Active material for battery, nonaqueous electrolyte battery, and battery pack

Abstract

According to one embodiment, there is provided a active material for a battery including a complex oxide containing niobium and titanium. A ratio M Nb /M Ti of a mole of niobium M Nb to a mole of titanium M Ti in the active material satisfies either the following equation (I) or (II). 0.5≦ M Nb /M Ti <2   (I) 2< M Nb /M Ti <5   (II)

1 . An active material comprising a complex oxide comprising niobium and titanium, wherein a ratio M Nb /M Ti  of moles of niobium M Nb  to moles of titanium M Ti  in the active material satisfies equation (II)
   2< M   Nb   /M   Ti <5   (II)
   
       and wherein the complex oxide comprising niobium and titanium comprises a monoclinic crystal structure and has a BET specific surface area of 0.1 m 2 /g or more and less than 100 m 2 /g. 
     
     
         2 - 17 . (canceled) 
     
     
         18 . The active material according to  claim 1 , wherein the complex oxide comprising niobium and titanium comprises a complex oxide represented by the formula Li x Nb y TiO {(5y+4)/2}+δ , where x, y, and δ satisfy relationships represented by the following equations 0≦x≦9, 2<y<4, and −0.5≦δ<0, respectively. 
     
     
         19 . The active material according to  claim 1 , comprising a first phase constituted of the complex oxide comprising niobium and titanium, and a second phase constituted of a titanium dioxide. 
     
     
         20 . The active material according to  claim 19 , wherein the complex oxide comprising niobium and titanium is represented by the formula Li x Nb y TiO {(5y+4)/2}+δ , where x, y, and δ satisfy relationships represented by the following equations 0≦x≦9, 2<y<4, and −0.5≦δ<0, respectively. 
     
     
         21 . The active material according to  claim 18 , comprising a first phase constituted of the complex oxide represented by the formula Li x Nb y TiO {(5y+4)/2}+δ , and a second phase constituted of a titanium dioxide, where x, y, and δ satisfy relationships represented by the following equations 0≦x≦9, 2<y<4, and −0.5≦δ<0, respectively. 
     
     
         22 . A nonaqueous electrolyte battery comprising:
 a negative electrode comprising a negative electrode layer;   a positive electrode; and   a nonaqueous electrolyte,   wherein the negative electrode layer comprises the active material according to  claim 1  and conductive agent, and the content of conductive agent in the negative electrode layer is in the range from 2% by mass to 10% by mass.   
     
     
         23 . A nonaqueous electrolyte battery comprising:
 a negative electrode comprising a negative electrode layer;   a positive electrode; and   a nonaqueous electrolyte,   wherein the negative electrode layer comprises the active material according to  claim 18  and conductive agent, and the content of conductive agent in the negative electrode layer is in the range from 2% by mass to 10% by mass.   
     
     
         24 . A nonaqueous electrolyte battery comprising:
 a negative electrode comprising a negative electrode layer;   a positive electrode; and   a nonaqueous electrolyte,   wherein the negative electrode layer comprises the active material according to  claim 19  and conductive agent, and the content of conductive agent in the negative electrode layer is in the range from 2% by mass to 10% by mass.   
     
     
         25 . A nonaqueous electrolyte battery comprising:
 a negative electrode comprising a negative electrode layer;   a positive electrode; and   a nonaqueous electrolyte,   wherein the negative electrode layer comprises the active material according to  claim 20  and conductive agent, and the content of conductive agent in the negative electrode layer is in the range from 2% by mass to 10% by mass.   
     
     
         26 . A nonaqueous electrolyte battery comprising:
 a negative electrode comprising a negative electrode layer;   a positive electrode; and   a nonaqueous electrolyte,   wherein the negative electrode layer comprises the active material according to  claim 21  and conductive agent, and the content of conductive agent in the negative electrode layer is in the range from 2% by mass to 10% by mass.   
     
     
         27 . A battery pack comprising:
 the nonaqueous electrolyte battery according to  claim 22 ; and   a container accommodating the battery.   
     
     
         28 . A battery pack comprising:
 the nonaqueous electrolyte battery according to  claim 23 ; and   a container accommodating the battery.   
     
     
         29 . A battery pack comprising:
 the nonaqueous electrolyte battery according to  claim 24 ; and   a container accommodating the battery.   
     
     
         30 . A battery pack comprising:
 the nonaqueous electrolyte battery according to  claim 25 ; and   a container accommodating the battery.   
     
     
         31 . A battery pack comprising:
 the nonaqueous electrolyte battery according to  claim 26 ; and   a container accommodating the battery.   
     
     
         32 . The active material according to  claim 1 , wherein the niobium in the complex oxide is tetravalent or trivalent, and the titanium in the complex oxide is trivalent.