The present invention relates, in general terms, to piezoelectric thin films with an empirical formula (K.sub.1xNa.sub.x).sub.yNbO.sub.3, wherein 0≤x≤1 and 0.64≤y≤0.95. In particular, the piezoelectric thin film comprises at least two adjacent NbO.sub.2 planes in an antiphase boundary, the at least two adjacent NbO.sub.2 planes displaced from each other by about half a lattice length in either the (100), (010) or (100) crystallographic plane. The present invention also relates to methods of fabricating the piezoelectric thin films.

Various lithium cobalt oxides materials having a chemical formula of Li.sub.xCo.sub.yO.sub.z, and method and apparatus of producing the various lithium cobalt oxides materials are provided. The method includes adjusting a molar ratio M.sub.LiSalt:M.sub.CoSalt of a lithium-containing salt, and a cobalt-containing salt within a liquid mixture to be equivalent to a ratio of x:y, drying a mist of the liquid mixture in the presence of a gas to form a gas-solid mixture, separating the gas-solid mixture into one or more solid particles of an oxide material, and annealing the solid particles of the oxide material in the presence of another gas flow to obtain crystallized particles of the lithium cobalt oxide material. The process system has a mist generator, a drying chamber, one or more gas-solid separator, and one or more reactors.

A device comprising a nonlinear optical (NLO) material according to the formula XLi.sub.2Al.sub.4B.sub.6O.sub.20F. A device comprising a nonlinear optical material (NLO) according to the formula KSrCO.sub.3F, wherein the NLO comprises at least one single crystal. A nonlinear optical material selected from the group consisting of KSrCO.sub.3F Rb.sub.3Ba.sub.3Li.sub.2Al.sub.4B.sub.6O.sub.20F and K.sub.3Sr.sub.3Li.sub.2Al.sub.4B.sub.6O.sub.20F.

Phosphors include a CaAlSiN.sub.3 family crystal phase, wherein the CaAlSiN.sub.3 family crystal phase comprises at least one element selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb.

A positive electrode for an all-solid secondary battery, comprising a positive electrode active material expressed by A.sub.2S.AX, wherein

A is an alkali metal; and

X is selected from I, Br, Cl, F, BF.sub.4, BH.sub.4, SO.sub.4, BO.sub.3, PO.sub.4, O, Se, N, P, As, Sb, PF.sub.6, AsF.sub.6, ClO.sub.4, NO.sub.3, CO.sub.3, CF.sub.3SO.sub.3, CF.sub.3COO, N(SO.sub.2F).sub.2 and N(CF.sub.3SO.sub.2).sub.2.

The present invention generally relates to P2-type layered materials for electrochemical devices such as Na-ion batteries with high rate performance, and methods of making or using such materials. In some embodiments, the P2-type layered material has the chemical formula Na.sub.X(Mn.sub.QFe.sub.RCo.sub.T)O.sub.2. The P2-type layered material may be synthesized, for example, by a solid state reaction. In some cases, the P2-type layered material may be used as an electrode in an electrochemical device. The electrochemical device may have higher initial discharge capacities at various charge/discharge rates in galvanostatic testing compared with the initial discharge capacities of other P2-type layered materials.

Provided are a positive active material, a positive electrode including the same, and a lithium secondary battery including the positive electrode. The positive active material includes lithium cobalt oxide containing a metal element, and the lithium cobalt oxide containing a metal element has a ratio of a peak intensity of the O3 phase to a peak intensity of the H1-3 phase, I.sub.O3/I.sub.H1-3, that is greater than 1 in a X-ray diffraction (XRD) analysis spectrum using Cu-Kα radiation. Accordingly, a lithium secondary battery including the positive active material may have improved lifespan characteristics even at a high voltage.

A production method of a battery active material of the present embodiment includes a step of obtaining a coprecipitated product containing Ti and Nb by mixing a solution with a pH of 5 or lower, in which a Ti compound is dissolved, and a solution with a pH of 5 or lower, in which a Nb compound is dissolved, such that molar ratio of Ti and Nb (Nb/Ti) is adjusted within a range of 1≦Nb/Ti≦28, and then further mixing with an alkali solution with a pH of 8 or higher; and a step of burning the coprecipitated product under condition of 635° C. or higher and 1200° C. or lower.

To provide a lithium ion conductive crystal body having a high density and a large length and an all-solid state lithium ion secondary battery containing the lithium ion conductive crystal body. A Li.sub.5La.sub.3Ta.sub.2O.sub.12 crystal body, which is one example of the lithium ion conductive crystal body, has a relative density of 99% or more, belongs to a cubic system, has a garnet-related type structure, and has a length of 2 cm or more. The Li.sub.5La.sub.3Ta.sub.2O.sub.12 crystal body is grown by a melting method employing a Li.sub.5La.sub.3Ta.sub.2O.sub.12 polycrystal body as a raw material. With the growing method, a Li.sub.5La.sub.3Ta.sub.2O.sub.12 crystal body having a relative density of 100% can also be obtained. In addition, the all-solid state lithium ion secondary battery has a positive electrode, a negative electrode, and a solid electrolyte, in which the solid electrolyte contains the lithium ion conductive crystal body.

A positive active material for a rechargeable lithium battery includes a compound represented by Chemical Formula 1, Li.sub.aNi.sub.xCo.sub.yMe.sub.zM.sup.1.sub.kM.sup.2.sub.pO.sub.2 wherein, 0.9≦a≦1.1, 0.7≦x≦0.93, 0<y≦0.3, 0<z≦0.3, 0.001≦k≦0.006, 0.001 ≦p≦0.005, x+y+z+k+p=1, Me is Mn or Al, M.sup.1 is a divalent element, and M.sup.2 is a tetravalent element.