar oxide with at least one precursor of the metal oxide in aqueous solution, followed by thermal treatment at a temperature no lower than 280° C.
1. A two-phase positive electrode material for a lithium battery consisting of:
particles of lithium-enriched layered oxide of formula Li 1+x (Mn a Ni b M c ) 1−x O 2 , and
a metal oxide of formula Li y VO z , covering at least a portion of a surface of the particles of lithium-enriched layered oxide,
wherein:
0.1≦x≦0.25,
a+b+c=1, with a, b and c being non-zero,
M is a metal selected from the group consisting of Mg, Zn, Al, Na, Ca and K,
0<y≦3, and
2.5<z<4.
2. The material of claim 1 , wherein the metal oxide is LiVO 3 .
3. The material of claim 1 , wherein the lithium-enriched layered oxide is Li 1.2 (Mn 0.7625 Ni 0.225 Mg 0.0125 ) 0.8 O 2 .
4. The material of claim 1 , wherein a percentage by weight of the metal oxide is between 5% and 15%, with respect to a total weight of the material.
5. The material of claim 1 , wherein the metal oxide is at least partially crystalline.
6. The material of claim 1 , wherein the metal oxide forms a coating with a thickness of between 3 nm and 15 nm at the surface of the particles of lithium-enriched layered oxide.
7. A process for producing the material of claim 1 , comprising:
mixing the lithium-enriched layered oxide with at least one precursor of the metal oxide placed in an aqueous solution, thereby obtaining a mixture, and
heat treating the mixture at a temperature of greater than or equal to 280° C., thereby obtaining the material.
8. The process of claim 7 , wherein the at least one precursor of the metal oxide is selected from the group consisting of NH 4 VO 3 and NaVO 3 .
9. The process of claim 7 , wherein the metal oxide is LiVO 3 .
10. The process of claim 7 , wherein the lithium-enriched layered oxide is obtained by a process comprising:
heat treating a pulverulent mixture comprising:
manganese carbonate,
nickel carbonate,
a compound comprising the metal M and selected from the group consisting of a carbonate, a sulfate and a nitrate, and
a lithium source selected from the group consisting of lithium carbonate and lithium hydroxide,
at a temperature of greater than or equal to 800° C., and
cooling the pulverulent mixture, thereby obtaining the lithium-enriched layered oxide.
11. The process of claim 10 , wherein the cooling occurs by quenching or with ambient air.
12. The process of claim 7 , wherein the lithium-enriched layered oxide is Li 1.2 (Mn 0.7625 Ni 0.225 Mg 0.0125 ) 0.8 O 2 .
13. A two-phase positive electrode material for a lithium battery comprising:
particles of lithium-enriched layered oxide of formula Li 1+x (Mn a Ni b M c ) 1−x O 2 , and
a metal oxide of formula Li y VO z , covering at least a portion of a surface of the particles of lithium-enriched layered oxide,
wherein:
0.1≦x≦0.25,
a+b+c=1, with a, b and c being non-zero,
M is a metal selected from the group consisting of Mg, Zn, Al, Na, Ca and K,
0<y≦3, and
2.5<z<4.
14. A lithium battery, comprising the two-phase positive electrode material of claim 1 .
15. A lithium battery, comprising the two-phase positive electrode material of claim 2 .
16. A lithium battery, comprising the two-phase positive electrode material of claim 3 .
17. A lithium battery, comprising the two-phase positive electrode material of claim 4 .
18. A lithium battery, comprising the two-phase positive electrode material of claim 5 .
19. A lithium battery, comprising the two-phase positive electrode material of claim 6 .
20. A lithium battery, comprising the two-phase positive electrode material of claim 13 .