The term “fast ionic conductor” is also known as superionic conductor, or solid electrolyte in some cases. The most basic feature distinguishing it from common ionic conductors is that it has an ionic conductivity (0.01 Ω·cm) comparable to that of a liquid electrolyte and a low ionic conduction activation energy (≤0.40 eV) within a certain temperature range. As an example, the fast ionic conductors that may be present in the first shell layer and the second shell layer of the present invention comprise, for example, LiAl_0.971Si_1.022O₄, Li₃BO₃, etc.

The term “precursor” of a certain element used herein may refer to a raw material, or a compound which is obtained from a certain treatment on an initial material to comprise the element before obtaining a target product and can further react under the conditions of the preparation method of the present application to obtain the target product. For example, “a precursor” can be an oxide, hydroxide or water-soluble salt of a corresponding element. As an example, when M represent, for example, an element aluminum, its precursor can be metaaluminate or aluminum hydroxide; as another example, the precursor of an element lithium can be lithium hydroxide; and as still another example, the high-nickel ternary precursor refers to a complex hydroxide formed by five elements of nickel, cobalt, manganese, oxygen and hydrogen.

The inventors of the present application have found in practical operations that: for the nickel-cobalt-manganese ternary positive electrode active material, increasing the content of lithium in its layered structure can significantly improve the charge/discharge gram capacity of the material and thus the energy density of the lithium-ion battery. However, when the number of nickel atoms in the nickel-cobalt-manganese ternary positive electrode active material is increased to a percentage of 60% or more (based on the total atomic number of nickel, cobalt and manganese), the corresponding lithium-ion battery encounters a host of phenomena severely threatening the electrochemical performance and safety performance of the battery, such as a serious decline in cycle performance and a sharp increase in gas production inside the battery.

Through numerous studies, the inventors have found that the reasons for the above-mentioned adverse effects of the high-nickel ternary positive electrode active material are as follows: Firstly, with the repeated intercalation/deintercalation of lithium ions, the high-nickel ternary positive electrode active material, compared with a low-nickel ternary positive electrode active material, is more prone to lattice distortion in its microscopic layered structure, and the layered structure is more likely to collapse, which leads to a loss of its ability in intercalating/de-intercalating the lithium ions and finally causes a serious decline in the energy density and cycle performance of the lithium-ion battery. Secondly, the high-nickel ternary positive electrode active material has more surface impurity lithium (e.g., lithium oxide and lithium carbonate), which leads to serious side reactions on an interface where it gets in contact with an electrolyte solution and thus a sharp increase in gas production inside the battery, thereby significantly degrading the cycle performance and safety performance of the battery.

Therefore, although the high-nickel ternary positive electrode active material can improve the energy density of the battery by increasing the nickel content, the cycle performance and safety performance of the battery will be significantly degraded accordingly.

In the face of the above-mentioned research topics, the inventors of the present application, with an aim to improve the comprehensive performance of a ternary lithium-ion battery, have developed a high-nickel ternary positive electrode active material capable of comprehensively improving the energy density, cycle performance and safety performance of the lithium-ion battery by modifying the high-nickel ternary positive electrode active material.

[High-Nickel Ternary Positive Electrode Active Material]

The present application provides a high-nickel positive electrode active material, which is a core-shell structure, wherein

- the core comprises Li_1+a[Ni_xCo_yMn_zM_b]O₂, wherein 0.6≤x<1, 0<y<0.3, 0<z<0.3, 0<a<0.2, 0<b<0.2, x+y+z+b=1, M being at least one of Mg, Ca, Sb, Ce, Ti, Zr, Sr, Al, Zn, Mo and B;
- the shell comprises a first shell layer coating the core, and a second shell layer coating the first shell layer; wherein
- the first shell layer is a fast ionic conductor consisting of four elements of lithium, aluminum, silicon and oxygen; and
- the second shell layer comprises an oxide of an element R, the R being selected from at least one of Al, B, Ti, P, Co and La.

In some embodiments, optionally, in the core of the positive electrode active material of the present application, a ratio of z to y is 2:1 to 1:2, and optionally 3:2 to 2:3.

In some embodiments, optionally, in the core of the positive electrode active material of the present application, a ratio of y to z and a ratio of y+z to x are 1:10 to 1:7, and optionally 1:9 to 1:8.

In some embodiments, optionally, the fast ionic conductor in the first shell layer is Li_αAl_XSi_YO₄, wherein 0<X<2.4, 0<Y<1.8, 0.8≤α≤1.2, and a ratio of the stoichiometric coefficient X of the element aluminum to the stoichiometric coefficient Y of the element silicon is 0.8 to 1.2.

The high-nickel positive electrode active material of the present application has a core-shell structure with two shell layers coating a core, where the core comprises Li_1+a[Ni_xCo_yMn_zM_b]O₂. The coating with two continuous shell layers can prevent collapse of the crystal structure that occurs after several charge/discharge cycles due to the intercalation/de-intercalation of lithium ions in the main body of the core material, namely, Li_1+a[Ni_xCo_yMn_zM_b]O₂on one hand; and on the other hand, it can isolate the core material from direct contact with an electrolyte solution, so as to reduce corrosion of the surface of the positive electrode active material by the corrosive substances in the electrolyte solution, reduce side reactions of the electrolyte solution on the positive electrode surface, and prevent gas production inside the battery. In addition, the coating with two continuous shell layers can also prevent a dissolution phenomenon of the transition metal elements of the core material during the cycle and storage processes of the battery, thereby avoiding deposition of the dissolved transition metal elements on the negative electrode surface. Last but not least, the coating with two continuous shell layers can significantly improve the surface impurity lithium amount of the high-nickel positive electrode active material, and remarkably increase the relative proportion of active lithium in the high-nickel positive electrode active material. In a word, with the above-mentioned four effects, the coating with two continuous shell layers can comprehensively improve the energy density, cycle performance and safety performance of the high-nickel ternary lithium-ion battery.

Further, the core of the high-nickel positive electrode active material of the present application comprises Li_1+a[Ni_xCo_yMn_zM_b]O₂. When the element M is doped into the core material, it can form Li_1+a[Ni_xCo_yMn_zM_b]O₂with other elements in the core material, so that the structural stability of the core material is improved and the structural collapse of the core material during repeated charge/discharge cycles is prevented, thereby improving the cycle performance of the battery.

Notably, the high-nickel positive electrode active material of the present application is particularly applicable to a high-nickel ternary lithium-ion battery, particularly in a range of a nickel content of 60% or more, and particularly in a range of a nickel content of 80% or more. Optionally, the nickel content can be 60%, 80% or 90%.

Notably, when M is at least one of Sb, Ti, Zr, Sr, Al and B, the charge/discharge capacity, capacity retention rate during cycling and gas production of the lithium-ion battery are improved more significantly.

Further, the first shell layer is a fast ionic conductor layer consisting of four elements of lithium, aluminum, silicon and oxygen. For example, the fast ionic conductor is Li_αAl_XSi_YO₄. In the presence of the fast ionic conductor Li_αAl_XSi_YO₄: on one hand, the impurity lithium component on the surface of the core material can be creatively converted into structural lithium in Li_αAl_XSi_YO₄, and thus the impurity lithium of the high-nickel ternary positive electrode active material can be effectively reduced, to improve side reactions at the interface between the material and the electrolyte solution and enhance the cycle performance of the battery; and on the other hand, Li_αAl_XSi_YO₄can significantly increase the intercalation/deintercalation rate of lithium ions, thereby improving the charge/discharge capacity and cycle performance of the battery.

Notably, for the fast ionic conductor Li_αAl_XSi_YO₄, a molar ratio of the Al atoms to the Si atoms, namely, a ratio of X to Y, is 0.8 to 1.2. When the ratio of X to Y is in the above-mentioned range, it is beneficial in forming a good fast ionic conductor on the surface of the positive electrode material, so that the reduction in the surface impurity lithium and interface side reactions of the material is facilitated, and also, the transport rate of lithium ions is increased, thereby improving the cycle performance and safety performance of the battery. Notably, when the content of Al or Si is too high, namely, the ratio of X to Y deviates from the above-mentioned range, low-activity substances of Al or Si are likely to form on the surface layer of the positive electrode material, which will affect the transport of lithium ions on the contrary.

