The invention relates to a method for preparing a sol-gel solution which can be used to prepare a barium titanate ceramic doped with hafnium and/or with at least one lanthanide element, comprising the following steps: a) a step to place a first mixture comprising a barium carboxylate and a diol solvent in contact with a second mixture comprising a titanium alkoxide and a hafnium alkoxide and/or an alkoxide of a lanthanide element in a monoalcohol solvent; b) a step to distil the mixture resulting from step a) to remove at least part of the monoalcohol solvent; c) a step to add acetic acid, under heat, to the distilled mixture of step b).

The piezoelectric composition is represented by the following Chemical Formula (1):
x[Bi.sub.mFeO.sub.3]-y[Ba.sub.mTiO.sub.3]-z[Sr.sub.mTiO.sub.3](1)
wherein 0.5x0.8, 0.02y0.4, 0.02z0.2, x+y+z=1, and 0.96m1.04.

There are provided a new type of crystal laminate of an alkaline earth metal titanate having improved catalytic activity, and a method for producing the same. The crystal laminate is provided having a crystal of the alkaline earth metal titanate as a constitutional unit, wherein the crystal being the constitutional unit is a cubic crystal, a tetragonal crystal or an orthorhombic crystal; the crystal being the constitutional unit has a primary particle diameter of 500 nm or less; and the crystal is layered with an orientation in a {100} plane direction thereof.

A positive active material for a rechargeable lithium battery includes a first oxide particle having a layered structure and a second oxide layer located in a surface of the first oxide particle and including a second oxide represented by the following Chemical Formula 1: M.sub.aL.sub.bO.sub.c, wherein in Chemical Formula 1, 0<a3, 1b2, 3.8c4.2, M is at least one element selected from the group of Mg, Al, Ga, and combinations thereof, and L is at least one element selected from of group Ti, Zr, and combinations thereof.

Disclosed are a barium titanate foam ceramic/thermosetting resin composite material and a preparation method therefor. An organic additive is used as an auxiliary; deionized water is used as a solvent; nanometer barium titanate is used as a ceramic raw material; and all of same are mixed and ground so as to form a slurry with a certain solid content. A pre-treated polymer sponge is impregnated into the slurry for slurry coating treatment, and then redundant slurry is removed and the polymer sponge is dried so as to obtain a barium titanate foam ceramic blank, and same is then sintered so as to obtain a barium titanate foam ceramic. A resin, being in a molten state and thermosettable, submerges the pores of the barium titanate foam ceramic, and a barium titanate foam ceramic/thermosetting resin composite material is obtained after a thermosetting treatment.

This composite titanium oxide compound is a composite titanium oxide compound wherein primary particles of an alkali metal titanate compound and primary particles of an alkaline earth metal titanate compound are joined to form secondary particles. The secondary particles have an average particle size of 1 to 80 m. When the concentration of elements in the secondary particles is analyzed, a region where the alkaline earth metal is detected covers 50% or more of the surface area in 3% or less of the total number of secondary particles.

A ceramic composition according to an embodiment of the present invention contains: a main phase component represented by CaMgSi.sub.2O.sub.6 or Ba.sub.4(Re.sub.(1-x), Bi.sub.x).sub.9.33Ti.sub.18O.sub.54; and an additive component containing a Li component and a B component, An observation field, a part of a sectional surface of the ceramic composition, is divided into a plurality of unit observation regions. Among all the unit observation regions, those containing no or little sintering agent component are referred to as the main crystal regions. An area percentage of main crystal regions relative to the observation field is 30% or more, the main crystal regions being the unit observation regions containing 0.5% or less by area of the additive component.

Provided is use of an oriented piezoelectric film including of a perovskite-type crystal represented by the following general formula (1): Ba.sub.1-xCa.sub.xTi.sub.1-yZr.sub.yO.sub.3 (0x0.2, 0y0.2) (1). The oriented piezoelectric film is formed on an oriented underlayer oriented in a (111) plane and contains first crystals oriented in the (111) plane with respect to a film surface and randomly oriented second crystal grains. The first crystal grains have an average grain diameter of from 300 nm to 600 nm and the second crystal grains have an average grain diameter of from 50 nm to 200 nm.

The present invention relates to an active material for a lithium secondary battery, which includes a secondary particle formed by agglomeration of primary particles which include a lithium titanium composite oxide represented by Formula 1 or Formula 2, wherein a pore volume is in a range of 0.001 cm.sup.3/g to 0.05 cm.sup.3/g, and a method of preparing the same, wherein the active material for a lithium secondary battery according to the present invention may maintain an adequate pore volume even during rolling, because strength of the secondary particle is improved by controlling a particle diameter of the primary particle by introducing a metallic element.

A manufacturing method of ceramic powder includes: synthesizing barium titanate powder from barium carbonate, titanium dioxide, manganese carbonate, and one of ammonium molybdate and tungsten oxide, wherein: a solid solution amount of the donor element is 0.05 mol or more and 0.3 mol or less; a solid solution amount of the accepter element with respect to the barium titanate is 0.02 mol or more and 0.2 mol or less on a presumption that the amount of the barium titanate is 100 mol and the acceptor element is converted into an oxide; and relationships y0.0003x+1.0106, y0.0002x+1.0114, 4x25 and y1.0099 are satisfied when a specific surface area of the ceramic powder is x and an axial ratio c/a of the ceramic powder is y.