WO2018120387A1

WO2018120387A1 - Composite active material for lithium-ion battery, preparation method for composite active material, electrode slurry of lithium-ion battery, positive electrode or negative electrode, and lithium-ion battery

Info

Publication number: WO2018120387A1
Application number: PCT/CN2017/074515
Authority: WO
Inventors: 先雪峰
Original assignee: 先雪峰
Priority date: 2016-12-30
Filing date: 2017-02-23
Publication date: 2018-07-05
Also published as: CN106505205A

Abstract

The present invention relates to the technical field of lithium-ion batteries, and provides a composite active material for a lithium-ion battery, a preparation method for the composite active material, an electrode slurry of a lithium-ion battery, a positive electrode or a negative electrode, and a lithium-ion battery. The composite active material for a lithium-ion battery is an additive-coated active material. The additive is M(PO₄)_a(HPO₄)_b·cH₂O, wherein M is at least one element in group IIA metal elements, group IB metal elements, group IIB metal elements, group IIIB metal elements, group IVB metal elements, group VIB metal elements, group VIIB metal elements, group VIII metal elements, and group VA metal elements, a is greater than or equal to 0, b is greater than or equal to 0, a and b are not simultaneously 0, and c is greater than 0. The composite active material for a lithium-ion battery serves as a positive and negative electrode active material and is used for preparing a positive electrode and/or a negative electrode of a lithium-ion battery; the security of the prepared lithium-ion battery can be obviously improved.

Description

Lithium ion battery composite active material and preparation method thereof, lithium ion battery electrode slurry, positive electrode or negative electrode, and lithium ion battery

Technical field

The present invention relates to the field of lithium ion battery technology, and in particular to a lithium ion battery composite active material and a preparation method thereof, a lithium ion battery electrode slurry, a positive electrode or a negative electrode, and a lithium ion battery.

Background technique

Lithium-ion battery is a new generation of green high-energy battery, with many advantages such as high voltage, high energy density, long life, small self-discharge, no memory effect, wide operating temperature range, etc., in the field of small mobile energy (such as mobile phones, digital cameras, etc. ), large mobile energy fields (such as plug-in hybrid vehicles, pure electric vehicles, etc.) and fixed energy fields (such as energy storage power stations, UPS, etc.) have broad application prospects.

The high voltage of the lithium ion battery also means that in the state of charge, the positive and negative electrodes of the battery have a large potential difference, which means that the negative electrode is more reductive, the positive electrode is more oxidized, and the thermal stability is worse. Especially for batteries using high-voltage positive electrode materials such as lithium cobaltate, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, etc., in the case of overcharging, acupuncture, extrusion, etc., it is often caused by heat runaway and even fire. Explosion, there are serious security risks.

In addition, compared with conventional lead-acid and alkaline batteries that use non-flammable and flame-retardant water as the electrolyte solvent, commercial lithium-ion batteries usually use a combustible carbonate-based organic solvent as the electrolyte solvent. Or gel-like polymers as electrolytes, under the abuse conditions, will further expand the consequences of safety accidents.

The safety hazards of existing lithium-ion batteries hinder the large-scale application of lithium-ion batteries. Therefore, it is of great practical significance to develop a lithium-ion battery with greatly improved safety.

Summary of the invention

The object of the present invention is to overcome the defects of low safety and serious safety hazards of the lithium ion battery in the prior art, and provide a lithium ion battery composite active material and a preparation method thereof, a lithium ion battery electrode slurry, and a A positive or negative electrode and a lithium ion battery.

In order to achieve the above object, in a first aspect, the present invention provides a lithium ion battery composite active material, wherein the lithium ion battery composite active material is an additive-coated active material, and the additive is M(PO ₄ ) _a (HPO) ₄ ) _b · cH ₂ O, wherein M is a Group IIA metal element, a Group IB metal element, a Group IIB metal element, a Group IIIB metal element, a Group IVB metal element, a Group VIB metal element, a Group VIIB metal element, a Group VIII metal At least one of the element and the VA group metal element, a ≥ 0, b ≥ 0, and a, b are not 0 at the same time, c > 0.

In a second aspect, the present invention provides a method for preparing a lithium ion battery composite active material, which comprises: preparing a hydrated phosphate of element M, and hydrating a phosphate of the element M with an active material in the presence of a dispersant Mixing and then subjecting the resulting mixture to heat treatment.

In a third aspect, the present invention provides a lithium ion battery electrode slurry, the electrode paste comprising a lithium ion battery active material, a binder, a conductive agent, a solvent, and an optional thickener, wherein the lithium The ion battery active material is a lithium ion battery composite active material according to the present invention.

In a fourth aspect, the present invention provides a positive electrode or a negative electrode of a lithium ion battery, the positive electrode or the negative electrode of the lithium ion battery comprising a current collector and an electrode dressing on the current collector, the electrode dressing containing a lithium ion battery active material and bonding The agent, the conductive agent and the optional thickener, wherein the lithium ion battery active material is a lithium ion battery composite active material according to the invention.

In a fifth aspect, the present invention provides a lithium ion battery including a battery case and a cell assembly and an electrolyte located inside the battery case, the cell assembly including a positive electrode, a negative electrode, and a diaphragm, and The positive electrode is the positive electrode of the lithium ion battery according to the present invention, and/or the negative electrode is the negative electrode of the lithium ion battery according to the present invention.

The inventors of the present invention have found in the research that the lithium ion battery composite active material of the present invention (the surface of the active material is coated with the additive of the present invention to prepare a lithium ion battery composite active material) is used as a positive and negative electrode activity. The preparation of the positive electrode and/or the negative electrode of the lithium ion battery can significantly improve the safety of the lithium ion battery thus prepared, and has almost no adverse effect on the conductivity and cycle performance of the lithium ion battery. Wherein, the additive of the present invention must contain crystal water to improve the lithium ion battery The safety performance is presumed to be due to the fact that under the abuse condition, the additive contained in the battery absorbs the heat generated by the battery by absorbing the crystal water by the heat absorption, thereby avoiding the thermal runaway of the battery, thereby improving the safety of the battery.

Other features and advantages of the invention will be described in detail in the detailed description which follows.

detailed description

Specific embodiments of the present invention will be described in detail below. It is to be understood that the specific embodiments described herein are merely illustrative and not restrictive.

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to include values that are close to the ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and the individual point values, and the individual point values can be combined with one another to yield one or more new ranges of values. The scope should be considered as specifically disclosed herein.

In a first aspect, the present invention provides a lithium ion battery composite active material, wherein the lithium ion battery composite active material is an additive coated active material, and the additive is M(PO ₄ ) _a (HPO ₄ ) _b · cH ₂ O, wherein M is a Group IIA metal element, a Group IB metal element, a Group IIB metal element, a Group IIIB metal element, a Group IVB metal element, a Group VIB metal element, a Group VIIB metal element, a Group VIII metal element, and a Group VA metal At least one of the elements, a ≥ 0, b ≥ 0, and a, b are not 0 at the same time, c > 0.

Among them, it should be understood by those skilled in the art that in M(PO ₄ ) _a (HPO ₄ ) _b · cH ₂ O, the choice of a and b conforms to the stoichiometric principle of the corresponding substance.

In the lithium ion battery composite active material of the present invention, preferably, in the additive, the Group IIA metal element is Mg, the Group IB metal element is Cu, the Group IIB metal element is Zn, and the Group IIIB metal The element is at least one of Y, Sc, La, Ce, Nd, Sm, Gd, and Er, the Group IVB metal element is Ti and/or Zr, the Group VIB metal element is Cr, and the Group VIIB metal The element is Mn, the Group VIII metal element is at least one of Fe, Co, and Ni, and the VA group metal element is Bi.

In the lithium ion battery composite active material of the present invention, the inventors of the present invention have found that a lithium ion battery active material having a better safety can be obtained by coating a specific additive on the surface of a lithium ion battery active material, and therefore, in order to further improve the preparation The safety of the obtained lithium ion battery, preferably, the additive is hydrated orthophosphate chromium (CrPO ₄ ·7/2H ₂ O), cobalt octahydrate orthophosphate (normalized formula is Co(PO ₄ ) _2/3 ·8/3H ₂ O) and at least one of hydrated magnesium phosphate (normalized formula of Mg(PO ₄ ) _0.6 (HPO ₄ ) _0.1 ·3/2H ₂ O).

In the lithium ion battery composite active material of the present invention, in order to improve the safety of the lithium ion battery and the energy density, the content of the additive is preferably 0.05-32 by weight based on the weight of the lithium ion battery composite active material. % is further preferably from 3 to 15% by weight, still more preferably from 5.6-1.6% by weight.

