KR20170117541A - High energy density nickel-cobalt based lithium ion cathode material and its manufacturing method - Google Patents

Abstract

In the high energy density nickel-cobalt based lithium ion cathode material of the present invention, the chemical formula of the substrate is Li _p Ni _x Co _{1 - x} M _m O ₂ , M is a dopant, and the coating material is an active material N; The positive electrode material of the lithium ion secondary battery is made of secondary particles or primary particles by aggregating primary particles or mixed particles of primary particles and secondary particles. The production method includes the production of a lithium ion secondary battery cathode material precursor; And manufacturing a lithium-ion secondary battery cathode material. In the present invention, the nickel-cobalt binary precursor is advantageous for controlling the shape because the continuous coprecipitation reaction proceeds, the elemental mixing is uniform and the reaction is sufficient, and the binary high nickel- Due to the reduction of the mixing phenomenon, the structure is stable, battery safety performance and high temperature performance are improved, and the coating active material improves the initial charging and discharging efficiency and energy density of the material to some extent.

Description

High energy density nickel-cobalt based lithium ion cathode material and its manufacturing method

The present invention relates to a cathode material for a lithium ion battery, and more particularly, to a cathode material for a nickel-cobalt based lithium ion battery having a high energy density and a method of manufacturing the same.

Lithium-ion batteries are widely used in mobile electronic products such as mobile phones and laptops because they are light in weight, have a small volume, high discharge plateau, large capacity, long cycle life and no memory effect It is also applied to satellite, electric car, aerospace and so on.

LiNi _x Co _{1 - x} O ₂ (0.6 <x <1) The anode material has the advantages of lithium cobalt oxide and lithium nickel oxide. It has high non-discharge capacity, excellent circulation performance, low cost and low environmental pollution. have. However, high nickel-based material is Ni ^{2 +} is because it is difficult to be completely oxidized to Ni ^{3 +} at high temperatures making process shown cation Mixing between Ni ^{2 +} and Ni ^{3 +} poor heat stability initial charge and discharge efficiency is lowered Disadvantages.

Conventionally, in order to solve the above-mentioned problem, the structure has been stabilized by improving the cation mixing phenomenon by proceeding with the doping coating deformation, etc. However, since the doping or coating material is an inactive material,

In order to solve the above problem, the present invention is doped with LiNi _x Co _{1 - x} O ₂ to transform into a stable material structure, and further coating the active material to further improve the electrochemical performance of the material. This not only improves material stability and high temperature performance, but also greatly improves the electrochemical performance of the material, especially its capacity and initial charge and discharge efficiency.

An object of the present invention is to overcome the disadvantages of the prior art by providing a cathode material of a nickel-cobalt based lithium ion battery having a high energy density and a manufacturing method thereof.

In order to achieve the above object, the present invention has been implemented through the following technical solutions. That is, in the nickel-cobalt based lithium ion cathode material having a high energy density, the chemical formula of the base material is Li _p Ni _x Co _{1 - x} M _m O ₂ where 0.95? P? 1.25, 0.6? 0.01 < = m < 0.12, M is a dopant, the coating material is an active material N, and N comprises 0.01 to 25 wt% of the total mass of the substrate; The positive electrode material of the lithium ion secondary battery is made of secondary particles or primary particles by aggregating primary particles or mixed particles of primary particles and secondary particles.

The method for manufacturing the high-energy density nickel-cobalt based lithium ion cathode material includes the following steps.

Step 1: Preparation of a cathode material precursor for a lithium ion secondary battery

a. Preparation of solution: Mixed salt solution A1 was prepared by mixing Ni: Co = x: 1-x at a molar ratio of 0.5 to 3 mol / L in the salt solution; An alkali solution having a concentration of 1.5 to 12 mol / L is formulated to prepare a complexing agent solution having a concentration of 0.5 to 5 mol / L, wherein 0.6? X? 1;

b. Preparation of the initial solution: Pure water is injected into the reaction vessel, the pH value of the solution is adjusted by using an alkali solution, the temperature of the reaction vessel is maintained at 40 to 80 ° C, the inert gas is simultaneously poured, Consistently progress the entire reaction process;

c. Reaction of the precursor: Al solution is added to the reaction vessel and the flow rate is maintained at 3 to 20 L / min. At the same time, an appropriate amount of complexing agent and alkali solution are slowly added, the temperature in the reaction vessel is maintained at 40 to 80 캜, The speed is adjusted to 200 to 950 r / min;

d. Solid-liquid separation: the surface treatment of the material of Step c is carried out, the synthesized binary precursor of the cathode material is transferred to an aging machine to carry out solid-liquid separation, the solid precursor obtained by solid-liquid separation using deionized water is washed, The required formulations of the binary precursors A2, A2 obtained after drying are Ni _x Co _1-x (OH) ₂ ;

