Oxide coatings on lithium oxide particles
The present invention generally relates to unique coatings for use with energy storage particles, such as lithium oxide energy storage materials. The invention provides unique coatings for particles, unique particle/coating combinations, and unique methods for making coatings and/or coated particles. In one aspect of the invention, a particle is formed having a core and a coating. The particle may comprise a core having a material such as LiFePO 4 , and a coating. The particle may be formed, in some embodiments, by using a non-stoichiometric combination of salts or other precursors, and sintering the same to form particles. LiFePO 4 may form as the core of the particle, while the remaining materials may form a coating around the LiFePO 4 . Typically, the LiFePO 4 is crystalline while the coating is generally amorphous, and in some instances, the coating may prevent large crystals of LiFePO 4 from forming. However, in other embodiments, a coating may be applied to a particle after formation of the particle to form a core/coating structure. The particles disclosed herein may have a relatively high energy capacity, and thus may find use in batteries and other energy storage devices. Other aspects of the invention relate to devices comprising such particles, methods of making such particles, kits for making such particles, methods of promoting the making or use of such particles, and the like.
1. An article, comprising:
a coated particle having a core and a coating surrounding at least a portion of the core, the coating having a composition:
Li x M y P z N w O m ,
wherein x, y, z, w, and m are each independently greater than 0, and M comprises one or more transition metals, and wherein:
(y/x) is a number less than or equal to about 0.3,
(x/z) is a number between, inclusively, about 1.25 and about 3,
m is greater than or equal to the quantity (x+2y+5z)/2 and less than or equal to the quantity (x+3y+5z)/2,
m is between, inclusively, about 1.6 and about 5.4, and
w is less than or equal to about 0.1.
2. The article of claim 1 , wherein the coating appears amorphous in transmission electron microscopy.
3. The article of claim 1 , wherein the coating appears amorphous.
4. The article of claim 1 , wherein the coating has a different crystal structure than the core.
5. The article of claim 1 , wherein the coating has an average thickness of less than about 70 nm.
6. The article of claim 1 , wherein the core comprises LiFePO 4 .
7. The article of claim 6 , wherein the core consists essentially of LiFePO 4 .
8. The article of claim 1 , wherein the core comprises LiMnPO 4 .
9. The article of claim 8 , wherein the core consists essentially of LiMnPO 4 .
10. The article of claim 1 , wherein the core comprises LiCoPO 4 .
11. The article of claim 1 , wherein the core comprises LiNiPO 4 .
12. The article of claim 1 , wherein the core is essentially crystalline.
13. The article of claim 1 , wherein the core has an average grain size of less than about 100 nm.
14. The article of claim 1 , wherein y is less than z.
15. The article of claim 1 , wherein the quantity (x/z) is a number between, inclusively, about 1 and about 1.5.
16. The article of claim 1 , wherein the quantity (1−y)/(1−z) is a number between, inclusively, about 1.7 and about 2.3.
17. The article of claim 1 , wherein M comprises at least one of iron, manganese, cobalt, and nickel.
18. The article of claim 1 , wherein w is between, inclusively, about 0.01 and about 1.1.
19. An article, comprising:
a coated particle having a core and a coating surrounding at least a portion of the core, wherein the core comprises lithium and M, wherein M comprises one or more transition metals, and wherein the coating has a composition:
Li x M y P z N w O m , and
wherein x, y, z, w, and m are each independently greater than 0, and wherein:
(y/x) is a number less than or equal to about 0.3,
(x/z) is a number between, inclusively, about 1.25 and about 3,
m is greater than or equal to the quantity (x+2y+5z)/2 and less than or equal to the quantity (x+3y+5z)/2,
m is between, inclusively, about 1.6 and about 5.4, and
w is less than or equal to about 0.1.
20. An article, comprising:
a coated particle having a core and a coating surrounding at least a portion of the core, the particle having an overall composition:
Li x M y P z N w O m ,
wherein:
x is between, inclusively, about 0.01 and about 1.1,
y is between, inclusively, about 0.5 and about 1.1,
z is between, inclusively, about 0.5 and about 1.1,
w is between, inclusively, 0 and about 0.1,
m is between, inclusively, about 1.6 and about 5.4, and
M comprises one or more transition metals.