Carbon-coated lithium titanium spinel

Abstract

A carbon-containing lithium titanium oxide containing spherical particle aggregate with a diameter of 1-80 μm, consisting of lithium titanium oxide primary particles coated with carbon. Also, a method for the production of such a carbon-containing lithium titanium oxide as well as an electrode containing such a carbon-containing lithium titanium oxide as active material as well as a lithium-ion secondary battery containing an above-described electrode.

1 . A carbon-containing lithium titanium oxide-containing spherical particle aggregates with a diameter of from 1 to 80 μm which consists of lithium titanium oxide primary particles coated with carbon. 
     
     
         2 . The aggregate of  claim 1  with a BET surface area in the range of from 1-10 m 2 /g. 
     
     
         3 . The aggregate of  claim 2  with a primary particle size of <1 μm. 
     
     
         4 . The aggregate of  claim 3  with a carbon content of from 0.05 to 2 wt.-%. 
     
     
         5 . The aggregate of  claim 4  with a carbon content of from 0.05 to 0.5 wt.-%. 
     
     
         6 . The aggregate of  claim 1 , wherein the lithium titanium oxide is Li 4 Ti 5 O 12 . 
     
     
         7 . A method for the production of carbon-containing lithium titanium oxide according to  claim 1 , comprising the steps of:
 (a) mixing a lithium salt, a titanium oxide and a carbon-containing compound in a solvent;   (b) drying the mixture from step a);   (c) calcining the dried mixture.   
     
     
         8 . The method of  claim 7 , wherein the solvent is water. 
     
     
         9 . The method of  claim 8 , having an atomic ratio Li/Ti of 4:5. 
     
     
         10 . The method of  claim 8 , wherein the lithium salt is selected from the group consisting of LiOH, Li 2 O, LiNO 3 , LiHCO 3 , and LiCH 3 COO. 
     
     
         11 . The method of  claim 9 , wherein the TiO 2  in anatase form or in amorphous form is used. 
     
     
         12 . The method of  claim 11 , wherein the carbon-containing compound is selected from the group consisting of hydrocarbons and their derivatives, carbohydrates and their derivatives, and polymers. 
     
     
         13 . The method of  claim 12 , wherein the carbon-containing compound is selected from sugars of the group consisting of lactose, sucrose and saccharose. 
     
     
         14 . The method of  claim 13 , wherein the drying is carried out as spray drying. 
     
     
         15 . The method of  claim 14 , wherein the spray drying is carried out at a temperature gradient of from 90-350° C. 
     
     
         16 . The method of  claim 7 , wherein the calcining is carried out at a temperature of from 700 to 1000° C. under protective atmosphere. 
     
     
         17 . A lithium titanium oxide obtained by the method of  claim 7 . 
     
     
         18 . An electrode comprising the carbon-containing lithium titanium oxide aggregate of  claim 1 . 
     
     
         19 . A lithium-ion secondary battery comprising the electrode of  claim 18 . 
     
     
         20 . The lithium-ion Lithium-ion secondary battery according to  claim 19  with a charge/discharge capacity at C/10 of >165 mAh/g.