This positive electrode active material for nonaqueous electrolyte secondary batteries includes a lithium transition metal complex oxide that has a spinel structure and that is represented by general formula Li.sub.1+αNi.sub.0.5-xMn.sub.1.5-y-zGe.sub.yM.sub.x+zO.sub.4 (in the formula, 0≤α<0.2, 0≤x<0.2, 0<y<0.45, and 0≤z<0.2 are satisfied, and M represents at least one element selected from the group consisting of Mg, Al, Sc, Ti, Cr, V, Fe, and Co). In a secondary particle of the lithium transition metal complex oxide, the mole number (Ge.sub.surf) of Ge at the surface portion when the total number of moles of metal elements other than Li is defined as 2 is larger than the mole number (Ge.sub.bulk) of Ge at the center portion when the total number of moles of metal elements other than Li is defined as 2.

A process for forming an active cathode material. The process comprises forming a precursor comprising a lithium salt and a multi-carboxylic acid salt of at least one of nickel, manganese or cobalt; heating the precursor in a metal lined vessel to a temperature of no more than 600° C. to form an intermediate material; and heating the intermediate material to a temperature of over 600° C. to form said active cathode material.

This positive electrode active material for a non-aqueous electrolyte secondary battery contains a lithium transition metal complex oxide capable of occluding and releasing Li. The lithium transition metal complex oxide is represented by general formula Li.sub.xM1.sub.yO.sub.zF.sub.w (in the formula, 0.5 ≤ × < 3.1, 1 ≤ y ≤ 2, 2 ≤ z+w ≤ 4, and M1 is at least one element selected from Ni, Co, Mn, Ti, Fe, Al, Ge, Si, and Nb), and M2 (M2 being at least one element selected from Ca, Sr, Sc, Er, Y, Zr, and W) is included in the interior of secondary particles of the lithium transition metal complex oxide.

The disclosure provides a method of manufacturing a uniform cathode material precursor, including steps of: (A) providing an acidic solution of co-precipitating cations including at least one co-precipitating cation; (B) mixing at least one basic solution with the acidic solution of co-precipitating cations to produce a co-precipitating colloid; (C) performing a nano-grinding process on the acidic solution of co-precipitating cations; and optionally (D) performing a hydrothermal aging process; wherein the step (C) is performed before and/or simultaneously with the step (B); and the optional step (D) is performed simultaneously with the step (B) and/or after the step (C); and wherein the step (B), the step (C) and the optional step (D) are performed continuously without washing and/or filtration post-processing.

A process for preparing a stable Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 is provided. The general formula of the potassium “A” site and Group VIII Period 4 (Fe, Co and Ni) “B” site modified lithium manganese-based AB.sub.2O.sub.4 spinel is Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 where Me is Fe, Co, or Ni. In addition, a Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 cathode material for electrochemical systems is provided. Furthermore, a lithium or lithium-ion rechargeable electrochemical cell is provided, incorporating the Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 cathode material in a positive electrode.

A positive electrode material includes: Li.sub.2Ni.sub.αM.sup.1.sub.βM.sup.2.sub.γMn.sub.ηO.sub.4-ε. α satisfies a relational expression of 0.50<α≦1.33. γ satisfies a relational expression of 0.33≦γ≦1.1. η satisfies a relational expression of 0≦η≦1.00. β satisfies a relational expression of 0≦β<0.67. ε satisfies a relational expression of 0≦ε≦1.00. M.sup.1 is at least one type selected from Co and Ga. M.sup.2 is at least one type selected from Ge, Sn, and Sb. Li.sub.2Ni.sub.αM.sup.1.sub.βM.sup.2.sub.γMn.sub.ηO.sub.4-ε has a layered structure which includes a Li layer and a Ni layer. A crystal structure of Li.sub.2Ni.sub.αM.sup.1.sub.βM.sup.2.sub.γMn.sub.ηO.sub.4-ε is a superlattice structure.

The present invention relates to a positive electrode comprising a Mn composite oxide having a tetragonal structure represented by formula (1): Li.sub.a(M.sub.xMn.sub.2-x-yY.sub.y)(O.sub.4-wZ.sub.w)(wherein 1<a≦2.6, 0≦x≦1.2, 0≦y, x+y<2, 0≦w≦1; M is at least one selected from the group consisting of Co, Ni, Fe, Cr and Cu; Y is at least one selected from the group consisting of Li, B, Na, Mg, Al, Ti, Si, K and Ca; Z is at least one of F or Cl; and a composite oxide having a layered structure represented by formula (2): Li(Li.sub.xM.sub.1-x-yY.sub.y)O.sub.2 (wherein 0≦x<0.3, 0≦y<0.3; M is at least one selected from the group consisting of Co, Fe, Ni and Mn; Y is at least one selected from the group consisting of Mg, Al, Zr, Ti and Zn. According to the present invention, a lithium secondary battery having a high capacity and being excellent in cycle life can be provided.

A lithium metal oxide powder for a cathode material in a rechargeable battery comprises a core and a surface layer. The surface layer is delimited by an outer and an inner interface. The inner interface is in contact with the core. The cathode material has a layered crystal structure comprising the elements Li, M, and oxygen. M has the formula M=(Ni.sub.z(Ni.sub.1/2 Mn.sub.1/2).sub.y Co.sub.x).sub.1-k A.sub.k, with 0.15≤x≤0.30, 0.20≤z≤0.55, x+y+z=1 and 0<k≤0.1. The Li content is stoichiometrically controlled with a molar ratio 0.95≤Li:M≤1.10. A is at least one dopant and comprises Al. The core at the inner interface has an Al content of 0.3-3 mol %. The surface layer comprises an intimate mixture of Ni, Co, Mn, LiF and Al.sub.2O.sub.3 determined by XPS. The surface layer has a Mn content that decreases from the Mn content at the inner interface to less than 50% of the Mn content at the outer interface.

The present invention relates to a lithium positive electrode active material for a high voltage secondary battery, where the lithium positive electrode active material comprising a spinel, and the spinel has a chemical composition of Li.sub.xNi.sub.yMn.sub.2-yO.sub.4, wherein: 0.95≤x≤1.05; and 0.43≤y≤0.47. The lithium positive electrode active material is synthesized from precursors containing Li, Ni, and Mn in a ratio Li:Ni:Mn:X:Y:2−Y, wherein: 0.95≤X≤1.05; and 0.42≤Y<0.5. The present invention also relates to a process of preparing the lithium positive electrode active material as well as a secondary battery comprising the lithium positive electrode active material.

The present invention relates to a lithium positive electrode active material for a high voltage secondary battery, where the lithium positive electrode active material comprises at least 94 wt % spinel. The spinel has a net chemical composition of Li.sub.xNi.sub.yMn.sub.2-yO.sub.4, wherein: 0.95≤x≤1.05; 0.43≤y≤0.47; and
wherein the lithium positive electrode active material has a capacity of at least 138 mAh/g, wherein y is determined by means of a method selected from the group consisting of electrochemical determination, X-ray diffraction and scanning transmission electron microscopy (STEM) in combination with energy dispersive X-ray spectroscopy (EDS). The invention also relates to a process for preparation of a lithium positive electrode active material for a high voltage secondary battery of the invention as well as a secondary battery comprising a lithium positive electrode active material according to the invention.