A positive electrode active material that is stable in a high potential state or a high temperature state and a highly safe secondary battery are provided. The positive electrode includes a first material and a second material and includes a region where at least part of a surface of the first material is covered with the second material. The first material includes a lithium cobalt oxide containing magnesium, fluorine, aluminum, and nickel. The second material includes a composite oxide (containing one or more selected from Fe, Ni, Co, and Mn) having an olivine crystal structure.

A solid electrolyte material for a lithium secondary battery, an electrode, and a battery, relating in particular to an additive material capable of improving rapid transmission of ions in lithium secondary battery electrodes, a preparation method therefor and application thereof, and a solid electrolyte material for a secondary battery, a preparation method therefor and application thereof, as well as an electrode, an electrolyte thin layer, and a preparation method therefor.

Disclosed is a modified iron oxyhydroxynitrate including iron oxyhydroxynitrate and hydrogen phosphate ions adsorbed on a surface thereof. Also disclosed is a method for preparing the same, a positive electrode for a lithium secondary battery including the modified iron oxyhydroxynitrate as a positive electrode additive, and a lithium secondary battery including the same.

A lithium-ion conductor includes an inorganic compound with a chemical composition of Li.sub.2−3x+y−zFe.sub.xO.sub.y(OH).sub.1−yCl.sub.1−z, where x is greater than or equal to 0 and less than 1, y is greater than or equal to 0 and less than or equal 1, and z is greater than or equal to 0 and less than or equal 0.25. Also, the inorganic compound has or exhibits a thermal decomposition temperature greater than 390° C., an ionic conductivity greater than about 1.0×10.sup.−4 S/cm at 25° C., and has a crystal structure that reflects or exhibits x-ray diffraction peaks with a 2θ between about 22.12° and about 24.12°, between about 31.97° and about 33.97°, between about 39.55° and about 41.55°, between about 46.46° and about 48.46°, between about 57.77° and about 59.77°, and between about 68.04° and about 70.04°.

A main object of the present disclosure is to provide a new active material that can be used in a fluoride ion battery. The present disclosure achieves the object by providing an active material to be used in a fluoride ion battery, the active material comprising: a crystal phase including an infinite layer structure, and represented by A.sub.pB.sub.qO.sub.r, provided that A is at least one of an alkali earth metal element and a rare earth element, B is a transition metal element, p satisfies 0.8≤p≤1, q satisfies 0.8≤q≤1, and r satisfies 1.5≤r≤2.5.

An object is to reduce variation in shape of crystals that are to be formed. Solutions containing respective raw materials are made in an environment where an oxygen concentration is lower than that in air, the solutions containing the respective raw materials are mixed in an environment where an oxygen concentration is lower than that in air to form a mixture solution, and with use of the mixture solution, a composite oxide is formed by a hydrothermal method.

This disclosure relates to a rechargeable battery cell comprising an active metal, at least one positive electrode, at least one negative electrode, a housing and an electrolyte, the positive electrode being designed as a high-voltage electrode and the electrolyte being based on SO.sub.2 and at least one first conducting salt having the formula (I),

##STR00001##

M being a metal selected from the group formed by alkali metals, alkaline earth metals, metals of group 12 of the periodic table of the elements, and aluminum; x being an integer from 1 to 3; the substituents R.sup.1, R.sup.2, R.sup.3 and R.sup.4 being selected independently of one another from the group formed by C.sub.1-C.sub.10 alkyl, C.sub.2-C.sub.10 alkenyl, C.sub.2-C.sub.10 alkynyl, C.sub.3-C.sub.10 cycloalkyl, C.sub.6-C.sub.14 aryl and C.sub.5-C.sub.14 heteroaryl; and Z being aluminum or boron.

This disclosure relates to a rechargeable battery cell comprising an active metal, at least one positive electrode having a discharge element, at least one negative electrode having a discharge element, a housing and an electrolyte, the negative electrode comprising metallic lithium at least in the charged state of the rechargeable battery cell and the electrolyte being based on SO.sub.2 and comprising at least one first conducting salt which has the formula (I),

##STR00001## M being a metal selected from the group formed by alkali metals, alkaline earth metals, metals of group 12 of the periodic table of the elements, and aluminum; x being an integer from 1 to 3; the substituents R.sup.1, R.sup.2, R.sup.3 and R.sup.4 being selected independently of one another from the group formed by C.sub.1-C.sub.10 alkyl, C.sub.2-C.sub.10 alkenyl, C.sub.2-C.sub.10 alkynyl, C.sub.3-C.sub.10 cycloalkyl, C.sub.6-C.sub.14 aryl and C.sub.5-C.sub.14 heteroaryl; and Z being aluminum or boron.

A hexagonal strontium ferrite powder, in which an average particle size is 10.0 to 25.0 nm, a content of one or more kinds of atom selected from the group consisting of a gallium atom, a scandium atom, an indium atom, and an antimony atom is 1.0 to 15.0 atom % with respect to 100.0 atom % of an iron atom, and a coercivity Hc is greater than 2,000 Oe and smaller than 4.000 Oe. A magnetic recording medium including: a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which the ferromagnetic powder is the hexagonal strontium ferrite powder. A magnetic recording and reproducing apparatus including this magnetic recording medium.

This application relates to a sodium-ion battery, a positive electrode plate for a sodium-ion battery, a battery module, a battery pack, and a device. The sodium-ion battery according to this application includes a positive electrode plate, a negative electrode plate, a separator, and an electrolytic solution. The positive electrode plate includes a positive active material. A molecular formula of the positive active material satisfies Na.sub.aLi.sub.bM.sub.0.7Fe.sub.0.3−bO.sub.2±δ, M is a transition metal ion, 0.67<a<1.1, 0<b<0.3, 0≤δ≤0.1, and a ratio of R.sub.ct to R.sub.f of the positive active material satisfies 1.0<R.sub.ct/R.sub.f<20.0. R.sub.ct is a charge transfer resistance of the positive active material measured in a button battery based on alternating current impedance spectroscopy, and R.sub.f is a diffusion resistance of the positive active material measured in the button battery based on the alternating current impedance spectroscopy.