In the lithium ion battery composite active material of the present invention, the active material is not particularly limited, and various active materials conventionally used in the art may be used. Preferably, the active material is a positive electrode active material or a negative electrode active material, and the positive electrode active material The substance is lithium cobaltate, lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium nickel manganese oxide, lithium manganate, lithium vanadate, lithium iron phosphate, lithium manganese phosphate, manganese phosphate At least one of iron lithium, lithium iron manganese phosphate, lithium manganese iron cobalt cobalt, lithium manganese iron nickel cobalt, lithium vanadium phosphate, and lithium iron silicate, the negative active material being graphite, lithium titanate, silicon, At least one of hard carbon, tin, and tin oxide.

In the preparation method of the present invention, the selection of the element M is the same as the element M in the above-mentioned additive, and the above-mentioned corresponding contents can be referred to, and the detailed description thereof will not be repeated here.

In the preparation method of the present invention, the preparation method of the hydrated phosphate of the above-mentioned different element M is not particularly limited, and various methods commonly used in the art can be used, which are well known to those skilled in the art and will not be described herein. Among them, it should be understood by those skilled in the art that in the preparation process, drying is carried out at a temperature of not more than 150 ° C or hydrothermal treatment with water as a main solvent at a temperature of not more than 200 ° C, hydrated phosphate of element M The crystal water in the medium is not lost, that is, the hydrated phosphate of the element M still contains crystal water; but the heat treatment at not lower than 400 ° C completely removes the crystal water in the hydrated phosphate of the element M, that is, the obtained element M phosphate does not contain crystal water.

In the preparation method of the present invention, it should be understood by those skilled in the art that the residual impurities in the hydrated phosphate of the prepared element M are removed before the hydrated phosphate of the element M is mixed with the active material. The method of the impurities is not particularly limited and may be various methods commonly used in the art, for example, washing with deionized water to remove impurities therein.

In the preparation method of the present invention, the kind of the dispersant is not particularly limited, and may be a solvent used in the process of preparing the precipitated hydrated phosphate of the element M. Preferably, the dispersant is isopropanol, deionized water, ethanol. At least one of butanol and acetone is further preferably isopropanol or deionized water.

In the preparation method of the present invention, preferably, the manner in which the hydrated phosphate of the element M is mixed with the active material is vigorous stirring, and the stirring condition preferably includes a rotation speed of 100 to 400 rpm and a time of 1 to 10 hours.

In the preparation method of the present invention, the manner of the heat treatment is not particularly limited, and may be various methods commonly used in the art. Preferably, the heat treatment is spray drying, microwave drying, fluidized bed drying or oven drying, in order to improve The efficiency is further preferably spray drying. The conditions of the heat treatment may include a temperature of 65 to 200 ° C and a time of 1 s to 12 h. The conditions for spray drying include a temperature of 65-200 ° C and a time of 1-100 s, preferably 1-10 s. For specific temperatures and times, the selection may be made according to different drying methods, which are well known to those skilled in the art and will not be described herein.

In the preparation method of the present invention, it will be understood by those skilled in the art that the mixture obtained by mixing the hydrated phosphate of the element M with the active material is dried at a temperature of not more than 150 ° C, the hydrated phosphate of the element M and The crystal water in the composite active material of the prepared lithium ion battery is not lost, that is, the hydrated phosphate of the element M and the lithium ion battery composite active material prepared therefrom still contain crystal water; but at not lower than 400 ° C The heat treatment completely removes the hydrated phosphate of the element M and the crystal water in the lithium ion battery composite active material prepared therefrom, that is, the obtained element M phosphate and the lithium ion battery composite active material prepared therefrom do not contain Crystal water.

According to the preparation method of the present invention, an active material having a surface coated with the foregoing additive can be prepared, that is, a lithium ion battery composite active material can be obtained, and a specific additive can be prepared by controlling the amount of the hydrated phosphate precipitate of the element M and the amount of the active material. The content of the lithium ion battery composite active material, preferably, the amount of the hydrated phosphate precipitate of the control element M and the active material is such that the content of the additive is 0.05-32% by weight based on the weight of the lithium ion battery composite active material. It is further preferably from 3 to 15% by weight, still more preferably from 5.6-1.6% by weight.

It should be understood by those skilled in the art that the lithium ion battery electrode slurry of the present invention may be a lithium ion battery positive electrode slurry or a lithium ion battery negative electrode slurry. In the lithium ion battery positive electrode slurry or the lithium ion battery negative electrode slurry, the selection and amount of the active material, the binder, the conductive agent, the solvent and the thickener are not particularly limited, and may be respectively the corresponding components in the field. The conventional type selection and dosage, for the purpose of considering the energy density of the battery and the comprehensive performance of the battery, preferably, the content of the binder on a dry basis is 0.5 based on the weight of the composite active material of the lithium ion battery. 5 wt%, the content of the conductive agent is 0.5 to 5% by weight, the content of the solvent is 55 to 200% by weight, and the content of the thickener is 0 to 2.5% by weight. Wherein, the thickener is generally not used in the lithium-ion battery positive electrode slurry, but is used in the lithium ion battery negative electrode slurry, and the content is 0.5-2.5% by weight based on the weight of the lithium ion battery composite active material.

In the lithium ion battery positive electrode slurry, the positive electrode active material in the lithium ion battery composite active material is not particularly limited, and may be various positive electrode active materials as described above, and the description thereof will not be repeated here.

In the lithium ion battery negative electrode slurry, the negative electrode active material in the lithium ion battery composite active material is not particularly limited, and may be various negative electrode active materials as described above, and the description thereof will not be repeated here.

In the lithium ion battery positive electrode slurry and the lithium ion battery negative electrode slurry, the binder is not particularly limited, and various binders conventionally used in the art may be used. Preferably, the binder is polyacrylamide or poly. At least one of vinylidene fluoride, polytetrafluoroethylene, styrene butadiene rubber, cellulose-based polymer, polyvinyl alcohol, polyolefin, fluorinated rubber, and polyurethane, the cellulose-based polymer may be selected from methyl cellulose One or more of ethyl cellulose, hydroxypropyl methyl cellulose, and hydroxypropyl ethyl cellulose. When the binder is a polymer, the number average molecular weight of each polymer is generally from 3 to 1.5 million.

In the lithium ion battery positive electrode slurry and the lithium ion battery negative electrode slurry, the conductive agent is not particularly limited, and various conductive agents conventionally used in the art may be used. Preferably, the conductive agent is Ketjen black, acetylene black, and graphite. Alkene, carbon nanotubes, carbon fiber (VGCF), At least one of microcrystalline graphite and conductive carbon black (Super-P).

Here, the solvent is not particularly limited and may be various solvents conventionally used in the art. Preferably, the solvent is N-methylpyrrolidone (NMP), deionized water, tetrahydrofuran, dimethyl sulfoxide, ethanol, and the like. At least one of propanol. Further, it is further preferred that in the lithium ion battery positive electrode slurry, the solvent is N-methylpyrrolidone; and in the lithium ion battery negative electrode slurry, the solvent is deionized water and/or N-methylpyrrolidone.

Among them, the thickener is mostly used in the negative electrode slurry of the lithium ion battery, and whether or not the thickener is added to the positive electrode slurry of the lithium ion battery can be selected according to the actual application, and the specific selection is well known to those skilled in the art, and preferably, The thickener is at least one of sodium carboxymethyl cellulose (CMC), polyvinylpyrrolidone, polyethylene glycol, and polyvinyl alcohol.

The method for preparing the lithium ion battery electrode slurry of the present invention is not particularly limited, and various methods commonly used in the art may be used as long as the slurry containing the above components can be uniformly mixed, for example, containing lithium ions. A slurry of a battery composite active material, a binder, a conductive agent, a solvent, and an optional thickener may be obtained by first mixing a binder and a solvent to obtain a mixed liquid, and then combining the active material of the lithium ion battery with the conductive agent and The optional thickener is mixed with the mixed solution, or may be mixed by adding a thickener or a binder and a solvent to obtain a mixed liquid, and then the lithium ion battery composite active material, the conductive agent, and the binder or thickener Mix with the mixture.

For the specific selection of the active material, the binder, the conductive agent and the thickener in the positive electrode or the negative electrode of the lithium ion battery of the present invention, reference may be made to the corresponding description above, and the detailed description is not repeated herein.

In the positive electrode or the negative electrode of the lithium ion battery of the present invention, in order to further improve the safety of the prepared lithium ion battery while taking into consideration the energy density of the battery and the comprehensive performance of the battery, the content of the additive is 0.05-22 by weight based on the dry weight of the electrode dressing. % is further preferably from 3 to 15% by weight, more preferably from 5.5 to 10.5% by weight. It will be understood by those skilled in the art that the dry weight of the electrode dressing refers to the weight of the material obtained after drying all of the slurry coated on the current collector.

