To provide a method for producing a positive electrode active material layer for lithium ion battery that can improve durability and internal resistance of lithium ion battery, and particularly lithium ion battery that operates at high voltage. The method for producing positive electrode active material layer for a lithium ion battery includes coating a substrate with positive electrode mixture slurry containing positive electrode active material, first lithium salt, second lithium salt and solvent, and drying off the solvent. First lithium salt is lithium phosphate, the second lithium salt is selected from the group including of lithium carbonate, lithium hydroxide, lithium nitrate, lithium acetate, lithium sulfate and combinations thereof, and the proportion of the second lithium salt with respect to the first lithium salt is 1 to 50 mol % based on the number of lithium atoms.

A process is provided for synthesizing a lithium, nickel, manganese and oxygen composition, Li.sub.wNi.sub.xMn.sub.yO.sub.z, where w is from about 0.8 to about 1.2, x is from about 0.3 to about 0.8, y is from about 1.3 to about 1.8, and z is from about 3.8 to about 4.2. The composition has a lattice parameter a value and wt % crystalline spinel value within the bounds defined by the following lattice parameter a and wt % crystalline spinel coordinate values of about (8.1690 , 98.5%), about (8.1765 , 98.5%), about (8.1810 , 96.2%), about (8.1810 , 93.4%), about (8.1771 , 93.4%), and about (8.1690 , 97.6%).

A lithium metal oxide powder for a cathode material in a rechargeable battery, consisting of a core and a surface layer, the surface layer being delimited by an outer and an inner interface, the inner interface being in contact with the core, the core having a layered crystal structure comprising the elements Li, M and oxygen, wherein M has the formula M=(Ni.sub.z(Ni.sub.1/2Mn.sub.1/2).sub.yCo.sub.x).sub.1-kA.sub.k, with 0.15x0.30, 0.20z0.55, x+y+z=1 and 0<k0.1, wherein the Li content is stoichiometrically controlled with a molar ratio 0.95Li:M1.10; wherein A is at least one dopant and comprises Al; wherein the core has an Al content of 0.3-3 mol % and a F content of less than 0.05 mol %; and wherein the surface layer has an Al content that increases continuously from the Al content of the core at the inner interface to at least 10 mol % at the outer interface, and a F content that increases continuously from less than 0.05 mol % at the inner interface to at least 3 mol % at the outer interface, the Al and F contents in the surface layer being determined by XPS. The surface layer may also have a Mn content that decreases continuously from the Mn content of the core at the inner interface, to less than 50% of the Mn content of the core at the outer interface.

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 application provides a lithium-nickel-manganese-containing composite oxide, a preparation method thereof, and a positive electrode plate, secondary battery, and electric apparatus containing the same. The lithium-nickel-manganese-containing composite oxide has a core-shell structure and includes a core and a shell enveloping surface of the core, where the core includes Li.sub.x(Ni.sub.yMn.sub.2-y).sub.1-mM.sub.mO.sub.4. M includes one or more selected from Mg, elements from group IVB to group VIB, elements from group IIIA to group VA, and lanthanide elements, where 0.95x1.10, 0.40y0.60, and 0.001m0.015. The shell includes lithium aluminum phosphate and optionally includes lithium aluminum phosphate and aluminum phosphate.

A method of preparing a lithium nickel manganese oxide cathode material comprises the following steps of providing a precursor material, the precursor material comprises a lithium compound, a nickel compound and a manganese compound, mixing and grinding the lithium compound, the nickel compound and the manganese compound to from a cathode material precursor having a specific span value or a specific value of 90 percent particle size volume distribution (D.sub.90), (wherein the specific span value is greater than or equal to 1.0 m and lesser than or equal to 2.0 m, the specific value of 90 percent particle size volume distribution is greater than or equal to 0.3 m and lesser than or equal to 0.4 m), and processing a thermal treatment to the cathode material precursor to form the lithium nickel manganese oxide cathode material.

A preparation method of a lithium nickel manganese oxide cathode material of a battery includes steps of providing a nickel compound, a manganese compound, a first quantity of lithium compound, a second quantity of lithium compound and a compound containing metallic ions, mixing the nickel compound, the first quantity of lithium compound, dispersant and deionized water to produce first product solution, adding the manganese compound into the first product solution and mixing to produce second product solution, performing a first grinding to produce first precursor solution, mixing the second quantity of lithium compound, the compound containing the metallic ions and the first precursor solution, then performing a second grinding to produce second precursor solution, and calcining the second precursor solution to produce the lithium nickel manganese oxide cathode material of the battery, the formula of which is written by Li.sub.1.0+xNi.sub.0.5Mn.sub.1.5M.sub.yO.sub.4. Therefore, the activation energy of reaction can be reduced.

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 0.15x0.30, 0.20z0.55, x+y+z=1 and 0<k0.1. The Li content is stoichiometrically controlled with a molar ratio 0.95Li:M1.10. 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.

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 0.15x0.30, 0.20z0.55, x+y+z=1 and 0<k0.1. The Li content is stoichiometrically controlled with a molar ratio 0.95Li:M1.10. 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.