A positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charging and discharging as compared with those of a known positive electrode active material. In order to form the positive electrode active material having the pseudo-spinel crystal structure in the charged state, it is preferable that a halogen source such as a fluorine and a magnesium source be mixed with particles of a composite oxide containing lithium, a transition metal, and oxygen, which is synthesized in advance, and then the mixture be heated at an appropriate temperature for an appropriate time.

A positive electrode active material precursor, a method of preparing the same, and a positive electrode active material, a positive electrode, and a lithium secondary battery prepared from the same. In some embodiments, a positive electrode active material precursor includes nickel, cobalt, and manganese, wherein the positive electrode active material precursor satisfies: Equation 1 (2.5≤C.sub.(100)/C.sub.(001)≤5.0) and Equation 2 (1.0≤C.sub.(101)/C.sub.(001)≤3.0), where C.sub.(001) is a crystalline size in a (001) plane, C.sub.(100) is a crystalline size in a (100) plane, and C.sub.(101) is a crystalline size in a (101) plane. The positive electrode active material precursor has particle growth of a (001) plane that is suppressed.

Disclosed are a positive active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same.

The positive active material includes a first positive active material in a form of secondary particles including a plurality of primary particles that are aggregated together, and a second positive active material having a single crystal form, wherein both of the first positive active material and the second positive active material are nickel-based positive active materials, each of the first positive active material and the second positive active material is coated with cobalt, and a maximum roughness of a surface of the second positive active material is greater than or equal to about 15 nm.

A method of preparing a positive electrode active material for a secondary battery includes preparing a positive electrode active material precursor including nickel (Ni), cobalt (Co), and at least one selected from the group consisting of manganese (Mn) and aluminum (Al); and forming a lithium composite transition metal oxide by mixing the positive electrode active material precursor and a lithium source and performing calcination, wherein the positive electrode active material precursor includes nickel (Ni) in an amount of 60 mol % or more out of the entire metal element, and a molar ratio (Li/M) of lithium (Li) of the lithium source to the entire metal element (M) of the positive electrode active material precursor is greater than 1.1.

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.

Embodiments related to cation-disordered lithium metal oxide compounds, their methods of manufacture, and use are described. In one embodiment, a cation-disordered lithium metal oxide includes Li.sub.aM.sub.bM′.sub.cO.sub.2 with a greater than 1. M includes at least one redox-active species with a first oxidation state n and an oxidation state n′ greater than n, and M is chosen such that a lithium-M oxide having a formula LiMO.sub.2 forms a cation-disordered rocksalt structure. M′ includes at least one charge-compensating species that has an oxidation state y that is greater than n.

A positive electrode active material that can achieve high thermal stability at low cost is provided.

Provided is a positive electrode active material for a lithium ion secondary battery, the positive electrode active material containing a lithium-nickel-manganese composite oxide, in which metal elements constituting the lithium-nickel-manganese composite oxide include lithium (Li), nickel (Ni), manganese (Mn), cobalt (Co), titanium (Ti), niobium (Nb), and optionally zirconium (Zr), an amount of substance ratio of the elements is represented as Li:Ni:Mn:Co:Zr:Ti:Nb=a:b:c:d:e:f:g (provided that, 0.97≤a≤1.10, 0.80≤b≤0.88, 0.04≤c≤0.12, 0.04≤d≤0.10, 0≤e≤0.004, 0.003<f≤0.030, 0.001<g≤0.006, and b+c+d+e+f+g=1), and in the amount of substance ratio, (f+g)≤0.030 and f>g are satisfied.

A process for making a mixed metal oxide, may involve: (a) providing a hydroxide or oxyhydroxide of TM with an average particle diameter (D50) in the range of from 0.1 μm to 5 mm; (b) subjecting the hydroxide or oxyhydroxide of TM to a stream of gas with a temperature in the range of from 150 to 2000° C., wherein TM contains nickel and at least one further transition metal selected from cobalt and manganese.

The present invention provides a method of preparing an MOF-coated monocrystal ternary positive electrode material. Firstly, a solution A of nickel, cobalt and manganese metal salts, an ammonia complexing agent solution and a caustic soda liquid are added to a reactor for reaction to obtain a precursor core; then, an organic carboxylate is dissolved in an amount of an organic solvent to obtain a solution B; the solution B and a manganese metal salt solution with a given concentration are added to the reactor and aged to obtain an MOF-coated core-shell structure precursor; the core-shell structure precursor is pre-sintered at a low temperature to obtain a nickel-cobalt-manganese oxide with monocrystal structure; the nickel-cobalt-manganese oxide with monocrystal structure is uniformly mixed with LiOH.H.sub.2O in a mortar and then calcined at a high temperature to obtain an MOF-coated monocrystal ternary positive electrode material.

The invention relates to a secondary particle for a cathode of a secondary lithium battery cell that comprises a plurality of primary particles, each having a layered crystalline structure in which transition metal oxide layers and lithium layers alternate. Each of the primary particles has a spatial extension in the direction of its crystallographic c-axis that is greater than in a direction perpendicular to this axis. The invention also relates to a method for producing such a particle.