A novel ionic liquid is provided. A highly safe secondary battery with high charge and discharge capacity is provided. The ionic liquid includes a cation represented by General Formula (G1) and an anion represented by Structural Formula (200). In the formula, X.sup.1 to X.sup.3 each independently represent any one of fluorine, chlorine, bromine, and iodine. One of X.sup.1 to X.sup.3 may be hydrogen. In addition, n and m each independently represent 0 to 5. Furthermore, a secondary battery including the above-described ionic liquid is provided.

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The nickel-containing composite hydroxide disclosed herein contain secondary particles, which are formed from an aggregation of numerous primary particles, which have an average particle size of the primary particles is 0.01 m to 0.40 m. These secondary particles have a spherical or ellipsoidal shape, an average particle size of 20 m to 50 m, and a BET value of 12 m.sup.2/g to 50 m.sup.2/g after being roasted in air for 2 hours at 800 C.

A positive electrode active material and its precursor capable of further improving output characteristics while maintaining capacity characteristics and cycle characteristics of a positive electrode active material having the solid structure is provided. A nucleation step and a particle growth step are clearly separated, and in the early period and middle period of the particle growth step which is 70% to 90% of time from the initiation of the particle growth step, the non-oxidizing atmosphere is maintained, and in the latter period of the particle growth step, the non-oxidizing atmosphere is switched to the oxidizing atmosphere, and then the oxidizing atmosphere is switched to the non-oxidizing atmosphere again so as to obtain a transition metal composite hydroxide comprising secondary particles formed by aggregates of plate-shaped primary particles and having a low-density layer formed from the aggregates of the fine primary particles having a smaller particle size than the plate-shaped primary particles near the surface of the secondary particles. The positive electrode active material obtained by using the transition metal composite hydroxide as the precursor comprising secondary particles formed by aggregates of a plurality of primary particles and its tap density is 1.5 g/cm.sup.3 or more, and the surface roughness index which is a value in which the measured specific surface area of the secondary particles is divided by the geometric surface area of the secondary particles when the secondary particles is assumed to be true sphere is within a range of 3.6 to 10.

Provided are electrochemically active secondary particles that provide excellent capacity and improved cycle life. The particles are characterized by selectively enriched grain boundaries where the grain boundaries are enriched Al. The enrichment with Al reduces impedance generation during cycling thereby improving capacity and cycle life. Also provided are methods of forming electrochemically active materials, as well as electrodes and electrochemical cells employing the secondary particles.

Disclosed are a cathode active material for sodium-ion batteries and a preparation method therefor and an application thereof. The cathode active material has a chemical formula of Na.sub.xNi.sub.yFe.sub.zMn.sub.gM.sub.hA.sub.mO.sub.2, where M is selected from the group consisting of Ti, Al, Mg, Ca, Zr, Y, Zn, Nb, W and combinations thereof, A is selected from the group consisting of B, P, C and combinations thereof, 0.80?x?1.40, 0.05?y?0.95, 0.05?z?0.95, 0.05?g?0.95, 0.01?h?0.50, and 0.01?m?0.30. By adding M and A elements to the ternary iron-manganese-nickel cathode active material for sodium-ion batteries, and controlling the ratio of all elements, the present disclosure can achieve the formation of a perfect layered single-crystal structure of the cathode active material for sodium-ion batteries, with large particles, ultimately achieving the stability of the active material, and when used in sodium-ion batteries, it can significantly improve the cycling performance at high temperatures while ensuring high gram capacity.

The present disclosure relates to the technical field of lithium ion battery, and discloses a Lithium-Manganese-rich material and a preparation method and a use thereof.

The present disclosure relates to a method of recycling a positive electrode active material and a recycled positive electrode active material prepared by the same. More particularly, the present disclosure relates to a method of recycling a positive electrode active material, the method including step A of fragmenting a waste battery including a positive electrode, a separator, and a negative electrode to form waste battery scraps; step B of removing the negative electrode by jetting compressed air onto the waste battery scraps; and step C of treating the waste battery scraps from which the negative electrode has been removed with a solvent to remove the separator and obtain positive electrode scraps, and a recycled positive electrode active material prepared by the method.

The present invention discloses a high-voltage ternary positive electrode material for lithium-ion battery and preparation method thereof. The chemical formula of the material is LiNi.sub.0.6-xMg.sub.xCo.sub.0.2-yAl.sub.yMn.sub.0.2-zTi.sub.zO.sub.2-dF.sub.d, wherein 0<x,y,z,d0.05. The precursor of the positive electrode material is synthesized by gradient co-precipitation method and the positive electrode material is prepared by solid phase method. The content of nickel in the synthesized precursor particles has a gradient distribution from the inside to the outside. The obtained precursor is mixed and grinded evenly with the lithium source and the fluorine source at a certain ratio and put into the tube furnace. The obtained precursor is then pre-sintered in the oxygen-enriched air atmosphere and then heated up to be sintered, to obtain the target product. The positive electrode material for lithium-ion battery prepared by the method is free from impurity phase and has a good crystallinity, which is a high energy density positive electrode material.

The invention relates to doped nickelate-containing material with the general formula: A.sub.a M.sup.1.sub.v M.sup.2.sub.w M.sup.3.sub.x M.sup.4.sub.y M.sup.5.sub.z O.sub.2- wherein A comprises one or more alkali metals selected from sodium, lithium and potassium; M.sup.1 is nickel in oxidation state 2+, M.sup.2 comprises one or more metals in oxidation state 4+, M.sup.3 comprises one or more metals in oxidation state 2+, M.sup.4 comprises one or more metals in oxidation state 4+, and M.sup.5 comprises one or more metals in oxidation state 3+ wherein 0.4a<0.9, 0<v<0.5, at least one of w and y is >0, x>0, z0, 00.1, and wherein a, v, w, x, y and z are chosen to maintain electroneutrality.

The present disclosure relates to a positive electrode material for a lithium ion battery and its preparation. The positive electrode material in accordance with the present disclosure has an intrinsic specific surface area of 5-13 m.sup.2/g. The positive electrode material in accordance with the present disclosure has an intrinsic specific surface area and an intrinsic pore size within the required ranges. In this regard, the positive electrode material in accordance with the present disclosure has excellent particle strength, excellent Li ion transference ability, and good resistance to electrolyte erosion. When used in lithium batteries, it may impart the batteries with excellent rate performance and cycle performance. The present disclosure also relates to a method for preparing the positive electrode material.