This positive electrode active material for a non-aqueous electrolyte secondary battery contains a lithium transition metal composite oxide represented by the composition formula Li.sub.xMn.sub.yNi.sub.zAL.sub.aM.sub.bO.sub.2-cF.sub.c (in the formula, M represents at least two elements selected from Ti, Co, Si, Sr, Nb, W, Mo, P, Ca, Mg, Sb, Na, B, V, Cr, Fe, Cu, Zn, Ge, Zr, Ru, K, and Bi; 1.0<x≤1.2; 0.4≤y≤0.8; 0≤z≤0.4; 0<a<0.01; 0<b<0.03; 0<c<0.1; and x+y+z+a+b≤2).

Process for making a lithiated oxide, said process comprising the following steps: (a) making a particulate hydroxide, oxide or oxyhydroxide of nickel, and, optionally, at least one of Co and Mn and, by combining an aqueous solution of sodium or potassium hydrox-ide with an aqueous solution containing a water-soluble salt of nickel and, optionally, a water-soluble salt of Co, Mn, Al, Ti, Zr, W, Mo, Ga, Nb, Ta, or Mg, (b) adding a source of lithium, (c) treating the mixture obtained from step (b) thermally at at least two different temperatures: (c1) at 300 to 500° C. under an atmosphere that may comprise oxygen, (c2) at 500 to 600° C. under an atmosphere of oxygen, wherein the temperature in step (c2) is set to be higher than in step (c1).

The invention relates to improved particulate lithium nickel oxide materials which are useful as cathode materials in lithium secondary batteries. The invention also provides processes for preparing such lithium nickel oxide materials, and electrodes and cells comprising the materials.

The present invention features a new way of doping layered cathode materials in lithium ion batteries. Using a .sup.“high entropy” doping strategy, more than four impurity elements can be introduced to the host materials. The present invention applies this high entropy doping strategy to a high nickel content layered oxide material and a lithium-manganese rich material. This new high entropy doping strategy allows the layered oxide materials used in the positive electrode of lithium ion battery to achieve high energy density, long life cycle and reduced reliance on the expensive and toxic cobalt, all of which are desired attributes for improving the performance of lithium ion batteries and reducing their cost.

The present invention features a new way of doping layered cathode materials in lithium ion batteries. Using a “high entropy” doping strategy, more than four impurity elements can be introduced to the host materials. The present invention applies this high entropy doping strategy to a high nickel content layered oxide material and a lithium-manganese rich material. This new high entropy doping strategy allows the layered oxide materials used in the positive electrode of lithium ion battery to achieve high energy density, long life cycle and reduced reliance on the expensive and toxic cobalt, all of which are desired attributes for improving the performance of lithium ion batteries and reducing their cost.

The present invention relates to a positive electrode active material and a lithium secondary battery including the same, and more particularly, to a positive electrode active material including a lithium composite oxide containing at least nickel and cobalt, wherein since the cobalt in the lithium composite oxide has a concentration gradient having at least different slopes from a surface portion toward a central portion, it is possible to improve the stability of particles not only in a surface portion of the lithium composite oxide but also in a central portion thereof, a positive electrode including the positive electrode active material, and a lithium secondary battery using the negative electrode.

The present invention relates to a positive electrode active material and a lithium secondary battery including the same, and more particularly, to a bimodal-type positive electrode active material including a first lithium composite oxide as a small particle and a second lithium composite oxide as a large particle, wherein the positive electrode active material may uniformly improve the particle stability of the small particle and the large particle by controlling a slope of a concentration gradient in which cobalt in the small particle and the large particle decreases from a surface portion toward a central portion, a positive electrode including the positive electrode active material, and a lithium secondary battery using the positive electrode.

A crystalline precursor compound for manufacturing a lithium transition metal based oxide powder usable as an active positive electrode material in lithium-ion batteries, the precursor having a general formula M(O).sub.x(OH).sub.2-x-y(CO.sub.3).sub.y, with 0<x≤1, 0<y<0.03 and M=Ni.sub.aMn.sub.bCo.sub.cA.sub.d. A being a dopant, with 0.30≤a<0.90, 0.10≤b<0.40, 0.10≤c<0.40, d<0.05 and a+b+c+d=1, the precursor having a Na content less than 200 ppm, a S content less than 250 ppm, the precursor having a specific surface area with a BET value expressed in m.sup.2/g and a tap density TD expressed in g/cm.sup.3, with a ratio BET/TD>30.10.sup.4 cm.sup.5/g.sup.2.

A lithium cobalt-based positive electrode active material is provided. The lithium cobalt-based positive electrode active material includes a core portion including a lithium cobalt-based oxide represented by Formula 1 and a shell portion including a lithium cobalt-based oxide represented by Formula 2, wherein the lithium cobalt-based positive electrode active material includes 2500 ppm or more, preferably 3000 ppm or more of a doping element M based on the total weight of the positive electrode active material. An inflection point does not appear in a voltage profile measured during charging/discharging a secondary battery including the lithium cobalt-based positive electrode active material.

Nanosized cubic lithium lanthanum zirconate is synthesized by forming a solution including an organic compound and compounds of lithium, lanthanum, and zirconium; drying the solution to yield a solid; and heating the solid in the presence of oxygen to pyrolyze the organic compound to yield a product comprising nanosized cubic lithium lanthanum zirconate.