A disordered rocksalt lithium metal oxide and oxyfluoride as in manganese-vanadium oxides and oxyfluorides well suited for use in high capacity lithium-ion battery electrodes such as those found in lithium-ion rechargeable batteries. A lithium metal oxide or oxyfluoride example is one having a general formula: Li.sub.xM′.sub.aM″.sub.bO.sub.2-yF.sub.y, with the lithium metal oxide or oxyfluoride having a cation-disordered rocksalt structure of one of (a) or (b), with (a) 1.09≤x≤1.35, 0.1≤a≤0.7, 0.1≤b≤0.7, and 0≤y≤0.7; M′ is a low valent transition metal and M″ is a high-valent transition metal; and (b) 1.1≤x≤1.33, 0.1≤a≤0.41, 0.39≤b≤0.67, and 0≤y≤0.3; M′ is Mn; and M″ is V or Mo. The oxides or oxyfluorides balance accessible Li capacity and transition metal capacity. An immediate application example is for high energy density Li-cathode battery materials, where the cathode energy is a key limiting factor to overall performance. The second structure (b) is optimized for maximal accessible Li capacity.

A positive electrode active material includes a lithium composite oxide having a crystal structure belonging to the space group Fd-3m and has an integrated intensity ratio I.sub.(18°-20°)/I.sub.(43°-46°) of greater than or equal to 0.05 and less than or equal to 0.90 and an integrated intensity ratio I.sub.(63°-65°)/I.sub.(17°-19°) of greater than or equal to 0.8 and less than or equal to 2.0. The integrated intensity ratio I.sub.(18°-20°)/I.sub.(43°-46°) is a ratio of an integrated intensity I.sub.(18°-20°) to an integrated intensity I.sub.(43°-46°). The integrated intensity ratio I.sub.(63°-65°)/I.sub.(17°-19°) is a ratio of an integrated intensity I.sub.(63°-65°) to an integrated intensity I.sub.(17°-19°). The integrated intensity I.sub.(A°-B°) is an integrated intensity of a maximum peak present in a range of angle of diffraction 2θ greater than or equal to A° and less than or equal to B° in the X-ray diffraction pattern of the positive electrode active material.

The present disclosure is related to a positive electrode active material for lithium secondary batteries, a method for preparing the positive electrode active material, and a lithium secondary battery including the positive electrode active material. The positive electrode active material for lithium secondary batteries includes an overlithiated layered oxide (OLO), and the overlithiated layered oxide includes primary particles having a size in a range of 300 nm to 10 μm in an amount ranging from 50 to 100% by volume with respect to the total overlithiated layered oxide.

A method for preparing a carbon-coated ternary positive electrode material has steps of preparing a ternary positive electrode material precursor, and preparing a suspension of the ternary positive electrode material precursor. Lithium acrylate is added to the suspension of the ternary positive electrode material precursor according to the molar ratio of Li:(Ni+Co+Mn) being 1.03-1.05:1. Ammonium persulphate is added to the lithium acrylate-containing suspension of the ternary positive electrode material precursor, so that the lithium acrylate undergoes a polymerisation reaction and a suspension of a lithium polyacrylate-coated ternary positive electrode material precursor is obtained. The suspension of the lithium polyacrylate-coated ternary positive electrode material precursor is dried to obtain spherical particles. The lithium polyacrylate-coated ternary positive electrode material precursor particles are sintered to obtain a carbon-coated ternary positive electrode material.

The present invention relates to the new process of preparation of a Li-rich layered oxide based on Mn and optionally on Ni and/or Co in which F is incorporated within the crystal of the oxide (or fluorinated oxide). It also relates to the new fluorinated oxide its use as a component in a cathode of a battery.

To provide a lithium-containing composite oxide capable of obtaining a lithium ion secondary battery having a large discharge capacity wherein the deterioration of the discharge voltage due to repetition of a charge and discharge cycle is suppressed, a cathode active material, a positive electrode for a lithium ion secondary battery and a lithium ion secondary battery. A lithium-containing composite oxide, which is represented by the formula I:
Li.sub.aiNi.sub.bCO.sub.cMn.sub.dM.sub.eO.sub.2Formula I,
wherein M is at least one member selected from the group consisting of Na, Mg, Ti, Zr, Al, W and Mo, a+b+c+d+e=2, 1.1a/(b+c+d+e)1.4, 0.2b/(b+c+d+e)0.5, 0c/(b+c+d+e)0.25, 0.3d/(b+c+d+e)0.6, and 0e/(b+c+d+e)0.1, and wherein the valence of Ni is from 2.15 to 2.45.

A sodium-based electrode active material and a secondary battery comprising the same are provided. The electrode active material is represented by the following Chemical Formula 1, and has an orthorhombic crystal system and a space group of Cmcm. [Chemical Formula 1] Na.sub.x[Mn.sub.1-y-zM.sup.1.sub.yM.sup.2.sub.z]O.sub.2-A.sub.. In Chemical Formula 1, x may be 0.5 to 0.8. M.sup.1 and M.sup.2 may be, regardless of each other, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nd, Mo, Tc, Ru, Rh, Pd, Pb, Ag, Cd, Al, Ga, In, Sn, or Bi. y may be from 0 to 0.25. z may be from 0 to 0.25. A may be N, O, F, or S, and may be 0 to 0.1.

A positive electrode active material includes a lithium composite oxide and a covering material that covers a surface of the lithium composite oxide. The covering material has an electron conductivity of 10.sup.6 S/m or less. The lithium composite oxide is a multiphase mixture including a first phase having a first crystal structure that belongs to a space group Fm-3m and a second phase having a second crystal structure that belongs to a space group other than a space group Fm-3m. The ratio I.sub.(18-20)/I.sub.(43-46) of a first integrated intensity I.sub.(18-20) of a first maximum peak present at a first diffraction angle 2 of 18 or more and 20 or less to a second integrated intensity I.sub.(43-46) of a second maximum peak present at a second diffraction angle 2 of 43 or more and 46 or less in an XRD pattern of the lithium composite oxide satisfies 0.05I.sub.(18-20)/I.sub.(45-46)0.90.

A positive electrode active material according to the present disclosure includes: a lithium composite oxide which contains Mn and at least one selected from the group consisting of F, Cl, and N, and S. The lithium composite oxide has a crystalline structure which belongs to a layered structure, and a relationship 0.95intensity ratio I.sub.Mn1/I.sub.Mn21.75 is satisfied. The intensity ratio I.sub.Mn1/I.sub.Mn2 is a ratio of an intensity I.sub.Mn1 to an intensity I.sub.Mn2. The intensity I.sub.Mn1 is an intensity of a first proximity peak of the Mn in a radial distribution function of the Mn contained in the lithium composite oxide. The intensity I.sub.Mn2 is an intensity of a second proximity peak of the Mn in the radial distribution function of the Mn contained in the lithium composite oxide.

A class of compositions in the LiMnOF chemical space for Li-ion cathode materials. The compositions are cobalt-free, high-capacity Li-ion battery cathode materials synthesized with cation-disordered rocksalt (DRX) oxide or oxyfluorides, with the general formula Li.sub.xMn.sub.2-xO.sub.2-yF.sub.y (1.1x1.3333; 0y0.6667). The compositions are characterized by: (i) high capacities (e.g., >240 mAh/g); (ii) high energy densities (e.g., >750 Wh/kg between 1.5-4.8V); (iii) favorable cyclability; and (iv) low cost.