Disordered rocksalt material and method of forming it
A disordered rocksalt (DRS) having improved characteristic has a cation comprised of lithium and one other metal and an anion comprised of oxygen and fluorine, and one or more of phosphorous, sulfur, and nitrogen. The substitution of one or more of P, S, and N on the oxygen anion site may realize improved cycle life of the battery and/or may be useful to make safer batteries.
1. A composition comprising a disordered rock salt having a cation comprised of lithium and at least one other metal and an anion comprised of oxygen and fluorine, and one or more of phosphorous, sulfur, and nitrogen.
2. The composition of claim 1 , wherein oxygen is the majority of the anion.
3. The composition of claim 2 , wherein fluorine is the majority of the fluorine and one or more of phosphorous, sulfur and nitrogen.
4. The composition of claim 1 , wherein F/(P, S and N) is 1 to 25 by moles.
5. The composition of claim 1 wherein the disordered rock salt is represented by Li x M′ y M z O 2−(a+b) F a Z b
where 1.0<x<1.75; 0≤y<0.55; 0.1<z<1; 0≤(a+b)<0.7; (b>0); M′ is one of Ti, Ta, Zr, W, Nb, or Mo; M is one or more of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh and Sb; and Z is one or more of P, N and S.
6. The composition of claim 5 , wherein (a+b) is 0.05 to 1.5.
7. The composition of claim 6 , wherein (a+b) is 0.05 to 0.95.
8. The composition of claim 5 , wherein a is from 0.05 to 0.25.
9. The composition of claim 5 , wherein Z is P, N or S.
10. The composition of claim 5 , wherein M′ is Nb and y is greater than 0.
11. The composition of claim 5 , wherein x is from 1.1 to 1.65.
12. The composition of claim 11 , wherein x is from 1.15 to 1.5.
13. The composition of claim 12 , wherein x is from 1.2 to 1.4.
14. The composition of claim 5 , wherein M is comprised of one or more of Ti, Mn, Fe, Co, V, Cr, Ni and Cu.
15. The composition of claim 14 , wherein M is comprised of Ti and Mn.
16. A cathode for a rechargeable battery, the cathode comprising a disordered rocksalt powder having a cation comprised of lithium and one other metal and an anion comprised of oxygen and fluorine, and one or more of phosphorous, sulfur, and nitrogen.
17. The cathode of claim 16 , wherein the disordered rocksalt powder is represented by: Li x M′ y M z O 2−(a+b) F a Z b
where 1.0<x<1.75; 0≤y<0.55; 0.1<z<1; 0≤(a+b)<0.7; (b>0); M′ is one of Ti, Ta, Zr, W, Nb, or Mo; M is one or more of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, Y, Mo, Ru, Rh and Sb; and Z is one or more of P, N and S.
18. The cathode of claim 17 , wherein at least some portion of Z is comprised of S.
19. The cathode of claim 18 , wherein Z is solely comprised of S.
20. The cathode of claim 16 , wherein the cathode has an anion redox voltage that is reduced compared to a disordered rocksalt cathode failing to have P, S or N.