Nanoporous titanium niobium oxide and titanium tantalum oxide compositions and their use in anodes of lithium ion batteries
Nanoporous metal oxide framework compositions useful as anodic materials in a lithium ion battery, the composition comprising metal oxide nanocrystals interconnected in a nanoporous framework and having interconnected channels, wherein the metal in said metal oxide comprises titanium and at least one metal selected from niobium and tantalum, e.g., TiNb 2-x Ta x O y (wherein x is a value from 0 to 2, and y is a value from 7 to 10) and Ti 2 Nb 10-v Ta v O w (wherein v is a value from 0 to 2, and w is a value from 27 to 29). A novel sol gel method is also described in which sol gel reactive precursors are combined with a templating agent under sol gel reaction conditions to produce a hybrid precursor, and the precursor calcined to form the anodic composition. The invention is also directed to lithium ion batteries in which the nanoporous framework material is incorporated in an anode of the battery.
1. A composition useful as an anodic material in a lithium ion battery, the composition comprising metal oxide nanocrystals interconnected in a nanoporous framework and having interconnected channels, wherein said metal oxide has the formula TiNb 2-x Ta x O y wherein x is a value of at least 0.2 and less than 2, and y is a value from 7 to 10.
2. The composition of claim 1 , wherein said nanocrystals have a primary particle size of 20-100 nm.
3. The composition of claim 1 , wherein said nanocrystals have a primary particle size of 20-30 nm.
4. The composition of claim 1 , wherein the composition has an average pore size of 10-60 nm.
5. The composition of claim 1 , wherein the composition has an average pore size of 10-20 nm.
6. A lithium ion battery comprising:
(a) an anode comprising metal oxide nanocrystals interconnected in a nanoporous framework and having interconnected channels, wherein said metal oxide has the formula TiNb 2-x Ta x O x , wherein x is a value of at least 0.2 and less than 2, and y is a value from 7 to 10;
(b) a cathode; and
(c) a lithium-containing electrolyte medium in contact with said anode and cathode.
7. The lithium ion battery of claim 6 , wherein said nanocrystals have a primary particle size of 20-100 nm.
8. The lithium ion battery of claim 6 , wherein said nanocrystals have a primary particle size of 20-30 nm.
9. The lithium ion battery of claim 6 , wherein the composition has an average pore size of 10-60 nm.
10. The lithium ion battery of claim 6 , wherein the composition has an average pore size of 10-20 nm.
11. The lithium ion battery of claim 6 , wherein the lithium ion battery exhibits a reversible storage capacity of at least 200 mAh/g.
12. The lithium ion battery of claim 6 , wherein the lithium ion battery exhibits a reversible storage capacity of at least 250 mAh/g.
13. The lithium ion battery of claim 6 , wherein the lithium ion battery exhibits a coulombic efficiency of at least 99% maintained over at least 100 cycles.
14. The lithium ion battery of claim 6 , wherein the lithium ion battery exhibits a coulombic efficiency of at least 99% maintained over at least 200 cycles.
15. The composition of claim 1 , wherein x is a value of 0.2 to 1.9.
16. The lithium ion battery of claim 6 , wherein x is a value of 0.2 to 1.9.