The present invention provides a positive electrode active material for lithium secondary batteries including: secondary particles obtained by aggregating primary particles capable of being doped and de-doped with lithium ions, in which the secondary particles have pores, and pore distribution obtained by a mercury intrusion method satisfies requirements (1) and (2) below: (1) pores that are present in any one or both of the secondary particles or spaces between the secondary particles have a pore peak within a range of a pore radius of equal to or greater than 10 nm and equal to or less than 200 nm; and (2) a total surface area of pores that have pore radii of equal to or greater than 100 nm and equal to or less than 10 μm among the pores that are present in any one or both of the secondary particles or spaces between the secondary particles is less than 1.1 m.sup.2/g.

The present invention relates to a new synthetic manganese oxide material, a method of synthesis of the new manganese oxide material, and use of the new synthetic manganese oxide as a secondary battery active cathode material in an electrochemical application.

A capacitive element and a dielectric thin film having a small dielectric loss and a large relative permittivity, particularly at low frequencies. [Solution] This dielectric thin film includes an A-B—O—N oxynitride. When the A-B—O—N oxynitride is represented by the compositional formula A.sub.aB.sub.bO.sub.oN.sub.n, (o+n)/a<3.00 is satisfied.

A technique disclosed herein provides a positive electrode active material having a granular shape and used for a positive electrode of a secondary battery. The positive electrode active material includes, as an essential component, a lithium transition metal composite oxide containing at least manganese as a transition metal element and having a layered rock salt structure. A concentration difference between an average Mn concentration and a local maximum Mn concentration is equal to or less than 4 atm %, the average Mn concentration being measured based on ICP emission spectroscopic analysis of the positive electrode active material, and the local maximum Mn concentration being measured based on energy dispersive X-ray analysis with a transmission electron microscope.

A system for utilizing zinc oxide includes a first electrode comprising a zinc oxide reagent material, a current collector electrically connected to the zinc oxide reagent material, and a second electrode. The zinc oxide reagent material is capable of electrochemical intercalation and de-intercalation reactions with an electrolyte, and the zinc oxide reagent material comprises a zinc oxide intercalated with electrons. The current collector is configured to provide electrons and voltage control to the zinc oxide reagent material. The electrolyte in contact with the zinc oxide reagent material and is capable of executing intercalation reactions with the zinc oxide reagent material. The electronics are configured to control electrochemical voltage of the current collector and the zinc oxide reagent material, and the second electrode comprises a counter-electrode or a reference electrode electrically coupled to one or more electronics.

A method for preparing a Na.sub.3V.sub.2(PO.sub.4).sub.2F.sub.3 material, including at least the steps: a) reducing the vanadium oxide, V.sub.2O.sub.5, under a reducing atmosphere in the absence of elementary carbon and in the presence of at least one phosphate anion precursor in order to form vanadium phosphate, VPO.sub.4; and b) exposing, under an inert atmosphere, a mixture of the VPO.sub.4 material obtained in step a) with an effective amount of sodium fluoride, NaF, and at least one hydrocarbon- and oxygen-containing compound which is a source of elementary carbon, to temperature conditions that are favourable for calcining said mixture so as to form said Na.sub.3V.sub.2(PO.sub.4).sub.2F.sub.3 compound. Also, a related electrode material, an electrode and a secondary sodium battery using the presented material.

A device comprising a nonlinear optical (NLO) material according to the formula XLi.sub.2Al.sub.4B.sub.6O.sub.20F. A device comprising a nonlinear optical material (NLO) according to the formula KSrCO.sub.3F, wherein the NLO comprises at least one single crystal. A nonlinear optical material selected from the group consisting of KSrCO.sub.3F Rb.sub.3Ba.sub.3Li.sub.2Al.sub.4B.sub.6O.sub.20F and K.sub.3Sr.sub.3Li.sub.2Al.sub.4B.sub.6O.sub.20F.

A lithium-rich oxide positive electrode material. At least one unit lattice parameter (a, b, c) of the material decreases as the temperature increases at a temperature between 50 to 350 degrees. After treatment for 0.5 to 10 hours under the condition of 150 to 350° C., the degree of ordering of the material structure is increased, and the material has a higher discharge specific capacity and a higher discharge voltage when applied to a positive electrode of a lithium ion battery.

When a non-aqueous electrolyte secondary battery in which a positive electrode active material comprising a layered lithium-composite oxide is used for a positive electrode is subjected to charge/discharge under a prescribed condition, in a graph showing the relationship between voltage “V” with discharge during 5.sup.th cycle and value dQ/dV from differentiation of battery capacity “Q” with discharge during 5.sup.th cycle by voltage “V”, peak intensity ratio “r” represented by the equation: r=|Ic|/(|Ia|+|Ib|+|Ic|) satisfies 0<r≤0.25, in which |Ia| is absolute value dQ/dV for a peak top within a range of more than 3.9V to 4.4V or less, |Ib| is absolute value dQ/dV for a peak top within a range of more than 3.5V to 3.9V or less, and |Ic| is absolute value dQ/dV for a peak top within a range of 2.0V or more to 3.5V or less.

A cathode active material includes a composition expressed as:

Li.sub.1+β(Ni.sub.xMn.sub.yCo.sub.z).sup.M1.sub.α(Ni.sub.x′Mn.sub.y′Co.sub.z′).sup.M2.sub.1−αO.sub.2; or

Na.sub.1+β(Ni.sub.xMn.sub.yCo.sub.z).sup.M1.sub.α(Ni.sub.x′Mn.sub.y′Co.sub.z′).sup.M2.sub.1−αO.sub.2;

where: M1 represents a core composition comprising of Ni, Mn, and/or Co or a combination of at two of thereof; M2 represents a surface composition having at least 50% Co, and, optionally Ni and/or Mn; the structure of M2 may be a composite structure and includes a rock-salt or disordered rock-salt phase; 0.5≤α<1, 0≤x≤1, 0≤y≤0.5, 0≤z≤1, 0≤x′≤0.5, 0≤y′≤0.5, 0.5≤z′≤1, and −0.1≤β≤0.1; the sum of x, y and z is 0.9-1.1, and the sum of x′, y′ and z′ is 0.9-1.1.