Notably, α in the Li_αAl_XSi_YO₄is in a range of 0.8 to 1.2, and optionally 1, or any natural number in the range of 0.8 to 1.2. When the value of a is lower than the above-mentioned range, the relative content of lithium ions of the fast ionic conductor in the first shell layer is relatively small, and the formed fast ionic conductor may have a poor transport rate of lithium ions, thereby affecting the battery performance. When the value of a is higher than the above-mentioned range, excessive lithium ions may lead to an increase in the impurity lithium amount on the surface of the positive electrode material and then an increase in side reactions at the interface with the electrolyte solution, thereby affecting the safety performance of the battery.

Further, the second shell layer comprises an oxide of an element R, the R being at least one of Al, B, Ti, P, Co and La. The provision of the second shell layer can prevent the component loss and structural damage of the fast ionic conductor Li_αAl_XSi_YO₄caused by soaking in the electrolyte solution and isolate the core material from contact with the electrolyte solution, and thus plays an important role in improving the stability of the high-nickel positive electrode active material and is beneficial in improving the energy density, cycle performance and safety performance of the battery.

Notably, when R is an element Co, if the sintering temperature is too low during preparation of the second shell layer, for example, 200° C., a hydroxide Co(OH)₂of the element Co may exist, which shall also be included in the scope of the present invention. Therefore, the term “an oxide of the element R” herein shall be interpreted as that in addition to the oxides of the element R, when R is an element Co, it also includes a hydroxide Co(OH)₂of the element Co.

Notably, when R is at least one of Al, La, B, Co and Ti, the charge/discharge capacity, capacity retention rate during cycling and gas production of the lithium-ion battery are improved more significantly.

In some embodiments, the shell further comprises a transition layer formed between the first shell layer and the second shell layer, and the transition layer comprises one or more fast ionic conductors Li_pR_qO_wformed by the first shell layer component and the second shell layer component, wherein 1≤p≤4, 1≤q≤5, 1≤w≤12, and p, q and w are all integers.

In the shell layer of the high-nickel positive electrode active material of the present application, the transition layer is a transition region formed by the first shell layer and the second shell layer, and the component Li_pR_qO_wincluded in the transition layer can further improve the intercalation/deintercalation rate of lithium ions in the high-nickel positive electrode active material. Therefore, in the high-nickel positive electrode active material of the present application, through a synergistic effect of two fast ionic conductor layers (namely, the first shell layer and the second shell layer), the gram capacity of the high-nickel positive electrode active material is greatly increased.

Notably, in the high-nickel positive electrode active material of the present application, a transition region similar to the transition layer between the first shell layer and the second shell layer can also be included between the core and the shell layer, which can be a continuous layered structure, or a discontinuous layered structure, with uniform or non-uniform thickness.

Notably, the transition layer formed between the first shell layer and the second shell layer is a continuous layered structure, and the connection between the first shell layer and the second shell layer is tighter because of the component Li_pR_qO_w, which prevents the second shell layer from falling during the use of the battery and is more beneficial in sufficiently increasing the gram capacity of the high-nickel positive electrode active material.

In some embodiments, optionally, the fast ionic conductor Li_pR_qO_win the transition layer is selected from at least one of LiAlO₂, Li₃BO₃, Li₄Ti₅O₁₂, Li₃PO₄, LiCoO₂or LiLaO.

In some embodiments, optionally, the x is 0.8≤x<1, the M is at least one of Sb, Ti, Zr, Sr, Al and B, and the R is at least one of Al, La, B, Co and Ti.

In some embodiments, optionally, in the high-nickel positive electrode active material of the present application, a mass ratio of the element lithium in the core layer to the element lithium in the shell layer is 40 to 1300:1.

In the high-nickel positive electrode active material of the present application, if a mass ratio of the element lithium in the core to the element lithium in the shell is within the above-mentioned range: on one hand, it can ensure the presence of enough active lithium in the core to contribute to a high gram capacity of the high-nickel positive electrode active material, thereby improving the energy density and cycle performance of the battery; on the other hand, it can ensure the presence of a proper amount of the element lithium in the first shell layer, the transition layer and the second shell layer to serve as an effective component to form fast ionic conductors Li_αAl_XSi_YO₄and Li_pR_qO_w; and in addition, a proper mass ratio of the element lithium in the core to the element lithium in the shell can effectively prevent the production of surface impurity lithium of the high-nickel positive electrode active material, so as to reduce the side reactions that occur inside the battery. In a word, through the above-mentioned three effects, a proper mass ratio of the element lithium in the core to the element lithium in the shell is beneficial in improving the energy density, cycle performance and safety performance of the battery (mainly embodied in an improvement in gas production inside the battery).

In some embodiments, optionally, when M is selected from one or more of Al, B or Ti, R is different from M, and based on the total mass of the high-nickel positive electrode active material, the mass content of the element M in the high-nickel positive electrode active material is 1,000 to 5,000 ppm, and optionally 3,000 to 5,000 ppm.

Compared with a low-nickel ternary positive electrode active material, the doping with the element M in the core material Li_1+a[Ni_xCo_yMn_zM_b]O₂can significantly improve the structural collapse and damage caused by repeated intercalation/deintercalation of lithium ions in the core material Li_1+a[Ni_xCo_yMn_zM_b]O₂, and build a more stable channel for the transport of lithium ions, which is beneficial in increasing the gram capacity of the high-nickel positive electrode active material, thereby improving the energy density and cycle performance of the lithium-ion battery.

In some embodiments, optionally, when M is selected from one or more of Al, B or Ti, R is different from M, and based on the total mass of the high-nickel positive electrode active material, the mass content of the element R is 100 to 20,000 ppm.

By limiting the mass content of the element R in a reasonable range: on one hand, an oxide of R with a more stable physical and chemical structure can be formed, so as to effectively block corrosion of the core material and the first shell layer by the electrolyte solution and reduce side reactions inside the battery; and on the other hand, in the presence of the second shell layer containing the oxide of the element R, cracking and breakage of the high-nickel positive electrode active material can be effectively avoided, to prevent thermal runaway inside the battery caused by small particles produced by the broken core material. In conclusion, through the above-mentioned effects, by limiting the mass content of the element R in a reasonable range, the energy density, cycle performance and safety performance of the battery can be improved.

Further, when the mass content of the element R is 500 to 15,000 ppm, the charge/discharge capacity, capacity retention rate during cycling and gas production of the lithium-ion battery are improved more significantly.

In some embodiments, optionally, in the high-nickel positive electrode active material, a mass ratio of the element Si to the element R is 0.1 to 7.0:1, and optionally 0.1 to 4.4:1.

In the high-nickel positive electrode active material, a proper mass ratio of the element Si to the element R means that a mass ratio of the first shell layer to the second shell layer is in a proper range. With too little element of R and too much element of Si, namely, incomplete coating of the second shell layer and too thick coating of the first shell layer, it may not realize an effect of reducing the side reactions between the electrolyte solution and the surface of the high-nickel material, and is also likely to reduce the gram capacity of the material itself because of the too thick first shell layer (the element Si does not contribute to the capacity), thereby resulting in a low discharge capacity of the battery. On the contrary, with too much element of R and too little element of Si, namely, incomplete coating of the first shell layer and too thick coating of the second shell layer, it may cause the high-nickel positive electrode active material unable to build a complete network structure for fast conduction of lithium ions, thereby lowering the intercalation/deintercalation rate of lithium ions, reducing the gram capacity of the high-nickel positive electrode active material and the discharge capacity of the battery, and affecting the cycle performance of the battery; and also, it is also likely to reduce the gram capacity of the material itself because of the too thick second shell layer (the element R does not contribute to the capacity), thereby resulting in a low discharge capacity of the battery.

In some embodiments, optionally, based on the total mass of the high-nickel positive electrode active material, the total mass content of the elements silicon and aluminum in the first shell layer is 435 to 13,150 ppm.

The total mass content of the elements silicon and aluminum in the first shell layer corresponds to the amount of Li_αAl_XSi_YO₄in the first shell layer. When the surface of the high-nickel active material is coated with a layer of a fast ionic conductor Li_αAl_XSi_YO₄, the transport rate of lithium ions can be effectively improved and side reactions between the surface and the electrolyte solution can be reduced, thereby improving the capacity and long-term performance; however, the coating should not be too little or too much because too little coating may have little effect, and too much coating may reduce the gram capacity of the material and increase the resistance to the transport of lithium ions.