Step 2: Production of cathode material for lithium ion secondary battery

e. Primary sintering: The lithium precursor material, A2 and the dopant M material are mixed according to the proportions in the molecular formula Li _p Ni _x Co _{1 -x} M _m O ₂ where 0.95? P? 1.25, 0.6? X <1, m < 0.12, M is a dopant, the sintering temperature is controlled to 400 to 1050 DEG C and the sintering time is controlled to 4 to 40 hours, and air or oxygen gas is poured in the sintering process, and the material after sintering is crushed, RTI ID = 0.0 &gt; A &lt; / RTI &gt;

f. Surface treatment: The material A is washed with water to lower the alkali content, the ratio of the material A to the water is 1: 1 to 1: 6, the water is washed and the material is dried and screened;

g. Coating: The substance A or substance A treated as the substrate is coated with the N material on the substrate, and the coating method is a dry coating, a wet coating or a coprecipitation coating method, wherein N is 0.01 to 25 wt%;

h. The sintering is carried out at a temperature of 400 to 1050 ° C, the sintering time of the main temperature zone is controlled to 3 to 35 hours, and the air or oxygen The sintering can be carried out three times or more according to the requirements for product performance, and the sintering conditions are the same as the sintering twice. The sintered material is processed by crushing, classifying, screening, iron-making processes as necessary.

Preferably, the alkali solution in step a is at least one mixed solution selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide; The complexing agent is at least one mixed solution selected from the group consisting of ammonia water, ammonia bicarbonate, ammonium sulfate, ammonium carbonate, citric acid, and disodium ethylene diamine tetraacetate (EDTA).

Preferably, the nickel salt or cobalt salt solution in step a) is at least one mixed solution selected from the group consisting of sulfate, nitrate, and chlorate.

Preferably, the pH value in step b is adjusted to 8.5 to 13.5.

Preferably, the pH value in step c is adjusted to 9.5 to 13.5.

Preferably, the D50 range of the precursor A2 is 5 to 22 mu m.

Preferably, the lithium precursor material is a mixture of one or more selected from the group consisting of lithium hydroxide, lithium carbonate, and lithium oxalate.

Preferably, the dopant M is selected from the group consisting of oxides, halides, hydroxides, hydroxides and hydroxides of Cr, La, Ce, Zr, Ni, Mg, Ti, Al, Ca, V, B, Be, Y, Mo, A mixture of at least one element selected from the group consisting of organic compounds, nitrates, sulphates, carbonates, phosphates, oxalates or other metal oxides or metal fluorides.

Preferably, the coating active material N is a complex oxide of Li and Cr, La, Ce, Zr, Ti, Al, Ca, V, B, Be, Y, Mo, Tb, Ho and Tm, A Li precursor material which is a mixture of at least one of lithium and lithium oxalate and an oxide, a halide, a hydroxide, a hydroxide and a transition metal of Cr, La, Ce, Zr, Ti, Al, Ca, V, B, Metal organics, nitrates, sulphates, carbonates, phosphates, oxalates, and mixtures thereof.

Advantageous effects of the present invention are as follows. In the present invention, the nickel-cobalt binary precursor is advantageous for controlling the shape because the continuous coprecipitation reaction proceeds and the elemental mixing is uniform and the reaction is sufficient. The two-component high-nickel-based materials have a stable structure due to a decrease in the cation mixing phenomenon through the elements suitable for doping, and the safety performance and the high temperature performance of the battery are improved. The coating active material has the initial charging and discharging efficiency and energy density It improved to some extent.

Hereinafter, exemplary embodiments of the present invention will be described in more detail.

Example 1

Preparation of Precursor Ni: Co = 0.6: 0.4 was mixed with 0.5 mol / L of a mixed solution A1, and a 1.5 mol / L sodium hydroxide solution and a 0.5 mol / L ammonium sulfate solution were compounded; The pH of the initial solution was adjusted to 8.5 using 1.5 mol / L sodium hydroxide solution, the temperature in the reaction vessel was adjusted to 40 ° C, the rotation speed was set to 200 r / min, nitrogen gas Pouring; The flow rate of the A1 solution is adjusted to 20 L / min. At the same time, sodium hydroxide and ammonium sulfate are slowly added dropwise. When the particles reach the required standard, solid-liquid separation and drying are carried out to obtain necessary precursor A2.

