Copper-manganese mixed oxide cathode material for use in alkaline cells having high capacity
View Patent ↗The present invention relates to a copper-manganese mixed oxide cathode material, which is suitable for use in a cathode of an electrochemical cell, and which has the formula Mn x Cu y O z .nH 2 O, wherein the oxidation state of Cu is between about +1 and about +3, the oxidation state of Mn is between about +2 and about +7, x is equal to about 3-y, y is less than about 3, z is calculated or experimentally determined, using means known in the art, based on the values of x and y, as well as the oxidation states of Mn and Cu, and nH 2 O represents the surface and structural water present in the mixed oxide material. The present invention further relates to an electrochemical cell comprising the noted cathode material.
1. A copper-manganese mixed oxide cathode active material having the formula Mn x Cu y O z .nH 2 O, wherein the oxidation state of Cu is between about +1 and about +3, the oxidation state of Mn is between about +2 and about +7, x is equal to about 3-y, y is less than about 3, z is calculated or experimentally determined based on the values of x and y, as well as the oxidation states of Mn and Cu, nH 2 O is the structural water molecules present in the mixed oxide cathode material, and n has a value between about 0.1 and about 10, wherein the discharge capacity of the mixed oxide cathode material at 1.1 V vs. a zinc wire reference electrode in a half-cell discharge test at 5 mA is at least about 50 mAh/gm.
2. The cathode material of claim 1 wherein Cu has an oxidation state between about +1 and about +2.
3. The cathode material of claim 1 , wherein Mn has an oxidation state between about +2 and about +4.
4. The cathode material of claim 1 , wherein y is between about 0.01 and 2.99.
5. The cathode material of claim 1 , wherein x is between about 0.01 and 2.99.
6. The cathode material of claim 1 , wherein z is between about 2.25 and about 7.5.
7. The cathode material of claim 1 , wherein the copper-manganese mixed oxide has a defect spinel-type structure.
8. The cathode material of claim 1 , wherein z is between about 2.25 and less than 4.0.
9. The cathode material of claim 1 , wherein z is between greater than 4.0 and about 7.5.
10. The cathode material of claim 1 , wherein Cu has an oxidation state between about +1 and about +3 and Mn has an oxidation state between about +2 and about +4.
11. The cathode material of claim 1 , wherein Cu has an oxidation state of about +2 and Mn has an oxidation state between about +3 and about +4.
12. The cathode material of claim 1 , wherein Cu has an oxidation state of about +2 and Mn has an oxidation state of about +4.
13. The cathode material of claim 1 , wherein said material has the formula:
Cu 1.5 Mn 1.5 O z .n H 2 O
wherein y, x, z and n are as defined in claim 1 .
14. A primary electrochemical cell comprising:
an anode;
a cathode comprising a copper-manganese mixed oxide cathode active material having the formula Mn x Cu y O z .nH 2 O, wherein the oxidation state of Cu is between about +1 and about +3, the oxidation state of Mn is between about +2 and about +7, x is equal to about 3-y, y is less than about 3, z is calculated or experimentally determined based on the values of x and y, as well as the oxidation states of Mn and Cu,nH 2 O is the structural water molecules present in the mixed oxide cathode material, and n has a value between about 0.1 and about 10;
a separator disposed between the anode and the cathode; and,
an electrolyte which is in fluid communication with the anode, the cathode, and the separator.
15. The electrochemical cell of claim 14 , wherein said separator comprises about 1 to less than 3 wraps of a free-standing polymer film, said film having a dry thickness of less than about 250 microns.
16. The electrochemical cell of claim 15 , wherein said separator has a resistivity of less than about 100 ohm-cm.
17. The electrochemical cell of claim 14 , wherein said separator comprises particles of a clay additive.
18. The electrochemical cell of claim 14 , wherein said separator comprises a metal sulfide additive.
19. The electrochemical cell of claim 14 , wherein the discharge capacity at 1.1 V vs. a zinc wire reference electrode in a half-cell discharge test at 5 mA is at least about 50 mAh/gm.
20. The electrochemical cell of claim 14 , wherein Cu has an oxidation state between about +1 and about +2.
21. The electrochemical cell of claim 14 , wherein Mn has an oxidation state between about +2 and about +4.
22. The electrochemical cell of claim 14 , wherein y is between about 0.01 and 2.99.
23. The electrochemical cell of claim 14 , wherein x is between about 0.01 and 2.99.
24. The electrochemical cell of claim 14 , wherein z is between about 2.25 and about 7.5.
25. The electrochemical cell of claim 14 , wherein the copper-manganese mixed oxide has a defect spinel-type structure.
26. The electrochemical cell of claim 14 , wherein z is between about 2.25 and less than 4.0.
27. The electrochemical cell of claim 14 , wherein Cu has an oxidation state between about +1 and about +3 and Mn has an oxidation state between about +2 and about +4.
28. The electrochemical cell of claim 14 , wherein Cu has an oxidation state of about +2 and Mn has an oxidation state between about +3 and about +4.
29. The electrochemical cell of claim 14 , wherein Cu has an oxidation state of about +2 and Mn has an oxidation state of about +4.
30. The electrochemical cell of claim 14 , wherein said material has the formula:
Cu 1.5 Mn 1.5 O z .n H 2 O
wherein y, x, z and n are as defined in claim 14 .