An aqueous secondary battery including: a positive electrode; a negative electrode; a separator; and an aqueous electrolytic solution including water and a metal salt represented by Chemical Formula 1 A.sub.xD.sub.y and having molality of about 5 M to about 40 M wherein in Chemical Formula 1, A is at least one metal ion selected from a sodium ion, a potassium ion, a magnesium ion, a calcium ion, a strontium ion, a zinc ion, or a barium ion, D is at least one type of atomic group ion selected from Cl.sup.−, SO.sub.4.sup.2−, NO.sub.3.sup.−, ClO.sub.4.sup.−, SCN.sup.−, CF.sub.3SO.sub.3.sup.−, C.sub.4F.sub.3SO.sub.3.sup.−, (CF.sub.3SO.sub.2).sub.2N.sup.−, AlO.sub.2.sup.−, AlCl.sub.4.sup.−, AsF.sub.6.sup.−, SbF.sub.6.sup.−, BR.sub.4.sup.−, and PO.sub.2F.sub.2.sup.−, and 0<x≤2, and 0<y≤2.

The epsilon polymorph of vanadyl phosphate, ε-VOPO.sub.4, made from the solvothermally synthesized H.sub.2VOPO.sub.4, is a high density cathode material for lithium-ion batteries optimized to reversibly intercalate two Li-ions to reach the full theoretical capacity at least 50 cycles with a coulombic efficiency of 98%. This material adopts a stable 3D tunnel structure and can extract two Li-ions per vanadium ion, giving a theoretical capacity of 305 mAh/g, with an upper charge/discharge plateau at around 4.0 V, and one lower at around 2.5 V.

Provided is an electrode material which is suitable for use as a material for forming electrodes for use in lithium ion secondary batteries, etc. and which makes it possible to heighten the rate characteristics of batteries. The electrode material is characterized by comprising a polymer having, in a side chain, a fluoflavin skeleton such as that shown by the formula and an inorganic active material, the polymer being contained in an amount of 1 mass % or less with respect to the solid components.

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The use of a blend of a lithium nickel oxide and a lithium manganese iron phosphate as an active material composition in the cathode of a lithium secondary electrochemical cell for automotive applications, such as hybrid and electric vehicles. This blend allows decreasing the porosity of a lithium manganese iron phosphate-based cathode. It also allows improving the detectability of a gas release in the cell in case of an abnormal operation of the cell. It allows lowering the cell impedance at a low state of charge, typically less than 30%, and reducing the impedance increase of the cell during the cell lifespan.

A composite cathode active material represented by Li.sub.x(Co.sub.1−wM1.sub.w).sub.yPO.sub.4 (Formula 1) having an olivine structure, wherein a unit-cell volume of the composite cathode active material is in a range of about 283 Å.sup.3 to about 284.6 Å.sup.3. A cathode including the composite cathode active material, and a secondary battery including the composite cathode active material are also disclosed.

In Formula 1, M1 includes i) at least one of Sc, Ti, V, Cr, Cu, or Zn, and optionally at least one of Fe or Ni, and 0.9≤x≤1.1, 0.9≤y≤1.1, and 0<w≤0.3.

The disclosure discloses an electrolyte and an electrochemical device thereof, and an electronic device. The electrolyte includes a compound represented by formula (I):

##STR00001##

wherein R.sub.1, R.sub.3, and R.sub.4 are each independently selected from hydrogen, a cyano group, a substituted or unsubstituted C.sub.1-12 hydrocarbon group, a substituted or unsubstituted C.sub.1-12 carboxy group, a substituted or unsubstituted C.sub.6-26 aryl group, a substituted or unsubstituted C.sub.2-12 amide group, a substituted or unsubstituted C.sub.0-12 phosphate group, a substituted or unsubstituted C.sub.0-12 sulfonyl group, a substituted or unsubstituted C.sub.0-12 siloxy group or a substituted or unsubstituted C.sub.0-12 boronate group, when being substituted, a substituent includes a halogen atom. The electrolyte of the disclosure may improve the high-temperature cycle performance and room-temperature cycle performance while reducing the internal resistance of the electrochemical device.

A flat-plate type sodium metal battery and an electrochemical device are described. The battery comprises a positive electrode plate and a negative electrode plate, the positive electrode plate provided with a first micro-through-hole arranged in an array on at least part of the surface thereof, the negative electrode plate provided with a second micro-through-hole arranged in an array on at least part of the surface thereof, wherein the first micro-through-hole and the second micro-through-hole have an overlapping area of ≥5% of the total area of the second micro-through-hole of the negative electrode plate. Disposing a first micro-through-hole on the positive electrode plate, and a second micro-through-hole on the negative electrode plate, and setting the aperture size and aperture spacing of micro-through-holes are beneficial to increasing infiltration and penetration of the electrolyte in the positive electrode plate and are conducive to rapid infiltration to large-sized electrode plates.

The present invention provides a crosslinker of formula (I) for electrolytes, and a electrolyte composition and a lithium-ion battery including the same, wherein M, R and X are as defined in the description. With the crosslinker of formula (I), not only the mechanical strength, heat resistance, ionic conductivity and electrochemical stability of the prepared electrolyte composition are improved, but also the long-term charge-discharge cycling stability of the lithium-ion battery is improved. The crosslinker has high industrial value.

The present application discloses a battery module, a battery pack, an apparatus, and a method and device for manufacturing a battery module. The battery module includes n first-type battery cells and m second-type battery cells, n≥1, m≥1, and the n first-type battery cells and them second-type battery cells are arranged and satisfy: VED.sub.1>VED.sub.2, ΔF.sub.1>ΔF.sub.2, and (ΔF.sub.1×n+ΔF.sub.2×m)/(n+m)≤0.8×ΔF.sub.1, where VED.sub.1, VED.sub.2, ΔF.sub.1 and ΔF.sub.2 are respectively defined in the description.

In fields related to battery cathode material technologies, a nano-silicon composite material and a preparation method thereof, an electrode material, and a battery are provided to resolve large volume expansion of a cathode material of a battery and a serious side reaction with an electrolyte. The nano-silicon composite material includes a core, a first coating layer, and a second coating layer. The core includes a nano-silicon crystal. The first coating layer covers a surface of the core. The first coating layer is of a porous structure. A material of the first coating layer includes bisilicate and silicon oxide in a deoxidized state. The second coating layer covers a surface of the first coating layer. A material of the second coating layer includes silicon dioxide in a deoxidized state.