In some embodiments, optionally, the volume-average particle size Dv50 of the high-nickel positive electrode active material is 1.5 to 20 μm, and the thickness of the shell layer is 0.001 to 1 μm. In the high-nickel positive electrode active material of the present application, if the volume-average particle size Dv50 of the particles is too large, it may increase the resistance to the intercalation/deintercalation of lithium ions and thus the internal resistance of the battery. And, the volume-average particle size Dv50 should not be too small, because a too small particle size increases the process complexity and the production cost on one hand, and also increase the contact area with the electrolyte solution on the other hand; and once the shell layer encounters loss of function, the battery performance may deteriorate sharply. Similarly, when the thickness of the shell layer is too large, the internal resistance of the battery is increased, and the gram capacity of the material is reduced. But when the thickness of the shell layer is too small, it may be difficult to effectively exert the beneficial functions of the shell layer.

The high-nickel positive electrode active material of the present application can be a polycrystalline ternary material, or a monocrystalline ternary material; and the polycrystalline ternary material has a polycrystalline structure, and the monocrystalline ternary material has a monocrystalline structure or a mono-like structure. When the high-nickel positive electrode active material is a polycrystalline structure, it contributes a higher gram capacity; and when the high-nickel ternary positive electrode active material is a monocrystalline structure or a mono-like structure, the corresponding lithium-ion battery has better cycle performance.

In some embodiments, the high-nickel positive electrode active material with a monocrystalline structure or mono-like structure of the present application can be synthesized by controlling the particle size of a high-nickel ternary precursor at 1 to 5 μm and increasing the roasting temperature of key preparation steps.

For example, in the method of the present application, a high-nickel positive electrode active material with a good monocrystalline or mono-like structure can be synthesized by increasing the sintering temperature of the step S2 from 700° C. to 950° C. and adjusting the particle size Dv50 of the precursor in the step S1 from 9 μm to 3 μm.

Those skilled in the art can select a high-nickel ternary positive electrode active material with a polycrystalline structure of the present application, or a high-nickel ternary positive electrode active material with a monocrystalline or mono-like structure according to different application scenarios of the lithium-ion battery.

The present application provides a method for preparing a high-nickel positive electrode active material, comprising the following steps:

- S1: a high-nickel ternary precursor coated with a silicon-aluminum hydroxide is provided to obtain a first intermediate;
- S2: the first intermediate and an M precursor and a lithium precursor are mixed and sintered to obtain a second intermediate; and
- S3: the second intermediate and an R precursor are mixed and sintered to obtain the high-nickel positive electrode active material;
- wherein the high-nickel positive electrode active material is a core-shell structure, the core comprises Li_1+a[Ni_xCo_yMn_zM_b]O₂, wherein 0.6≤x<1, 0<y<0.3, 0<z<0.3, 0<a<0.2, 0<b<0.2, x+y+z+b=1, M being at least one of Mg, Ca, Sb, Ce, Ti, Zr, Sr, Al, Zn, Mo and B;
- the shell comprises a first shell layer coating the core, and a second shell layer coating the first shell layer; wherein
- the first shell layer is a fast ionic conductor consisting of four elements of lithium, aluminum, silicon and oxygen; and
- the second shell layer comprises an oxide of an element R, the R being selected from at least one of Al, B, Ti, P, Co and La.

According to preparation method of the present application, the raw materials have a wide range of sources, low cost and simple process, which is more conducive to large-scale industrialization.

In some embodiments, optionally in the step S1, a process of preparing the high-nickel ternary precursor coated with a silicon-aluminum hydroxide is as follows:

- (a) an aluminum precursor and a silicon precursor are completely dissolved in an alkaline solution, and then a high-nickel ternary precursor is added, to obtain a solid-liquid mixture; and
- (b) the pH of the solid-liquid mixture is lowered to initiate a hydrolysis-in-situ precipitation reaction between the aluminum precursor and the silicon precursor, to obtain a high-nickel ternary precursor coated with a silicon-aluminum hydroxide.

In the step (a), the aluminum precursor can be one or more of sodium metaaluminate (NaAlO₂), potassium metaaluminate (KAlO₂) and lithium metaaluminate (LiAlO₂), and the silicon precursor can be one or more of sodium silicate (Na₂O·nSiO₂), potassium silicate (K₂O·nSiO₂) and lithium silicate (Li₂O·nSiO₂).

In the step (a), the solid-liquid mixture remains at a relatively high pH, which can ensure that the aluminum precursor and the silicon precursor are fully dissolved to such an extent as not to cause excessive hydrolysis of the aluminum precursor and the silicon precursor. The addition of the high-nickel ternary precursor provides a precipitation surface for the subsequent hydrolysis-in-situ precipitation reaction between the aluminum precursor and the silicon precursor.

Further, in the step (b), lowering the pH of the solid-liquid mixture can initiate a hydrolysis-in-situ precipitation reaction between the aluminum precursor and the silicon precursor, such that the silicon-aluminum hydroxides produced by the hydrolysis are co-precipitated on the surface of the high-nickel ternary precursor, to obtain the first intermediate.

Further, in the step (a), the aluminum precursor and the silicon precursor are added into the alkaline solution in a molar ratio of aluminum to silicon of 0.8 to 1.2:1.

Further, in the step (a), based on the total mass of the solid-liquid mixture, the mass proportion of the high-nickel ternary precursor is 16% to 50%.

Further, in the step (a), the pH of the alkaline solution is 11 to 13, to prevent hydrolysis of the aluminum precursor and the silicon precursor.

Further, a weakly acid gas is introduced into the solid-liquid mixture at a flow rate of 1 to 20 mL/min, to lower the pH of the solid-liquid mixture to 8 to 10.

In some embodiments, optionally, the weakly acid gas is one or more of CO₂and SO₂.

Further, in the step (b), the reaction temperature of the hydrolysis-in-situ precipitation reaction is 20 to 40° C., the reaction time is 0.1 to 2 h, and the linear speed of stirring is 1 to 6 m/s.

In some embodiments, optionally, in the step S2, letting the total molar weight of nickel atoms, cobalt atoms and manganese atoms in the first intermediate be Me2, then:

- the lithium precursor in an addition amount enabling the lithium atoms to be (0.9 to 1.1)Me2 and the M precursor in an addition amount enabling the M atoms to be (8×10⁻⁴to 180×10⁻⁴)Me2 are mixed with the first intermediate.

Further, in the step S2, the sintering temperature is 700 to 950° C., the sintering time is 10 to 20 h, and the sintering atmosphere is air or oxygen.

In some embodiments, optionally, in the step S3, letting the total molar weight of nickel atoms, cobalt atoms and manganese atoms in the second intermediate be Me3, then:

- the R precursor in an addition amount enabling the R atoms to be (16×10⁻⁴to 330×10⁻⁴)Me3 is mixed with the second intermediate.

In some embodiments, the R precursor can be one or more of Al-containing oxides, hydroxides or inorganic acid salts, the R precursor can be one or more of B-containing oxides, hydroxides or inorganic acid salts, the R precursor can be one or more of Ti-containing oxides, hydroxides or inorganic acid salts, the R precursor can be one or more of P-containing oxides, hydroxides or inorganic acid salts, the R precursor can be one or more of Co-containing oxides, hydroxides or inorganic acid salts, and the R precursor can be one or more of La-containing oxides, hydroxides or inorganic acid salts.

In some embodiments, optionally, in the step S3, the sintering temperature is 200 to 700° C., the sintering time is 5 to 15 h, and the sintering atmosphere is air or oxygen. Here, notably, the sintering temperature in the step S3 is at least 500° C. lower than that in the step S2 such that the element M in the step S2 enters the core structure, but the element R in the step S3 generally does not enter the core structure.

[Positive Electrode Plate]

The present application provides a positive electrode plate, comprising a high-nickel positive electrode active material of the present application.

The positive electrode plate comprises a positive electrode current collector and a positive electrode material provided on at least one surface of the positive electrode current collector. As an example, the positive electrode current collector has two surfaces opposite in its own thickness direction, and the positive electrode material is provided on either or both of the two opposite surfaces of the positive electrode current collector.

In the lithium ion battery of the present application, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, an aluminum foil can be used. The composite current collector may comprise a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on a polymer material substrate (a substrate such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), 1,3-propanesultone (PS), polyethylene (PE), etc.), but the present application is not limited to these materials.

