A positive electrode active material for a lithium secondary battery, including secondary particles formed by aggregation of primary particles capable of being doped and undoped with lithium ions, said positive electrode active material having: an α-NaFeO.sub.2 type crystal structure represented by formula: Li[Li.sub.x(Ni.sub.aCo.sub.bMn.sub.cM.sub.d).sub.1-x]O.sub.2 (I), wherein 0≦x≦0.1, 0.7<a<1, 0<b<0.2, 0≦c<0.2, 0<d<0.1, a+b+c+d=1, and M is at least one metal element selected from the group consisting of Fe, Cr, Ti, Mg, Al, Zr, Ca, Sc, V, Cr, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In and Sn; and a crystallite size α/crystallite size β ratio (α/β) of 1.60 to 2.40, wherein the crystallite size α is within a peak region of 2θ=18.7±1° and the crystallite size β is within a peak region of 2θ=44.4±1°, each determined by a powder X-ray diffraction measurement using Cu-Kα radiation.

[Object] Provided is a means which is capable, with respect to a non-aqueous electrolyte secondary battery, of suppressing a decrease in capacity when the battery is used for a long period of time, and improving cycle characteristics. [Solving Means] Disclosed is a positive electrode active substance for a non-aqueous electrolyte secondary battery comprising a composite oxide containing lithium and nickel, in which the positive electrode active substance has a structure of secondary particles formed by aggregation of primary particles, the average particle diameter of the primary particles (D1) is 0.9 μm or less, and the ratio value (D2/D1)) of the average particle diameter of the secondary particles (D2) to the average particle diameter of the primary particles (D1) is 11 or more. [Representative Drawing] None

Provided are electrochemically active secondary particles that provide excellent capacity and improved cycle life. The particles are characterized by a plurality of nanocrystals with small average crystallite size. The reduced crystallite size reduces impedance generation during cycling thereby improving capacity and cycle life. Also provided are methods of forming electrochemically active materials, as well as electrodes and electrochemical cells employing the secondary particles.

The present invention relates to a calcined shaped alumina and to a method of preparing a calcined shaped alumina. The method comprises that the alumina in the alumina suspension is hydrothermally aged to have a specific crystallite size. This in turn produces a highly stable alumina in the form of a calcined shaped alumina particularly at temperatures of 1200° C. and above.

A silicide-based alloy material and a device in which the silicide-based alloy material is used are disclosed. The silicide-based alloy material can reduce environmental impact and provide high thermoelectric FIGURE of merit at room temperature. Provided is a silicide-based alloy material comprising, as major components, silver, barium and silicon, wherein atomic ratios of elements that constitute the alloy material are as follows: 9 at %≤Ag/(Ag+Ba+Si)≤27 at %, 20 at %≤Ba/(Ag+Ba+Si)≤53 at %, and 37 at %≤Si/(Ag+Ba+Si)≤65 at %, where Ag represents a content of the silver, Ba represents a content of the barium and Si represents a content of the silicon, and the silicide-based alloy material has an average grain size of less than or equal to 20 μm.

A semiconductor sintered body comprising a polycrystalline body, wherein the polycrystalline body comprises silicon or a silicon alloy, and the average grain size of the crystal grains constituting the polycrystalline body is 1 μm or less, and the electrical conductivity is 10,000 S/m or higher.

The invention relates to active electrode materials and to methods for the manufacture of active electrode materials. Such materials are of interest as active electrode materials in lithium-ion or sodium-ion batteries. The invention provides an active electrode material expressed by the general formula M1.sub.aM2.sub.2-aM3.sub.bNb.sub.34-bO.sub.87-c-dQ.sub.d.

A positive electrode active material of the present invention comprising a composite oxide containing Li and Ni, and optionally containing at least one element other than Li and Ni, is characterized in one of the following: primary particles constituting each of secondary particles of the composite oxide and having a variation coefficient of span of 17% or less, the span being a formula: (D.sub.190−D.sub.110)/D.sub.150 (D.sub.110, D.sub.150, D.sub.190: particle diameter corresponding to 10%, 50%, 90% of an integrated value in a number standard-particle diameter distribution of primary particle size); the primary particles having a variation coefficient of D.sub.150 of 19% or less; and the secondary particles having each of values of 1.00% or less, the values being formulae: |[ER1−ER21)/ER1]|×100, |[ER1−ER22)/ER1]|×100, |[ER1−ER23)/ER1]|×100 (ER1, ER21, ER22, ER23: element ratio (Li/(Ni+Other element(s))) of entire secondary particles, small particles, middle particles, large particles).

A cathode active material for a lithium secondary battery according to an embodiment of the present invention has a structure of a lithium-nickel-based composite oxide. A crystallite size ratio obtained by an XRD analysis is in a range from 1.5 to 3.5, and D(003) exceeds 200 nm. The crystallite size is adjusted to promote movement of lithium ions in the cathode active material so that an initial efficiency of a lithium secondary battery is improved.

A method of making an alumina including providing an alumina slurry, aging the slurry, adding a tricarboxylic acid to the aged alumina slurry, further aging the slurry, and spray drying, the method being characterized by the addition of a dicarboxylic acid either at the same time as the tricarboxylic acid, or after the second aging and before the spray drying. The resulting alumina is dispersible at a pH greater than 9.5 above 95% and has a viscosity below 0.4 Pa.S for 10 wt% sols.