The method for preparing the positive electrode or the negative electrode of the lithium ion battery is not particularly limited, and may be various methods commonly used in the art, for example, may include: coating the lithium ion battery electrode slurry of the present invention on a current collector, drying.

In the positive electrode of the lithium ion battery, the current collector is not particularly limited, and various positive electrode current collectors commonly used in the art may be used. For example, the positive electrode current collector may be aluminum foil.

In the negative electrode of the lithium ion battery, the current collector is not particularly limited, and various negative electrode current collectors commonly used in the art may be used. For example, the negative electrode current collector may be a copper foil.

There is no particular limitation on the method of coating, and various methods commonly used in the art can be used, which are well known to those skilled in the art and will not be described herein.

The method for drying is not particularly limited and may be various methods commonly used in the art. Preferably, the drying conditions include: a temperature of 80-180 ° C.

In the lithium ion battery of the present invention, it should be understood by those skilled in the art that at least one of the positive electrode and the negative electrode is a positive electrode or a negative electrode prepared by the lithium ion battery composite active material of the present invention, that is, the positive electrode is the invention. The positive electrode of the lithium ion battery or the negative electrode is the negative electrode of the lithium ion battery according to the present invention, or the positive electrode and the negative electrode are respectively the positive electrode and the negative electrode of the lithium ion battery according to the present invention.

In the lithium ion battery of the present invention, the separator and the electrolytic solution forming the lithium ion battery may be a separator and a nonaqueous electrolyte which are conventionally used in the art.

Wherein the separator is disposed between the positive electrode and the negative electrode, and has electrical insulating properties and liquid retaining properties, and the cell assembly and the non-aqueous electrolyte are housed together in the battery can. The separator may be various separators commonly used in the art, such as a polymer microporous film, including a polypropylene microporous film and a multilayer composite microporous film of polypropylene and polyethylene. The position, nature and type of the separator are well known to those skilled in the art and will not be described herein.

Among them, the nonaqueous electrolytic solution is a mixed solution of an electrolyte lithium salt and a nonaqueous solvent, and it is not particularly limited, and a conventional nonaqueous electrolytic solution in the art can be used. For example, the electrolyte lithium salt is selected from one or more of lithium hexafluorophosphate (LiPF ₆ ), lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium halide, lithium chloroaluminate, and lithium fluorocarbon sulfonate. The non-aqueous solvent is a mixed solution of a chain acid ester and a cyclic acid ester, wherein the chain acid ester may be dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and methyl propylene carbonate. At least one of ester (MPC), dipropyl carbonate (DPC) and other fluorine-containing, sulfur-containing or unsaturated chain-containing chain organic esters, and the cyclic acid ester may be ethylene carbonate (EC) or carbonic acid. At least one of propylene ester (PC), vinylene carbonate (VC), γ-butyrolactone (γ-BL), sultone and other fluorine-containing, sulfur-containing or unsaturated bond-containing cyclic organic esters Kind. The injection amount of the electrolyte is generally 5-8 g/amperes, and the concentration of the electrolyte is generally 0.8-1.2 mol/liter.

In the lithium ion battery of the present invention, the battery case is not particularly limited, and various battery cases commonly used in the art can be used, which are well known to those skilled in the art and will not be described herein.

In the lithium ion battery of the present invention, the method for preparing the battery is a common method in the art. Generally, the positive electrode and the negative electrode and the separator form a cell assembly, and the obtained cell assembly and non-aqueous electrolyte are sealed in the battery case. In the middle, you can get a lithium-ion battery. The specific methods are well known to those skilled in the art and will not be described herein.

Example

The invention is described in detail below by way of examples, without restricting the invention, unless otherwise specified, the materials used are commercially available, and the methods used are all conventional methods in the art.

Lithium nickel cobalt manganese oxide LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} purchased from Shanghai Shanshan Technology Co., Ltd.

Lithium cobaltate LiCoO _{2 was} purchased from Tianjin Bamo Technology Co., Ltd.

Lithium nickel cobalt aluminum oxide LiNi _0.8 Co _0.15 Al _0.05 O _{2 was} purchased from Toda Industry Co., Ltd., Japan.

The Pvdf binder HSV900 was purchased from Arkema, France.

The PTFE emulsion binder D210 had a solid content of 60% and was purchased from Daikin Industries Co., Ltd., Japan.

The conductive agent Super-P was purchased from the Swiss company Temco.

Natural graphite was purchased from Shenzhen Beitray New Energy Materials Co., Ltd.

The thickener CMC was purchased from Japan Daiichi Pharmaceutical Co., Ltd.

The styrene-butadiene rubber latex binder has a solid content of 50% and was purchased from Japan Rayon Co., Ltd.

Example 1

a. Preparation of composite active material coated with hydrated chromium orthophosphate additive

4000 g of chromium nitrate nonahydrate was dissolved in 20,000 g of deionized water to prepare a chromium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L1, 100 g of L1 was taken, and the water was replaced with absolute ethanol, and then under an air atmosphere at 100 ° C. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 28.42 g, whereby the solid content of the filter cake L1 was estimated to be 28.42%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 323 g of filter cake L1, 1500 g of deionized water was added, vigorously stirred at 290 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material in which hydrated orthophosphate chromium (CrPO ₄ ·7/2H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (the content of the additive was 8.4% by weight based on the weight of the composite active material) was obtained.

b. Production of single cells

(1) Preparation of battery positive electrode sheets

23375 g of the positive electrode composite active material prepared above, 750 g of the binder HSV900, and 875 g of the conductive agent Super-P were mixed by the method of dissolving the binder HSV900 with 25000 g of NMP as a solvent, and respectively, and stirring the cathode. The composite active material and the conductive agent Super-P are mixed with the solution of the above binder, and then stirred to form a uniform positive electrode slurry;

The positive electrode slurry was uniformly coated on an aluminum foil having a thickness of 25 μm, the coating width was 160 mm, and the double-sided surface density of the dressing was 340.7 g/m ² (the density of the double-sided surface of the dressing was measured by the weight after drying, the same below, The content of the additive was 7.9% by weight based on the dry weight of the electrode dressing, and then dried at 110 ° C to obtain a positive electrode tab.

(2) Preparation of battery negative pole piece

12480g natural graphite anode material, 130g thickener CMC, 130g conductive agent Super-P and 520g styrene-butadiene rubber latex binder are mixed by: 12500g deionized water as solvent, and the thickener CMC is dissolved. And stirring, respectively, the styrene-butadiene rubber latex binder, the conductive agent Super-P, the natural graphite anode material and the above thickener solution are mixed, and then stirred to form a uniform anode slurry;

The negative electrode slurry was uniformly coated on a copper foil having a thickness of 18 μm, the coating width was 164 mm, and the double-sided surface density of the dressing was 161.6 g/m ² (based on the weight after drying, the same below), and then at 100 Drying at ° C to obtain a negative electrode tab.

(3) Assembly of single cells

The positive electrode piece is cut into a size of 120 mm×160 mm as a positive electrode, the negative electrode piece is cut into a size of 125 mm×164 mm as a negative electrode, and a polypropylene film is used as a separator, assembled into a battery core assembly, and placed in a soft aluminum-plastic film battery case. In the body, the positive and negative poles are respectively welded with the aluminum plastic film, and the insulation between the polar ear and the battery case is ensured in the process. After calculation, the weight of the lithium nickel cobalt manganese active ingredient is about 191 g, and the negative electrode active material Natural graphite weighs approximately 104g and the battery has a nominal capacity of 30Ah. Subsequently, LiPF _{6 was} dissolved in a mixed solvent of EC/DMC=1:1 (volume ratio) at a concentration of 1 mol/liter to form a non-aqueous electrolyte, and 160 g of this electrolyte was injected into the above-mentioned battery semi-finished product under the protection of a nitrogen atmosphere. And seal the battery. The battery was aged at 45 ° C for 48 hours, then charged to 4.00 V with a current of 0.6 A, and then aged for another 48 hours at 45 ° C. Finally, the battery was produced under the protection of a nitrogen atmosphere. The gas was taken out and the battery was sealed twice to obtain a lithium ion battery A1.