The positive electrode material further optionally comprises a conductive agent. However, the type of the conductive agent is not limited specifically, and can be selected by those skilled in the art according to actual requirements. An example, the conductive agent for the positive electrode material may be selected from at least one of superconductive carbon, acetylene black, carbon black, ketjenblack, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

In the present application, the positive electrode plate can be prepared according to a method known in the art. As an example, the positive electrode active material of the present application, a conductive agent and a binder can be dispersed into a solvent (e.g., N-methylpyrrolidone (NMP)) to form a uniform positive electrode slurry; and the positive electrode slurry is coated onto a positive electrode current collector, and is then subjected to procedures such as drying and cold pressing, so as to obtain the positive electrode plate.

[Negative Electrode Plate]

A negative electrode plate comprises a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode film layer comprises a negative electrode active material.

As an example, the negative electrode current collector has two surfaces opposite in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

In the lithium-ion battery of the present application, the negative electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, a copper foil can be used. The composite current collector may comprise a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be formed by forming metal materials (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.), but the present application is not limited to these materials.

In the negative electrode plate of the present application, the negative electrode film layer usually comprises the negative electrode active material and an optional binder, an optional conductive agent and other optional auxiliary agents, and is usually formed by coating a negative electrode slurry, followed by drying. The negative electrode slurry is generally formed by dispersing a negative electrode active material, and an optional conductive agent and a binder etc., into a solvent and uniformly stirring same. The solvent can be N-methylpyrrolidone (NMP) or deionized water.

As an example, the conductive agent can be selected from at least one of superconductive carbon, acetylene black, carbon black, ketjenblack, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

In the negative electrode plate of the present application, in addition to the negative electrode active material, the negative electrode film layer further optionally comprises other common negative electrode active materials, and examples of other common negative electrode active materials may include artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials and lithium titanate. The silicon-based material can be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites and silicon alloys. The tin-based material can be selected from at least one of elemental tin, tin oxide compounds, and tin alloys.

[Electrolyte]

An electrolyte is located between the positive electrode plate and the negative electrode plate and functions for ionic conduction. The type of the electrolyte is not particularly limited in the present application, and can be selected according to actual requirements. For example, the electrolyte can be selected from at least one of solid electrolyte and liquid electrolyte (i.e., electrolyte solution).

In some embodiments, an electrolyte solution is used as the electrolyte. The electrolyte solution comprises an electrolyte salt and a solvent.

In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate (LiPF₆), lithium tetrafluoroborate (LiBF₄), lithium perchlorate (LiClO₄), lithium hexafluoroarsenate (LiAsF₆), lithium bisfluorosulfonimide (LiFSI), lithium bistrifluoromethanesulfonimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium bisoxalatodifluorophosphate (LiDFOP) and lithium tetrafluorooxalate phosphate (LiTFOP).

In some embodiments, the solvent can be selected from at least one of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS) and diethyl sulfone (ESE).

In some embodiments, the electrolyte solution further optionally comprises an additive. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and also an additive that can improve certain performance of the battery, such as an additive that improve the overcharge performance of the battery, an additive that improve the high temperature performance of the battery, and an additive that improve the low temperature performance of the battery.

[Separator]

A lithium ion battery using an electrolyte solution and some lithium ion batteries using a solid electrolyte further comprise a separator. The separator is provided between the positive electrode plate and the negative electrode plate, and functions for separation. The type of the separator is not particularly limited in the present application, and any well known porous-structure separator with good chemical stability and mechanical stability can be selected. In some embodiments, the material of the separator can be selected from at least one of glass fibers, non-woven fabrics, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film and also a multi-layer composite film, and is not limited particularly. When the separator is a multi-layer composite film, the materials in the respective layers may be same or different, which is not limited particularly.

[Lithium-Ion Battery]

In some embodiments, the positive electrode plate, the negative electrode plate and the separator can be made into an electrode assembly by a winding process or a lamination process, and the positive electrode plate comprises a high-nickel positive electrode active material of the present application.

In some embodiments, the lithium ion battery may comprise an outer package. The outer package can be used to encapsulate the above-mentioned electrode assembly and electrolyte.

In some embodiments, the outer package of the lithium-ion battery can be a hard housing, for example, a hard plastic housing, an aluminum housing, a steel housing, etc. The outer package of the lithium-ion battery can also be a soft bag, for example, a pouch-type soft bag. The material of the soft package may be plastics, and the examples of plastics may include polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS), etc.

The shape of the lithium-ion battery is not particularly limited in the present application, and can be a cylindrical shape, a square shape or any other shape. For example, FIG. 3 is a lithium-ion battery 5 of a square structure as an example.

In some embodiments, referring to FIG. 4, the outer package may comprise a housing 51 and a cover plate 53. Herein, the housing 51 may comprise a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodating cavity. The housing 51 has an opening in communication with the accommodating cavity, and the cover plate 53 can cover the opening to close the accommodating cavity. The positive electrode plate, the negative electrode plate and the separator can form an electrode assembly 52 by a winding process or a lamination process. The electrode assembly 52 is encapsulated in the accommodating cavity. An electrolyte solution is infiltrated into the electrode assembly 52. The number of the electrode assemblies 52 contained in the lithium-ion battery 5 may be one or more, and can be selected by those skilled in the art according to specific requirements.

[Battery Module]

In some embodiments, the lithium-ion batteries can be assembled into a battery module, and the number of the lithium-ion batteries contained in the battery module may be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

FIG. 5 shows a battery module 4 as an example. With reference to FIG. 5, in the battery module 4, a plurality of lithium ion batteries 5 can be provided in sequence in the length direction of the battery module 4. Apparently, the secondary batteries can also be arranged in any other manner. Further, the plurality of lithium-ion batteries 5 can be fixed with fasteners.

Optionally, the battery module 4 may further comprise a housing with an accommodating space, and a plurality of lithium-ion batteries 5 are accommodated in the accommodating space.

[Battery Pack]

In some embodiments, the above battery module can also be assembled into a battery pack, and the number of the battery modules contained in the battery pack can be selected by those skilled in the art according to the application and capacity of the battery pack.

FIG. 6 and FIG. 7 show a battery pack 1 as an example. Referring to FIG. 6 and FIG. 7, the battery pack 1 may comprise a battery case and a plurality of battery modules 4 provided in the battery case. The battery case comprises an upper case body 2 and a lower case body 3, wherein the upper case body 2 can cover the lower case body 3 to form a closed space for accommodating the battery modules 4. A plurality of battery modules 4 can be arranged in the battery case in any manner.

[Power Consuming Device]

In addition, the present application also provides a power consuming device, comprising at least one of a lithium-ion battery, a battery module, or a battery pack provided by the present application. The lithium-ion battery, the battery module or the battery pack may be used as a power supply of the device, or as an energy storage unit of the device. The device may be, but is not limited to, a mobile device (e.g., a mobile phone, a laptop computer, etc.), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck), an electric train, ship, and satellite, an energy storage system, and the like.

As for the power consuming device, the lithium-ion battery, the battery module or the battery pack can be selected according to the usage requirements thereof.

FIG. 8 shows a device as an example. The device may be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or the like. In order to meet the requirements of the device for a high power and a high energy density of a lithium ion battery, a battery pack or a battery module can be used.

As another example, the device may be a mobile phone, a tablet, a laptop computer, etc. This device is generally required to be thin and light, and a lithium ion battery can be used as a power supply.

EXAMPLES

Hereinafter, the examples of the present application will be explained. The examples described below are exemplary and are merely for explaining the present application, and should not be construed as limiting the present application. The techniques or conditions that are not specified in examples are according to the techniques or conditions described in documents in the art or the product introduction. Reagents or instruments for which manufacturers are not specified, are all commonly used conventional products in the art that are commercially available. The content of each component in the examples of the present application is based on mass, unless otherwise stated.

