Negative electrode active material , nonaqueous electrolyte battery, battery pack and vehicle

Abstract

A negative electrode active material includes lithium-titanium composite oxide porous particles having an average pore size of 50 to 500 Å.

1 - 20 . (canceled) 
     
     
         21 . A method of manufacturing a negative electrode active material comprising:
 subjecting lithium-titanium composite oxide particles containing a lithium-titanium oxide having a spinel structure to pulverization with a pulverizing aid, to obtain a pulverized powder; and   baking the pulverized powder at 250 to 900° C. for one minute to 10 hours.   
     
     
         22 . The method according to  claim 21 , wherein the lithium-titanium composite oxide particles satisfy that each of a main peak intensity of a rutile type TiO 2 , a main peak intensity of an anatase type TiO 2  and a main peak intensity of Li 2 TiO 3  is not larger than 7 when a main peak intensity of the lithium-titanium oxide is determined by an X-ray diffractometer set at 100. 
     
     
         23 . The method according to  claim 21 , wherein the lithium-titanium composite oxide particles are obtained by a method comprising:
 adding a titanium oxide to a solution of lithium salt to obtain a mixture containing Li and Ti in an atomic ratio of 4:5;   drying the mixture while stirring the mixture to obtain a baking precursor; and   baking the baking precursor at 680 to 1000° C. for 1 to 24 hours.   
     
     
         24 . The method according to  claim 21 , wherein the pulverization is performed in a ball mill using zirconia balls as a medium. 
     
     
         25 . The method according to  claim 21 , wherein the pulverization is a wet pulverization. 
     
     
         26 . The method according to  claim 21 , wherein the pulverizing aid comprises polyol, ethanol, ethylene glycol, benzene or hexane. 
     
     
         27 . The method according to  claim 26 , wherein the pulverizing aid comprises polyol and the polyol is at least one selected from the group consisting of pentaerythritol, triethylol ethane, and trimethylol propane. 
     
     
         28 . A negative electrode active material comprising lithium-titanium composite oxide particles, manufactured by the method according to  claim 21 . 
     
     
         29 . The active material according to  claim 28 , wherein the lithium-titanium composite oxide particles have an average pore size of 50 to 500 Å and a pH value falling within a range of 10 to 11.2. 
     
     
         30 . The active material according to  claim 29 , wherein the lithium-titanium composite oxide particles have pores which have a pore size of 10 Å or less and a volume of the pores is not less than 0.001 mL/g. 
     
     
         31 . The active material according to  claim 29 , wherein the lithium-titanium composite oxide particles have a specific volume of pores which is not less than 0.01 mL/g. 
     
     
         32 . A nonaqueous electrolyte battery comprising:
 a positive electrode;   a negative electrode comprising the negative electrode active material according to  claim 28 ; and   a nonaqueous electrolyte.   
     
     
         33 . A battery pack comprising a battery module of the nonaqueous electrolyte battery according to  claim 32 .