Process for the preparation of lithium titanium spinel and its use

Abstract

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.