Manganese phosphates and related electrode active materials
View Patent ↗The invention provides electrode active materials comprising lithium or other alkali metals, manganese, a +3 oxidation state metal ion, and optionally other metals, and a phosphate moiety. Such electrode active materials include those of the formula: A a Mn b MI c MII d MIII e PO 4 wherein (a) A is selected from the group consisting of Li, Na, K, and mixtures thereof, and 0<a≦1; (b) 0<b≦1; (c) MI is a metal ion in the +3 oxidation state, and 0<c<0.5; (d) MII is metal ion, a transition metal ion, a non-transition metal ion or mixtures thereof, and 0≦d<0.5; (e) MIII is a metal ion in the +1 oxidation state and 0<e<0.5; and wherein A, Mn, MI, MII, MIII, PO 4 , a, b, c, d and e are selected so as to maintain electroneutrality of said compound.
1. An electrode active material of the formula:
A a Mn b MI c MII d MIII e PO 4
wherein:
(a) A is Li, and a is 1;
(b) 0<≦1;
(c) MI is a metal ion in the +3 oxidation state, and 0<c≦0.5;
(d) MII is metal ion, a transition metal ion, a non-transition metal ion or mixtures thereof, and 0<d≦0.5;
(e) MIII is Li and 0<e≦0.5; and
wherein A, Mn, MI, MII, MII, PO 4 , a, b, c, d and e are selected so as to maintain electroneutrality of said electrode active material.
2. The electrode active material according to claim 1 , wherein MI is selected from the group consisting of Al 3+ , B 3+ and V 3+ .
3. The electrode active material according to claim 1 , wherein MII is selected from the group consisting of Fe 2+ , Mg 2+ , Co 2+ , Ni 2+ , Cu 2+ , Ca 2+ , and Zn 2+ .
4. The electrode active material according to claim 1 , wherein 0.5≦b≦1.
5. The electrode active material according to claim 1 , wherein 0<c≦0.25.
6. The electrode active material according to claim 1 , wherein 0≦d≦0.25.
7. The electrode active material according to claim 1 , wherein 0<e≦0.5.
8. The electrode active material according to claim 1 of the formula LiMn b Al c Fe d Co f Li e PO 4 wherein 0≦f≦0.2.
9. An electrode active material comprising the formula LiMn 0.75 Al 0.05 Fe 0.1 Co 0.05 Li 0.05 PO 4 .
10. An electrochemical cell comprising the electrode active material according to claim 1 .
11. An electrochemical cell comprising the electrode active material according to claim 9 .
12. An electrochemical cell comprising:
a cathode comprised of an electrode active material, the electrode active material having a general formula A a Mn b MI c MII d MIII e PO 4 , wherein A is Li, a is 1, 0<b≦1; MI is a metal ion in the +3 oxidation state, 0<c≦0.5; MII is metal ion, a transition metal ion, a non-transition metal ion or mixtures thereof, and 0<d≦0.5; MIII is Li and 0<e≦0.5; and
the electrochemical cell has a reversible capacity greater than 83 mAh/g at C/15.
13. The electrochemical cell of claim 12 , wherein MI is selected from the group consisting of Al 3+ , B 3+ and V 3+ .
14. The electrochemical cell of claim 12 , wherein MII is selected from the group consisting of Fe 2+ , Mg 2+ , Co 2+ , Ni 2+ , Cu 2+ , Ca 2+ , and Zn 2+ .
15. The electrochemical cell of claim 12 , wherein the electrochemical cell has a capacity of 130 mAh/g at C/15.
16. The electrochemical cell of claim 12 , wherein the electrochemical cell has an initial specific capacity of 110 mAh/g.
17. The electrochemical cell of claim 16 , wherein the electrochemical cell retains 90% capacity after 200 cycles.