Example 2

A lithium ion battery A2 was prepared in accordance with the method of Example 1, except that the coating of LiNi _0.8 Co was coated with cobalt octahydrate (normalized as Co(PO ₄ ) _2/3 ·8/3H ₂ O) additive. A positive electrode composite active material of _0.15 Al _0.05 O ₂ is used instead of chromium orthophosphate (CrPO ₄ ·7/2H ₂ O) to coat a positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein cobalt octahydrate octahydrate ( A normalized composite active material having a normalized formula of Co(PO ₄ ) _2/3 ·8/3H ₂ O) additive coated with LiNi _0.8 Co _0.15 Al _0.05 O ₂ was prepared as follows:

2910 g of cobalt hexahydrate was dissolved in 15000 g of deionized water to prepare a cobaltous cobalt nitrate solution, and 1093 g of anhydrous trisodium phosphate was dissolved in 10,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring and nitrogen protection, and the mixing time was controlled to 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring and nitrogen protection to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L2, 100 g of L2 was taken, and the water was replaced with absolute ethanol, and then under a nitrogen atmosphere at 100 ° C. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 26.57 g, whereby the solid content of the filter cake L2 was estimated to be 26.57%. 1000g of a lithium nickel cobalt aluminum oxide positive electrode material having a chemical formula of LiNi _0.8 Co _0.15 Al _0.05 O ₂ as an active ingredient was added to 345 g of filter cake L2, and 1500 g of deionized water was added thereto, and vigorously stirred at 320 rpm for 5 hours under a nitrogen atmosphere at 120 ° C. Under spray drying, a positive electrode composite active material coated with LiNi _0.8 Co _0.15 Al _0.05 O ₂ coated with cobalt octahydrate (normalized as Co(PO ₄ ) _2/3 ·8/3H ₂ O) is obtained. The content of the additive was 8.4% by weight based on the weight of the active material.

Example 3

A lithium ion battery A3 was prepared according to the method of Example 1, except that the hydrated magnesium phosphate (normalized by the formula Mg(PO ₄ ) _0.6 (HPO ₄ ) _0.1 ·3/2H ₂ O) was coated with LiCoO _{2 .} A positive electrode composite active material instead of chromic orthophosphate (CrPO ₄ ·7/2H ₂ O) coated with LiNi _0.5 Co _0.2 Mn _0.3 O _{2 as} a positive electrode composite active material, wherein hydrated magnesium phosphate (normalized formula is Mg) (PO ₄ ) _0.6 (HPO ₄ ) _0.1 ·3/2H ₂ O) The positive electrode composite active material coated with LiCoO _{2 as} an additive was prepared as follows:

2560g of magnesium nitrate hexahydrate was dissolved in 10000g of deionized water to prepare a magnesium nitrate solution, and 984g of anhydrous trisodium phosphate and 358g of disodium hydrogen phosphate dodecahydrate were dissolved in 10000g of deionized water to obtain trisodium phosphate and hydrogen phosphate. Sodium mixed solution. Under stirring, the magnesium nitrate solution was mixed with a mixed solution of trisodium phosphate and disodium hydrogen phosphate, and the mixing time was controlled to 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L3, 100 g of L3 was taken, water was replaced with absolute ethanol, and then air-conditioned at 100 ° C. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 25.82 g, whereby the solid content of the filter cake L3 was estimated to be 25.82%. 1000 g of lithium cobaltate positive electrode material of LiCoO ₂ as an active ingredient was added to 355 g of filter cake L3, 1500 g of deionized water was added, vigorously stirred at 350 rpm for 5 hours, and spray dried at 110 ° C to obtain hydrated magnesium phosphate (normalized). The general formula is Mg(PO ₄ ) _0.6 (HPO ₄ ) _0.1 ·3/2H ₂ O) a positive electrode composite active material coated with LiCoO ₂ (the content of the additive is 8.4% by weight based on the weight of the composite active material).

Example 4

A lithium ion battery A4 was prepared in accordance with the method of Example 1, except that:

(1) LiNi _0.5 Co _0.2 Mn _0.3 O ₂ lithium nickel cobalt manganese oxide cathode material was not surface coated with additives, and the battery positive electrode sheet was prepared by surface coating without LiNi _0.5 Co _0.2 Mn _0.3 O ₂ lithium nickel cobalt manganese. Oxygen cathode material, and the double-sided surface density of the dressing is 312.1g/m ² when the battery positive electrode sheet is prepared; (2) When the battery negative electrode sheet is prepared, the surface coated hydrated chromium orthophosphate (CrPO ₄ · 7/2H) is used. ₂ O) Adding natural graphite to the natural graphite without surface coating, the specific method for preparing natural graphite coated with chrome orthophosphate (CrPO ₄ ·7/2H ₂ O) additive is:

4000 g of chromium nitrate nonahydrate was dissolved in 20,000 g of deionized water to prepare a chromium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L4, 100 g of L4 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 28.11 g, whereby the solid content of the filter cake L4 was estimated to be 28.11%. 1000 g of natural graphite negative electrode material as an active ingredient was added to 326 g of filter cake L4, 1500 g of deionized water was added, vigorously stirred at 290 rpm for 5 hours, and spray dried at 115 ° C to obtain hydrated orthophosphate chromium (CrPO ₄ ·7/2H ₂ O). A negative electrode composite active material coated with natural graphite (the content of the additive is 8.4% by weight based on the weight of the composite active material).

(3) The density of the double-sided surface of the negative electrode dressing was adjusted to 176.4 g/m ² .

Example 5

A lithium ion battery A5 was prepared in accordance with the method of Example 1, except that (1) a positive electrode composite active material coated with a surface hydrated chromium orthophosphate (CrPO ₄ ·7/2H ₂ O) additive was prepared as follows:

4000 g of chromium nitrate nonahydrate was dissolved in 20,000 g of deionized water to prepare a chromium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L5, 100 g of L5 was taken, and the water was replaced with absolute ethanol, and then under an air atmosphere, 100 ° C. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 27.85 g, whereby the solid content of the filter cake L5 was estimated to be 27.85%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 221 g of filter cake L5, 1500 g of deionized water was added, vigorously stirred at 290 rpm for 5 hours, and spray dried at 105 ° C. A positive electrode composite active material in which hydrated orthophosphate chromium (CrPO ₄ ·7/2H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (the content of the additive was 5.8% by weight based on the weight of the composite active material) was obtained.

(2) When the positive electrode tab of the battery was prepared, the density of the double-sided surface of the positive electrode dressing was adjusted to 331.3 g/m ² (the weight of the positive electrode lithium nickel cobalt manganese active component in the battery was the same as in Example 1).

Example 6

A lithium ion battery A6 was prepared in accordance with the method of Example 1, except that (1) a positive electrode composite active material coated with a surface hydrated chromium orthophosphate (CrPO ₄ ·7/2H ₂ O) additive was prepared as follows:

4000 g of chromium nitrate nonahydrate was dissolved in 20,000 g of deionized water to prepare a chromium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L6, 100 g of L6, and water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 27.38 g, whereby the solid content of the filter cake L6 was 27.38%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 428 g of filter cake L6, 1500 g of deionized water was added, vigorously stirred at 290 rpm for 5 hours, and spray dried at 120 ° C. A positive electrode composite active material in which hydrated orthophosphate chromium (CrPO ₄ ·7/2H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (the content of the additive was 10.5% by weight based on the weight of the composite active material) was obtained.

(2) When the battery positive electrode tab was prepared, the double-sided surface density of the positive electrode dressing was adjusted to 348.7 g/m ² (the weight of the positive electrode lithium nickel cobalt manganese oxide active component in the battery was the same as in Example 1).

Example 7

A lithium ion battery A7 was prepared in the same manner as in Example 1, except that (1) a positive electrode composite active material coated with a surface hydrated chromium orthophosphate (CrPO ₄ ·7/2H ₂ O) additive was prepared as follows:

4000 g of chromium nitrate nonahydrate was dissolved in 20,000 g of deionized water to prepare a chromium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L7, 100 g of L7 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 29.14 g, whereby the solid content of the filter cake L7 was estimated to be 29.14%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 121 g of filter cake L7, 1500 g of deionized water was added, vigorously stirred at 290 rpm for 5 hours, and spray dried at 115 ° C. A positive electrode composite active material in which hydrated orthophosphate chromium (CrPO ₄ ·7/2H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (the content of the additive was 3.4% by weight based on the weight of the composite active material) was obtained.

(2) When the positive electrode tab of the battery was prepared, the density of the double-sided surface of the positive electrode dressing was adjusted to 323.1 g/m ² (the weight of the positive electrode lithium nickel cobalt manganese oxide active component in the battery was the same as in Example 1).

Example 8

A lithium ion battery A8 was prepared in the same manner as in Example 1, except that (1) a positive electrode composite active material coated with a surface hydrated chromium orthophosphate (CrPO ₄ ·7/2H ₂ O) additive was prepared as follows:

4000 g of chromium nitrate nonahydrate was dissolved in 20,000 g of deionized water to prepare a chromium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L8, 100 g of L8 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 29.14 g, whereby the solid content of the filter cake L8 was estimated to be 29.14%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 31 g of filter cake L8, 1500 g of deionized water was added thereto, vigorously stirred at 290 rpm for 5 hours, and spray dried at 110 ° C. orthophosphoric acid to give a hydrated chromium _{_{(CrPO 4 · 7 / 2H 2}} O) coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ positive active material composite (in weight of the composite active material, the content of the additive is 0.9 wt%).

