A process for preparing a metal hydroxide comprising (i) at least one metal chosen from nickel and cobalt and optionally (ii) at least one metal chosen from manganese, lithium and aluminum. The process comprises: reacting a metal sulfate comprising (i) at least one metal chosen from nickel and cobalt and optionally (iii) at least one metal chosen from manganese and aluminum with sodium hydroxide and optionally a chelating agent in order to obtain a solid comprising the metal hydroxide and a liquid comprising sodium sulfate; separating the liquid and the solid from one another to obtain the metal hydroxide; submitting the liquid comprising sodium sulfate to an electromembrane process for converting the sodium sulfate into sodium hydroxide; and reusing the sodium hydroxide obtained by the electromembrane process for reacting with the metal sulfate.

Exemplary embodiments of positive electrode active materials in the form of single particles, and a method of preparing each of them, are provided. The single particles of the exemplary embodiments include single particles of a nickel-based lithium composite metal oxide, having a plurality of crystal grains, each having a size of 180 nm to 300 nm, as analyzed by a Cu Kα X-ray (X-rα). The single particles include a metal doped in the crystal lattice thereof. One embodiment includes a surface coating. The total content of the metal doped in the crystal lattice thereof and the metal of the metal oxide coated on the surface thereof is controlled in the range of 2500 ppm to 6000 ppm.

The present invention relates to a positive electrode active material having improved electrical characteristics by adjusting an aspect ratio gradient of primary particles included in a secondary particle, a positive electrode including the positive electrode active material, and a lithium secondary battery using the positive electrode.

A positive electrode active material precursor for a lithium secondary battery containing at least Ni, in which S/D.sub.50 that is a ratio of a BET specific surface area S to a 50% cumulative volume particle size D.sub.50 is 2×10 to 20×10.sup.6 m/g, and, in powder X-ray diffraction measurement using a CuKα ray, A/B that is a ratio of an integrated intensity A of a diffraction peak within a range of 2θ=37.5±1° to an integrated intensity B of a diffraction peak within a range of 2θ=62.8±1° is more than 0.80 and 1.33 or less.

A lithium metal composite oxide having a layered structure, containing at least Li, Ni, and an element X, in which the element X is one or more elements selected from the group consisting of Co, Mn, Mg, Ca, Sr, Ba, Zn, B, Al, Ga, Ti, Zr, Ge, Fe, Cu, Cr, V, W, Mo, Sc, Y, Nb, La, Ta, Tc, Ru, Rh, Pd, Ag, Cd, In, and Sn, L/D.sub.50 that is a ratio of an average primary particle diameter L to a 50% cumulative volume particle size D.sub.50 is 0.3 to 1.5, and, in powder X-ray diffraction measurement using a CuKα ray, a crystallite diameter A calculated from a diffraction peak within a range of 2θ=44.5±1° is 700 Å or less.

The disclosure provides a modified positive electrode material, a preparation method therefor, and a lithium ion battery. The modified positive electrode material includes a core and a coating layer. The core contains Mn and Ni, the coating layer includes a first oxide coating layer coating on a surface of the core. A first element forming the first oxide coating layer is selected from one or more of a group of Si, Ti, V, Zr, Mo, W, Bi, Nb, and Au. The first element with a high-valent state can partially enter the surface core structure of the positive electrode material to occupy the sites of manganese ions, and form a chemical bond stronger than a Mn—O. Thus, 0 and Mn in the core structure are difficult to precipitate, and the coating layer is difficult to fall off in cycle process. Moreover, structural stability of the modified positive electrode material is improved.

A process for producing a surface-modified particulate lithium nickel metal oxide material is provided. The process comprises the addition of a controlled quantity of a coating liquid comprising a cobalt-containing compound to nickel metal precursor particles using an incipient wetness process followed by a calcination step.

The present invention relates to a surface-modified particulate lithium nickel oxide material. The invention also relates to a process of making a surface-modified particulate lithium nickel oxide material. Further aspects of the invention include a cathode comprising the surface-modified particulate lithium nickel oxide material, a lithium secondary cell or battery comprising such a cathode, and the use of the particulate lithium nickel oxide to improve the capacity retention of a lithium secondary cell or battery.

Provided is a positive electrode active material for a non-aqueous electrolyte secondary battery, the active material including a lithium-transition metal composite oxide containing lithium, nickel, cobalt, and manganese, having a layered structure, having a ratio D.sub.50/D.sub.SEM of from 1 to 4, and having a ratio of a number of moles of nickel to a total number of moles of metals other than lithium of greater than 0.8 and less than 1, a ratio of a number of moles of cobalt to the total number of moles of metals other than lithium of less than 0.2, a ratio of a number of moles of manganese to the total number of moles of metals other than lithium of less than 0.2, and a ratio of the number of moles of manganese to a sum of the number of moles of cobalt and the number of moles of manganese of less than 0.58.

Provided are processes of removing lithium from an electrochemically active composition. The process of removing lithium from an electrochemically active composition may include providing an electrochemically active composition and combining the electrochemically active composition with a strong oxidizer optionally at a pH of 1.5 or greater for a lithium removal time. The electrochemically active composition may include Li, Ni, and O. The electrochemically active composition may optionally have an initial Li/M at % ratio of 0.8 to 1.3. According to some embodiments of the present disclosure, the lithium removal time may be such that a second Li/M at % ratio following the lithium removal time is 0.6 or less, thereby forming a delithiated electrochemically active composition.