Example 1

[Preparation of a High-Nickel Ternary Positive Electrode Active Material]

S1, preparation of a first intermediate: 13.02 g of sodium metaaluminate (based on NaAlO₂) and 19.37 g of sodium silicate (based on Na₂O SiO₂) were dissolved in 2 L of an aqueous solution of NaOH with pH=12.2, then 953.00 g of a high-nickel ternary precursor (Ni_0.9Co_0.05Mn_0.05)(OH)₂with a median particle size Dv50 of 9.0 μm was added, and stirring was started; during the stirring, a gas CO₂was introduced at a flow rate of 10 mL/min, and the stirring was performed continuously at 30° C. for 2 h at a linear speed of 3 m/s; and after the stirring was stopped, suction filtration, drying and sieving were performed to obtain a high-nickel ternary precursor coated with a silicon-aluminum hydroxide, namely, the first intermediate;

- S2, preparation of a second intermediate: 980.62 g of the first intermediate, 472 g of lithium hydroxide (based on LiOH H₂O) and 8.33 g of titanium oxide (based on TiO₂) were mixed uniformly, and sintered at 700° C. for 20 h in an oxygen atmosphere, to obtain the second intermediate; and
- S3, obtaining of a target product: 1,000 g of the second intermediate and 3.18 g of boron oxide (based on B203) were mixed uniformly, and sintered at 200° C. for 5 h in an oxygen atmosphere, to obtain a high-nickel positive electrode active material of Example 1.

Specific parameters for preparing the high-nickel positive electrode active materials in other examples and comparative examples are shown in Tables A to H.

The product parameters of the high-nickel active materials and the performance parameters of the lithium-ion batteries in the examples and comparative examples are shown in Tables 1 to 8.

[Positive Electrode Plate]

The above-mentioned high-nickel positive electrode active material, a binder polyvinylidene fluoride (PVDF) and a conductive agent acetylene black were uniformly mixed with a solvent N-methyl pyrrolidone (NMP) in a mass ratio of 94:3:3, to obtain a positive electrode slurry; and the positive electrode slurry was coated onto an aluminum foil, followed by drying, cold pressing and slitting, to obtain a positive electrode plate.

[Negative Electrode Plate]

Negative electrode active materials artificial graphite and hard carbon, a conductive agent acetylene black, a binder styrene butadiene rubber (SBR) and a thickening agent sodium carboxymethylcellulose (CMC-Na) were uniformly mixed with deionized water in a mass ratio of 90:5:2:2:1 to give a mixture, and the mixture was coated onto a copper foil, followed by drying and cold pressing, to obtain a negative electrode plate of Example 1.

[Electrolyte Solution]

EC, DEC and DMC were mixed in a volume ratio of 1:1, and LiPF₆was added to form an electrolyte solution, where in the electrolyte solution, the concentration of LiPF₆was 1 mol/L.

[Separator]

Polypropylene Separator.

[Preparation of a Lithium-Ion Battery]

The positive electrode plate, the separator and the negative electrode plate were laminated in sequence, with the separator being located between the positive electrode plate and the negative electrode plate to function for separation, and wound to form a square bare cell; the square bare cell was put into an aluminum plastic film, a corresponding non-aqueous electrolyte solution was injected, and the aluminum plastic film was sealed; and the procedures such as standing, hot and cold pressing, forming, clamping and capacity grading were performed, to obtain a lithium-ion battery.

[Test of Relevant Parameters of the High-Nickel Positive Electrode Active Material]

1. Test of Surface Impurity Lithium Amount

Acid-base titration method: 30 g of the high-nickel positive electrode active material of the example was put into 100 ml of deionized water and stirred for 30 min, and allowed to stand for 5 min before suction filtration. 10 mL of a supernatant was titrated with a 0.05 mol/L standard solution of hydrochloric acid. With a pH electrode as an indicator electrode, end points were determined using the sudden leap produced by potential changes, and the surface impurity lithium amount Q (unit: ppm) of the positive electrode plate was calculated. A specific formula was: Q=V2×C×6.94×n×100/(m×1,000)×100,000, where C is the concentration of the standard solution of hydrochloric acid (unit: mol/L); V2 is the total volume (unit: mL) of the standard solution of hydrochloric acid consumed from the start of titration to the second end point of titration; n is a ratio of V2 to V1, and V1 is the total volume of 10 mL of the supernatant and V2 after the titration; and m is the mass of the sample (unit: g).

2. Test of the Content of Each Element in the High-Nickel Positive Electrode Active Material

A plasma emission spectrometer (ICP-OES) of model ICAP7400 of US Thermo Fisher Scientific was used. 1 g of the sample was put into a beaker, 25 ml of a HNO3 solution with a mass fraction of 25% was added to the sample to dissolve the sample, 475 ml of deionized water was used for dilution, then the diluted liquid was put into the instrument for analysis of a target element, and the content of the target element was calculated.

3. Test of the Mass Distribution of Element Lithium in the Core and Element Lithium in the Shell Layer

An ion polisher IB-19500CP and an EPMA (Electron Probe Microanalysis) device were used together. The tools for sample preparation were washed, a glue for sample preparation (a colloid formed by dispersing PVDF into NMP, with a mass content of PVDF of 8%) was uniformly mixed with the sample powder (the powder weight was about 5 times that of the glue), and the mixture was coated onto a copper foil and dried at 60° C. for 30 min. The prepared sample was cut with a pair of scissors into a size of 6 mm×6 mm, and the sample was fixed on a sample table and put into the ion polisher (model: IB-19500CP) for cutting, to obtain a section with an obvious boundary between the core structure and the layer structure; with reference to the section and through an EPMA test, 3 points were chosen from the core and the shell layer respectively for analysis and test of the element lithium, and an average was taken as the mass percentage content of the element lithium in the core and the shell layer respectively. Refer to the standard NF A92-801-4-2006 (NF A92-801-4-2006, Advanced Industrial Ceramics, Test Method of Ceramic Coatings, Part 4: Use electron probe microanalysis (EPMA) to measure chemical components) for the detailed operation procedure of EPMA.

4. Test of Volume-Average Particle Size Dv50

An appropriate amount of a test sample was added into a clean beaker, and treated with 120 W ultrasound for 5 min to ensure that the sample was completely dispersed. The test instrument was US Malvern 2000. The sample was poured into a sample injection tower and circulated with the solution to a test light path system; and with the particles exposed to a laser beam, the scattered light was received and its energy distribution was measured to obtain the particle size distribution characteristics of the particles (shading degree: 8-12%). A particle size-volume distribution diagram was drawn from the test data (for example, FIG. 2 is a particle size-volume distribution diagram of a high-nickel active material of Example 1). It can be known from the distribution diagram that: if the diameter of the particles occupying 50% of the total volume is greater than a certain Dv50 value, and the diameter of other particles occupying 50% of the total volume is less than the Dv50 value, then the Dv50 value is the volumetric average particle size of the particles.

5. Test of Shell Layer Thickness

An ion polisher IB-19500 and a US FEI Tecanai G2 transmission electron microscope were used together. The tools for sample preparation were washed, a glue for sample preparation (a colloid formed by dispersing PVDF into NMP, with a mass content of PVDF of 8%) was uniformly mixed with the sample powder (the powder weight was about 5 times that of the glue), and the mixture was coated onto a copper foil and dried at 60° C. for 30 min. The prepared sample was cut with a pair of scissors into a size of 6 mm×6 mm, and the sample was fixed on a sample table and put into the ion polisher (model: IB-19500CP) for cutting. The cut sample was put into the US FEI Tecanai G2 transmission electron microscope for a test of shell layer thickness, so that the shell layer thickness of the particles could be tested.

The method for determining the above-mentioned relevant parameters in the comparative examples was the same as that in the examples.

[Test of Battery Performance]

1. Initial Discharge Capacity

The lithium-ion battery of the example was put into an oven at 25° C., and allowed to stand for 5 min before a charge/discharge test. A charge/discharge process was as follows: the battery was discharged to 2.8 V with a constant current of ⅓ C, allowed to stand for 5 min, and charged to 4.25 V with a constant current of ⅓ C, then charged to a current of ≤0.05 mA with a constant voltage of 4.25 V, allowed to stand for 5 min, and discharged to 2.8 V with a constant current of ⅓ C; and the discharge capacity at this moment was the initial discharge capacity referred to in the present application.

2. Capacity Retention Rate During Cycling

At 25° C., the lithium-ion batteries of all examples and comparative examples were subjected to a charge/discharge test. A charge/discharge cycle process was as follows: The battery was charged to 4.25 V with a constant current of 1 C, charged to a current of ≤0.05 mA with a constant voltage of 4.25 V, allowed to stand for 5 min, and then discharged to 2.8 V with a constant current of 1 C, at which moment, the battery capacity was recorded as C1, forming a charge/discharge cycle of the battery. After 300 cycles of the above process, the battery capacity at this moment was recorded as C300. Then, the capacity retention rate during cycling=C300/C1×100%.

