Exemplary embodiments of positive electrode active materials in the form of single particles, and a method of preparing each of them, are provided. The single particles of the exemplary embodiments include single particles of a nickel-based lithium composite metal oxide, having a plurality of crystal grains, each having a size of 180 nm to 300 nm, as analyzed by a Cu Kα X-ray (X-rα). The single particles include a metal doped in the crystal lattice thereof. One embodiment includes a surface coating. The total content of the metal doped in the crystal lattice thereof and the metal of the metal oxide coated on the surface thereof is controlled in the range of 2500 ppm to 6000 ppm.

The present disclosure relates to a negative temperature coefficient product comprising an electrically conductive percolation network of printable NTC material as particles in a cross-linked dielectric polymer matrix and to a method of manufacturing thereof. The particles comprising a spinel phase, preferably a C-spinel phase, having a general formula M.sub.3O.sub.4 comprising at least a first metal M.sup.I that is manganese and second metal M.sup.II that is nickel. In addition the particles include a nickel oxide phase. The printable NTC material can be dispersed in a printable NTC ink comprising a dispersant, from which the NTC product, e.g. a thermistor, can be formed, e.g., after drying of the dispersant. During processing the ink is kept at a temperature below 300° C. Optionally, the spinel phase comprises a further metal M.sup.III. The weight fraction of nickel oxide with respect to the overall mass of the printable NTC material is preferably in a range between one and twenty weight percent.

Manganese-cobalt (Mn—Co) spinel oxide nanowire arrays are synthesized at low pressure and low temperature by a hydrothermal method. The method can include contacting a substrate with a solvent, such as water, that includes Mn04- and Co2 ions at a temperature from about 60° C. to about 120° C. The method preferably includes dissolving potassium permanganate (KMn04) in the solvent to yield the Mn04- ions. the substrate is The nanoarrays are useful for reducing a concentration of an impurity, such as a hydrocarbon, in a gas, such as an emission source. The resulting material with high surface area and high materials utilization efficiency can be directly used for environment and energy applications including emission control systems, air/water purifying systems and lithium-ion batteries.

A process for preparing a stable Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 is provided. The general formula of the potassium “A” site and Group VIII Period 4 (Fe, Co and Ni) “B” site modified lithium manganese-based AB.sub.2O.sub.4 spinel is Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 where Me is Fe, Co, or Ni. In addition, a Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 cathode material for electrochemical systems is provided. Furthermore, a lithium or lithium-ion rechargeable electrochemical cell is provided, incorporating the Li.sub.xK.sub.yMn.sub.2-zMe.sub.zO.sub.4 cathode material in a positive electrode.

A positive electrode of an active material of interconnected polycrystalline and porous particles for secondary battery has been developed to achieve greater diffusion, excellent specific capacity and life cycle. The active material of the positive electrode for secondary battery is obtained from a hot-pressing process to which the composite fiber membrane is subjected with the precursors of the active metals and the polymer, obtaining morphologies such as monocrystalline particles, two-dimensional plates, and bars.

An active material is provided for use in a solid-state battery. The active material exhibits at least one peak in the range of 0.145 to 0.185 nm and at least one peak in the range of 0.280 to 0.310 nm in a radial distribution function obtained through measurement of an X-ray absorption fine structure thereof. In the particle size distribution, by volume, of the active material obtained through a particle size distribution measurement by laser diffraction scattering method, the ratio of the absolute value of the difference between the mode diameter of the active material and the D.sub.10 of the active material (referred to as the “mode diameter” and the “D.sub.10” respectively) to the mode diameter in percentage terms, (|mode diameter - D.sub.10 / mode diameter) x 100, satisfies 0% < (( | mode diameter - D.sub.10| / mode diameter) x 100) ≤ 58.0%.

A porous body comprises a framework having a three-dimensional network structure, the framework having a body including nickel and cobalt as constituent elements, the body of the framework including the cobalt at a proportion in mass of 0.2 or more and 0.8 or less relative to a total mass of the nickel and the cobalt, the framework having a surface with an arithmetic mean roughness of 0.05 μm or more, the porous body being increased in volume by 1% or more for a shape of an external appearance thereof after the porous body undergoes a heat treatment in the atmosphere at 800° C. for 200 hours with a load of 16 kPa applied.

A composite cathode active material and a cathode and a lithium battery including the composite cathode active material. The composite cathode active material has a core including a plurality of primary particles including a nickel-containing first lithium transition metal oxide having a layered crystal structure; a grain boundary disposed between adjacent primary particles of the plurality of primary particles; and a shell on the core, the shell including a second lithium transition metal oxide having a spinel crystal structure, wherein the grain boundary includes a first composition having a spinel crystal structure.

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.

Described are lithium transition metal halides which have ionic conductivity for lithium ions, a process for preparing them, their use as a solid electrolyte for an electrochemical cell, and electrochemical cells comprising lithium transition metal halides.