33results about How to "Reduce surface residual alkali content" patented technology

Belonging to the technical field of lithium ion batteries, the invention discloses a lithium ion battery cathode material and a preparation method thereof. The chemical molecular formula of the cathode material is Lix(NiaCobMnc)1-yMyO2, wherein x is greater than or equal to 0.96 and smaller than or equal to 1.04, y is greater than or equal to 0.01 and smaller than or equal to 0.06, a is greater than or equal to 0.8 and smaller than or equal to 0.9, and a+b+c=1, M has a general formula of BzM'1-z, M' is composed of one or several of the following elements: Al, Mg, Ti and Zr, and z is greater than or equal to 0.1 and smaller than or equal to 0.5. The cathode material is coated by a layer of compound containing L, B, Ni, Co and Mn, the content of B in the outermost surface of the coating layer is at least two times that of the B in the innermost layer of the coating layer. According to the invention, the high capacity cathode material is acquired from a high nickel content ternary system, additionally multielement doping is employed to stabilize the crystal structure of the material, and then by means of washing, boron element surface modification and two-step sintering process, the material surface structure can be improved, and the surface residual alkali content can be reduced to improve the interface stability. The whole technological process of the invention is simple, and is easy for large scale production.

The main idea for solving the problem of excessively high residual alkalinity on a surface of a ternary material is in a way that the residual alkalinity on the surface of the material can be reducedby washing. Although the residual alkalinity on the surface of the high-nickel ternary material can be reduced after washing, and the lithium content after washing is reduced to cause that the specific capacity also can be reduced and the battery performance is affected. The invention discloses a method for improving residual alkalinity on a surface of a ternary positive electrode material of a lithium ion battery. The method comprises the following steps of mixing powdered Ni-Co-Mn layered positive electrode material with molecular formula being LiNi<x>Co<y>Mn<z>O<2> and water, and performingcentrifugal separation to obtain a washed powder material; adding a lithium source to absolute ethyl alcohol for uniformly mixing, adding the washed powder material for uniformly mixing, and performing complete evaporation, drying and sintering to obtain the ternary positive electrode material of the lithium ion battery. After washing, lithium supplement and secondary sintering are performed on the ternary material by an ethyl alcohol system, the lithium which is lost during washing is supplemented, and the performance of the material is improved; and moreover, the process flow is simple, andindustrial production is convenient to implement.

The embodiment of the invention relates to a method for reducing the content of residual alkali on the surface of a high-nickel positive electrode material of a lithium ion battery. The method comprises the following steps: adding a certain amount of acid or a derivative of the acid into a certain amount of non-aqueous inactive hydrogen organic solvent at a stirring speed of 1m/s to 10m/s at normal temperature, and stirring until the acid or the derivative of the acid is completely dissolved, so as to obtain a washing solution for reducing residual alkali on the surface of the high-nickel positive electrode material of the lithium ion battery; wherein the mass ratio of the to-be-treated high-nickel positive electrode material to the non-aqueous non-active hydrogen organic solvent is 1:0.5-1:4; wherein the molar concentration of the acid or the derivative of the acid in the washing liquid is 0.5-1.5 times of the molar weight of the residual alkali on the surface of the to-be-treated high-nickel positive electrode material; adding a to-be-treated high-nickel positive electrode material into the washing liquid while stirring at a linear speed of 1m/s to 10m/s, and stirring for 1 to 120 minutes; and centrifuging to remove the solvent, vacuumizing, heating and drying at 20-80 DEG C to obtain the treated high-nickel positive electrode material.

The invention discloses a method for preparing a high-rate nickel cobalt lithium aluminate anode material. The method comprises the following steps: (1) preparing a nickel cobalt lithium aluminate precursor; (2) performing lithium-site doping and modifying on potassium ions; and (3) constructing a cladding layer of a lithium-containing compound. According to the method, the dispersing speed of lithium ions is effectively increased by lithium-site replacement of potassium ions, and the rate capability of a material can be improved; the lithium-containing compound layer constructed on the material surface can be used for reducing the content of alkali remained on the material surface and reduce later cell bubbling; side reaction can be effectively inhibited, and the material structure stability in the cycling process can be promoted; and the lithium-containing compound layer has high conducting performance for lithium ions, embedding and separating of lithium ions can be accelerated, the problem of poor lithium ion conductivity when conventional metal oxide is used as the cladding layer can be solved, and the cycling performance and rate performance of the material can be improved.

The invention discloses a lithium ion battery positive electrode material with low surface lithium ion content. The lithium ion battery positive electrode material is characterized by being prepared from nano oxide and Lix (NiaCobMnc)O2 powder at the mass ratio of 2-12:1000 through mixing and sintering; and the content of free lithium on the surface of the positive electrode material is 1,800ppm or below. According to the method, the surface residual alkali content is reduced by water washing and oxide surface coating modification, the content of free lithium on the surface of the material iscontrolled, meanwhile, the crystal structure of the material can be stabilized, and the cycling stability and the safety performance of the material are improved. According to the method disclosed bythe invention, the whole process flow is simple, and a liquid phase coating method is synchronously carried out in the process of water washing and residual alkali reducing, so that the process flow is simplified; and meanwhile, the liquid-phase coating uniformity is higher, so that the large-scale production can be executed easily.