The capacity retention rates during cycling in the Tables 1 to 8 were all measured after 300 cycles.

3. Test of Expansion Performance at 70° C.

For the batteries (with nominal capacity of 2.25 Ah) in 100% SOC (State of Charge), the initial volume V0 of a single battery was measured at 70° C. with the drainage method, and the battery was taken out and stored in a storage furnace at 70° C. for 48 h; after the battery was cooled to room temperature, the battery volume V1 was measured again with the drainage method. The above steps were repeated. After 20 days of storage, the battery volume V10 was measured with the drainage method, and the expansion amount=(V10−V0)/2.25.

The expansion amounts in Tables 1 to 8 were all measured after 20 days of storage.

The method for determining the battery performance in the comparative examples was the same as that in the examples.

TABLE A

Process parameters of high-nickel active materials in examples and comparative examples

Step S1

High-nickel

Step S2

Serial
Sodium
Sodium
NaOH
ternary

First

No.
metaaluminate/g
silicate/g
solution/L
precursor/g
CO₂/(mL/min)
intermediate/g

C1
/
/
/
/
/
953.00^a

C2
/
/
/
/
/
953.00

C3
13.02
19.37
2.00
953.00
10.00
980.62

E1
13.02
19.37
2.00
953.00
10.00
980.62

E2
13.02
19.37
2.00
951.00
10.00
978.62

E3
13.02
19.37
2.00
947.00
10.00
974.62

E4
13.02
19.37
2.00
953.00
10.00
980.62

Step S2
Step S3

Serial

M
Amount of M
Second
R
Amount of R

No.
LiOH•H₂O/g
precursor
precursor/g
intermediate/g
precursor
precursor/g

C1
472
TiO₂
8.33
/
/
/

C2
472
TiO₂
8.33
1,000
B₂O₃
3.18

C3
472
TiO₂
8.33
/
/
/

E1
472
TiO₂
8.33
1,000
B₂O₃
3.18

E2
472
TiO₂
8.33
1,000
B₂O₃
3.18

E3
472
TiO₂
8.33
1,000
B₂O₃
3.18

E4
472
B₂O₃
15.91
1,000
B₂O₃
1.89

Note:

1. Except the parameters listed in Table A, other preparation processes in the examples are the same as those in Example 1.

2. C1-C4 are Comparative examples 1-4, and E1-E4 are Examples 1-4, same below.

3. ^aSince step S1 is not performed, the first intermediates in the Comparative examples C1 and C2 are high-nickel ternary precursors (Ni_0.9Co_0.05Mn_0.05)(OH)₂.

TABLE 1

Product parameters of high-nickel active materials and performance of corresponding

lithium-ion batteries in the examples and comparative examples

Shell

First shell layer

Total

mass

content of

elements

Core

silicon and

Second shell layer

Content

aluminum
Transition

Content of

Serial
Li_1+α[Ni_xCo_y
of element
Li_αAl_xSi_yO₄
in first shell
layer
Oxide
element

No.
Mn_zM_b]O₂
M/ppm
(value of X:Y)
layer/ppm
Li_pR_qO_w
of R
R/ppm

C1
Li_1.0[Ni_0.891Co_0.0495
5,000
/
/
/
/
/

Mn_0.0495Ti_0.01]O₂

C2
Li_1.0[Ni_0.891Co_0.0495
5,000
/
/
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

C3
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
8.734
/
/
/

Mn_0.0495Ti_0.01]O₂

E1
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
8.734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E2
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
8.734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E3
Li_1.0[Ni_0.891Co_0.04955
5,000
LiAlSiO₄(1)
8.734
LiBO₂
B₂O₃
1,000

Mn_0.049Ti_0.01]O₂

E4
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
8.734
LiAlO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

Battery performance parameters

Capacity

retention

Mass ratio of

Ex-
Surface
rate

element
Mass ratio
Initial
pan-
impurity
during

Shell layer
lithium
of element
discharge
sion/
lithium
cycling

Serial

Thickness/
in core layer
silicon to
capacity/
(mL/
amount/
at

No.
Dv50/μm
μm
and shell layer
element R
(mAh/g)
Ah)
ppm
25° C./%

C1
9.0
/
/
/
196
28.2
3,287
86.5

C2
9.0
0.03
5,803
/
208
12.5
2,356
92.3

C3
9.0
0.38
86
/
206
14.6
2,576
91.3

E1
9.0
0.45
70
4.4
216
6.8
1,502
96.1

E2
9.0
0.42
69
4.4
200
5.4
1,298
97.1

E3
9.0
0.44
72
4.4
189
4.5
976
97.8

E4
9.0
0.44
71
4.4
214
6.5
1,482
96.3

Through comprehensive analysis of Examples E1-4 and Comparative examples C1-3 in Table 1, the surface impurity lithium amount and expansion amount of the lithium-ion batteries corresponding to Examples E1-4 are significantly lower than those in Comparative examples C1-3, that is, the lithium-ion batteries have a good discharge capacity, safety performance and cycle performance.

Through comparison between Comparative examples C1 and C2, the presence of the second shell layer can significantly improve the surface impurity lithium amount and battery expansion amount of the lithium-ion battery, thereby improving the safety performance and cycle performance of the battery; but the batteries in both comparative examples have a good discharge capacity.

Through comparison between Comparative examples C1 and C3, the presence of the first shell layer can significantly improve the surface impurity lithium amount of the positive electrode and the expansion amount inside the lithium-ion battery, thereby improving the safety performance and cycle performance of the battery; but the batteries in both comparative examples have a good discharge capacity.

TABLE B

Process parameters of high-nickel active materials in the examples

Step S1

Nickel-

containing

Step S2

Serial
Sodium
Sodium
NaOH
ternary
CO₂/
First

No.
metaaluminate/g
silicate/g
solution/L
precursor/g
(mL/min)
intermediate/g

E1
13.02
19.37
2.00
953.00
10.00
980.62

E6
11.46
21.21
2.00
953.00
10.00
980.59

E7
12.66
19.82
2.00
953.00
10.00
980.63

E8
14.31
17.75
2.00
953.00
10.00
980.58

E9
9.55
23.68
2.00
953.00
10.00
980.72

E10
15.41
16.38
2.00
953.00
10.00
980.55

Step S2

Amount of
Step S3

Serial
LiOH ·
M
M
Second
R
Amount of R

No.
H₂O/g
precursor
precursor/g
intermediate/g
precursor
precursor/g

E1
472
TiO₂
8.33
1,000
B₂O₃
3.18

E6
472
TiO₂
8.33
1,000
B₂O₃
3.18

E7
472
TiO₂
8.33
1,000
B₂O₃
3.18

E8
472
TiO₂
8.33
1,000
B₂O₃
3.18

E9
472
TiO₂
8.33
1,000
B₂O₃
3.18

E10
472
TiO₂
8.33
1,000
B₂O₃
3.18

Note:

Except the parameters listed in Table B, other preparation processes in the examples are the same as those in Example 1.

TABLE 2

Product parameters of high-nickel active materials and performance of corresponding lithium-ion batteries in the examples

Shell

First shell layer

Total mass

content of

Core

elements

Content

silicon and

of

aluminum
Transition
Second shell layer

Serial
Li_1+α[Ni_xCo_yMn_z
element
Li_αAl_xSi_yO₄
first shell
layer
Oxide
Content of element

No.
M_b]O₂
M/ppm
(Value of X:Y)
layer/ppm
Li_pR_qO_w
of R
R/ppm

E1
Li_1.0[Ni_0.89Co_0.0495
5,000
LiAlSiO₄(1)
8,734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E6
Li_1.0[Ni_0.89Co_0.0495
5,000
LiAl_0.875Si_1.094O₄(0.8)
8,667
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E7
Li_1.0[Ni_0.89Co_0.0495
5,000
LiAl_0.971Si_1.022O₄(0.95)
8,719
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E8
Li_1.0[Ni_0.89Co_0.0495
5,000
LiAl_1.105Si_0.921O₄(1.2)
8,806
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E9
Li_1.0[Ni_0.89Co_0.0495
5,000
LiAl_0.724Si_1.207O₄(0.6)
8,584
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

Battery performance parameters

Capacity

retention

Mass

Ex-
Surface
rate

ratio of
Initial
pan-
impurity
during

Shell layer
Mass ratio of
element
discharge
sion/
lithium
cycling

Serial

thickness/
element lithium in core
silicon to
capacity/
(mL/
amount/
at

No.
Dv50/μm
μm
layer and shell layer
element R
(mAh/g)
Ah)
ppm
25° C./%

E1
9.0
0.45
70
4.4
216
6.8
1,502
96.1

E6
9.0
0.44
71
4.89
215
6.7
1,456
96.3

E7
9.0
0.42
70
4.55
216
6.6
1,543
96.2

E8
9.0
0.43
69
4.07
217
6.8
1,432
96.2

E9
9.0
0.46
71
4.15
212
7.2
1,657
94.5

Through comprehensive analysis of Example 1 and Examples 6-10 in Table 2, when the value of X:Y is 0.8 to 1.2, the surface impurity lithium amount of the positive electrode and the expansion amount inside the lithium-ion battery are improved, and the lithium-ion battery has a good discharge capacity, safety performance and cycle performance.

