A magnetic hydrotalcite composite which is useful in fields such as wastewater treatment, ultraviolet absorption, electromagnetic wave absorption and acid gas absorption, and a production method thereof. The magnetic hydrotalcite composite comprises an inner layer and an outer layer, in which the inner layer is made of a hydrotalcite compound and the outer layer is made of a ferrite compound.

Layered double hydroxides organo-modified by 3-(4-hydroxyphenyl)propionic acid (HPPA), by 2-(4-hydroxyphenyl)ethylsulfonic acid or by a hydroxyphenylpropenoic acid, and to composite polymer materials having same. The composite materials are advantageously made of biosourced polymers such as poly(butylene succinate). These composite materials have improved properties over the polymers that make up the composition thereof, and over the composites of the prior art.

Disclosed is an -phase nickel hydroxide and a preparation method and use thereof. The method for preparing an -phase nickel hydroxide comprises the following steps: subjecting a biomass calcium source to a calcination to obtain a porous calcium oxide; under a protective atmosphere, mixing the porous calcium oxide with a first methanol-ethanol solvent to obtain a calcium oxide heterogeneous solution; under a protective atmosphere, mixing the calcium oxide heterogeneous solution with a nickel source homogeneous solution to obtain a mixture, and subjecting the mixture to a coprecipitation to obtain a nickel calcium hydroxide precursor, wherein the nickel source homogeneous solution is prepared with a nickel source containing crystal water as a solute and a second methanol-ethanol solvent as a solvent; and subjecting the nickel calcium hydroxide precursor to a calcium hydroxide removal treatment to obtain the -phase nickel hydroxide.

The present invention relates to a method for extracting magnesium and lithium and also producing layered double hydroxides (LDH) from brine, comprising the steps of: adding an aluminum salt to brine, to prepare a mixed salt solution A for preparing MgAl-LDH; adding an alkaline solution to carry out co-precipitation, followed by crystallization; after the crystallization is complete, performing solid-liquid separation to obtain a solid product of MgAl-LDH and a filtrate; concentrating the filtrate by evaporation to obtain a lithium-rich brine, adding an aluminum salt thereto to prepare a mixed salt solution B for preparing LiAl-LDH; adding the mixed salt solution B to an alkaline solution to carry out precipitation; after the precipitation is complete, performing solid-liquid separation to obtain a solid product of LiAl-LDH and a filtrate; and concentrating the filtrate by evaporation, returning the solution concentrated by evaporation to the lithium-rich brine for recycled use. This method uses mild reaction and simple equipment, has a small loss of Li, can achieve isolation of resources from salt lakes, and can also obtain functional materials having a high added value.

The present invention provides a layered double hydroxide with improved conductivity, a layered double hydroxide and a composite material containing the layered double hydroxide. The layered double hydroxide is represented by the general formula: [Mg.sup.2+.sub.(1-y)M1.sup.+.sub.y].sub.1-x[Al.sup.3+.sub.(1-z)M2.sup.+.sub.z].sub.x(OH).sub.2A.sup.n.sub.x/n.mH.sub.2O, wherein 0.1x0.4, 0y0.95, and 0z0.95, provided that both y and z are not 0 at the same time; =1 or 2; =2 or 3; A.sup.n is an n-valent anion, provided that n is an integer of 1 or greater; m0; M1.sup.+ is a cation of at least one substituent element selected from monovalent elements, transition metal elements, and other elements with an ionic radius greater than that of Mg.sup.2+; and M2.sup.+ is a cation of at least one element selected from divalent elements, transition metals, and other elements with an ionic radius greater than that of Al.sup.3+.

A process for preparing particles of a layered double hydroxide of the general formula

[M.sub.p.sup.z+M.sub.q.sup.y+(OH).sub.2].sup.a+(X.sup.n).sub.a/n.bH.sub.2O(I)

wherein M.sup.z+ and M.sup.y+ are metal cations or mixtures of metal cations, z=1 or 2; y=3 or 4; p+q=1; b=0 to 10, X.sup.n is an anion, n is 1 to 5 and a is determined by p, q, y and z such that a=zp+yq2, comprises (a) mixing, in aqueous solution, M.sup.z+ cations, M.sup.y+ cations and X.sup.n anions, with a base; and (b) allowing the layered double hydroxide of formula (I) to precipitate from the solution mixed in step (a).

