A material having a layered structure having at least a first layer, comprising a carbon-based material or a substrate of a material other than said carbon-based material, a second layer, comprising said carbon-based material, and a third, intermediate layer that separates and interconnects the first and second layers, wherein said carbon-based material comprises at least 50 at. % carbon, has a hexagonal lattice and wherein the layer or layers comprising said carbon-based material has/have a thickness of 1-20 times the size of a carbon atom. Said at least one intermediate layer is a layer that comprises a salt having ions that comprise at least two separate cyclic, planar groups that are capable of forming --stacking with the material of at least said second layer and that the third, intermediate layer is connected to at least the second layer by --stacking caused by said cyclic planar groups of the salt ions.

A positive electrode active material including a nickel-containing lithium transition metal oxide containing nickel in an amount of 60 mol % or more based on a total number of moles of transition metals excluding lithium, and a coating layer which is formed on a surface of the nickel-containing lithium transition metal oxide and includes a lithium-containing inorganic compound, a nickel oxide, and a nickel oxyhydroxide is provided. A method of preparing the positive electrode active material, and a positive electrode for a lithium secondary battery and a lithium secondary battery which include the positive electrode active material are also provided.

The invention relates to a lithium metaborate crystal and a preparation method and use thereof. The crystal has a chemical formula of LiBO.sub.2, a molecular weight of 49.75, and is a member of the monoclinic crystal system. The crystal has a P2.sub.1/c space group and lattice constants of a=5.85(8) , b=4.35(7) , c=6.46(6) , =115(5), and Z=4. The crystal can be applied in wavelengths of infrared-visible-deep ultraviolet, and is grown by utilizing a melt crystallization method or a flux method. The crystal obtained using the method described in the invention is easily grown and processed, and can be used in the manufacture of a polarizing beam splitting prism such as a Glan prism, a Wollaston prism, a Rochon prism or a beam-splitting polarizer, and other optical components, enabling crucial applications in the fields of optics and communication.

A nonlinear optical crystal of cesium fluorooxoborate, and a method of preparation and use thereof. The crystal has a chemical formula of CsB.sub.4O.sub.6F and a molecular weight of 291.15. It belongs to an orthorhombic crystal system, with a space group of Pna2.sub.1, crystal cell parameters of a=7.9241 , b=11.3996 , c=6.6638 , and ===90, and a unit cell volume of 601.95 .sup.3. A melt method, high temperature solution method, vacuum encapsulation method, hydrothermal method or room temperature solution method is used to grow the crystal of CsB.sub.4O.sub.6F.

A positive electrode active material for a secondary battery contains second particles which are produced by aggregation of primary particles of a lithium transition metal oxide containing Ni and W, and a boron compound present inside and on the surfaces of the secondary particles.

A main object of the present disclosure is to provide a cathode active material capable of suppressing the reaction with a solid electrolyte. The present disclosure achieves the object by providing a coated cathode active material comprising: a cathode active material, and a coating portion coating at least a part of a surface of the cathode active material, and the coating portion includes a scandium lithium phosphate based compound or a lithium borate based compound.

The invention relates to a lithium metaborate crystal and a preparation method and use thereof. The crystal has a chemical formula of LiBO.sub.2, a molecular weight of 49.75, and is a member of the monoclinic crystal system. The crystal has a P2.sub.1/c space group and lattice constants of a=5.85(8) , b=4.35(7) , c=6.46(6) , =115(5) I, and Z=4. The crystal can be applied in wavelengths of infrared-visible-deep ultraviolet, and is grown by utilizing a melt crystallization method or a flux method. The crystal obtained using the method described in the invention is easily grown and processed, and can be used in the manufacture of a polarizing beam splitting prism such as a Glan prism, a Wollaston prism, a Rochon prism or a beam-splitting polarizer, and other optical components, enabling crucial applications in the fields of optics and communication.

A compound M.sub.jX.sub.p which is particularly suitable for use in a battery prepared by the complexometric precursor formulation methodology wherein: M.sub.j is at least one positive ion selected from the group consisting of alkali metals, alkaline earth metals and transition metals and j is an integer representing the moles of said positive ion per moles of said M.sub.jX.sub.p; and X.sub.p, a negative anion or polyanion from Groups IIIA, IVA, VA, VIA and VIIA and may be one or more anion or polyanion and p is an integer representing the moles of said negative ion per moles of said M.sub.jX.sub.p.

A main object of the present disclosure is to provide a cathode active material capable of suppressing the reaction with a solid electrolyte. The present disclosure achieves the object by providing a coated cathode active material comprising: a cathode active material, and a coating portion coating at least a part of a surface of the cathode active material, and the coating portion includes a scandium lithium phosphate based compound or a lithium borate based compound.

The present invention has an object to provide a positive electrode active material for a non-aqueous electrolyte secondary battery which not only suppresses gelation of a positive electrode mixed material paste upon producing the non-aqueous electrolyte secondary battery but also improves the stability thereof. Provided is the positive electrode active material represented by general formula Li.sub.sNi.sub.1xyzCo.sub.xMn.sub.yM.sub.zO.sub.2+ (0x0.35, 0y0.35, 0z0.10, 0.95s1.30, and 00.2, and M represents at least one element selected from V, Mg, Mo, Nb, Ti, W, and Al) and containing secondary particles formed by agglomeration of primary particles, wherein at least part of the surface of the primary particles thereof is covered with a lithium boron compound, and the amount of redundant lithium hydroxide of the positive electrode active material measured with a neutralization titration is at least 0.003% by mass and up to 0.5% by mass relative to the total of the positive electrode active material.