Abstract: A cathode active material for a positive electrode for a lithium ion secondary battery, comprising a lithium-containing composite oxide represented by aLi(Li1/3Mn2/3)O2·(1-a)LiMO2 (M: at least one transition metal element selected from Ni, Co and Mn, and 0<a<1), wherein in an X-ray diffraction pattern of the lithium-containing composite oxide, the ratio of the height (H020) of a peak of (020) plane assigned to a crystal structure with space group C2/m to the height (H003) of a peak of (003) plane assigned to a crystal structure with space group R-3m (i.e. H020/H003) is at most 0.038, and the ratio of the height (H110) of a peak of (110) plane assigned to a crystal structure with space group C2/m to the height (H003) of a peak of (003) plane assigned to a crystal structure with space group R-3m (i.e. H110/H003) is at most 0.013.

Abstract: To provide a carbonate compound and a cathode active material, whereby a lithium ion secondary battery having excellent cycle characteristics can be obtained. A process for producing a carbonate compound, which comprises mixing a sulfate (A) comprising a sulfate comprising a sulfate of Mn and a sulfate of Ni, or a sulfate comprising a sulfate of Mn, a sulfate of Ni and a sulfate of Co, and a carbonate (B) which is at least one carbonate selected from the group consisting of sodium carbonate and potassium carbonate, in the form of aqueous solutions and controlling the proportion of Mn to the total of Ni, Co and Mn contained in the sulfate (A) to be higher than 65 mol % at the initiation of the mixing, to precipitate a carbonate compound having a proportion of Mn of from 33.3 to 65 mol %, a proportion of Ni of from 17.5 to 50 mol % and a proportion of Co of from 0 to 33.3 mol % to the total of Ni, Co and Mn in the total average composition.

Abstract: A cathode active material comprising secondary particles having a plurality of primary particles of a lithium-containing composite oxide agglomerated, the lithium-containing composite oxide being represented by LixNiaCobMncMdOy (x: 1.1 to 1.7, a: 0.15 to 0.5, b: 0 to 0.33, c: 0.33 to 0.85, M: another metal element, d: 0 to 0.05, a+b+c+d=1, and y: the number of moles of oxygen atom (O) required to satisfy the valences of the metal elements), and I020/I003 in an X-ray diffraction pattern being from 0.02 to 0.3, wherein the porosity in a cross section of the secondary particles is from 5 to 20%, and the percentage of the maximum void in a cross section of the secondary particles is from 0.1 to 10%.

Abstract: To provide a lithium rich cathode active material capable of obtaining a lithium ion secondary battery excellent in the discharge capacity and cycle characteristics; a positive electrode for such a lithium ion secondary battery; and such a lithium ion secondary battery. The cathode active material comprises a lithium-containing composite oxide, wherein the lithium-containing composite oxide is represented by aLi(Li1/3Mn2/3)O2·(1?a)LiMO2 (wherein M is at least one transition metal element selected from the group consisting of Ni, Co and Mn, and a is more than 0 and less than 1), and in an X-ray diffraction pattern of the lithium-containing composite oxide, the integral breadth of a peak of (020) plane assigned to a crystal structure with space group C2/m is at most 0.55 deg.

Abstract: A cathode active material for a positive electrode for a lithium ion secondary battery, comprising a lithium-containing composite oxide represented by aLi(Li1/3Mn2/3)O2·(1-a)LiMO2 (M: at least one transition metal element selected from Ni, Co and Mn, and 0<a<1), wherein in an X-ray diffraction pattern of the lithium-containing composite oxide, the ratio of the height (H020) of a peak of (020) plane assigned to a crystal structure with space group C2/m to the height (H003) of a peak of (003) plane assigned to a crystal structure with space group R-3m (i.e. H020/H003) is at most 0.038, and the ratio of the height (H110) of a peak of (110) plane assigned to a crystal structure with space group C2/m to the height (H003) of a peak of (003) plane assigned to a crystal structure with space group R-3m (i.e. H110/H003) is at most 0.013.

Abstract: To provide a cathode active material which achieves a high discharge capacity and excellent cycle durability. A cathode active material represented by LiaMOx (wherein M is an element including at least one member selected from Ni element, Co element and Mn element (other than Li element and O element), “a” is from 1.1 to 1.7, and x is the number of moles of O element required to satisfy the valences of Li element and M), wherein in an X-ray diffraction pattern, the ratio (I/r) of the crystallite size (I) of (003) plane to the crystallite size (r) of (110) plane assigned to a crystal structure with space group R-3m is at least 2.6.

Abstract: To provide a cathode active material to be used for a positive electrode of a lithium ion secondary battery having a high discharge capacity and favorable cycle durability. A cathode active material, which comprises a lithium-containing composite oxide containing at least one transition metal element (X) selected from the group consisting of Ni element, Co element and Mn element, and Li element (provided that the molar ratio (Li/X) of the Li element based on the total amount of the transition metal element (X) is from 1.1 to 1.7), wherein the aspect ratio of primary particles is from 2.5 to 10, and in an X-ray diffraction pattern, the ratio (I020/I003) of the integrated intensity (I020) of a peak of (020) plane assigned to a crystal structure with space group C2/m to the integrated intensity (I003) of a peak of (003) plane assigned to a crystal structure with space group R-3m is from 0.02 to 0.3.

Abstract: To provide a cathode active material with which a lithium ion secondary battery which has a high discharge capacity, of which initial DCR is not high, and of which an increase of DCR is suppressed even when a charge and discharge cycle is repeatedly carried out, can be obtained. A cathode active material comprising secondary particles having a plurality of primary particles of a lithium-containing composite oxide agglomerated, the lithium-containing composite oxide being represented by LixNiaCobMncMdOy (x: 1.1 to 1.7, a: 0.15 to 0.5, b: 0 to 0.33, c: 0.33 to 0.85, M: another metal element, d: 0 to 0.05, a+b+c+d=1, and y: the number of moles of oxygen atom (O) required to satisfy the valences of the metal elements), and I020/I003 in an X-ray diffraction pattern being from 0.02 to 0.3, wherein the porosity in a cross section of the secondary particles is from 5 to 20%, and the percentage of the maximum void in a cross section of the secondary particles is from 0.1 to 10%.

Abstract: To provide a carbonate compound and a cathode active material, whereby a lithium ion secondary battery having excellent cycle characteristics can be obtained. A process for producing a carbonate compound, which comprises mixing a sulfate (A) comprising a sulfate comprising a sulfate of Mn and a sulfate of Ni, or a sulfate comprising a sulfate of Mn, a sulfate of Ni and a sulfate of Co, and a carbonate (B) which is at least one carbonate selected from the group consisting of sodium carbonate and potassium carbonate, in the form of aqueous solutions and controlling the proportion of Mn to the total of Ni, Co and Mn contained in the sulfate (A) to be higher than 65 mol % at the initiation of the mixing, to precipitate a carbonate compound having a proportion of Mn of from 33.3 to 65 mol %, a proportion of Ni of from 17.5 to 50 mol % and a proportion of Co of from 0 to 33.3 mol % to the total of Ni, Co and Mn in the total average composition.

Abstract: To provide a method for producing an organic acid, whereby the desired organic acid can be efficiently recovered without necessity for adjusting the pH to a neutral level in the fermentation step. The method for producing an organic acid, comprises a first step of producing an organic acid by fermentation to obtain a crude liquid containing the organic acid and having a pH of from 1 to 5, and a second step of extracting the organic acid from the crude liquid containing the organic acid obtained in the first step by means of an extraction medium containing a C10-30 diester compound and an alkylamine compound to obtain an extract (1).