Method for producing dense lithium lanthanum tantalate lithium-ion conducting ceramics
A method to produce high density, uniform lithium lanthanum tantalate lithium-ion conducting ceramics uses small particles that are sintered in a pressureless crucible that limits loss of Li 2 O.
1. A method for producing a lithium lanthanum tantalate ceramic, comprising:
dissolving lithium nitrate in an alcohol solvent;
dissolving lanthanum acetate in an acid solvent;
suspending tantalum oxide in an alcohol;
blending the lithium nitrate solution, the lanthanum acetate solution, and the tantalum oxide suspension and evaporating the solvents to provide a stoichiometric mixture;
combusting the stoichiometric mixture at a sufficiently high temperature to remove organics, thereby providing an inorganic mixture;
calcining the inorganic mixture at a sufficiently high temperature to remove carbonates, thereby providing a mixed oxide powder; and
sintering the mixed oxide powder in a closed and non-reactive crucible at a sufficiently high temperature and pressure to provide a dense lithium lanthanum tantalate ceramic.
2. The method of claim 1 , wherein the alcohol solvent for dissolving lithium nitrate comprises ethanol.
3. The method of claim 1 , wherein the acid solvent for dissolving lanthanum acetate comprises propionic acid.
4. The method of claim 1 , wherein the alcohol for suspending tantalum oxide comprises ethanol.
5. The method of claim 1 , wherein the sufficiently high temperature for combusting is greater than 500° C.
6. The method of claim 1 , wherein the sufficiently high temperature for calcining is greater than 800° C.
7. The method of claim 1 , wherein the sufficiently high temperature for sintering is greater than 1000° C.
8. The method of claim 1 , wherein the sufficiently high pressure for sintering is ambient pressure.
9. The method of claim 1 , wherein the closed and non-reactive crucible comprises a platinum crucible.
10. The method of claim 1 , wherein the closed and non-reactive crucible comprises a transition metal crucible.
11. The method of claim 10 , wherein the transition metal comprises nickel, platinum, palladium, iridium, or alloys thereof.