Methods of forming spinel ferrite nanoparticles containing a chromium-substituted copper ferrite as well as properties (e.g. particle size, crystallite size, pore size, surface area) of these spinel ferrite nanoparticles are described. Methods of preventing or reducing microbe growth on a surface by applying these spinel ferrite nanoparticles onto the surface in the form of a suspension or an antimicrobial product are also described.

A production method for a magnetic material, which is expressed by a chemical structure formula Fe(Al.sub.1-xMn.sub.x).sub.2O.sub.4, where 0<x<1, and exhibits ferromagnetism, includes: preparing a mixed aqueous solution by dissolving, in distilled water, Fe nitrate, Al nitrate, and an oxide including Mn, the Fe nitrate, the Al nitrate, and the oxide being parent materials; preparing a metal-citric acid complex by mixing citric acid and ethylene glycol with the mixed aqueous solution; obtaining a precursor by boiling the metal-citric acid complex to a gel and drying the gel; and obtaining the magnetic material by sintering the precursor.

A positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charging and discharging as compared with those of a known positive electrode active material. In order to form the positive electrode active material having the pseudo-spinel crystal structure in the charged state, it is preferable that a halogen source such as a fluorine and a magnesium source be mixed with particles of a composite oxide containing lithium, a transition metal, and oxygen, which is synthesized in advance, and then the mixture be heated at an appropriate temperature for an appropriate time.

A method of producing a positive-electrode active material for a non-aqueous electrolyte secondary battery is provided. The method includes obtaining a precipitate containing nickel and manganese from a solution containing nickel and manganese, heat-treating the resulting precipitate at a temperature of from 850 C. to less than 1100 C. to obtain a first heat-treated product, mixing the first heat-treated product and a lithium compound, and heat-treating the resulting lithium-containing mixture at a temperature of from 550 C. to 1000 C. to obtain a second heat-treated product. The second heat-treated product contains a group of lithium transition metal composite oxide particles having an average particle diameter D.sub.SEM of from 0.5 m to less than 3 m and D.sub.50/D.sub.SEM of 1 to 2.5. The lithium transition metal composite oxide particles have a spinel structure based on nickel and manganese.

Provided is an improved method for forming a coated lithium ion cathode materials specifically for use in a battery. The method comprises forming a first solution comprising a digestible feedstock of a first metal suitable for formation of a cathode oxide precursor and a multi-carboxylic acid. The digestible feedstock is digested to form a first metal salt in solution wherein the first metal salt precipitates as a salt of deprotonated multi-carboxylic acid thereby forming an oxide precursor and a coating metal is added to the oxide precursor. The oxide precursor is heated to form the coated lithium ion cathode material.

A method for removing methoxyethanol from a mixture comprising methoxyethanol and morpholine makes use of the selective adsorption of methoxyethanol onto a mixed oxide comprising a spinel phase. The mixed oxide comprises 20 to 30% by weight MgO and 80 to 70% by weight Al.sub.2O.sub.3. The spinel phase has the formula MgAl.sub.2O.sub.4. The mixture is a pre-purified reaction output of the reaction of diethylene glycol with ammonia in the presence of an amination catalyst.

A positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charging and discharging as compared with those of a known positive electrode active material. In order to form the positive electrode active material having the pseudo-spinel crystal structure in the charged state, it is preferable that a halogen source such as a fluorine and a magnesium source be mixed with particles of a composite oxide containing lithium, a transition metal, and oxygen, which is synthesized in advance, and then the mixture be heated at an appropriate temperature for an appropriate time.

A magnetic fiber comprises a core comprising a spinel ferrite of formula Me.sub.1-xM.sub.xFe.sub.yO.sub.4, wherein Me is Mg, Mn, Fe, Co, Ni, Cu, Zn, or a combination thereof, x=0 to 0.25, and y=1.5 to 2.5, wherein the core is solid or at least partially hollow; and a shell at least partially surrounding the core, and comprising a Me.sub.1-xM.sub.xFe.sub.y alloy, wherein when the core is solid with Me=Ni and x=0 the magnetic fiber has a diameter of greater than 0.3 micrometer. A magneto-dielectric material having a magnetic loss tangent of less than or equal to 0.03 at 1 GHz comprises a polymer matrix; and a plurality of the magnetic fibers.

Li-ion battery materials, such as Li-ion cathodes, are provided that have spinels characterized by a close-packed face-centered-cubic rocksalt-type structure and spinel-like ordered TM (the TM preferably occupying one of the two octahedral sites 16c and 16d) that favor fast Li transport kinetics. Such spinels have a larger deviation from a normal spinel and have a formula. Li.sub.1+xTM.sub.2-yO.sub.4-zF.sub.z where 0.2x1, 0.2y0.6, and 0z0.8; and TM is Mn, Ni, Co, Al, Sc, Ti, Zr, Mg, Nb, or a mixture thereof. The spinels achieve a higher gravimetric energy density than traditional spinels while still retaining high capacity at an extremely fast charging/discharging rate.

Positive electrode active material particle powder includes: lithium manganese oxide particle powder having Li and Mn as main components and a cubic spinel structure with an Fd-3m space group. The lithium manganese oxide particle powder is composed of secondary particles, which are aggregates of primary particles, an average particle diameter (D50) of the secondary particles being from 4 m to 20 m, and at least 80% of the primary particles exposed on surfaces of the secondary particles each have a polyhedral shape having at least one plane that is adjacent to two planes.