Production method of battery active material, battery active material, nonaqueous electrolyte battery and battery pack

Abstract

A production method of a battery active material of the present embodiment includes a step of obtaining a coprecipitated product containing Ti and Nb by mixing a solution with a pH of 5 or lower, in which a Ti compound is dissolved, and a solution with a pH of 5 or lower, in which a Nb compound is dissolved, such that molar ratio of Ti and Nb (Nb/Ti) is adjusted within a range of 1≦Nb/Ti≦28, and then further mixing with an alkali solution with a pH of 8 or higher; and a step of burning the coprecipitated product under condition of 635° C. or higher and 1200° C. or lower.

1 . A production method of a battery active material comprising:
 a step of obtaining a coprecipitated product containing Ti and Nb by mixing a solution with a pH of 5 or lower, in which a Ti compound is dissolved, and a solution with a pH of 5 or lower, in which a Nb compound is dissolved, such that molar ratio of Ti and Nb (Nb/Ti) is adjusted within a range of 1≦Nb/Ti≦28, and then further mixing with an alkali solution with a pH of 8 or higher; and   a step of burning the coprecipitated product under condition of a burning temperature of 635° C. or higher and 1200° C. or lower.   
     
     
         2 . The production method of a battery active material according to  claim 1 , wherein a burning time of the burning is 30 seconds or more and 12 hours or less. 
     
     
         3 . The production method of a battery active material according to  claim 1 , wherein composition of the battery active material obtained by the burning step is represented by a following compositional formula (1):
   Ti x-a M1 a Nb y-b M2 b O z   (1)
   
       in the composition formula (1), z=2(x+a)+2.5(y+b) is satisfied; x, y, a, b and z respectively satisfy 1≦(y−b)/(x−a)≦28, 0<x≦1, 0<y≦1, 0≦a≦0.1 and 0≦b≦0.1; M1 and M2 each independently represents one, or two or more elements selected from Ti, Nb, Zr, B, Na, Mg, Al, Si, S, P, K, Ca, Mo, W, Cr, Mn, Co, Ni and Fe. 
     
     
         4 . The production method of a battery active material according to  claim 1 , wherein the Ti compound is any of titanyl sulfate, titanium oxide, titanium ammonium oxalate, metatitanic acid, isopropyl titanate and titanium chloride. 
     
     
         5 . The production method of a battery active material according to  claim 1 , wherein the Nb compound is any of niobium chloride, niobium hydroxide, ammonium niobium oxalate, niobium oxide and niobium ethoxide. 
     
     
         6 . The production method of a battery active material according to  claim 1 , wherein a carbon source is added to the battery active material obtained after the burning, and then burning is further carried out in a reducing atmosphere. 
     
     
         7 . A battery active material which is obtained by the production method according to  claim 1 . 
     
     
         8 . A nonaqueous electrolyte battery which contains a battery active material obtained by the production method according to  claim 1 . 
     
     
         9 . A battery pack comprising the nonaqueous electrolyte battery according to  claim 8 . 
     
     
         10 . A production method of a battery active material comprising:
 a step of obtaining a coprecipitated product containing Ti and Nb by mixing a solution, in which a Ti compound and a Nb compound are dissolved, molar ratio of Ti and Nb (Nb/Ti) is adjusted within a range of 1≦Nb/Ti≦28, and a pH is adjusted to 5 or lower, with an alkali solution with a pH of 8 or higher; and   a step of burning the coprecipitated product under condition of a burning temperature of 635° C. or higher and 1200° C. or lower.   
     
     
         11 . The production method of a battery active material according to  claim 10 , wherein a burning time of the burning is 1 hour or more and 12 hours or less. 
     
     
         12 . The production method of a battery active material according to  claim 10 , wherein composition of the battery active material obtained by the burning step is represented by a following compositional formula (1):
   Ti x-a M1 a Nb y-b M2 b O z   (1)
   
       in the composition formula (1), z=2(x+a)+2.5(y+b) is satisfied; x, y, a, b and z respectively satisfy 1≦(y−b)/(x−a)≦28, 0<x≦1, 0<y≦1, 0≦a≦0.1 and 0≦b≦0.1; M1 and M2 each independently represents one, or two or more elements selected from Ti, Nb, Zr, B, Na, Mg, Al, Si, S, P, K, Ca, Mo, W, Cr, Mn, Co, Ni and Fe. 
     
     
         13 . The production method of a battery active material according to  claim 10 , wherein the Ti compound is any of titanyl sulfate, titanium oxide, titanium ammonium oxalate, metatitanic acid, isopropyl titanate and titanium chloride. 
     
     
         14 . The production method of a battery active material according to  claim 10 , wherein the Nb compound is any of niobium chloride, niobium hydroxide, ammonium niobium oxalate, niobium oxide and niobium ethoxide. 
     
     
         15 . The production method of a battery active material according to  claim 10 , wherein a carbon source is added to the battery active material obtained after the burning, and then burning is further carried out in a reducing atmosphere. 
     
     
         16 . A battery active material which is obtained by the production method according to  claim 10 . 
     
     
         17 . A nonaqueous electrolyte battery which contains a battery active material obtained by the production method according to  claim 10 . 
     
     
         18 . A battery pack comprising the nonaqueous electrolyte battery according to  claim 17 .