(2) When the positive electrode tab of the battery was prepared, the density of the double-sided surface of the positive electrode dressing was adjusted to 314.9 g/m ² (the weight of the positive electrode lithium nickel cobalt manganese active component in the battery was the same as in Example 1).

Example 9

A lithium ion battery A9 was prepared in accordance with the method of Example 1, except that (1) a positive electrode composite active material coated with a surface hydrated chromium orthophosphate (CrPO ₄ ·7/2H ₂ O) additive was prepared as follows:

4000 g of chromium nitrate nonahydrate was dissolved in 20,000 g of deionized water to prepare a chromium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. Then, the suspension was transferred to a hydrothermal reaction vessel, and heat-treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L9, 100 g of L9 was taken, water was replaced with absolute ethanol, and then, under an air atmosphere, 100 ° C After heat treatment for 5 hours, a dry solid was obtained, and the weight was 28.60 g, whereby the solid content of the filter cake L9 was estimated to be 28.60%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 603 g of filter cake L9, 1500 g of deionized water was added, vigorously stirred at 290 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material in which hydrated orthophosphate chromium (CrPO ₄ ·7/2H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (the content of the additive was 14.7% by weight based on the weight of the composite active material) was obtained.

(2) When the positive electrode tab of the battery was prepared, the density of the double-sided surface of the positive electrode dressing was adjusted to 365.9 g/m ² (the weight of the positive electrode lithium nickel cobalt manganese oxide active component in the battery was the same as in Example 1).

Example 10

A lithium ion battery A10 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with titanium monohydrogen phosphate (Ti(HPO ₄ ) ₂ .2H ₂ O). Instead of hydrated chromium orthophosphate (CrPO ₄ ·7/2H ₂ O), a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein titanium tetrahydrogen phosphate dihydrate (Ti(HPO ₄ ) ₂ ·2H ₂ O The positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ was prepared as follows:

In a 0 ° C water bath and vigorous stirring at 300 rpm, 1900 g of titanium tetrachloride liquid was slowly added to 2306 g of 85% by mass concentrated phosphoric acid, and the time of adding titanium tetrachloride was controlled for 2 hours. After the reaction was completed, a suspension was obtained. . The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove chloride ions therein, and vacuum filtered to obtain a uniform filter cake L10, 100 g of L10 was taken, water was replaced with absolute ethanol, and then heat-treated at 100 ° C for 5 hours in an air atmosphere. The dried solid was obtained and found to have a weight of 25.18 g, thereby estimating the solid content of the filter cake L10 to be 25.18%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 364 g of filter cake L10, 1500 g of deionized water was added, vigorously stirred at 370 rpm for 5 hours, and spray dried at 110 ° C. hydrogen phosphate dihydrate to give a titanium _{_{(Ti (HPO 4) 2 ·}} 2H 2 O) coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ positive active material composite (in weight of the composite active material, the content of the additive is 8.4 wt. %).

Example 11

A lithium ion battery A11 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with zirconium hydrogen phosphate monohydrate (Zr(HPO ₄ ) ₂ ·H ₂ O). Instead of hydrated chromium orthophosphate (CrPO ₄ ·7/2H ₂ O), a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein zirconium hydrogen phosphate monohydrate (Zr(HPO ₄ ) ₂ ·H ₂ O The positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ was prepared as follows:

2330 g of zirconium tetrachloride powder was slowly added to 2306 g of 85% by mass concentrated phosphoric acid in a water bath at 0 ° C and vigorously stirred at 280 rpm. The time of adding zirconium tetrachloride was controlled for 2 hours, and a suspension was obtained after the reaction was completed. . The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove chloride ions therein, and vacuum filtered to obtain a uniform filter cake L11, 100 g of L11 was taken, water was replaced with absolute ethanol, and then heat-treated at 100 ° C for 5 hours in an air atmosphere. The dried solid was obtained and found to have a weight of 25.85 g, whereby the solid content of the filter cake L11 was estimated to be 25.85%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 355 g of filter cake L11, 1500 g of deionized water was added, vigorously stirred at 330 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ coated with zirconium hydrogen phosphate monohydrate (Zr(HPO ₄ ) ₂ ·H ₂ O) is obtained (based on the weight of the composite active material, the content of the additive is 8.4 weight) %).

Example 12

A lithium ion battery A12 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with yttrium orthophosphate monohydrate (YPO ₄ ·H ₂ O) instead of hydrated orthophosphate chromium. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein YPO ₄ ·H ₂ O monohydrate is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

3830 g of cerium nitrate hexahydrate was dissolved in 10,000 g of deionized water to prepare a cerium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L12, 100 g of L12 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 29.27 g, whereby the solid content of the filter cake L12 was estimated to be 29.27%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 313 g of filter cake L12, 1500 g of deionized water was added, vigorously stirred at 300 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ coated with yttrium orthophosphate monohydrate (YPO ₄ ·H ₂ O) was obtained (the content of the additive was 8.4% by weight based on the weight of the composite active material).

Example 13

A lithium ion battery A13 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with strontium orthophosphate monohydrate (ScPO ₄ ·H ₂ O) instead of hydrated chromium orthophosphate. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein strontium orthophosphate monohydrate (ScPO ₄ ·H ₂ O) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

3390 g of cerium nitrate hexahydrate was dissolved in 10,000 g of deionized water to prepare a cerium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L13, 100 g of L13 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 29.49 g, whereby the solid content of the filter cake L13 was estimated to be 29.49%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 311 g of filter cake L13, 1500 g of deionized water was added, vigorously stirred at 300 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material in which ruthenium orthophosphate monohydrate (ScPO ₄ ·H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (the content of the additive was 8.4% by weight based on the weight of the composite active material) was obtained.

Example 14

A lithium ion battery A14 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with lanthanum orthophosphate monohydrate (LaPO ₄ ·H ₂ O) instead of hydrated chromium orthophosphate. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein lanthanum orthophosphate monohydrate (LaPO ₄ ·H ₂ O) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

4330 g of cerium nitrate hexahydrate was dissolved in 20,000 g of deionized water to prepare a cerium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L14, 100 g of L14 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 30.66 g, whereby the solid content of the filter cake L14 was estimated to be 30.66%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 299 g of filter cake L14, 1500 g of deionized water was added, vigorously stirred at 260 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material of LaNi _0.5 Co _0.2 Mn _0.3 O ₂ coated with lanthanum orthophosphate monohydrate (LaPO ₄ ·H ₂ O) was obtained (the content of the additive was 8.4% by weight based on the weight of the composite active material).

Example 15

A lithium ion battery A15 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with lanthanum orthophosphate monohydrate (CePO ₄ ·H ₂ O) instead of hydrated chromium orthophosphate. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein cerium orthophosphate monohydrate (CePO ₄ ·H ₂ O) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

4340 g of cerium nitrate hexahydrate was dissolved in 20,000 g of deionized water to prepare a cerium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L15, 100 g of L15 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. The heat treatment was carried out for 5 hours to obtain a dried solid, and the weight was found to be 30.03 g, whereby the solid content of the filter cake L15 was estimated to be 30.03%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 305 g of filter cake L15, 1500 g of deionized water was added, vigorously stirred at 280 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ coated with lanthanum orthophosphate monohydrate (CePO ₄ ·H ₂ O) was obtained (the content of the additive was 8.4% by weight based on the weight of the composite active material).

Example 16

A lithium ion battery A16 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with ruthenium orthophosphate monohydrate (NdPO ₄ ·H ₂ O) instead of hydrated chromium orthophosphate. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein NdPO ₄ ·H ₂ O monohydrate is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

4380 g of cerium nitrate hexahydrate was dissolved in 20,000 g of deionized water to prepare a cerium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L16, 100 g of L16 was taken, and the water was replaced with absolute ethanol, and then under an air atmosphere at 100 ° C. After heat treatment for 5 hours, a dry solid was obtained, and the weight was 27.62 g, and the solid content of the filter cake L16 was estimated to be 27.62%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 332 g of filter cake L16, 1500 g of deionized water was added, vigorously stirred at 230 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material of NdPO ₄ ·H ₂ O monohydrate coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (the content of the additive was 8.4% by weight based on the weight of the composite active material) was obtained.