TABLE C

Process parameters of high-nickel active materials in the examples

Step S1

Nickel-

containing

Step S2

Serial
Sodium
Sodium
NaOH
ternary
CO₂/
First

No.
metaaluminate/g
silicate/g
solution/L
precursor/g
(mL/min)
intermediate/g

E1
13.02
19.37
2.00
953.00
10.00
980.62

E11
19.52
29.05
2.00
953.00
10.00
994.43

E12
1.69
2.52
2.00
953.00
10.00
956.59

E13
0.65
0.97
2.00
953.00
10.00
954.38

E14
26.03
38.73
2.00
953.00
10.00
1008.24

E15
0.07
0.10
2.00
953.00
10.00
953.14

Step S2

Amount of
Step S3

Serial
LiOH ·
M
M
Second
R
Amount of R

No.
H₂O/g
precursor
precursor/g
intermediate/g
precursor
precursor/g

E1
472
TiO₂
8.33
1,000
B₂O₃
3.18

E11
472
TiO₂
8.33
1,000
B₂O₃
63.64

E12
472
TiO₂
8.33
1,000
B₂O₃
3.18

E13
472
TiO₂
8.33
1,000
B₂O₃
0.32

E14
472
TiO₂
8.33
1,000
B₂O₃
3.18

E15
472
TiO₂
8.33
1,000
B₂O₃
3.18

Note:

Except the parameters listed in Table C, other preparation processes in the examples are the same as those in Example 1.

TABLE 3

Product parameters of high-nickel active materials and performance of corresponding lithium-ion batteries in the examples

Shell

First shell layer

Total mass

content of

Core

elements

Second shell layer

Content

silicon and

Content

of

aluminum
Transition

of

Serial
Li_1+α[Ni_xCo_yMn_z
element
Li_αAl_xSi_yO₄
first shell
layer
Oxide
element

No.
M_b]O₂
M/ppm
(Value of X:Y)
layer/ppm
Li_pR_qO_w
of R
R/ppm

E1
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
8,734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E11
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
13,101
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E12
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
1,135
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E13
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
437
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E14
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
17,469
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E15
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
44
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

Battery performance parameters

Capacity

retention

Ex-
Surface
rate

Mass ratio of
Mass ratio
Initial
pan-
impurity
during

Shell layer
element lithium
of element
discharge
sion/
lithium
cycling

Serial

thickness/
in core layer
silicon to
capacity/
(mL/
amount/
at

No.
Dv50/μm
μm
and shell layer
element R
(mAh/g)
Ah)
ppm
25° C./%

E1
9.0
0.45
70
4.4
216
6.8
1,502
96.1

E11
9.0
0.96
40
0.33
213
5.8
1,452
96.3

E12
9.0
0.17
500
0.57
215
7.3
1,523
96.2

E13
9.0
0.04
1,300
2.2
214
7.6
1,587
95.5

E14
9.0
0.84
32
8.8
198
7.8
1,520
93.8

E15
9.0
0.06
4,806
0.022
210
13.9
2,108
92.8

Through comprehensive analysis of Example 1, Examples 11-13 and Examples 14-15 in Table 3, in the high-nickel positive electrode active material, when a mass ratio of element lithium in the core to element lithium in the shell layer is 40 to 1,300:1, the surface impurity lithium amount of the positive electrode and the expansion amount inside the lithium-ion battery are improved, and the lithium-ion battery has a good discharge capacity, safety performance and cycle performance.

TABLE D

Process parameters of high-nickel active materials in the examples

Step S1

Nickel-

containing

Step S2

Serial
Sodium
Sodium
NaOH
ternary
CO₂/
First

No.
metaaluminate/g
silicate/g
solution/L
precursor/g
(mL/min)
intermediate/g

E1
13.02
19.37
2.00
953.00
10.00
980.62

E16
13.02
19.37
2.00
953.00
10.00
980.62

E17
13.02
19.37
2.00
953.00
10.00
980.62

E18
13.02
19.37
2.00
953.00
10.00
980.62

E19
13.02
19.37
2.00
953.00
10.00
980.62

Step S2

Amount of
Step S3

Serial
LiOH ·
M
M
Second
R
Amount of R

No.
H₂O/g
precursor
precursor/g
intermediate/g
precursor
precursor/g

E1
472
TiO₂
8.33
1,000
B₂O₃
3.18

E16
472
TiO₂
1.67
1,000
B₂O₃
3.18

E17
472
TiO₂
5.00
1,000
B₂O₃
3.18

E18
472
TiO₂
0.17
1,000
B₂O₃
3.18

E19
472
TiO₂
10.00
1,000
B₂O₃
3.18

Note:

Except the parameters listed in Table D, other preparation processes in the examples are the same as those in Example 1.

TABLE 4

Product parameters of high-nickel active materials and performance of corresponding lithium-ion batteries in the examples

Shell

First shell layer

Total mass

content of

Core

elements

Content

silicon and

of

aluminum
Transition
Second shell layer

Serial
Li_1+α[Ni_xCo_yMn_z
element
Li_αAl_xSi_yO₄
first shell
layer
Oxide
Content of element

No.
M_b]O₂
M/ppm
(Value of X:Y)
layer/ppm
Li_pR_qO_w
of R
R/ppm

E1
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
8,734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E16
Li_1.0[Ni_0.891Co_0.0495
1,000
LiAlSiO₄(1)
8,734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E17
Li_1.0[Ni_0.891Co_0.0495
3,000
LiAlSiO₄(1)
8,734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E18
Li_1.0[Ni_0.891Co_0.0495
100
LiAlSiO₄(1)
8,734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E19
Li_1.0[Ni_0.891Co_0.0495
6,000
LiAlSiO₄(1)
8,734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

Mass ratio

Battery performance parameters

of
Mass

Capacity

element
ratio of

retention

Shell
lithium
element
Initial
Ex-
Surface
rate

layer
in core
silicon
discharge
pan-
impurity
during

thick-
layer
to
capacity/
sion/
lithium
cycling

Serial

ness/
and shell
element
(mAh/
(mL/
amount/
at

No.
Dv50/μm
μm
layer
R
g)
Ah)
ppm
25° C./%

E1
9.0
0.45
70
4.4
216
6.8
1,502
96.1

E16
9.0
0.45
70
4.4
218
7.1
1,622
95.6

E17
9.0
0.45
70
4.4
217
6.5
1,567
95.8

E18
9.0
0.45
70
4.4
219
8.2
1,890
92.5

E19
9.0
0.45
70
4.4
212
7.8
1,820
93.4

Through comprehensive analysis of Example 1, Examples 16-17 and Examples 18-19 in Table 4, based on the total mass of the high-nickel positive electrode active material, when the mass content of the element M in the high-nickel positive electrode active material is 1,000 to 5,000 ppm, the surface impurity lithium amount of the positive electrode and the expansion amount inside the lithium-ion battery are improved, and the lithium-ion battery has a good discharge capacity, safety performance and cycle performance.

