Patent ID: 7285357

Claim:
An electrochemically active material resulting from substituting a portion of the nickel in a single-phase composite oxide of nickel and lithium of the LiNiO 2 type, characterized in that the active material satisfies the formula: Li(M 1 (1-a-b-c) Li a M 2 b M 3 c )O 2 in which: 0.02<a≦0.25; 0≦b<0.30; 0≦c<0.30; (a+b+c)<0.50; M 3 is at least one element selected from Al, B, and Ga; M 2 is at least one element selected from Mg and Zn; and M 1 =Ni (1-x-y-z) Co x Mn y M 4 z in which M 4 is at least one element selected from Fe, Cu, Ti, Zr, V, Ga, and Si; and 0≦x<0.70 0.10≦y<0.55 0≦z<0.30 0.20<(1-x-y-z) b+c+z>0; and in that said active material, regardless of its state of charge, satisfies the following relationship: 0.40<R<0.90 where: R=(1- a - b - c )*[3−[( n U /n MA +d ox )/(4-2 b -3 c )]*(2- b -2 c )] in which: n U is the lithium content expressed in moles; n MA is the sum of the contents of Ni, Mn, Co, and M 4 expressed in moles; and d ox is the overall degree of oxidation of M 1 .