Example 17

A lithium ion battery A17 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with strontium orthophosphate monohydrate (SmPO ₄ ·H ₂ O) instead of hydrated chromium orthophosphate. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein bismuth orthophosphate monohydrate (SmPO ₄ ·H ₂ O) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

4440 g of cerium nitrate hexahydrate was dissolved in 20,000 g of deionized water to prepare a cerium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L17, 100 g of L17 was taken, and the water was replaced with absolute ethanol, and then under an air atmosphere, 100 ° C. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 27.26 g, whereby the solid content of the filter cake L17 was estimated to be 27.26%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 336 g of filter cake L17, 1500 g of deionized water was added, vigorously stirred at 240 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material in which lanthanum orthophosphate monohydrate (SmPO ₄ ·H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (the content of the additive was 8.4% by weight based on the weight of the composite active material) was obtained.

Example 18

A lithium ion battery A18 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with yttrium orthophosphate monohydrate (GdPO ₄ ·H ₂ O) instead of hydrated orthophosphate chromium. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein ruthenium orthophosphate monohydrate (GdPO ₄ ·H ₂ O) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

4510 g of cerium nitrate hexahydrate was dissolved in 20,000 g of deionized water to prepare a cerium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L18, 100 g of L18 was taken, and the water was replaced with absolute ethanol, and then in an air atmosphere at 100 ° C. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 29.32 g, whereby the solid content of the filter cake L18 was estimated to be 29.32%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 313 g of filter cake L18, 1500 g of deionized water was added, vigorously stirred at 310 rpm for 5 hours, and spray dried at 110 ° C. orthophosphoric acid monohydrate to give gadolinium (GdPO ₄ · H ₂ O) coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ positive active material composite (in weight of the composite active material, the content of the additive is 8.4 wt%).

Example 19

A lithium ion battery A19 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with ruthenium orthophosphate monohydrate (ErPO ₄ ·H ₂ O) instead of hydrated chromium orthophosphate. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein erbium orthophosphate monohydrate (ErPO ₄ ·H ₂ O) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

4433 g of cerium nitrate pentahydrate was dissolved in 20,000 g of deionized water to prepare a cerium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L19, 100 g of L19 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was 28.73 g, whereby the solid content of the filter cake L19 was estimated to be 28.73%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 319 g of filter cake L19, 1500 g of deionized water was added, vigorously stirred at 300 rpm for 5 hours, and spray dried at 110 ° C. orthophosphoric acid monohydrate obtained erbium (ErPO ₄ · H ₂ O) coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ positive active material composite (in weight of the composite active material, the content of the additive is 8.4 wt%).

Example 20

A lithium ion battery A20 was prepared according to the method of Example 1, except that a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ with iron orthophosphate dihydrate (FePO ₄ · 2H ₂ O) was used instead of hydrated chromium orthophosphate. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein iron orthophosphate dihydrate (FePO ₄ ·2H ₂ O) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

4040 g of iron nitrate nonahydrate was dissolved in 15000 g of deionized water to prepare a ferric nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was maintained at 3 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L20, 100 g of L20 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 26.05 g, whereby the solid content of the filter cake L20 was estimated to be 26.05%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 352 g of filter cake L20, 1500 g of deionized water was added, and the mixture was vigorously stirred at 270 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material in which iron orthophosphate dihydrate (FePO ₄ ·2H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (the content of the additive was 8.4% by weight based on the weight of the composite active material) was obtained.

Example 21

A lithium ion battery A21 was prepared according to the method of Example 1, except that the positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with manganese orthophosphate monohydrate (MnPO ₄ ·H ₂ O) instead of chromic orthophosphate. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein manganese orthophosphate monohydrate (MnPO ₄ ·H ₂ O) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

3580 g of a 50 wt% aqueous solution of manganese nitrate was diluted with 20,000 g of deionized water to prepare a manganese nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 3 with concentrated nitric acid having a mass fraction of 65%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L21, 100 g of L21 was taken, and the water was replaced with absolute ethanol, and then in an air atmosphere at 100 ° C. The heat treatment was carried out for 5 hours to obtain a dried solid, and the weight was found to be 27.16 g, whereby the solid content of the filter cake L21 was 27.16%. As the active ingredient 1000g of formula LiNi _0.5 Co _0.2 Mn _0.3 O lithium nickel ₂ cobalt manganese oxide cathode material was added 338g cake L21 added 1500g deionized water with vigorous stirring 260rpm 5 hours, 110 deg.] C at spray-drying, A positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ coated with manganese orthophosphate monohydrate (MnPO ₄ ·H ₂ O) was obtained (the content of the additive was 8.4% by weight based on the weight of the composite active material).

Example 22

A lithium ion battery A22 was prepared according to the method of Example 1, except that a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ with nickel orthophosphate monohydrate (NiPO ₄ ·H ₂ O) was used instead of hydrated orthophosphate chromium. (CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein nickel nicotinate monohydrate (NiPO ₄ ·H ₂ O) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O The positive electrode composite active material of ₂ was prepared as follows:

2910 g of nickel hexahydrate hexahydrate was dissolved in 20,000 g of deionized water to prepare a nickel nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 3 with concentrated nitric acid having a mass fraction of 65%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L22, 100 g of L22 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 26.64 g, whereby the solid content of the filter cake L22 was estimated to be 26.64%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 344 g of filter cake L22, 1500 g of deionized water was added, vigorously stirred at 240 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material in which LiNi _0.5 Co _0.2 Mn _0.3 O _{2 was} coated with nickel orthophosphate monohydrate (NiPO ₄ ·H ₂ O) (the content of the additive was 8.4% by weight based on the weight of the composite active material).

Example 23

A lithium ion battery A23 was prepared according to the method of Example 1, except that a positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ coated with bismuth orthophosphate (BiPO ₄ · 2/3H ₂ O) was used instead of hydrated orthophosphoric acid. Chromium (CrPO ₄ ·7/2H ₂ O) coated with a positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein hydrated orthophosphoric acid ruthenium (BiPO ₄ ·2/3H ₂ O) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ positive active material composite was prepared as follows:

4850 g of lanthanum nitrate pentahydrate was added to 20,000 g of dilute aqueous nitric acid solution having a mass fraction of 2% to prepare a cerium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L23, 100 g of L23 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 30.44 g, whereby the solid content of the filter cake L23 was estimated to be 30.44%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 301 g of filter cake L23, 1500 g of deionized water was added, vigorously stirred at 220 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material in which hydrated orthophosphoric acid ruthenium (BiPO ₄ · 2/3H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (the content of the additive was 8.4% by weight based on the weight of the composite active material) was obtained.

Example 24

A lithium ion battery A24 was prepared according to the method of Example 1, except that copper phosphate trihydrate (normalized to Cu(PO ₄ ) _{2 /3} · H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn _0.3 O a positive electrode composite active material of ₂ , which is substituted with chromic orthophosphate (CrPO ₄ ·7/2H ₂ O), and a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein copper phosphate trihydrate (normalized formula is Cu(PO ₄ ) _2/3 ·H ₂ O) A positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ was prepared as follows:

2420 g of copper nitrate trihydrate was dissolved in 10,000 g of deionized water to prepare a copper nitrate solution, and 1093 g of anhydrous trisodium phosphate was dissolved in 10,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the mixing time was controlled to 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L24, 100 g of L24 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was found to be 28.80 g, whereby the solid content of the filter cake L24 was estimated to be 28.80%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 318 g of filter cake L24, 1500 g of deionized water was added thereto, vigorously stirred at 210 rpm for 5 hours, and spray dried at 110 ° C. Obtaining a positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ coated with copper phosphate trihydrate (normalized to Cu(PO ₄ ) _2/3 ·H ₂ O) (based on the weight of the composite active material, The content of the additive was 8.4% by weight).

Example 25

A lithium ion battery A25 was prepared according to the method of Example 1, except that zinc phosphate dihydrate (normalized to Zn(PO ₄ ) _2/3 · 2/3H ₂ O) was coated with LiNi _0.5 Co _0.2 Mn. A positive electrode composite active material of _0.3 O ₂ instead of chromic orthophosphate (CrPO ₄ ·7/2H ₂ O) coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein zinc phosphate dihydrate (Golden Chemical Co., Ltd.) A positive electrode composite active material of the formula Zn(PO ₄ ) _2/3 · 2/3H ₂ O) coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ was prepared as follows:

2970 g of zinc nitrate hexahydrate was dissolved in 10,000 g of deionized water to prepare a zinc nitrate solution, and 1093 g of anhydrous trisodium phosphate was dissolved in 10,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the mixing time was controlled to 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L25, 100 g of L25 was taken, and the water was replaced with absolute ethanol, and then at 100 ° C in an air atmosphere. The heat treatment was carried out for 5 hours to obtain a dried solid, and the weight was found to be 29.26 g, whereby the solid content of the filter cake L25 was estimated to be 29.26%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 313 g of filter cake L25, 1500 g of deionized water was added thereto, vigorously stirred at 230 rpm for 5 hours, and spray dried at 110 ° C. A positive electrode composite active material of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ coated with zinc phosphate dihydrate (normalized as Zn(PO ₄ ) _2/3 ·2/3H ₂ O) is obtained (by the weight of the composite active material) The standard, the content of the additive was 8.4% by weight).