Preparation of the cathode material: Lithium hydroxide, A2 and aluminum hydroxide were mixed according to the proportions in the molecular formula Li _p Ni _x Co _{1 - x} M ₂ O ₂ where p = 1.25, x = 0.6, m = 0.12, The sintering time is set to 40 hours, the air is poured into the sintering process, and the sintered material is subjected to a process such as crushing, classification, and iron making to obtain the material A;

Surface treatment: water washing at a ratio of A: water = 1: 1, drying and screening proceed;

Coating: The treated sample is used as a substrate and LiCrO ₂ is coated thereon. As a coating method, a dry coating is used, and N accounts for 0.01% of the total weight of the substrate.

Two sintering: The sintered material is sintered twice, the main sintering temperature is controlled to 400 ° C, and the sintering time of the main temperature zone is 35 hours, pouring air in the sintering process.

Example 2.

Preparation of Precursor: Ni: Co = 0.85: 0.15 was mixed with 3 mol / L of a mixed solution A1, and 12 mol / L sodium hydroxide solution and 5 mol / L ammonium sulfate solution were blended; The pH of the initial solution was adjusted to 13.5 using 8 mol / L sodium hydroxide solution, the temperature in the reaction vessel was adjusted to 80 DEG C, the rotation speed was set to 200 r / min, and nitrogen gas was poured Pour; The flow rate of the A1 solution is adjusted to 3 L / min. At the same time, sodium hydroxide and ammonium sulfate are slowly added to the solution. When the particles reach the required standard, solid-liquid separation and drying are carried out to obtain necessary precursor A2.

Preparation of cathode material: Lithium hydroxide, A2, and aluminum hydroxide were mixed according to the ratio in the molecular formula Li _p Ni _x Co _{1 -x} M ₂ O ₂ where p = 0.95, x = 0.85, m = 0.01, The sintering time is adjusted to 400 hours, the air is poured into the sintering process, and the sintered material is subjected to a process such as crushing, classification, and iron making to obtain the material A;

Surface treatment: Water washing at a ratio of A: water = 1: 6, drying and screening.

Coating: The treated sample is used as a substrate and a mixture of aluminum oxide and Li ₂ CO ₃ is coated thereon. A dry coating is used as a coating method, and N accounts for 0.01% of the total weight of the substrate.

Two sintering: The sintered material is sintered twice, the main sintering temperature is controlled to 1050 ° C, and the sintering time in the main temperature zone is 3 hours, pouring air in the sintering process.

Example 3

Preparation of Precursor: Ni: Co = 0.80: 0.20 was mixed with 2 mol / L of a mixed solution A1 and mixed with 2.5 mol / L sodium hydroxide solution and 1.8 mol / L ammonium sulfate solution; The pH of the initial solution was adjusted to 12 using a 2.5 mol / L sodium hydroxide solution, the temperature in the reaction vessel was adjusted to 60 ° C, the rotation speed was set to 500 r / min, and nitrogen gas Pouring; The flow rate of the A1 solution is adjusted to 10 L / min, while simultaneously sodium hydroxide and ammonium sulfate are slowly added. When the particles reach the required standard, solid-liquid separation and drying are carried out to obtain necessary precursor A2.

Preparation of the cathode material: Lithium hydroxide, A2 and aluminum hydroxide were mixed according to the proportions in the molecular formula Li _p Ni _x Co _{1 -x} M ₂ O ₂ where p = 0.11, x = 0.80, m = 0.04, The sintering time is adjusted to 400 hours, the air is poured into the sintering process, and the sintered material is subjected to a process such as crushing, classification, and iron making to obtain the material A;

Coating: A is used as a substrate and LiAlO ₂ is coated thereon. The coating method is dry coating, and N accounts for 0.08% of the total weight of the substrate.

Two sintering: The sintered material is sintered twice, the main sintering temperature is controlled to 750 ° C, and the sintering time in the main temperature zone is 6 hours, pouring air in the sintering process.

Claims (10)

