Process for making lithiated transition metal oxides

Abstract

The present invention is directed towards a process for making a lithiated transition metal oxide, said process comprising the following steps: (a) providing a precursor selected from mixed oxides, hydroxides, oxyhydroxides, and carbonates of nickel and at least one transition metal selected from manganese and cobalt, wherein at least 45 mole-% of the cations of the precursor are Ni cations, (b) mixing said precursor with at least one lithium salt selected from LiOH, Li 2 O, Li 2 CO 3 , and LiNO 3 , thereby obtaining a mixture, (c) adding at least one phosphorus compound of general formula (I) X y H 3−y PO 4 (I) wherein X is selected from NH 4 and Li, y is 1 or 2, to the mixture obtained in step (b), wherein steps (b) and (c) may be performed consecutively or simultaneously, treating the mixture so obtained at a temperature in the range of from 650 to 950° C.

1 : A process for making a lithiated transition metal oxide, the process comprising:
 (a) providing a precursor selected from the group consisting of mixed oxides, mixed hydroxides, mixed oxyhydroxides, and mixed carbonates of nickel and at least one transition metal selected from the group consisting of manganese and cobalt, wherein at least 45 mole-% of the cations of the precursor are Ni cations;   (b) mixing said precursor with at least one lithium salt selected from the group consisting of LiOH, Li 2 O, Li 2 CO 3 , and LiNO 3 , thereby obtaining a mixture;   (c) adding at least one phosphorus compound of general formula (I):
   X y H 3−y PO 4   (I)
 
 wherein: 
 X is selected from NH 4  and Li, 
 y is 1 or 2, 
   
       to the mixture obtained in step (b), wherein steps (b) and (c) may be performed consecutively or simultaneously; and
 (d) treating the mixture so obtained at a temperature in the range of from 650 to 950° C. 
 
     
     
         2 : The process according to  claim 1 , wherein the precursor contains nickel cations, cobalt cations, and manganese cations. 
     
     
         3 : The process according to  claim 1 , wherein:
 the precursor has a composition of the transition metals of Ni a Co b Mn c M d ;   a is in the range of from 0.45 to 0.9;   b is in the range of from 0.05 to 0.3;   c is in the range of from 0.05 to 0.3;   d is in the range of from zero to 0.1;   a+b+c+d=1; and   M is one or more of Al, Ti, V, Zn, Ca, and Mo.   
     
     
         4 : The process according to  claim 1 , wherein in step (b) the molar ratio of lithium in lithium salt to transition metals in the precursor is in the range of from 1.11:1 to 1:1.03. 
     
     
         5 : The process according to  claim 1 , in step (c) the weight ratio of phosphorus compound and lithium salt of step (b) is in the range of from 1:100 to 1:50. 
     
     
         6 : The process according to  claim 1 , wherein compound (I) is (NH 4 ) 2 HPO 4 . 
     
     
         7 : The process according to  claim 1 , wherein step (d) is being performed in an atmosphere of oxygen or oxygen-enriched air. 
     
     
         8 : A cathode active material having the general formula (II):
   Li 1+x (Ni a Co b Mn c M d ) 1−x O 2   .y  lithium phosphate  (II),
   wherein:   x is in the range of from zero to 0.1;   a is in the range of from 0.45 to 0.9;   b is in the range of from 0.05 to 0.3;   c is in the range of from 0.05 to 0.3;   d is in the range of from zero to 0.1;   y is in the range of from 0.005 to 0.03;   a+b+c+d=1;   M is one or more of Al, Ti, V, Zn, Ca, and Mo; and   said lithium phosphate is present in homogeneously dispersed form within the particles of Li 1+x (Ni a Co b Mn c M d ) 1−x O 2  or in form of separate particles.   
     
     
         9 : The cathode active material according to  claim 8 , wherein the lithium phosphate is selected from Li 3 PO 4  and Li 4 P 2 O 7 . 
     
     
         10 : The cathode active material according to  claim 8 , having a residual carbonate content of 0.3% or less. 
     
     
         11 : An electrode for a lithium ion battery, the electrode comprising:
 (A) at least one cathode active material according to  claim 8 ;   (B) carbon in an electrically conductive state; and   (C) a binder.   
     
     
         12 : An electrochemical cell, comprising at least one electrode according to  claim 11 .