This positive electrode active material is for a secondary battery and contains a lithium transition metal complex oxide. The lithium transition metal complex oxide is represented by general formula Li.sub.xMn.sub.yNi.sub.zSb.sub.aO.sub.bF.sub.c (x+y+z+a≤b+c=2, 1≤x≤1.2, 0.4≤y≤0.8, 0≤z≤0.4, 0<a<0.01, and 1.8<b<2 are satisfied) and does not include Co.

A method of preparing a positive electrode active material includes preparing a lithium transition metal oxide containing nickel in an amount of 60 mol % or more based on a total number of moles of metals excluding lithium, impregnating the lithium transition metal oxide with 300 ppm to 1,000 ppm of moisture based on 100 parts by weight of the lithium transition metal oxide, and performing a heat treatment on the lithium transition metal oxide impregnated with the moisture, wherein a lithium by-product present on a surface of the lithium transition metal oxide and the moisture react to form a passivation layer on the surface of the lithium transition metal oxide. A positive electrode active material prepared by the above-described preparation method, and a positive electrode and a lithium secondary battery which include the positive electrode active material are also provided.

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.

Techniques including methods and apparatuses for selective measurement and monitoring of halide concentrations in processing solutions for iron triad metals and their alloys are provided. Methods include monitoring of a halide ion, for example, based on a first analytical method such as conductivity with a compensation of the results for a main metal concentration such as a second analytical measurement of concentration of an iron triad metal (e.g., nickel (Ni)). From such measurements, a concentration of certain halide ions can be selectively determined.

An organic electrolytic solution includes a first lithium salt; an organic solvent; a bicyclic sulfate-based compound represented by Formula 1 below; and a monocyclic phosphate-based compound represented by Formula K1 below:

##STR00001## wherein in Formula 1, each of A.sub.1, A.sub.2, A.sub.3, and A.sub.4 is independently a covalent bond, a substituted or unsubstituted C.sub.1-C.sub.5 alkylene group, a carbonyl group, or a sulfinyl group, wherein both A.sub.1 and A.sub.2 are not a covalent bond and both A.sub.3 and A.sub.4 are not a covalent bond, and in Formula K1, each of A.sub.5 and A.sub.6 is independently a substituted or unsubstituted C.sub.1-C.sub.5 alkylene group.

A positive electrode active material for lithium secondary batteries includes a lithium composite metal compound containing secondary particles that are aggregates of primary particles which are capable of being doped or dedoped with lithium ions and satisfies all of specific requirements (1) to (4).

A process for producing a surface-modified particulate lithium nickel metal oxide material is provided. The process comprises the dry mixing lithium nickel metal oxide particles with at least one metal-containing compound using acoustic energy and then calcining the mixture at a temperature of less than or equal to 800 # C.

A method for producing a lithium-transition metal composite oxide includes steps of preparing a first mixture including a lithium-containing compound and a transition metal compound, obtaining a compressed body by compressing the first mixture at least once, obtaining a molded body by molding at least the compressed body, and obtaining a sintered body by sintering the molded body.

This disclosure provides systems, methods, and apparatus related to lithium-ion batteries. In one aspect, a method includes synthesizing an intermediate selected from a group of a nickel-manganese-cobalt nitrate, a nickel-manganese-cobalt acetate, a nickel-manganese-cobalt sulfate, a nickel-manganese-cobalt chloride, and a nickel-manganese-cobalt phosphate. The intermediate is mixed with a lithium salt selected from a group of LiOH, LiCl, LiNO.sub.3, LiSO.sub.4, LiF, LiBr, Li.sub.3PO.sub.4, Li.sub.2CO.sub.3, and combinations thereof to form a mixture. The mixture is annealed at a sequence of temperatures and times to form a plurality of single crystals of a lithium nickel-manganese-cobalt oxide, with no cooling of the mixture between operations of the sequence of temperatures and times.

This application provides a positive active material and a preparation method thereof, an electrochemical battery, a battery module, a battery pack, and an apparatus. The positive active material includes an inner core and a coating layer, where the coating layer coats a surface of the inner core. The inner core is selected from a ternary material with a molecular formula of Li.sub.1+a[Ni.sub.xCo.sub.yMn.sub.zM.sub.bM′.sub.c]O.sub.2−dY.sub.d, where distribution of each of the doping elements M, M′, and Y in the inner core meets the following condition: there is a reduced mass concentration gradient from an outer side of the inner core to a center of the inner core. The positive active material herein features high gram capacity, high structural stability, and high thermal stability, so that the electrochemical battery has excellent cycle performance and storage performance and high initial discharge gram capacity.