Wherein the chemical formula of the substrate is Li _p Ni _x Co _{1 - x} M _m O ₂ wherein 0.95? P? 1.25, 0.6? X <1, 0.01? M <0.12, M is a dopant, , And N occupies 0.01 to 25 wt% of the total mass of the substrate; Wherein the positive electrode material of the lithium ion secondary battery comprises a primary particle and a secondary particle or a mixed particle of a primary particle and a secondary particle. Anode material. The method according to claim 1,
A method of manufacturing a nickel-cobalt based lithium ion cathode material having a high energy density includes the following steps,
Step 1: Preparation of a cathode material precursor for a lithium ion secondary battery
a. Preparation of solution: Mixed salt solution A1 was prepared by mixing Ni: Co = x: 1-x at a molar ratio of 0.5 to 3 mol / L in the salt solution; An alkali solution having a concentration of 1.5 to 12 mol / L is formulated to prepare a complexing agent solution having a concentration of 0.5 to 5 mol / L, wherein 0.6? X? 1;
b. Preparation of the initial solution: Pure water is injected into the reaction vessel, the pH value of the solution is adjusted by using an alkali solution, the temperature of the reaction vessel is maintained at 40 to 80 ° C, the inert gas is simultaneously poured, Consistently progress the entire reaction process;
c. Reaction of the precursor: Al solution is added to the reaction vessel and the flow rate is maintained at 3 to 20 L / min. At the same time, an appropriate amount of complexing agent and alkali solution are slowly added, the temperature in the reaction vessel is maintained at 40 to 80 캜, The speed is adjusted to 200 to 950 r / min;
d. Solid-liquid separation: the surface treatment of the material of Step c is carried out, the synthesized binary precursor of the cathode material is transferred to an aging machine to carry out solid-liquid separation, the solid precursor obtained by solid-liquid separation using deionized water is washed, The required formulations of the binary precursors A2, A2 obtained after drying are Ni _x Co _1-x (OH) ₂ ;
Step 2: Production of cathode material for lithium ion secondary battery
e. Primary sintering: The lithium precursor material, A2 and the dopant M material are mixed according to the proportions in the molecular formula Li _p Ni _x Co _{1 -x} M _m O ₂ where 0.95? P? 1.25, 0.6? X <1, m < 0.12, M is a dopant, the sintering temperature is controlled to 400 to 1050 DEG C and the sintering time is controlled to 4 to 40 hours, and air or oxygen gas is poured in the sintering process, and the material after sintering is crushed, RTI ID = 0.0 &gt; A &lt; / RTI &gt;
f. Surface treatment: The material A is washed with water to lower the alkali content, the ratio of the material A to the water is 1: 1 to 1: 6, the water is washed and the material is dried and screened;
g. Coating: The substance A or substance A treated as the substrate is coated with the N material on the substrate, and the coating method is a dry coating, a wet coating or a coprecipitation coating method, wherein N is 0.01 to 25 wt%;
h. The sintering is carried out at a temperature of 400 to 1050 ° C, the sintering time of the main temperature zone is controlled to 3 to 35 hours, and the air or oxygen The gas can be poured out and sintered at least three times according to the requirements for product performance, wherein the sintering conditions are the same as twice sintering; Wherein the sintered material is subjected to a crushing, classification, screening, iron-making process or the like according to the necessity, as required, to produce a nickel-cobalt-based lithium-ion cathode material having a high energy density. The method according to claim 1,
Wherein the alkali solution in step a is at least one mixed solution selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide; The complexing agent is at least one mixed solution selected from the group consisting of ammonia water, ammonia bicarbonate, ammonium sulfate, ammonium carbonate, citric acid, disodium ethylene diamine tetraacetate (EDTA) A method for manufacturing a high energy density nickel-cobalt based lithium ion cathode material. The method according to claim 1,
Wherein the nickel salt or cobalt salt solution in step a is at least one mixed solution selected from the group consisting of sulfate, nitrate, and chlorate. The method according to claim 1,
Wherein the pH value in step b is adjusted to 8.5 to 13.5. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The method according to claim 1,
Wherein the pH value in step c is adjusted to 9.5 to 13.5. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The method according to claim 1,
Wherein the D50 range of the precursor A2 is 5 to 22 占 퐉. The method according to claim 1,
Wherein the lithium precursor material is at least one selected from the group consisting of lithium hydroxide, lithium carbonate, and lithium oxalate. The method according to claim 1,
The dopant M may be at least one selected from the group consisting of oxides, halides, hydroxides, metal organic substances, nitrates, and oxides of Cr, La, Ce, Zr, Ni, Mg, Ti, Al, Ca, V, B, Wherein the lithium-transition metal complex is at least one compound selected from the group consisting of complex oxides of sulfates, carbonates, phosphates, oxalates or other metal elements or metal fluorides. The method according to claim 1,
The coating active material N may be a composite oxide of Li and Cr, La, Ce, Zr, Ti, Al, Ca, V, B, Be, Y, Mo, Tb, Ho and Tm, or lithium hydroxide, lithium carbonate, lithium oxalate And a mixture of one or more of the oxides, halides, hydroxides, metal organic substances, nitrates of the Li precursor material and Cr, La, Ce, Zr, Ti, Al, Ca, V, B, Be, Y, Mo, And a mixture of at least one selected from the group consisting of sodium carbonate, sodium carbonate, sodium carbonate, potassium carbonate, sodium carbonate, sodium carbonate, potassium carbonate, sodium carbonate,