ECOPRO BM CO., LTD.

Provided are a positive electrode active material for a sodium secondary battery including: a sodium manganese-based oxide which includes at least sodium (Na), nickel (Ni), and manganese (Mn) and contains 55 mol % or more of manganese in all metals other than sodium, wherein the sodium manganese-based oxide is a secondary particle formed by agglomeration of at least one primary particles, and a surface and an inside of the secondary particles are doped with cobalt (Co), a method for producing the positive electrode active material, and a positive electrode and a sodium secondary battery including the positive electrode active material.

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 cathode active material of the present invention comprises a lithium nickel-based composite oxide comprising secondary particles formed by the aggregation of primary particles, wherein some cations and some anions in the lithium nickel-based composite oxide are replaced by a cation M′ and a fluoride anion (F − ), respectively, which are contained in a fluorine-based compound, and the average Ni occupancy in the Li 3a site, obtained through Rietveld refinement using X-ray diffraction of the secondary particles, is 1.1-1.5%.

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 having improved electrochemical characteristics and improved stability, and a lithium secondary battery using a positive electrode including the positive electrode active material, and more particularly, to a positive electrode active material which may prevent decreases in electrochemical characteristics and stability of the positive electrode active material, which are caused by Li impurities, in advance by controlling the content of the Li impurities remaining on the surface of the positive electrode active material without a washing process to reduce the amount of residual lithium present on the surface thereof, and a lithium secondary battery using a positive electrode containing the positive electrode active material.

The present invention relates to a positive electrode active material, and a lithium secondary battery comprising a positive electrode including the positive electrode active material.

The present disclosure relates to a positive electrode active material and a lithium secondary battery including the same, and more particularly, to a positive electrode active material and a lithium secondary battery including the same, in which electrochemical characteristics and stability are improved by removing lithium-containing impurities present on the surface of a lithium composite oxide without a washing process.

The present disclosure relates to a novel polycrystalline cathode active material, and more specifically, provides a novel polycrystalline cathode active material having an effect of improving lifetime characteristics while securing excellent output and capacity characteristics by determining an optimal size and number of primary particles and a size of secondary particles by utilizing peak intensities of an H2 phase and an H3 phase.

The present invention relates to a positive electrode active material and a lithium secondary battery comprising the same, and more particularly, to a positive electrode active material, in which, instead of coating the surface of a unit particle constituting a lithium transition metal oxide, a cobalt-enriched region in which the distribution of cobalt is concentrated is formed in a surface portion of the unit particle, thereby reducing conductivity variation between unit particles caused by the formation of a non-uniform coating layer and improving electrochemical properties, including capacity characteristic and rate characteristic, and to a lithium secondary battery comprising the same.

The present invention relates to a positive electrode active material and a lithium secondary battery comprising the same, and more particularly, to a positive electrode active material comprising a mid-Ni type lithium transition metal oxide having a relatively low nickel content, wherein the c-axis length of unit particles constituting the lithium transition metal oxide is increased to enhance the efficiency of reversible intercalation/deintercalation of lithium ions, thereby improving electrochemical characteristics, which are relatively insufficient compared to those of a high-Ni type lithium transition metal oxide having a relatively high nickel content, and to a lithium secondary battery comprising the same.