Comparative example 1

A lithium ion battery D1 was prepared according to the method of Example 1, except that (1) LiNi _0.5 Co _0.2 Mn _0.3 O ₂ lithium nickel cobalt manganese oxide cathode material was not surface-coated with an additive, and the battery positive electrode sheet was prepared without Surface-coated LiNi _0.5 Co _0.2 Mn _0.3 O ₂ lithium nickel cobalt manganese oxide cathode material;

(2) When the positive electrode tab of the battery was prepared, the density of the double-sided surface of the positive electrode dressing was adjusted to 312.1 g/m ² (the weight of the positive electrode lithium nickel cobalt manganese active component in the battery was the same as in Example 1).

Comparative example 2

A lithium ion battery D2 was prepared according to the method of Example 2, except that (1) LiNi _0.8 Co _0.15 Al _0.05 O ₂ lithium nickel cobalt aluminum oxide cathode material was not surface-coated with an additive, and the battery positive electrode sheet was prepared without Surface coated LiNi _0.8 Co _0.15 Al _0.05 O ₂ lithium nickel cobalt aluminum oxide cathode material;

(2) When the positive electrode tab of the battery was prepared, the density of the double-sided surface of the positive electrode dressing was adjusted to 312.1 g/m ² (the weight of the positive electrode lithium nickel cobalt aluminum oxide active component in the battery was the same as in Example 2).

Comparative example 3

Lithium ion battery D3 was prepared according to the method of Example 3, except that (1) lithium cobaltate LiCoO ₂ cathode material was not surface-coated with an additive, and the battery positive electrode sheet was prepared by using lithium cobalt oxide LiCoO which was not surface-coated. ₂ cathode material;

(2) When the positive electrode tab of the battery was prepared, the density of the double-sided surface of the positive electrode dressing was adjusted to 312.1 g/m ² (the weight of the active component of the positive electrode lithium cobaltate in the battery was the same as in Example 3).

Comparative example 4

A lithium ion battery D4 was prepared according to the method of Example 1, except that a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ with chromium orthophosphate (CrPO ₄ , containing no crystal water) was used instead of chromium orthophosphate ( CrPO ₄ ·7/2H ₂ O) a positive electrode composite active material coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , wherein chromium orthophosphate (CrPO ₄ , free of crystal water) is coated with LiNi _0.5 Co _0.2 Mn _0.3 O ₂ The positive electrode composite active material was prepared as follows:

4000 g of chromium nitrate nonahydrate was dissolved in 20,000 g of deionized water to prepare a chromium nitrate solution, and 1640 g of anhydrous trisodium phosphate was dissolved in 16,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring, and the pH of the mixed system was adjusted to 5 with a concentrated phosphoric acid having a mass fraction of 85%, and the mixing time was controlled for 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L26, 100 g of L26, and water was replaced with absolute ethanol, and then in an air atmosphere at 500 ° C. After heat treatment for 8 hours, a dry solid was obtained, and the weight was found to be 25.88 g, whereby the content of chromium orthophosphate (CrPO ₄ , containing no crystal water) in the filter cake L26 was estimated to be 25.88%. 1000 g of a lithium nickel cobalt manganese oxide positive electrode material having a chemical formula of LiNi _0.5 Co _0.2 Mn _0.3 O ₂ as an active ingredient was added to 354 g of filter cake L26, 1500 g of deionized water was added, vigorously stirred at 290 rpm for 5 hours, and spray dried at 110 ° C. then under an air atmosphere, a heat treatment 500 deg.] C for 8 hours to obtain a positive chromium phosphate (CrPO _4, containing no water of crystallization) coated LiNi _0.5 Co _0.2 Mn _0.3 O ₂ positive active material composite (in weight of the composite active material as a reference, The content of chromium orthophosphate (CrPO ₄ , free of crystal water) was 8.4% by weight).

Comparative example 5

A lithium ion battery D5 was prepared according to the method of Example 2 except that Cobalt Orthophosphate (normalized to Co(PO ₄ ) _2/3 , free of water of crystallization) was coated with LiNi _0.8 Co _0.15 Al _0.05. O composite positive electrode active material in place of ₂ cobaltous orthophosphate octahydrate (normalized formula _{_{Co (PO 4) 2/3 · 8}} / 3H 2 O) coated with LiNi _0.8 Co _0.15 Al _0.05 O ₂ composite positive electrode active The substance, wherein the cobalt orthophosphate (normalized formula is Co(PO ₄ ) _2/3 , free of crystal water) and the positive electrode composite active material coated with LiNi _0.8 Co _0.15 Al _0.05 O ₂ is prepared as follows:

2910 g of cobalt hexahydrate was dissolved in 15000 g of deionized water to prepare a cobaltous cobalt nitrate solution, and 1093 g of anhydrous trisodium phosphate was dissolved in 10,000 g of deionized water to obtain a trisodium phosphate solution. The above two solutions were mixed under stirring and nitrogen protection, and the mixing time was controlled to 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring and nitrogen protection to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L27, 100 g of L27 was taken, and the water was replaced with absolute ethanol, and then under a nitrogen atmosphere at 500 ° C. After heat treatment for 8 hours, a dry solid was obtained, and the weight was 19.57 g, thereby estimating the content of cobalt orthophosphate (normalized formula of Co(PO ₄ ) _2/3 , containing no crystal water) in the filter cake L27. 19.57%. 1000 g of LiNi _0.8 Co _0.15 Al _0.05 O ₂ lithium nickel cobalt aluminum oxide as an active ingredient was added to 469 g of filter cake L27, 1500 g of deionized water was added, vigorously stirred under a nitrogen atmosphere at 320 rpm for 5 hours, spray dried at 110 ° C, and then under a nitrogen atmosphere, a heat treatment 500 deg.] C for 8 hours to give cobaltous orthophosphate (normalized formula Co (PO ₄₎ _2/3, containing no water of crystallization) coated LiNi _0.8 Co _0.15 Al _0.05 O ₂ lithium nickel cobalt aluminum The positive electrode composite active material of oxygen (the content of cobaltous orthophosphate (normalized to Co(PO ₄ ) _2/3 , free of crystal water) is 8.4% by weight based on the weight of the composite active material).

Comparative example 6

A lithium ion battery D6 was prepared according to the method of Example 3 except that magnesium cobaltate (normalized to Mg(PO ₄ ) _0.6 (HPO ₄ ) _0.1 , free of crystal water) was coated with lithium cobalt oxide LiCoO _{2 .} a positive electrode composite active material instead of hydrated magnesium phosphate (normalized to Mg(PO ₄ ) _0.6 (HPO ₄ ) _0.1 ·3/2H ₂ O) coated with LiCoO ₂ positive electrode composite active material, wherein magnesium phosphate A positive electrode composite active material having a general formula of Mg(PO ₄ ) _0.6 (HPO ₄ ) _0.1 and containing no crystal water) coated with lithium cobaltate LiCoO ₂ was prepared as follows:

2560g of magnesium nitrate hexahydrate was dissolved in 10000g of deionized water to prepare a magnesium nitrate solution, and 984g of anhydrous trisodium phosphate and 358g of disodium hydrogen phosphate dodecahydrate were dissolved in 10000g of deionized water to obtain trisodium phosphate and hydrogen phosphate. Sodium mixed solution. Under stirring, the magnesium nitrate solution was mixed with a mixed solution of trisodium phosphate and disodium hydrogen phosphate, and the mixing time was controlled to 2 hours to obtain a suspension. The suspension was then transferred to a hydrothermal reaction vessel and heat treated at 180 ° C for 10 hours under stirring to obtain a precipitate. The precipitate was washed with deionized water to remove sodium ions and phosphates, and vacuum filtered to obtain a uniform filter cake L28, 100 g of L28, and water was replaced with absolute ethanol, and then at 500 ° C in an air atmosphere. After heat treatment for 5 hours, a dry solid was obtained, and the weight was 19.24 g, thereby estimating the magnesium phosphate in the filter cake L28 (normalized formula of Mg(PO ₄ ) _0.6 (HPO ₄ ) _0.1 , containing no crystal water) The content is 19.24%. 1000 g of lithium cobaltate LiCoO ₂ cathode material as an active ingredient was added to 477 g of filter cake L28, 1500 g of deionized water was added, vigorously stirred at 350 rpm for 5 hours, spray dried at 110 ° C, and then heat treated at 500 ° C for 8 hours in an air atmosphere. , obtaining a positive electrode composite active material of magnesium phosphate (normalized to Mg(PO ₄ ) _0.6 (HPO ₄ ) _0.1 , containing no crystal water) coated with lithium cobaltate LiCoO ₂ (based on the weight of the composite active material, Magnesium phosphate (normalized to Mg(PO ₄ ) _0.6 (HPO ₄ ) _0.1 , free of crystal water) was 8.4% by weight).

