Amorphous and partially amorphous nanoscale ion storage materials
Amorphous or partially amorphous nanoscale ion storage materials are provided. For example, lithium transition metal phosphate storage compounds are nanoscale and amorphous or partially amorphous in an as-prepared state, or become amorphous or partially amorphous upon electrochemical intercalation or de-intercalation by lithium. These nanoscale ion storage materials are useful for producing devices such as high energy and high power storage batteries.
1. A method of transforming crystalline material into amorphous material, the method comprising lithiating and/or delithiating a predominantly crystalline nanoscale lithium transition metal phosphate material comprising only one transition metal, thereby transforming the crystalline nanoscale lithium transition metal phosphate material into amorphous nanoscale lithium transition metal phosphate material, wherein
the predominantly crystalline nanoscale lithium transition metal phosphate material has a specific surface area of at least about 20 m 2 /g; and
a primary particle size with an average smallest cross-sectional dimension of about 100 nm or less.
2. The method of claim 1 , wherein lithiating and/or delithiating the predominantly crystalline nanoscale lithium transition metal phosphate material comprises incorporating the material into the cathode of a storage battery and charging and/or discharging the battery.
3. The method of claim 1 , wherein the predominantly crystalline nanoscale lithium transition metal phosphate material has a specific surface area of at least about 25 m 2 /g.
4. The method of claim 1 , wherein the predominantly crystalline nanoscale lithium transition metal phosphate material has a specific surface area of at least about 50 m 2 /g.
5. The method of claim 1 , wherein the predominantly crystalline nanoscale lithium transition metal phosphate material has an overall composition of Li 1-x MPO 4 , wherein M is one transition metal selected from the group consisting of Ti, V, Cr, Mn, Fe, Co and Ni.
6. The method of claim 5 , wherein M is Fe.
7. The method of claim 5 , wherein x in the as-prepared predominantly crystalline nanoscale lithium transition metal phosphate material is at least about 0.05.
8. The method of claim 5 , wherein x in the as-prepared predominantly crystalline nanoscale lithium transition metal phosphate material is at least about 0.15.
9. The method of claim 1 , wherein the as-prepared predominantly crystalline nanoscale lithium transition metal phosphate material contains lithium at a concentration of at least about 5% by mole relative to the transition metal concentration.
10. The method of claim 1 , wherein the as-prepared predominantly crystalline nanoscale lithium transition metal phosphate material contains lithium at a concentration of at least about 10% by mole relative to the transition metal concentration.
11. The method of claim 1 , wherein the predominantly crystalline nanoscale lithium transition metal phosphate material has a specific surface area of at least about 30 m 2 /g.
12. The method of claim 1 , wherein the predominantly crystalline nanoscale lithium transition metal phosphate material has a specific surface area of at least about 35 m 2 /g.
13. The method of claim 1 , wherein the predominantly crystalline nanoscale lithium transition metal phosphate material has a specific surface area of at least about 40 m 2 /g.
14. The method of claim 1 , wherein the predominantly crystalline nanoscale lithium transition metal phosphate material has a specific surface area of at least about 45 m 2 /g.
15. The method of claim 1 , wherein the predominantly crystalline nanoscale lithium transition metal phosphate material is lithium iron phosphate.