According to one embodiment, a secondary battery is provided. The secondary battery includes: a positive electrode containing a positive electrode active material; a negative electrode; a separator arranged between the positive electrode and the negative electrode; and a first aqueous electrolyte held in at least the positive electrode. pH of the first aqueous electrolyte is more than 7. The positive electrode active material contains a lithium-containing compound that exhibits an average operating potential of less than 4.0 V based on lithium metal.

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.

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.

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 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.

A negative electrode for a lithium secondary battery includes a negative electrode current collector and a negative electrode layer. The negative electrode layer includes a dielectric particle and a negative electrode active material including either or both of a lithium metal and a lithium alloy.

An electrochemical cell includes a solid state material that functions as an electrolyte and a separator within the electrode assembly. The solid state material is a mixture of a polymer that is interspersed with an ionically conductive ceramic material.

The nonaqueous electrolyte energy storage device according to an aspect of the present invention includes a negative electrode including graphite and graphitizable carbon, in which a ratio of a mass of the graphitizable carbon to a total mass of the graphite and the graphitizable carbon is less than 26% by mass, and a median diameter of the graphitizable carbon is smaller than a median diameter of the graphite.

A negative electrode for a rechargeable lithium battery and a rechargeable lithium battery including the same are disclosed. The negative electrode may include a silicon-based negative active material and a binder, where the binder is an acryl-based copolymer, the acryl-based copolymer including an acrylic acid first monomer, an acrylonitrile second monomer, and a (meth)acrylate third monomer. The acrylic acid first monomer may include acrylic acid substituted with lithium ions. The (meth)acrylate third monomer may include an ethylene glycol group, and a weight-average molecular weight (Mw) of the (meth)acrylate third monomer is less than about 900 g/mol.

A method of manufacturing a negative electrode includes styrene butadiene rubber on at least one surface of a negative electrode current collector, applying a second slurry including a negative electrode active material and a polyacrylic acid-based binder onto the first slurry, and drying and rolling the negative electrode current collector to which the first slurry and the second slurry are applied. The negative electrode active material includes a silicon-based negative electrode active material. According to the present disclosure, expansion and contraction of a silicon-based negative electrode active material during charging and discharging may be alleviated, and electrode flexibility may be improved, resulting in a significant improvement in lifespan properties of a secondary battery.