High voltage lithium ion positive electrode material
A positive electrode material having a nominal stoichiometry Li 1+y/2 Co 1−x−y−z−d Si z Fe x M y M′ d (PO 4 ) 1+y/2 where M is a trivalent cation selected from at least one of Cr, Ti, Al, Mn, Ni, V, Sc, La and/or Ga, M′ is a divalent cation selected from at least one of Mn, Ni, Zn, Sr, Cu, Ca and/or Mg, y is within a range of 0<y≤0.10 and x is within a range of 0≤x≤0.2. The use of double compositional modification to LiCoPO 4 increases the discharge capacity from ˜100 mAh/g to about 130 mAh/g while retaining the discharge capacity retention of the singly Fe-substituted LiCoPO 4 . Additional compositional modification to include Si increases the cycle life and greatly improved the coulombic efficiency to between 97-100% at a C/3 cycle rate.
1. A lithium-ion battery, the battery comprising:
a positive electrode, comprising a compound of formula Li 1+y/2 Co 1−x−y−z−d Si z Fe x M y M′ d (PO 4 ) 1+y/2 wherein,
M is a trivalent cation selected from at least one of Cr, Ti, Al, Mn, Ni, V, Sc, La, and/or Ga;
M′ is a divalent cation selected from at least one of Mn, Ni, Zn, Sr, Cu, Ca, and/or Mg;
y is within a range of 0<y≤0.10;
x is within a range of 0<x≤0.20;
z is within a range of 0≤z≤0.10; and
d is within a range of 0≤d≤0.20;
the positive electrode having an initial capacity of at least 120 mAhg −1 ; and
a negative electrode; and
an electrolyte.
2. The battery of claim 1 , wherein z=0, y is within the range of 0.02≤y<0.08 and x is within the range of 0.05≤x≤0.15 and M=Cr.
3. The battery of claim 1 , wherein y is within the range of 0.04≤y<0.06 and x is within the range of 0.08≤x≤0.12.
4. The battery of claim 1 , wherein z=0.
5. The battery of claim 1 , wherein d=0.
6. The battery of claim 1 , wherein y=0.05 and x=0.10.
7. The battery of claim 1 , wherein 0<z≤0.10.
8. The battery of claim 1 , wherein 0<d≤0.20.
9. The battery of claim 1 , wherein x is within the range of 0.08≤x≤0.12.
10. The battery of claim 1 , wherein y is 0.02≤y<0.08.
11. A lithium-ion battery, the battery comprising:
a positive electrode, comprising a compound of formula Li 1+y/2 Co 1−x−y−z−d Si z Fe x M y M′ d (PO 4 ) 1+y/2 wherein,
M is a trivalent cation selected from at least one of Cr, Ti, Al, Mn, Ni, V, Sc, La, and/or Ga;
M′ is a covalent cation selected from at least one of Mn, Ni, Zn, Sr, Cu, Ca, and/or Mg;
y is within a range of 0<y≤0.10;
x is within a range of 0<x≤0.20;
z is within a range of 0≤z≤0.10; and
d is within a range of 0≤d≤0.20;
the positive electrode having a capacity of at least 100 mAhg −1 after 500 cycles; and
a negative electrode; and
an electrolyte.
12. The battery of claim 11 , wherein z=0, y is within the range of 0.02≤y<0.08 and x is within the range of 0.05≤x≤0.15 and M=Cr.
13. The battery of claim 11 , wherein y is within the range of 0.04≤y<0.06 and x is within the range of 0.08≤x≤0.12.
14. The battery of claim 11 , wherein z=0.
15. The battery of claim 11 , wherein d=0.
16. The battery of claim 11 , wherein y=0.05 and x=0.10.
17. The battery of claim 11 , wherein 0<z≤0.10.
18. The battery of claim 11 , wherein 0<d≤0.20.
19. The battery of claim 11 , wherein x is within the range of 0.08≤x≤0.12.
20. The battery of claim 11 , wherein y is 0.02≤y<0.08.
21. The battery of claim 11 , wherein the positive electrode has a coulombic efficiency between 97-100% at a C/3 cycle rate.
22. The battery of claim 11 , wherein the positive electrode has an initial capacity of at least 125 mAhg −1 .