MATIERE ELECTROCHIMIQUEMENT ACTIVE POUR ELECTRODE POSITIVE DE GENERATEUR ELECTROCHIMIQUE RECHARGEABLE AU LITHIUM

La présente invention a pour objet une matière électrochimiquement active résultant de la substitution d'une partie du nickel d'un oxyde mixte monophasé de nickel et de lithium du type LiNiO2, caractérisée en ce que ladite matière active répond à la formule :Li (M1(1-a-b-c) Lia M2b M3c) O2dans laquelle 0.02< a ≤ 0,250 ≤ b < 0,300 ≤ c < 0,30(a+b+c) < 0,50M3 est au moins un élément choisi parmi Al, B et Ga,M2 est au moins un élément choisi parmi Mg et Zn,et M1 = Ni(1-x-y-z) COx Mny M4zoù M4 est au moins un élément choisi parmi Fe, Cu, Ti,Zr, V, Ga et Si,et 0 ≤ x < 0,700,10 ≤ y < 0,550 ≤ z < 0,300,20 < (1-x-y-z)b+c+z>0et en ce que ladite matière active vérifie, quel que soit son état de charge, la relation R suivante telle que 0,40 < R < 0,90 :R = (1-a-b-c) * [ 3 - [ (nLi / nMA + dox) / (4-2b-3c) ] * (2-b-2c) ]où nLi est la teneur en lithium exprimée en molenMA est la somme des teneurs en Ni, Mn, Co et M4, exprimée en mole, etdox est le degré d'oxydation global de M1. A new electrochemically active material (I) is obtained by substitution of part of the nickel in a monophase mixed nickel-lithium (1:1) oxide with (i) lithium, (ii) manganese, (iii) at least one of aluminum, boron, gallium, magnesium, zinc, iron, copper, titanium, zirconium, vanadium, gallium and/or silicon and optionally (iv) cobalt. A new electrochemically active material, obtained by substitution of part of the nickel in a monophase mixed nickel-lithium oxide of the LiNiO 2type, is of formula Li (M 1>(1-a-b-c)Li aM 2>bM 3>c) O 2(I) and has an R value of 0.40 to 0.90 exclusive (preferably 0.60 to 0.85 exclusive), irrespective of the state of charge. a : 0.02 - 0.25 (excluding 0.02); b, c : 0 - 0.30 (excluding 0.30); (a + b + c) : less than 0.50; M 3>aluminum, boron and/or gallium; M 2>magnesium and/or zinc; M 1>Ni (1-x-y-z)Co xMn yM 4>z; M 4>iron, copper, titanium, zirconium, vanadium, gallium and/or silicon; x : 0 - 0.70 (excluding 0.70); y : 0.10 - 0.55 (excluding 0.55); z : 0 - 0.30 (excluding 0.30); (1 - x - y - z) : more than 0.20; b + c + z : more than zero; R : (1 - a - b - c) . (3 - ((n l/n m+ d ox) / (4 - 2b - 3c)) . (2 - b - 2c)); n lmolar content of lithium; n msum of the molar contents of Ni, Mn, Co and M 4>; and M 1>overall degree of oxidation of M 1>. Independent claims are also included for: (1) positive electrodes of rechargeable lithium batteries, comprising a conductive support covered with an active layer containing (I); and (2) rechargeable lithium batteries having at least