Process for making an electrode active material wherein said process comprises the following steps: (a) Providing a hydroxide TM(OH).sub.2 or at least one oxide TMO or oxyhydroxide of TM or combination of at least two of the foregoing wherein TM contains at least 99 mol-% Ni and, optionally, in total up to 1 mol-% of at least one metal selected from Ti, Zr, V, Co, Zn, Ba, or Mg, (b) mixing said hydroxide TM(OH).sub.2 or oxide TMO or oxyhydroxide of TM or combination with a source of lithium and an aqueous solution of a compound of Me wherein Me is selected from Al or Ga or a combination of the foregoing and wherein the molar amount of TM corresponds to the sum of Li and Me, (c) removing the water by evaporation, (d) treating the solid residue obtained from step (c) thermally at a temperature in the range of from 500 to 800° C. in the presence of oxygen.

Provided by the present disclosure are a carbonate precursor that has a high-nickel and low-cobalt sandwich structure, a preparation method therefor and an application thereof. The precursor comprises an inner core and an outer shell layer, wherein the outer shell layer covers at least a part of the outer surface of the inner core. The carbonate precursor having the sandwich structure has the advantages of narrow particle size distribution, good fluidity, and an excellent electrochemical performance, and may be stably produced in both an ammonia-free system and an ammonia-containing system.

The present disclosure provides a lithium-rich carbonate precursor, a preparation method therefor, and an application thereof. The lithium-rich carbonate precursor has a solid spherical structure, and the chemical formula of the lithium-rich carbonate precursor is Ni.sub.xCo.sub.yMn.sub.(1−x−y)CO.sub.3. The precursor has the advantages of having controllable particle size, uniform particle size distribution, high sphericity, high tap density, good fluidity, and excellent electrochemical performance and energy density.

A ternary positive electrode material, a method for preparing the same, a positive electrode sheet and a lithium ion battery in which the ternary positive electrode material has a chemical composition of Li.sub.a(Ni.sub.xCo.sub.yM.sub.1-x-y).sub.1-bM′bO.sub.2-cA.sub.c, wherein 0.75≤a≤1.2, 0.5≤x<1, 0<y≤0.1, 0≤b≤0.01, 0≤c≤0.2; M is at least one selected from the group consisting of Mn and Al; M′ is at least one selected from the group consisting of Al, Zr, Ti, Y, Sr, W and Mg; A is at least one selected from the group consisting of S, F and N; and 2%≤C.sub.Col−C.sub.Co, 5%≤C.sub.Al−C.sub.All. The lithium ion battery shows better short-term kinetic performances and long-term kinetic performances, and it also exhibits excellent stability in long-term cycles.

A positive electrode material includes a first lithium manganese iron phosphate material in an aggregate form, a second and third lithium manganese iron phosphate materials in an aggregate and/or single-crystal-like form, and a fourth and fifth lithium manganese iron phosphate materials in a single-crystal-like form. D.sub.50.sup.5<D.sub.50.sup.4<D.sub.50.sup.3<D.sub.50.sup.2<D.sub.50.sup.1, D.sub.50.sup.2=aD.sub.50.sup.1, D.sub.50.sup.3=bD.sub.50.sup.1, D.sub.50.sup.4=cD.sub.50.sup.1, D.sub.50.sup.5=dD.sub.50.sup.1, and 5 μm≤D.sub.50.sup.1≤15 μm. 0.35≤a≤0.5, 0.2≤b≤0.27, 0.17≤c≤0.18, and 0.15≤d≤0.16. Molar ratios of manganese to iron in the first, the second, the third and the fourth lithium manganese iron phosphate materials increase sequentially, and a molar ratio of manganese to iron in the fifth lithium manganese iron phosphate material is greater than that in the third lithium manganese iron phosphate material.

A method for reusing a positive electrode active material includes dry-milling a positive electrode scrap comprising an active material layer on a current collector to convert the active material layer into a powdered state and to separate the active material layer from the current collector. The active material layer is a lithium composite transition metal oxide positive material active material layer. The method further includes adding a lithium precursor to a the active material layer. The method further includes thermally treating the active material layer in the powdered state to collect an active material. The method further includes obtaining a reusable active material by washing the collected active material with a basic lithium compound aqueous solution and drying the collected active material.

A boron-sulfur-codoped porous carbon material and a preparation method is disclosed. The boron-sulfur-codoped porous carbon material includes a porous carbon, and B and S doped in the surface and pores of the porous carbon; where B has a doping content of 5.56 wt.% to 7.85 wt.%, and S has a doping content of 0.90 wt.% to 1.55 wt.%. Test results of examples show that the boron-sulfur-codoped porous carbon material has high doping contents of B and S, and abundant pores; in a three-electrode system, the material shows a maximum specific capacitance of 168 F.Math.g.sup.- .sup.1 to 290.7 F.Math.g.sup.-1 at 0.5 A.Math.g.sup.-1; after the material is assembled into a symmetrical supercapacitor, the supercapacitor has an ultra-high energy density of 11.3 Wh.Math.kg.sup.-1 to 16.65 Wh.Math.kg.sup.-1 in a neutral electrolyte system, and has a capacitance retention rate of 97.09% to 100.67% after 10,000 life tests.

As for a secondary battery using lithium cobalt oxide as a positive electrode active material, the positive electrode active material with which a decrease in battery capacity due to repeated charge and discharge is inhibited is provided. Alternatively, a positive electrode active material particle which hardly deteriorates is provided. The positive electrode active material includes lithium, cobalt, oxygen, magnesium, aluminum, and fluorine and is a crystal represented by a layered rock-salt structure. The space group of the crystal is represented by R−3m. The concentration of fluorine in a surface portion of the crystal is higher than that inside the crystal. The concentration of magnesium in the surface portion of the crystal is higher than that inside the crystal. The atomic ratio of magnesium to aluminum in the surface portion of the crystal is higher than that inside the crystal.

A cathode active material for a lithium secondary battery according to an embodiment of the present invention includes a lithium metal oxide particle that contains tungsten and has a secondary shape in which a plurality of primary particles are aggregated. The lithium metal oxide particle includes a sulfur-containing portion formed between the primary particles in an inner region of the lithium metal oxide particle.

The present invention relates to a MXene electrode for electronic products having excellent oxidation stability and flexibility and a method for manufacturing the same, and more specifically to a MXene electrode which has excellent stability from changes such as oxidation in a driving environment, excellent transparency and mechanical properties and high electrical conductivity such that it is appropriate to be used as a transparent electrode in electronic devices, and a method for manufacturing the same.