The present invention belongs to the field of battery materials, and relates to a process for preparing a particulate lithium manganese nickel spinel compound, and materials produced by the process. The process of the invention uses Mn-containing precursors, Ni-containing precursors, Li-containing precursors and optionally M-containing precursor which form substantially no NOx ases during calcination. The particulate lithium manganese nickel spinel compound product of the process may find use in a lithium ion battery.

A positive electrode active material is constituted by lithium transition metal-containing composite oxide particles having a layered rock salt type crystal structure and are composed of secondary particles each formed of an aggregation of primary particles. The secondary particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 1.8 to 5.5 m.sup.2/g, a pore peak diameter of 0.01 to 0.30 μm, and a log differential pore volume [dV/d(log D)] of 0.2 to 0.6 ml/g within a range of the pore peak diameter. In each of a plurality of primary particles having a primary particle size of 0.1 to 1.0 μm, a coefficient of variation of the concentration of an additive element M is 1.5 or less.

A material for an electrode, the material for as well as a method of making the material for an electrode comprising or consisting of a compound of formula (1)

M2Ni1−xCoxO4+δ

and/or of formula (2)

La1−yMyNi1−xCoxO4+δ

where M represents Pr and/or Nd, 0.0≤x≤0.2, 0.25≤δ≤0.3 and 0<y≤10 0.5.

Process for making a manganese composite (oxy)hydroxide with a mean particle diameter D50 in the range from 2 to 16 μm comprising the step(s) of combining (a) an aqueous solution containing salts of nickel and of manganese, and, optionally, at least one of Al, Mg, or transition metals other than nickel and manganese wherein at least 50 mole-% of the metal is manganese, (b) with an aqueous solution of an alkali metal hydroxide and (c) an organic acid or its alkali or ammonium salt wherein said organic acid bears at least two functional groups per molecule and at least one of the functional groups is a carboxylate group.

A positive electrode active material that has high capacity and excellent charge and discharge cycle performance for a secondary battery is provided. The positive electrode active material includes a group of particles including a first group of particles and a second group of particles. The group of particles includes lithium, cobalt, nickel, aluminum, magnesium, oxygen, and fluorine. When the number of cobalt atoms included in the group of particles is taken as 100, the number of nickel atoms is greater than or equal to 0.05 and less than or equal to 2, the number of aluminum atoms is greater than or equal to 0.05 and less than or equal to 2, and the number of magnesium atoms is greater than or equal to 0.1 and less than or equal to 6. When particle size distribution in the group of particles is measured by a laser diffraction and scattering method, the first group of particles has a first peak and the second group of particles has a second peak; the first peak has a local maximum value at longer than or equal to 2 μm and shorter than or equal to 4 μm, and the second peak has a local maximum value at longer than or equal to 9 μm and shorter than or equal to 25 μm.

The positive electrode active material is capable of reducing positive electrode resistance, exhibiting better output characteristics, and having high mechanical strength when the positive electrode active material is used in a lithium ion secondary battery. Secondary particles have a d50 of 3.0 to 7.0 μm, a BET specific surface area of 2.0 to 5.0 m.sup.2/g, a tap density of 1.0 to 2.0 g/cm.sup.3, and an oil absorption amount of 30 to 60 ml/100 g. In each of a plurality of primary particles having a primary particle size of 0.1 to 1.0 μm, a coefficient of variation of the concentration of an additive element M is 1.5 or less. The volume of a linking section between the primary particles per primary particle, obtained from the total volume of the linking section and the number of primary particles constituting the secondary particles, is 5×10.sup.5 to 9×10.sup.7 nm.sup.3.

The positive electrode active material for a secondary battery includes a lithium-transition metal composite oxide. The lithium-transition metal composite oxide is represented by the general formula Li.sub.α[Li.sub.xMn.sub.yCo.sub.zMe.sub.(1−x−y−z)]O.sub.2 (in the formula, Me is at least one selected from Ni, Fe, Ti, Bi, and Nb, 0.5<α<1, 0.05<x<0.25, 0.4<y <0.7, 0<z<0.25) and has a crystal structure of O2 structure. The particle size distribution of the lithium-transition metal composite oxide has a first peak on the small particle size side and a second peak on the large particle size side.

A method for relithiating cathode material from spent lithium-based batteries, the method comprising: (i) mixing delithiated cathode material and a lithium salt with an ionic liquid in which the lithium salt is at least partially soluble to form an initial mixture; (ii) heating the initial mixture to a temperature of 100° C. to 300° C. to result in relithiation of the delithiated cathode material; and (iii) separating the ionic liquid from the relithiated cathode material; wherein, in embodiments, the cathode material is a lithium metal oxide, wherein the metal is selected from the group consisting of Ni, Co, Fe, Mn, Al, Zr, Ti, Nb, and combinations thereof, or wherein the cathode material has the formula LiNi.sub.xMn.sub.yCo.sub.zO.sub.2, wherein x>0, y>0, z>0, and x+y+z=1; wherein, in some embodiments, the ionic liquid has a nitrogen-containing cationic portion, such as an imidazolium ionic liquid.

A cathode active material precursor for a lithium metal oxide is provided. The cathode active material precursor comprises a metal-containing oxyhydroxide. The metal-containing oxyhydroxide comprises nickel and an additional metal. At least 50 mol. % of the nickel of the metal-containing oxyhydroxide has an oxidation state of +3. A method of forming a cathode active material precursor is also provided. The method comprises combining a nickel-containing compound, an additional metal-containing compound, an oxidizing agent, and a solvent to form a solution. The method further comprises exposing the solution to heat at a temperature of from about 30° C. to about 90° C. to form a precipitate comprising the metal-containing oxyhydroxide.

The invention relates to a method for preparing materials with composition gradient characteristics. After mixing a lithium source with the prepared precursor, raise the temperature from room temperature to 300° C.˜600° C. at 2° C./min˜10° C./min and maintain it, and then sinter for 5 hours˜18 hours, cool with the furnace, then raise the temperature from room temperature to 600° C.˜1200° C. at 2° C./min˜10° C./min and maintain it, and sinter for 5 hours˜18 hours, and the material is thus obtained. The material prepared with the method provided by the invention has composition gradient characteristic, and its application to the positive electrode of battery enables the battery to have higher energy density and better thermal stability, and prolonged service life.