Preferably, M is Li, Mg, Zn, Fe, Ni, Co, Cu, Ca, or a mixture of two or more. Preferably, y is 3, and M is Al, Ga, In, Fe or a mixture of two or more thereof. Also provided are particles obtainable by the process, especially wherein M is Ca, M is Al, and X.sup.n is NO.sub.3.sup.. Particles of a layered double hydroxide wherein the particles have a particle size of not greater than 2000 nm, preferably not greater than 300 nm and especially not greater than 100 nm, are also provided. The layered double hydroxides according to the invention are useful in certain applications, for example, as adsorbents, coatings and catalyst supports.

A preparation method of a battery composite material includes steps of providing phosphoric acid, manganese carbonate, water and a first reactant; processing a reaction of the phosphoric acid, the manganese carbonate and the water to produce a first product; calcining the first product to produce a precursor, which is written by Mn.sub.2P.sub.2O.sub.7; processing a reaction of the precursor and at least the first reactant to get a reaction mixture, and then calcining the reaction mixture to produce the battery composite material. As a result, the present invention achieves the advantages of reducing the times of the reduction-oxidation reaction, so that the stability of the processes is enhanced, and the difficulty of the processes is reduced.

The present invention provides a layered double hydroxide with improved conductivity, a layered double hydroxide and a composite material containing the layered double hydroxide. The layered double hydroxide is represented by the general formula: [Mg.sup.2+.sub.(1-y)M1.sup.+.sub.y].sub.1-x[Al.sup.3+.sub.(1-z)M2.sup.+.sub.z].sub.x(OH).sub.2A.sup.n.sub.x/n.mH.sub.2O, wherein 0.1x0.4, 0y0.95, and 0z0.95, provided that both y and z are not 0 at the same time; =1 or 2; =2 or 3; A.sup.n is an n-valent anion, provided that n is an integer of 1 or greater; m0; M1.sup.+ is a cation of at least one substituent element selected from monovalent elements, transition metal elements, and other elements with an ionic radius greater than that of Mg.sup.2+; and M2.sup.+ is a cation of at least one element selected from divalent elements, transition metals, and other elements with an ionic radius greater than that of Al.sup.3+.

An oxide composite positive electrode material coated with borate in situ, includes A.sub.xB.sub.yO.sub.zNa.sub.aLi.sub.bNi.sub.cCu.sub.dMn.sub.eM.sub.fO.sub.2+. In the material, Li, Ni, Cu, Mn, and element M for doping and substituting a transition metal site together occupy the position of transition metal ions in the crystal structure. The space group of the layered oxide composite positive electrode material is P63/mmc or P63/mcm or R3m, or the corresponding structure is a P2 phase or an O3 phase. A.sub.xB.sub.yO.sub.z is a coating layer that has a needle-like structure and is generated in situ on the surface of Na.sub.aLi.sub.bNi.sub.cCu.sub.dMn.sub.eM.sub.fO.sub.2+, being formed by, during a sintering process, coating a material precursor and a layered oxide precursor for generating Na.sub.aLi.sub.bNi.sub.cCu.sub.dMn.sub.eM.sub.fO.sub.2+; is the mass fraction of the coating material precursor in the layered oxide precursor, 0.1 wt %10 wt %; and A is Li and/or Na.

Layered electrode materials, positive electrodes, rechargeable zinc batteries, and methods are provided. A layered electrode material for use in a rechargeable zinc battery includes a plurality of active metal slab layers in a layered configuration. The active metal slab layer includes a plurality of redox active metal centers and a closely-packed anionic sublattice. A plurality of interlamellar spaces separate adjacent active metal slab layers in the layered configuration. The interlamellar space includes at least one pillar species. The layered electrode material has a combined average metal oxidation state in a range of +3 to +4 in an initial charged state. The layered electrode material accepts solvated zinc cations via intercalation into the interlamellar space upon reduction.