NASICON-type sodium cathode material
A compound of Formula I: Na x Mn a M b (PO 4−δ ) 3 (I) wherein M is V, Nb, Ga, Cr, Ti, Zr, or a combination thereof, a is equal to or greater than 0.8 to equal to or less than 1.5, b is equal to or greater than 0.5 to equal to or less than 1.2, x is greater than 0 to equal to or less than 4, δ is equal to or greater than 0 to equal to or less than 1, and a sum of a and b is 2.
1. A compound of Formula I:
Na x Mn a M b (PO 4−δ ) 3 (I)
wherein
M comprises Nb, Ga, Cr, Ti, or a combination thereof,
a is equal to or greater than 0.8 to equal to or less than 1.5,
b is equal to or greater than 0.5 to equal to or less than 1.2,
x is greater than 0 to equal to or less than 4,
δ is equal to or greater than 0 to equal to or less than 1, and
a sum of a and b is 2.
2. The compound of claim 1 , wherein M comprises Cr.
3. The compound of claim 2 , wherein M is Cr.
4. The compound of claim 1 , wherein x is 1≤x≤4.
5. The compound of claim 4 , wherein the compound of Formula I is Na x MnCr(PO 4 ) 3 .
6. The compound of claim 1 , wherein a crystal structure of the compound of Formula 1 comprises a PO 4 tetrahedron and a metal-centered oxygen octahedron.
7. The compound of claim 6 , wherein the PO 4 tetrahedron and the metal-centered oxygen octahedron share a corner.
8. The compound of claim 7 , wherein a metal of the metal-centered oxygen octahedron comprises Nb, Ga, Cr, Ti, or a combination thereof.
9. An electrode composition comprising:
the compound of claim 1 ; and
a conductive agent, a binder, or a combination thereof.
10. The electrode composition of claim 9 , wherein the compound of Formula I is Na x MnCr(PO 4 ) 3 .
11. A positive electrode comprising:
a current collector; and
the compound of claim 1 on the current collector.
12. The positive electrode of claim 11 , wherein the compound of Formula I is Na x MnCr(PO 4 ) 3 .
13. A sodium-ion battery comprising:
a positive electrode;
a negative electrode; and
an electrolyte between the positive electrode and the negative electrode, wherein the positive electrode comprises the compound of claim 1 .
14. The sodium-ion battery of claim 13 , wherein M is Cr.
15. A method of manufacturing a positive electrode, the method comprising:
disposing a composition comprising the compound of claim 1 on a current collector to manufacture the positive electrode.
16. A method of manufacturing a sodium-ion battery, the method comprising:
providing a positive electrode comprising the compound of claim 1 , a negative electrode, and separator;
disposing the separator between the positive electrode and the negative electrode; and
contacting the positive electrode and the negative electrode with the electrolyte between to manufacture the sodium ion battery.
17. A method of synthesizing a compound of Formula I, the method comprising:
providing a precursor comprising Na, a precursor comprising Mn, and a precursor comprising M, wherein the precursor comprising Na, the precursor comprising Mn, the precursor comprising M, or combination thereof, is a phosphate;
combining the precursor comprising Na, the precursor comprising Mn and the precursor comprising M to provide a mixture; and
thermally treating the mixture to synthesize the compound of Formula I
Na x Mn a M b (PO 4−δ ) 3 (I)
wherein
M comprises Nb, Ga, Cr, Ti, or a combination thereof,
a is equal to or greater than 0.8 to equal to or less than 1.5,
b is equal to or greater than 0.5 to equal to or less than 1.2,
x is greater than 0 to equal to or less than 4,
δ is equal to or greater than 0 to equal to or less than 1, and
a sum of a and b is 2.
18. The method of claim 17 , wherein the compound of Formula I is Na x MnCr(PO 4 ) 3 .
19. A compound of Formula I:
Na x Mn a M b (PO 4−δ ) 3 (I)
wherein
M comprises V, Nb, Ga, Cr, Ti, Zr, or a combination thereof,
a is greater than 1 to less than 1.3,
b is greater than 0.7 to less than 1,
x is greater than 0 to equal to or less than 4,
δ is equal to or greater than 0 to equal to or less than 1, and
a sum of a and b is 2.
20. The compound of claim 19 , wherein M comprises Cr.