A layered double hydroxide is represented by the following formula (I): Ni.sup.2+.sub.1−(x+y+z)Fe.sup.3+.sub.xV.sup.3+.sub.yCo.sup.3+.sub.z(OH).sub.2A.sup.n−.sub.(x+y+z)/n.Math.mH.sub.2O . . . (I). In one embodiment, in the formula (I), (x+y+z) is from 0.2 to 0.5, “x” represents more than 0 and 0.3 or less, “y” represents from 0.04 to 0.49, and “z” represents more than 0 and 0.2 or less.

The present invention generally relates to a method for preparing metal oxide nanosheets. In a preferred embodiment, graphene oxide (GO) or graphite oxide is employed as a template or structure directing agent for the formation of the metal oxide nanosheets, wherein the template is mixed with metal oxide precursor to form a metal oxide precursor-bonded template. Subsequently, the metal oxide precursor-bonded template is calcined to form the metal oxide nanosheets. The present invention also relates to a lithium-ion battery anode comprising the metal oxide nanosheets. In a further preferred embodiment, the battery anode may comprise a reduced template, which is reduced graphene oxide (rGO) or reduced graphite oxide.

The present invention generally relates to a method for preparing metal oxide nanosheets. In a preferred embodiment, graphene oxide (GO) or graphite oxide is employed as a template or structure directing agent for the formation of the metal oxide nanosheets, wherein the template is mixed with metal oxide precursor to form a metal oxide precursor-bonded template. Subsequently, the metal oxide precursor-bonded template is calcined to form the metal oxide nanosheets. The present invention also relates to a lithium-ion battery anode comprising the metal oxide nanosheets. In a further preferred embodiment, the battery anode may comprise a reduced template, which is reduced graphene oxide (rGO) or reduced graphite oxide.

Herein are described two-dimensional metal organic frameworks (2D MOFs). The 2D MOFs includes a plurality of multivalent metals or metal ions and a plurality of multidentate ligands arranged to form a crystalline structure having a lateral size of at least about 2.5 μm and a thickness of less than about 5 nm. Herein are also described methods for preparing the 2D MOFs. The 2D MOFs can be used, for example, in electrochromic devices such as smart windows and flexible displays.

Herein are described two-dimensional metal organic frameworks (2D MOFs). The 2D MOFs includes a plurality of multivalent metals or metal ions and a plurality of multidentate ligands arranged to form a crystalline structure having a lateral size of at least about 2.5 μm and a thickness of less than about 5 nm. Herein are also described methods for preparing the 2D MOFs. The 2D MOFs can be used, for example, in electrochromic devices such as smart windows and flexible displays.

A method of preparing a bimodal positive electrode active material precursor and a positive electrode active material prepared from the same are disclosed herein. In some embodiments, the method includes inputting a first reaction source material including a first aqueous transition metal solution into a reactor, precipitating at pH 12 or more to induce nucleation of a first positive electrode active material precursor particle, and at less than pH 12 to induce growth of the same, inputting a second reaction source material including a second aqueous transition metal solution into the reactor containing the first positive electrode active material precursor particle, precipitating at pH 12 or more to induce the nucleation of a second positive electrode active material precursor particle, and at less than pH 12 to induce simultaneous growth of the first and second positive electrode active material precursor particles, thereby preparing a bimodal positive electrode active material precursor.

A method of preparing a bimodal positive electrode active material precursor and a positive electrode active material prepared from the same are disclosed herein. In some embodiments, the method includes inputting a first reaction source material including a first aqueous transition metal solution into a reactor, precipitating at pH 12 or more to induce nucleation of a first positive electrode active material precursor particle, and at less than pH 12 to induce growth of the same, inputting a second reaction source material including a second aqueous transition metal solution into the reactor containing the first positive electrode active material precursor particle, precipitating at pH 12 or more to induce the nucleation of a second positive electrode active material precursor particle, and at less than pH 12 to induce simultaneous growth of the first and second positive electrode active material precursor particles, thereby preparing a bimodal positive electrode active material precursor.

Process for making a lithiated oxide, said process comprising the following steps: (a) making a particulate hydroxide, oxide or oxyhydroxide of nickel, and, optionally, at least one of Co and Mn and, by combining an aqueous solution of sodium or potassium hydrox-ide with an aqueous solution containing a water-soluble salt of nickel and, optionally, a water-soluble salt of Co, Mn, Al, Ti, Zr, W, Mo, Ga, Nb, Ta, or Mg, (b) adding a source of lithium, (c) treating the mixture obtained from step (b) thermally at at least two different temperatures: (c1) at 300 to 500° C. under an atmosphere that may comprise oxygen, (c2) at 500 to 600° C. under an atmosphere of oxygen, wherein the temperature in step (c2) is set to be higher than in step (c1).

Provided are a nickel-manganese composite hydroxide capable of producing a secondary battery having a high particle fillability and excellent battery characteristics when used as a precursor of a positive electrode active material and a method for producing the same. A nickel-manganese composite hydroxide is represented by General Formula: Ni.sub.xMn.sub.yM.sub.z(OH).sub.2+α and contains a secondary particle formed of a plurality of flocculated primary particles. The primary particles have an aspect ratio of at least 3, and at least some of the primary particles are disposed radially from a central part of the secondary particle toward an outer circumference thereof. The secondary particle has a ratio I(101)/I(001) of a diffraction peak intensity I(101) of a 101 plane to a peak intensity I(001) of a 001 plane, measured by an X-ray diffraction measurement, of up to 0.15.

Provided are a nickel-manganese composite hydroxide capable of producing a secondary battery having a high particle fillability and excellent battery characteristics when used as a precursor of a positive electrode active material and a method for producing the same. A nickel-manganese composite hydroxide is represented by General Formula: Ni.sub.xMn.sub.yM.sub.z(OH).sub.2+α and contains a secondary particle formed of a plurality of flocculated primary particles. The primary particles have an aspect ratio of at least 3, and at least some of the primary particles are disposed radially from a central part of the secondary particle toward an outer circumference thereof. The secondary particle has a ratio I(101)/I(001) of a diffraction peak intensity I(101) of a 101 plane to a peak intensity I(001) of a 001 plane, measured by an X-ray diffraction measurement, of up to 0.15.