The present invention provides an active electrode material comprising a mixture of (a) at least one niobium oxide and (b) at least one mixed niobium oxide; wherein the mixed niobium oxide has the composition M1.sub.aM2.sub.1-aM3.sub.bNb.sub.12-bO.sub.33-c-dQ.sub.d, wherein: M1 and M2 are different; M1 is selected from Mg, Ca, Sr, Y, La, Ce, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, Zn, Cd, B, Al, Ga, In, Si, Ge, Sn, Pb, P, Sb, Bi and mixtures thereof; M2 is Mo or W; M3 is selected from Mg, Ca, Sr, Y, La, Ce, Ti, Zr, Hf, V, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, Zn, Cd, B, Al, Ga, In, Si, Ge, Sn, Pb, P, Sb, Bi, and mixtures thereof; Q is selected from F, Cl, Br, I, N, S, Se, and mixtures thereof; 0≤a<0.5; 0≤b≤2; −0.5≤c≤1.65; 0≤d≤1.65; one or more of a, b, c and d does not equal zero; and when a, b, and d equal zero, c is greater than zero. Such materials are of interest as active electrode materials in lithium-ion or sodium-ion batteries.

An electrochemical device and electronic device, including a positive electrode plate and a negative electrode plate, wherein the positive electrode plate includes a positive electrode current collector and a positive electrode active material, and the negative electrode plate includes a negative electrode current collector and a group of step coatings disposed on surface of the negative electrode current collector close to the positive electrode plate, and a weight of the positive electrode active material per unit area on the positive electrode current collector is g.sub.a expressed in cm.sup.2, a gram capacity of the positive active material is C.sub.a expressed in mAh/g, a thickness of the step coating is L expressed in μm, and a theoretical volume gram capacity of sodium metal is X expressed in mAh/cm.sup.3, and L satisfies Formula (I) are described.

[00001]$\begin{array}{cc}L=\frac{C_a*g_a}{X}*10000*\left(1\pm 0\text{.1}\right).& \left(I\right)\end{array}$

An electrochemical device and electronic device, including a positive electrode plate and a negative electrode plate, wherein the positive electrode plate includes a positive electrode current collector and a positive electrode active material, and the negative electrode plate includes a negative electrode current collector and a group of step coatings disposed on surface of the negative electrode current collector close to the positive electrode plate, and a weight of the positive electrode active material per unit area on the positive electrode current collector is g.sub.a expressed in cm.sup.2, a gram capacity of the positive active material is C.sub.a expressed in mAh/g, a thickness of the step coating is L expressed in μm, and a theoretical volume gram capacity of sodium metal is X expressed in mAh/cm.sup.3, and L satisfies Formula (I) are described.

[00001]$\begin{array}{cc}L=\frac{C_a*g_a}{X}*10000*\left(1\pm 0\text{.1}\right).& \left(I\right)\end{array}$

Disclosed is a positive electrode material having inhibited increase in heat release when exposed to high temperature. The positive electrode material of the disclosure comprises a positive electrode active material, a first solid electrolyte and a second solid electrolyte, wherein the positive electrode active material comprises a lithium-containing oxide, the first solid electrolyte comprises Li and X as constituent elements and comprises no S, X is one or more elements selected from the group consisting of F, Cl, Br and I, the second solid electrolyte comprises Li and S as constituent elements, the first solid electrolyte covers at least part of the surface of the positive electrode active material, the second solid electrolyte contacts with the positive electrode active material across the first solid electrolyte, and the average covering thickness of the first solid electrolyte is 104 nm or greater.

A sacrificial positive active material for a lithium-ion electrochemical element which is a compound of formula (Li.sub.2O).sub.x (MnO.sub.2).sub.y(MnO).sub.z(MO.sub.a).sub.t in which: x+y+z+t=1; 1−x−y≥0; 0.97≥x≥0.6; y≤0.45; x −0.17; y≥0; y+z>0; t≥0; 1≤a<3. M is selected from the group consisting of Fe, Co, Ni, B, Al, Ti, Si, V, Mo, Zr and a mixture thereof.

This application describes a process for the preparation of carbon-coated particles, where the particles comprise an electrochemically active material. The process comprises the steps of emulsion polymerization, drying and thermally treating the polymer to obtain a nano-layer of carbon on the particles, where the carbon layer comprises fibers and nitrogen-containing polyaromatics have a graphene-like structure. The application also further relates to the particles produced by the method as well as to electrode materials, electrodes and electrochemical cells comprising the particles.

This application describes a process for the preparation of carbon-coated particles, where the particles comprise an electrochemically active material. The process comprises the steps of emulsion polymerization, drying and thermally treating the polymer to obtain a nano-layer of carbon on the particles, where the carbon layer comprises fibers and nitrogen-containing polyaromatics have a graphene-like structure. The application also further relates to the particles produced by the method as well as to electrode materials, electrodes and electrochemical cells comprising the particles.

A battery unit may comprise a first cell type and a second cell type electrically connected at least in series, wherein the first cell type may include N first cells, the second cell type may include M second cells, and N and M are positive integers; the first cell may have a discharge cell balance rate of CB1, the second cell may have a discharge cell balance rate of CB2, with 0.5≤CB1≤CB2≤1.4, and when the battery unit is charged to 95%-100% of the state of charge, the first cell may have a corresponding open-circuit voltage change rate of not greater than 0.005 V/% SOC, and the second cell type may have a corresponding open-circuit voltage change rate greater than that of the first cell.

A battery unit may comprise a first cell type and a second cell type electrically connected at least in series, wherein the first cell type may include N first cells, the second cell type may include M second cells, and N and M are positive integers; the first cell may have a discharge cell balance rate of CB1, the second cell may have a discharge cell balance rate of CB2, with 0.5≤CB1≤CB2≤1.4, and when the battery unit is charged to 95%-100% of the state of charge, the first cell may have a corresponding open-circuit voltage change rate of not greater than 0.005 V/% SOC, and the second cell type may have a corresponding open-circuit voltage change rate greater than that of the first cell.

Provided is a current collector electrode sheet (10) including a slurry application area (11) formed by intermittently applying and drying a slurry containing an active material and a non-application area (12), on both surfaces of a metal foil (9), in which the application area (11) and the non-application area (12) are alternately formed in a winding direction of the metal foil (9) having a strip shape, and, in a compression step of continuously compressing the slurry application area (11) and the non-application area (12) using a pair of compression rollers in a thickness direction of the current collector electrode sheet (10), an area which is not compressed by the compression rollers, is present in a tailing portion (14) at a terminal end (13) of each application area (11).