Phase-pure lithium aluminium titanium phosphate and method for its production and its use

1. A method for producing a phase-pure lithium aluminum titanium phosphate of the formula Li 1+x Ti 2−x Al x (PO 4 ) 3 comprising the steps of:

a) providing an aqueous liquid phosphoric acid,

b) adding a mixture of a lithium compound, titanium dioxide and an oxygen-containing aluminum compound to the aqueous phosphoric acid of step a),

c) heating the mixture of step b) in order to obtain a solid intermediate product, and

d) calcining the solid intermediate product of step c), wherein x is ≦0.4 and >0, and the concentration of magnetic metals and magnetic metal compounds of the elements Fe, Cr and Ni in the phase-pure lithium aluminum titanium phosphate is ≦1 ppm.

2. The method according to claim 1 , wherein the aqueous liquid phosphoric acid is aqueous liquid orthophosphoric acid.

3. The method according to claim 1 , wherein lithium carbonate is used as lithium compound.

4. The method according to claim 1 , wherein Al(OH) 3 is used as oxygen-containing aluminum compound.

5. The method according to claim 1 , wherein the step of heating is carried out at a temperature of from 200 to 300° C.

6. The method according to claim 5 , wherein the calcining takes place at a temperature in the range from 850° C. to 1000° C.

7. The method according to claim 6 , wherein the calcining is carried out over a period of from 5 to 24 hours.

8. The method according to claim 1 , wherein a stoichiometric excess of lithium compound is used in step b).

9. A method for producing a phase-pure lithium aluminum titanium phosphate of the formula Li 1+x Ti 2−x Al x (PO 4 ) 3 comprising the steps of:

a) providing 85% orthophosphoric acid,

b) adding a mixture of a lithium compound, titanium dioxide and an oxygen-containing aluminum compound to the 85% orthophosphoric acid of step a),

c) heating the mixture of step b) in order to obtain a solid intermediate product, and

d) calcining the solid intermediate product of step c),

wherein x is ≦0.4 and >0, and the concentration of magnetic metals and magnetic metal compounds of the elements Fe, Cr and Ni in the phase-pure lithium aluminum titanium phosphate is ≦1 ppm.

10. The method according to claim 9 , wherein lithium carbonate is used as lithium compound.

11. The method according to claim 9 , wherein Al(OH) 3 is used as oxygen-containing aluminum compound.

12. The method according to claim 9 , wherein the step of heating is carried out at a temperature of from 200 to 300° C.

13. The method according to claim 12 , wherein the calcining takes place at a temperature in the range from 850° C. to 1000° C.

14. The method according to claim 13 , wherein the calcining is carried out over a period of from 5 to 24 hours.

15. The method according to claim 9 , wherein a stoichiometric excess of lithium compound is used in step b).