A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material particle. The positive electrode active material particle includes a layered rock-salt lithium composite oxide and a spinel metal oxide. The positive electrode active material particle has therein the spinel metal oxide provided on at least a surface of a particle including the layered rock-salt lithium composite oxide. The electrolytic solution includes a chain carboxylic acid ester and a cyclic ether.

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.

A positive electrode active material precursor for a nonaqueous electrolyte secondary battery is provided that includes a nickel-cobalt-manganese carbonate composite represented by general formula Ni.sub.xCo.sub.yMn.sub.zM.sub.tCO.sub.3 (where x+y+z+t=1, 0.05≤x≤0.3, 0.1≤y≤0.4, 0.55≤z≤0.8, 0≤t≤0.1, and M denotes at least one additional element selected from a group consisting of Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W) and a hydrogen-containing functional group. The ratio H/Me of the amount of hydrogen H to the amount of metal components Me included in the positive electrode active material precursor is less than 1.60. The positive electrode active material further includes a secondary particle formed by a plurality of primary particles that have been aggregated.

A positive-electrode active material contains a lithium composite oxide, wherein the lithium composite oxide is a multiphase mixture including a first phase, of which a crystal structure belongs to a space group Fm-3m, and a second phase, of which a crystal structure belongs to a space group Fd-3m; and in an XRD pattern of the lithium composite oxide, the integrated intensity ratio I.sub.(18°-20°)/I.sub.(43°-46°) of a first maximum peak I.sub.(18°-20°) within a first range of 18 degrees to 20 degrees at a diffraction angle 2θ to a second maximum peak I.sub.(43°-46°) within a second range of 43 degrees to 46 degrees at the diffraction angle 2θ satisfies 0.05≤I.sub.(18°-20°)/I.sub.(43°-46°)≤0.90.

There are provided processes for preparing a metal hydroxide comprising (i) at least one metal chosen from nickel and cobalt and optionally (ii) at least one metal chosen from manganese, lithium and aluminum, the process comprising: reacting a metal sulfate comprising (i) at least one metal chosen from nickel and cobalt and optionally (ii) at least one metal chosen from manganese, lithium and aluminum with lithium hydroxide, sodium hydroxide and/or potassium hydroxide and optionally a chelating agent in order to obtain a solid comprising the metal hydroxide and a liquid comprising lithium sulfate, sodium sulfate and/or potassium sulfate; separating the liquid and the solid from one another to obtain the metal hydroxide; submitting the liquid comprising lithium sulfate, sodium sulfate and/or potassium sulfate to an electromembrane process for converting the lithium sulfate, sodium sulfate and/or potassium sulfate into lithium hydroxide, sodium hydroxide and/or potassium hydroxide respectively; reusing the sodium hydroxide obtained by the electromembrane process for reacting with the metal sulfate; and reusing the lithium hydroxide obtained by the electromembrane process for reacting with the metal sulfate and/or with the metal hydroxide.

Mixed-metal oxides and lithiated mixed-metal oxides are disclosed that involve compounds according to, respectively, Ni.sub.xMn.sub.yCo.sub.zMe.sub.αO.sub.β and Li.sub.1+γNi.sub.xMn.sub.yCo.sub.zMe.sub.αO.sub.β. In these compounds, Me is selected from B, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ru, Ag, In, and combinations thereof; 0≤x≤1; 0≤y≤1; 0≤z<1; x+y+z>0; 0≤α≤0.5; and x+y+α>0. For the mixed-metal oxides, 1≤β≤5. For the lithiated mixed-metal oxides, −0.1≤γ≤1.0 and 1.9≤β≤3. The mixed-metal oxides and the lithiated mixed-metal oxides include particles having an average density greater than or equal to 90% of an ideal crystalline density.

A positive electrode active material according to the present disclosure includes a lithium composite oxide that contains at least one element selected from the group consisting of F, Cl, N, and S, and at least one element selected from the group consisting of Bi, La, Ce, Ga, Sr, Y, and Sn. Mathematical formula 0.05≤integrated intensity ratio I.sub.(18°-20°)/I.sub.(43°-46°)≤0.90 is satisfied. The integrated intensity ratio I.sub.(18°-20°)/I.sub.(43°-46°) is a ratio of an integrated intensity I.sub.(18°-20°) to an integrated intensity I.sub.(43°-46°). The integrated intensity I.sub.(A°-B°)is an integrated intensity of a maximum peak present in a range of angle of diffraction 2θ greater than or equal to A° and less than or equal to B° in the X-ray diffraction pattern of the lithium composite oxide.

A battery includes a positive electrode, a negative electrode, and an electrolyte. The positive electrode includes Li.sub.xAl.sub.2(OH).sub.7-y.zH.sub.2O where 0.9<x<1.1, −0.1<y<0.1, 0≤z<2.1.

A disordered rocksalt lithium metal oxide and oxyfluoride as in manganese-vanadium oxides and oxyfluorides well suited for use in high capacity lithium-ion battery electrodes such as those found in lithium-ion rechargeable batteries. A lithium metal oxide or oxyfluoride example is one having a general formula: Li.sub.xM′.sub.aM″.sub.bO.sub.2-yF.sub.y, with the lithium metal oxide or oxyfluoride having a cation-disordered rocksalt structure of one of (a) or (b), with (a) 1.09≤x≤1.35, 0.1≤a≤0.7, 0.1≤b≤0.7, and 0≤y≤0.7; M′ is a low valent transition metal and M″ is a high-valent transition metal; and (b) 1.1≤x≤1.33, 0.1≤a≤0.41, 0.39≤b≤0.67, and 0≤y≤0.3; M′ is Mn; and M″ is V or Mo. The oxides or oxyfluorides balance accessible Li capacity and transition metal capacity. An immediate application example is for high energy density Li-cathode battery materials, where the cathode energy is a key limiting factor to overall performance. The second structure (b) is optimized for maximal accessible Li capacity.

The present disclosure is related to a positive electrode active material for lithium secondary batteries, a method for preparing the positive electrode active material, and a lithium secondary battery including the positive electrode active material. The positive electrode active material for lithium secondary batteries includes an overlithiated layered oxide (OLO), and the overlithiated layered oxide includes primary particles having a size in a range of 300 nm to 10 μm in an amount ranging from 50 to 100% by volume with respect to the total overlithiated layered oxide.