The invention provides a treatment process for improving stability and conductivity of a high-nickel positive electrode material. The high-nickel positive electrode material obtained by sintering in an ozone atmosphere is subjected to carbon dioxide annealing treatment and carbon dioxide plasma treatment separately. According to the method, the material sintering time can be shortened, the productivity can be improved, the gas consumption can be reduced, and the cost can be lowered; in addition, the lithium-nickel mixing degree of the high-nickel positive electrode material can be reduced, theconsistency and the stability of the material can be improved, and the service life of the battery can be prolonged; continuous introduction of carbon dioxide gas for annealing treatment is carried out after sintering is completed, so that the carbon dioxide gas can react with lithium hydroxide remaining on the surface of the high-nickel positive electrode material, the content of residual alkalion the surface of the material is reduced, the sensitivity of the material to air is reduced, the storage time of the material is prolonged, and the processing performance of the material is improved; and finally, carbon dioxide plasma treatment is carried out, a layer of carbon layer coats the surface of the material, and the conductivity of the material is improved, so that the material rate performance is improved.

The invention discloses a composite high-nickel ternary positive electrode material and a preparation method thereof. The composite high-nickel ternary positive electrode material is composed of a high-nickel ternary positive electrode material, a metal oxide coating the surface of the high-nickel ternary positive electrode material and sulfonate coating the surface of the metal oxide. The problemthat the high-nickel ternary material is poor in cycling stability all the time is effectively solved, meanwhile, the coating treatment process is relatively simple, and the method is suitable for large-scale industrial production.

The invention provides a preparation method of a lithium cobalt oxide-coated high-nickel ternary material. The method comprises the following steps of: S1: taking and uniformly mixing a precursor of ahigh-nickel ternary material with an alkaline solution, and putting the mixture in a vacuum drying oven for drying to obtain mixed powder; S2: putting the dried mixed powder into an ozone oxidation reaction device, introducing ozone gases into the ozone oxidation reaction device, and performing stirring and oxidation; S3: washing the precursor in the step S2 by using hot deionized water, and drying the precursor after washing; and S4: uniformly mixing the dried precursor in the step S3 and a lithium source, and putting the mixture into a high-temperature furnace, performing temperature rise in an oxygen atmosphere in a sintering temperature from the room temperature to a sintering temperature, performing heat preservation, and performing natural cooling after heat preservation to obtain alithium cobalt oxide-coated high-nickel ternary material. The method employs the ozone oxidation method to perform oxidation for the Co2+ at the surface of the precursor to allow the surface of the precursor to generate structural recombination to generate a layer of CoOOH, and the precursor with the CoOOH at the surface is mixed with the lithium source for high-temperature calcinations to obtaina CoOOH-coated high-nickel ternary material.

The invention discloses a high-nickel ternary material, a surface modification method and a lithium ion battery. The surface modification method comprises the following steps: firstly introducing soluble salt of cation Li+ as a first additive in the washing process, and then introducing a TiOSO4 acid solution, wherein the third additive is an Al2(SO4)3 acid solution, and the fourth additive is a NaAlO2 alkaline solution; and finally performing separating, drying and calcining to obtain the surface-modified high-nickel ternary material. The high-nickel ternary material obtained by the surface modification method can effectively reduce the residual alkali on the surface of the high-nickel ternary material and improve the structural stability.

The invention provides a preparation technology capable of improving the cycle performance and the electrical conductivity of a high-nickel positive electrode material. The preparation technology comprises the steps of mixing a high-nickel positive electrode material precursor with a lithium salt evenly at a certain ratio; sintering in ozone-containing oxygen or air atmosphere; and carrying out carbon dioxide plasma processing after sintering is ended. According to the method, the sintering time of the material ca be shortened, the productivity is improved, the amount of a gas is reduced, thecost is reduced, the lithium-nickel mixed discharge degree of the high-nickel positive electrode material is reduced and the consistency and the stability of the material are improved; carbon dioxideplasma processing is carried out after sintering is ended, so that the residual alkali content on the surface can be reduced; and a carbon film can be formed on the surface, so that the electrical conductivity and the rate capability of the material are improved.

The invention provides a ternary positive electrode material of a lithium ion battery and a preparation method and application thereof. The chemical general formula of the ternary positive electrode material of the lithium ion battery is LiNi1-x-yCoxMnyMaFbO2, wherein x is larger than 0.1 and smaller than 0.3, y is larger than 0.1 and smaller than 0.3, a is larger than 0.01 and smaller than 0.1, and b is larger than 0.01 and smaller than 0.05; and M is selected from one of Ga, Zn, Na and Al. The ternary positive electrode material of the lithium ion battery has excellent cycling stability andhigh-quality specific capacity, and the lithium ion battery prepared by applying the ternary positive electrode material to the lithium ion battery has the advantages of high capacity, good cycling stability and long service life.

The invention provides an interface composite modification method of a positive electrode material, the positive electrode material and application, and the interface composite modification method comprises the following steps: mixing a precursor, a lithium source and a nano oxide for the first time, conducting calcining to obtain a sintered material, mixing the sintered material, an inducer and a boron source for the second time, and conducting calcining to obtain a single crystal positive electrode material. According to the interface composite modification method provided by the invention, the content of residual alkali on the surface of the positive electrode material is reduced in a co-coating manner, so that the cycling stability, the rate capability and the thermal stability of the positive electrode material are improved.

The invention discloses a lithium ion battery positive electrode material as well as a preparation method and application thereof. The preparation method comprises the steps of dissolving a water-soluble titanium source and a water-soluble aluminum source in water according to a chemical general formula Al2Ti<1+a>O5, and uniformly mixing to obtain a mixed solution; uniformly mixing hydrogel and a ternary positive electrode material to obtain a first mixture; dropwise adding the mixed solution into the first mixture to obtain a second mixture; and performing plasma activation on the second mixture, sintering, crushing and sieving to obtain the lithium ion battery positive electrode material. The preparation method is simple to operate and low in cost, and the obtained lithium ion battery positive electrode material is low in residual alkali content, stable in interface structure and excellent in electrochemical performance.