Mixed phosphate-diphosphate electrode materials and methods of manufacturing same
This invention relates generally to electrode materials, electrochemical cells employing such materials, and methods of synthesizing such materials. The electrode materials have a crystal structure with a high ratio of Li to metal M, which is found to improve capacity by enabling the transfer of a greater amount of lithium per metal, and which is also found to improve stability by retaining a sufficient amount of lithium after charging. Furthermore, synthesis techniques are presented which result in improved charge and discharge capacities and reduced particle sizes of the electrode materials.
1. An electrode material comprising Li 9 (V,Mo) 3 (P 2 O 7 ) 3 (PO 4 ) 2 .
2. The electrode material of claim 1 , comprising at least one dopant selected from the group consisting of nickel, cobalt, manganese, iron, titanium, copper, silver, magnesium, calcium, strontium, zinc, aluminum, chromium, gallium, germanium, tin, tantalum, niobium, zirconium, fluorine, sulfur, yttrium, tungsten, silicon, and lead.
3. The electrode material of claim 1 , wherein (V,Mo) comprises V, Mo, or any combination of V and Mo.
4. The electrode material of claim 1 , wherein (V,Mo) is V.
5. The electrode material of claim 1 , wherein (V,Mo) is Mo.
6. An electrode material comprising:
Li a M b D c (P 2 O 7 ) d (PO 4 ) e
wherein M is at least one of vanadium (V) and molybdenum (Mo);
D is at least one member selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, nickel, cobalt, manganese, iron, titanium, copper, silver, zinc, aluminum, chromium, gallium, germanium, tin, tantalum, niobium, zirconium, fluorine, sulfur, yttrium, tungsten, silicon, and lead;
5≦a≦12, 1.5≦b≦4, 0≦c≦1.5, 2.75≦d≦3.25, and 1.67≦e≦2.33.
7. The electrode material of claim 6 , wherein a=9, b=3, c=0, d=3, and e=2.
8. The electrode material of claim 6 , wherein M is V.
9. The electrode material of claim 6 , wherein M is Mo.
10. A lithium battery comprising the electrode material of claim 1 .
11. The lithium battery of claim 10 , configured such that at least one member selected from the group consisting of V, Mo, and (V,Mo) is reduced during operation of the battery.
12. A composition of matter comprising Li 9 V 3 (P 2 O 7 ) 3 (PO 4 ) 2 .