PROCESS FOR THE PREPARATION OF LITHIUM TITANIUM SPINEL AND ITS USE
Non-doped and doped lithium titanate Li 4 Ti 5 O 12 obtainable by the thermal reaction of a stoichiometric composite oxide containing Li 2 TiO 3 and TiO 2 , the preparation of the stoichiometric composite oxide, as well as a process for the preparation of lithium titanate Li 4 Ti 5 O 12 and its use as anode material in rechargeable lithium-ion batteries.
1 . Lithium titanate Li 4 Ti 5 O 12 obtainable by the thermal reaction of a composite oxide containing Li 2 TiO 3 and TiO 2 , wherein the molar ratio of TiO 2 to Li 2 TiO 3 lies in a range from 1.3 to 1.85.
2 . Lithium titanate according to claim 1 , doped with a metal ion.
3 . Lithium titanate according to claim 2 , wherein the metal ion is selected from metal ions of the metals of the group consisting of Al, Mg, Ga, Fe, Co, Sc, Y, Mn, Ni, Cr, V or mixtures thereof.
4 . Lithium titanate according to claim 1 , having a particle size d 90 of <25 μm.
5 . Lithium titanate according to claim 4 , having a particle size d 50 of <1 μm.
6 . Lithium titanate according to claim 5 , having a BET surface area lies in the range from 2-15 m 2 /g.
7 . Lithium titanate according to claim 6 , wherein the Li 2 TiO 3 of the composite oxide is present in cubic phase.
8 . Lithium titanate according to claim 7 , wherein the TiO 2 of the composite oxide is present in the anatase modification.
9 . A process for the preparation of a composite oxide containing x parts Li 2 TiO 3 in cubic phase and y parts TiO 2 in anatase modification, wherein x and y independently of each other stand for a number between 0.1 and 4, comprising the steps of:
a) providing an aqueous solution of LION; and
b) reacting the aqueous LiOH solution by adding solid TiO 2 at a temperature in the range from 100-250° C.
10 . The process according to claim 9 , wherein TiO 2 is used in its anatase modification.
11 . The process according to claim 10 , wherein the aqueous LiOH solution is kept at a temperature of 100-250° C. during the reaction in step b).
12 . The process according to claim 11 , wherein the reaction takes place over a period of 10 to 30 hours.
13 . The process according to claim 12 , wherein before or during step b) a compound containing Al, Mg, Ga, Fe, Co, Sc, Y, Mn, Ni, Cr, V or mixtures thereof is further added.
14 . The process according to claim 12 , wherein the product of the reaction from step b) is then separated.
15 . The process according to claim 14 , wherein the separated product is obtained in a particle size of 100-300 nm.
16 . A composite oxide containing x parts Li 2 TiO 3 in cubic form and y parts TiO 2 in anatase modification and z parts of a metal oxide, wherein x and y independently of each other are a number between 0.1 and 4, and 0≦z≦1 and the metal is selected from Al, Mg, Ga, Fe, Co, Sc, Y, Mn, Ni, Cr, V or mixtures thereof, obtainable by a process according to one of claim 10 .
17 . A process for the preparation of phase-pure doped or non-doped lithium titanate Li 4 Ti 5 O 12 , wherein a composite oxide containing x parts Li 2 TiO 3 and y parts TiO 2 as well as z parts of a metal oxide, wherein x and y independently of each other are a number between 0.1 and 4, and 0≦z≦1 and the metal is selected from Al, Mg, Ga, Fe, Co, Sc, Y, Mn, Ni, Cr, V or mixtures thereof, is sintered at a temperature of ≦850° C.
18 . The process according to claim 17 , wherein the duration of the sintering is 1 to 20 hours.
19 . The process according to claim 18 , wherein the sintering is carried out at a temperature of ≦750° C.
20 . (canceled)
21 . A rechargeable lithium-ion battery, comprising an anode and a cathode as well as an electrolyte, wherein the anode contains non-doped or doped lithium titanate Li 4 Ti 5 O 12 according to claim 1 .
22 . The battery according to claim 21 , wherein the anode has a capacity retention of at least 90% at a rate of 20 C.
23 . The battery according to claim 22 , wherein the anode has a specific charge/discharge capacity of >160 Ah/kg.