Alkali-transition metal phosphates having a +3 valence non-transition element and related electrode active materials

1. An electrode active material comprising a compound of the formula

Li a M 1 e M 2 f M 3 g XY 4

wherein:

(a) 0<a≦2;

(b) M 1 is one or more transition metals, where e>0;

(c) M 2 is one or more +2 oxidation state non-transition metals, where f>0;

(d) M 3 is one or more +3 oxidation state non-transition metals, where g>0, with the proviso that when M 1 is Ni or Co, M 2 is one or more +2 oxidation state non-transition metals other than Mg and Si, and M 3 is one or more +3 oxidation state non-transition metals other than Al; and

(e) XY 4 is selected from the group consisting of X′O 4−x Y′ x , X′O 4−y Y′ 2y , X″S 4 , and mixtures thereof, where X′ is selected from the group consisting of P, As, Sb, Si, Ge, V, S, and mixtures thereof; X″ is selected from the group consisting of P, As, Sb, Si, Ge, V and mixtures thereof; Y′ is selected from the group consisting of halogen, S, N, and mixtures thereof; 0≦×≦3; and 0<y≦2; and

wherein (e+f+g)<2, and M 1 , M 2 , M 3 , XY 4 , a, e, f, g, x, and y are selected so as to maintain electroneutrality of said compound.

2. An electrode active material according to claim 1 ,wherein 1 comprises a +2 oxidation state transition metal.

3. An electrode active material according to claim 2 , wherein said +2 oxidation state transition metal is selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, and mixtures thereof.

4. An electrode active material according to claim 3 , wherein M′ is selected from the group consisting of Fe, Co. and mixtures thereof.

5. An electrode active material according to claim 2 , wherein M 1 comprises Fe and Co.

6. An electrode active material according to claim 1 , wherein M 1 comprises a +3 oxidation state transition metal.

7. An electrode active material according to claim 1 , wherein M 2 is selected from the group consisting of Be, Mg, Ca, Sr, Ba, and mixtures thereof.

8. An electrode active material according to claim 1 , wherein M 3 is selected from the group consisting of B, Al, Ga, In and mixtures thereof.

9. An electrode active material according to claim 1 , wherein 0.8≦(e+f+g)≦1.2.

10. An electrode active material according to claim 9 , wherein 0.9 ≦(e+f+g)≦1.

11. An electrode active material according to claim 1 , wherein XY 4 is PO 4 .

12. An electrode active material according to claim 1 , wherein XY 4 is PO 4−x F x , and 0<×≦1.

13. An electrode comprising an active material of claim 1 .

14. An electrode active material according to claim 1 , wherein XY 4 is PO 4−x Y′ x , M 1 is a +2 oxidation state transition metal, and a +2e+2f +3g=3×x.

15. An electrode active material selected from the group consisting of Li 1.025 Co 0.85 Fe 0.05 Al 0.025 Mg 0.05 PO 4 , Li 1.025 Co 0.7 (Fe 0.4 Mn 0.6 ) 0.2 Al 0.025 Mg 0.05 PO 4, , Li 1.025 Co 0.8 Fe 0.1 Al 0.025 Mg 0.05 PO 4 , Li 1.025 Co 0.75 Fe 0.15 Al 0.025 Mg 0.05 PO 4 , Li 1.025 Co 0.9 Al 0.025 Mg 0.05 PO 4 , and LiCo 0.8 Fe 0.1 Al 0.025 Mg 0.05 PO 3,975 F 0.025 , Li 1.025 Co 0.8 Fe 0.1 Ti 0.025 Al 0.025 PO 4 , and mixtures thereof.