Test case

Single cell abuse test

1, overcharge test

The single cells (including the lithium ion batteries A1-A25 prepared in Examples 1-25 and the lithium ion batteries D1-D6 prepared in Comparative Examples 1-6) were charged at a current of 30 A to 8.5 V, and at 8.5 V. The constant pressure was maintained for 1 hour under voltage, and the phenomenon during the process was observed and recorded. Each of the 30 single cells was tested in parallel. The results are shown in Table 1.

2, 30% extrusion test

The single cells (including the lithium ion batteries A1-A25 prepared in Examples 1-25 and the lithium ion batteries D1-D6 prepared in Comparative Examples 1-6) were charged at a current of 30 A to 4.25 V, and at 4.25 V. Constant voltage charging under voltage until the current is less than 1.5A. Extend the battery from the end face of the semi-cylindrical body with a radius of 75 mm from the direction perpendicular to the pole piece of the battery. The extrusion speed is 5 mm/s until the deformation of the battery reaches 30%. After the extrusion is completed, stay for one hour, observe and record. The phenomenon in the process. Each of the 30 single cells was tested in parallel. The results are shown in Table 2.

3, 50% extrusion test

The single cells (including the lithium ion batteries A1-A25 prepared in Examples 1-25 and the lithium ion batteries D1-D6 prepared in Comparative Examples 1-6) were charged at a current of 30 A to 4.25 V, and at 4.25 V. Constant voltage charging under voltage until the current is less than 1.5A. Extend the battery from the end face of the semi-cylindrical body with a radius of 75 mm from the direction perpendicular to the pole piece of the battery. The extrusion speed is 5 mm/s until the deformation of the battery reaches 50%. After the extrusion is completed, it is allowed to stand for one hour, observe and record. The phenomenon in the process. Each of the 30 single cells was tested in parallel. The results are shown in Table 3.

4, acupuncture test

The single cells (including the lithium ion batteries A1-A25 prepared in Examples 1-25 and the lithium ion batteries D1-D6 prepared in Comparative Examples 1-6) were charged at a current of 30 A to 4.25 V, and at 4.25 V. Constant voltage charging under voltage until the current is less than 1.5A. A 6 mm diameter nail was passed through the battery at a rate of 25 mm/s in a direction perpendicular to the long and wide faces of the battery, and allowed to stand for one hour to observe and record the phenomenon during the process. Each of the 30 single cells was tested in parallel. The results are shown in Table 4.

Table 1

Table 2

table 3

Table 4

Comparing the data of the respective examples and comparative examples in Tables 1-4, it can be seen that the lithium ion battery composite active material obtained by coating the active material with the hydrated phosphate additive according to the present invention when preparing the positive electrode or the negative electrode can be significantly improved. The safety of the lithium ion battery thus prepared, and the introduced additive must contain crystal water, and when the corresponding substance containing no crystal water is introduced, the corresponding substance cannot effectively absorb the heat of the battery under the abuse condition, and thus cannot be obtained. Significantly improve the safety of the battery.

Comparing the results of Example 1 and Examples 7-9 in Tables 1-4, it is known that lithium ions having an additive content of 5.6-10.6% by weight based on the weight of the lithium ion battery composite active material are introduced in the preparation of the positive electrode or the negative electrode. The battery composite active material can further improve the safety of the lithium ion battery thus prepared, and can further improve the safety of the prepared lithium ion battery under extremely severe conditions when the amount of the additive is further increased.

Comparing the results of Examples 1-4 in Tables 1-4 with Examples 10-25, the additive is hydrated chromium orthophosphate (CrPO ₄ ·7/2H ₂ O), cobalt octahydrate orthophosphate (normalized) The general formula is Co(PO ₄ ) _2/3 ·8/3H ₂ O) and hydrated magnesium phosphate (normalized formula is Mg(PO ₄ ) _0.6 (HPO ₄ ) _0.1 ·3/2H ₂ O) At least one of them can further improve the safety of the prepared lithium ion battery.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solutions of the present invention within the scope of the technical idea of the present invention. These simple variants All fall within the scope of protection of the present invention.

It should be further noted that the specific technical features described in the above specific embodiments may be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention has various possibilities. The combination method will not be described separately.

In addition, any combination of various embodiments of the invention may be made as long as it does not deviate from the idea of the invention, and it should be regarded as the disclosure of the invention.

Claims

A lithium ion battery composite active material, characterized in that the lithium ion battery composite active material is an additive-coated active material, and the additive is M(PO 4 ) a (HPO 4 ) b · cH 2 O, wherein , M is at least one of a Group IIA metal element, a Group IB metal element, a Group IIB metal element, a Group IIIB metal element, a Group IVB metal element, a Group VIB metal element, a Group VIIB metal element, a Group VIII metal element, and a Group VA metal element. An element, a≥0, b≥0, and a,b are not 0 at the same time, c>0.
The lithium ion battery composite active material according to claim 1, wherein, in the additive, the Group IIA metal element is Mg, the Group IB metal element is Cu, and the Group IIB metal element is Zn, The Group IIIB metal element is at least one of Y, Sc, La, Ce, Nd, Sm, Gd, and Er, the Group IVB metal element is Ti and/or Zr, and the Group VIB metal element is Cr, The group VIIB metal element is Mn, the group VIII metal element is at least one of Fe, Co and Ni, and the VA group metal element is Bi;

Preferably, the additive is in CrPO 4 ·7/2H 2 O, Co(PO 4 ) 2/3 ·8/3H 2 O and Mg(PO 4 ) 0.6 (HPO 4 ) 0.1 ·3/2H 2 O At least one.
The lithium ion battery composite active material according to claim 1 or 2, wherein the content of the additive is 0.05 to 32% by weight, preferably 3 to 15% by weight based on the weight of the lithium ion battery composite active material. % is further preferably 5.6 to 10.6% by weight.
The lithium ion battery composite active material according to any one of claims 1 to 3, wherein the active material is a positive electrode active material or a negative electrode active material, and the positive electrode active material is lithium cobaltate, lithium nickel oxide, lithium Nickel cobalt oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium nickel manganese oxide, lithium manganate, lithium vanadate, lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium manganese iron phosphate, manganese phosphate At least one of iron cobalt lithium, lithium manganese iron nickel cobalt oxide, lithium vanadium phosphate, and lithium iron silicate, the negative electrode active material being at least one of graphite, lithium titanate, silicon, hard carbon, tin, and tin oxide. Kind.
The method for producing a lithium ion battery composite active material according to any one of claims 1 to 4, characterized in that the method comprises: preparing a hydrated phosphate of the element M, and in the presence of the dispersing agent, the element M The hydrated phosphate is mixed with the active material, and then the resulting mixture is subjected to heat treatment.
The method according to claim 5, wherein the dispersing agent is at least one of isopropyl alcohol, deionized water, ethanol, butanol, and acetone.
The method according to claim 5, wherein the heat treatment is by spray drying, microwave drying, fluidized bed drying or oven drying, preferably spray drying.
A lithium ion battery electrode slurry, characterized in that the electrode paste comprises a lithium ion battery active material, a binder, a conductive agent, a solvent and an optional thickener, wherein the lithium ion battery active material A lithium ion battery composite active material according to any one of claims 1 to 4;

Preferably, the binder is contained in an amount of 0.5 to 5% by weight on a dry basis, and the content of the conductive agent is 0.5 to 5% by weight, based on the weight of the lithium ion battery composite active material, The content of the solvent is from 55 to 200% by weight, and the content of the thickener is from 0 to 2.5% by weight.
A positive electrode or a negative electrode of a lithium ion battery, characterized in that the positive electrode or the negative electrode of the lithium ion battery comprises a current collector and an electrode dressing on the current collector, the electrode dressing containing a lithium ion battery active material, a binder and a conductive agent And an optional thickener, wherein the lithium ion battery active material is the lithium ion battery composite active material according to any one of claims 1 to 4.
A lithium ion battery, characterized in that the lithium ion battery comprises a battery case and electricity inside the battery case a core assembly and an electrolyte, the battery assembly including a positive electrode, a negative electrode, and a separator, and the positive electrode is the lithium ion battery positive electrode according to claim 9, and/or the negative electrode is the lithium ion battery according to claim 9. negative electrode.