The invention relates to a method for exchanging interlayer anions of a layered double hydroxide (LDH) with other anions whose affinity for the LDH is lower than the one of the starting interlayer anions, which comprises the successive steps of: (1) exchanging the starting interlayer anions of a layered double hydroxide with polyoxometalate anions in order to obtain a layered double hydroxide with polyoxometalate anions as interlayer anions, and (2) exchanging the polyoxometalate anions of the layered double hydroxide obtained in step (1) with other anions whose affinity for the LDH is lower than the one of the starting interlayer anions in order to obtain a layered double hydroxide with other anions as interlayer anions.

The present invention relates to a method for preparing a CaMgAl mixed oxide comprising the steps: a) providing a modified layered double hydroxide of the formula (I) wherein in formula (I) 0<x<0.9; b is from 0 to 10, preferably 1 to 10; c is from 0 to 10, preferably 1 to 10 and the AMO-solvent is an organic solvent miscible with water; b) calcining the modified layered double hydroxide; c) reacting the calcined modified layered double hydroxide with a calcium salt in the presence of an (a) organic acid; and d) calcining the product obtained in step c) to obtain the CaMgAl mixed oxide; a CaMgAl mixed oxide obtainable this way; and the use thereof.

A nickel hydroxide includes stacked nickel hydroxide layers. Each of the nickel hydroxide layers includes Ni.sup.2+ and OH.sup.. At least one of the nickel hydroxide layers further includes a type of polyatomic anions. The polyatomic anions include a type of anions that are not SO.sub.4.sup.2 or CO.sub.3.sup.2.

Methods for preparing a layered metal nanocomposite and a layered metal nanocomposite. The method includes mixing a magnesium salt and a aluminum salt to form a Mg.sup.2+/Al.sup.3+ solution. The Mg/Al has a molar ratio of between 0.5:1 to 6:1. Then a diamondoid compound is added to the Mg.sup.2+/Al.sup.3+ solution to form a reactant mixture. The diamondoid compound has at least one carboxylic acid moiety. The reactant mixture is heated at a reaction temperature for a reaction time to form a Mg/Al-diamondoid intercalated layered double hydroxide. The Mg/Al-diamondoid intercalated layered double hydroxide is thermally decomposed under a reducing atmosphere for a decomposition time at a decomposition temperature to form the layered metal nanocomposite.

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.

Provided is an active material for a fluoride-ion secondary battery, the active material containing a composite fluoride. The composite fluoride has a layered structure and is represented by a composition formula A.sub.mM.sub.nF.sub.x, where A is an alkali metal, M is a transition metal, 0<m2, 1n2, and 3x4. The alkali metal may be at least one kind selected from the group consisting of Na, K, Rb, and Cs. The transition metal may be a 3d transition metal.

Further described herein are extensions to the basic concept of LHs as electrode materials, include both new materials for use with LHs and higher order poly-layer hydroxides (PLHs) as well as methods for synthesizing improved LH material such as with conductive supports or through the use of cross-linking. Finally, also described herein are embodiments enabling the use of LHs as flow electrodes as well as the use of 2-d LH materials for surface redox reactions.

A method for producing hydrotalcite particles includes dissolving aluminum hydroxide in an alkaline solution to prepare an aluminate solution, causing a reaction of the aluminate solution prepared in the first step with carbon dioxide to precipitate a low-crystallinity aluminum compound, causing a first-order reaction by mixing the low-crystallinity aluminum compound with a magnesium compound to prepare a reactant containing hydrotalcite nuclear particles, and causing a hydrothermal reaction of the reactant to synthesize hydrotalcite particles. The hydrotalcite particles can impart excellent heat resistance, transparency, flowability, and are useful as a resin stabilizer.

Electrode materials for electrochemical cells and batteries and methods of producing such materials are disclosed herein. The electrode materials comprise an active lithium metal oxide material prepared by: (a) contacting the lithium metal oxide material with an aqueous acidic solution containing one or more metal cations; and (b) heating the so-contacted lithium metal oxide from step (a) to dryness at a temperature below 200 C. The metal cations in the aqueous acidic solution comprise one or more metal cations selected from the group consisting of an alkaline earth metal ion, a transition metal ion, and a main group metal ion.

The present disclosure relates to a method for producing lanthanide doped layered double hydroxides (Ln-doped LDHs). The method includes the steps of preparing a carbonate free alkaline solution; preparing a solution of metal salts comprising a salt of a lanthanide; co-precipitating the alkaline solution and the solution of metal salts to form a mixture and Ln-doped LDH precipitate wherein the pH of the mixture is maintained at a constant value; aging the precipitate; and separating the precipitate from the solution. The alkaline solution is an aqueous ammonia solution. The present disclosure is also related to lanthanide-doped layered double hydroxides (La-doped LDHs) obtainable by such a method, as well as to the use of the lanthanide-doped layered double hydroxides obtainable by such a method.