TABLE E

Process parameters of high-nickel active materials in the examples

Step S1

Nickel-

containing

Step S2

Serial
Sodium
Sodium
NaOH
ternary
CO₂/
First

No.
metaaluminate/g
silicate/g
solution/L
precursor/g
(mL/min)
intermediate/g

E1
13.02
19.37
2.00
953.00
10.00
980.62

E20
0.65
0.97
2.00
953.00
10.00
954.38

E21
19.52
29.05
2.00
953.00
10.00
994.43

E22
26.03
38.73
2.00
953.00
10.00
1008.24

E23
0.07
0.10
2.00
953.00
10.00
953.14

Step S2

Amount of
Step S3

Serial
LiOH ·
M
M
Second
R
Amount of R

No.
H₂O/g
precursor
precursor/g
intermediate/g
precursor
precursor/g

E1
472
TiO₂
8.33
1,000
B₂O₃
3.18

E20
472
TiO₂
8.33
1,000
B₂O₃
3.18

E21
472
TiO₂
8.33
1,000
B₂O₃
3.18

E22
472
TiO₂
8.33
1,000
B₂O₃
3.18

E23
472
TiO₂
8.33
1,000
B₂O₃
3.18

Note:

Except the parameters listed in Table E, other preparation processes in the examples are the same as those in Example 1.

TABLE 5

Product parameters of high-nickel active materials and performance of corresponding lithium-ion batteries in the examples

Shell

First shell layer

Total

mass

content

of

elements

Core

silicon

Content

and

of

aluminum
Transition
Second shell layer

Serial
Li_1+α[Ni_xCo_yMn_z
element
Li_αAl_xSi_yO₄
first shell
layer
Oxide
Content of element

No.
M_b]O₂
M/ppm
(Value of X:Y)
layer/ppm
Li_pR_qO_w
of R
R/ppm

E1
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
8,734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E20
Li_1.0[Ni_0.891Co_0.0495
1,000
LiAlSiO₄(1)
437
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E21
Li_1.0[Ni_0.891Co_0.0495
3,000
LiAlSiO₄(1)
13,101
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E22
Li_1.0[Ni_0.891Co_0.0495
100
LiAlSiO₄(1)
17,469
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E23
Li_1.0[Ni_0.891Co_0.0495
6,000
LiAlSiO₄(1)
444
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

Mass ratio
Mass
Battery performance parameters

of
ratio

Capacity

element
of

retention

Shell
lithium
element
Initial
Ex-
Surface
rate

layer
in core
silicon
discharge
pan-
impurity
during

thick-
layer
to
capacity/
sion/
lithium
cycling

Serial

ness/
and shell
element
(mAh/
(mL/
amount/
at

No.
Dv50/μm
μm
layer
R
g)
Ah)
ppm
25° C./%

E1
9.0
0.45
70
4.4
216
6.8
1,502
96.1

E20
9.0
0.1
867
0.22
216
7.3
1,567
95.5

E21
9.0
0.65
56
6.6
214
6.6
1453
96.4

E22
9.0
0.84
32
8.8
198
7.8
1,520
93.8

E23
9.0
0.06
4,806
0.022
210
13.9
2,108
92.8

Through comprehensive analysis of Example 1, Examples 20-21 and Examples 22-23 in Table 5, based on the total mass of the high-nickel positive electrode active material, when the total mass content of the elements silicon and aluminum in the first shell layer of the high-nickel positive electrode active material is 435 to 13,150 ppm, the surface impurity lithium amount of the positive electrode and the expansion amount inside the lithium-ion battery are improved, and the lithium-ion battery has a good discharge capacity, safety performance and cycle performance.

TABLE F

Process parameters of high-nickel active materials in the examples

Step S1

Nickel-

containing

Step S2

Serial
Sodium
Sodium
NaOH
ternary
CO₂/
First

No.
metaaluminate/g
silicate/g
solution/L
precursor/g
(mL/min)
intermediate/g

E24
19.52
29.05
2.00
953.00
10.00
994.43

E25
1.95
2.90
2.00
953.00
10.00
957.14

E26
19.52
29.05
2.00
953.00
10.00
994.43

E27
1.95
2.90
2.00
953.00
10.00
957.14

E28
19.52
29.05
2.00
953.00
10.00
994.43

Step S2

LiOH ·

Amount of
Step S3

Serial
H₂O/
M
M
Second
R
Amount of R

No.
g
precursor
precursor/g
intermediate/g
precursor
precursor/g

E24
472
TiO₂
8.33
1,000
Co(OH)₂
31.53

E25
472
TiO₂
8.33
1,000
Co(OH)₂
0.16

E26
472
TiO₂
8.33
1,000
Co(OH)₂
15.76

E27
472
TiO₂
8.33
1,000
Co(OH)₂
0.02

E28
472
TiO₂
8.33
1,000
Co(OH)₂
55.17

Note:

Except the parameters listed in Table F, other preparation processes in the examples are the same as those in Example 1.

TABLE 6

Product parameters of high-nickel active materials and performance of corresponding lithium-ion batteries in the examples

Shell

First shell layer

Total

mass

content

of

elements

Core

silicon

Content

and

of

aluminum
Transition
Second shell layer

Serial
Li_1+α[Ni_xCo_yMn_z
element
Li_αAl_xSi_yO₄
first shell
layer
Oxide
Content of element

No.
M_b]O₂
M/ppm
(Value of X:Y)
layer/ppm
Li_pR_qO_w
of R
R/ppm

E1
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
8,734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E24
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
13,101
LiCoO₂
Co(OH)₂
20,000

Mn_0.0495Ti_0.01]O₂

E25
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
1,310
LiCoO₂
Co(OH)₂
100

Mn_0.0495Ti_0.01]O₂

E26
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
13,101
LiCoO₂
Co(OH)₂
10,000

Mn_0.0495Ti_0.01]O₂

E27
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
1,310
LiCoO₂
Co(OH)₂
10

Mn_0.0495Ti_0.01]O₂

E28
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
13,101
LiCoO₂
Co(OH)₂
35,000

Mn_0.0495Ti_0.01]O₂

Mass ratio
Mass
Battery performance parameters

of
ratio

Capacity

element
of

retention

Shell
lithium
element
Initial
Ex-
Surface
rate

layer
in core
silicon
discharge
pan-
impurity
during

thick-
layer
to
capacity/
sion/
lithium
cycling

Serial

ness/
and shell
element
(mAh/
(mL/
amount/
at

No.
Dv50/μm
μm
layer
R
g)
Ah)
ppm
25° C./%

E1
9.0
0.45
70
4.4
216
6.8
1,502
96.1

E24
9.0
0.96
40
0.33
213
5.8
1,452
96.3

E25
9.0
0.18
287
0.66
215
7.5
1,675
95.8

E26
9.0
0.79
48
0.66
214
6.1
1,546
96.5

E27
9.0
0.17
311
66.6
208
15.9
2,398
91

E28
9.0
1.2
34
0.19
205
5.4
1,561
92.1

Through comprehensive analysis of Example 1, Examples 24-26 and Examples 27-28 in Table 6, based on the total mass of the high-nickel positive electrode active material, when the mass content of the element R in the high-nickel positive electrode active material is 100 to 20,000 ppm, the surface impurity lithium amount of the positive electrode and the expansion amount inside the lithium-ion battery are improved, and the lithium-ion battery has a good discharge capacity, safety performance and cycle performance.

TABLE G

Process parameters of high-nickel active materials in the examples

Step S1

Nickel-

containing

Step S2

Serial
Sodium
Sodium
NaOH
ternary
CO₂/
First

No.
metaaluminate/g
silicate/g
solution/L
precursor/g
(mL/min)
intermediate/g

E1
13.02
19.37
2.00
953.00
10.00
980.62

E29
0.88
1.31
2.00
953.00
10.00
954.87

E30
11.73
17.45
2.00
953.00
10.00
977.88

E31
10.26
15.26
2.00
953.00
10.00
974.77

E32
26.03
38.73
2.00
953.00
10.00
1008.24

E33
0.07
0.10
2.00
953.00
10.00
953.14

Step S2

Amount of
Step S3

Serial
LiOH ·
M
M
Second
R
Amount of R

No.
H₂O/g
precursor
precursor/g
intermediate/g
precursor
precursor/g

E1
472
TiO₂
8.33
1,000
B₂O₃
3.18

E29
472
TiO₂
8.33
1,000
B₂O₃
9.55

E30
472
TiO₂
8.33
1,000
B₂O₃
3.18

E31
472
TiO₂
8.33
1,000
B₂O₃
1.59

E32
472
TiO₂
8.33
1,000
B₂O₃
3.18

E33
472
TiO₂
8.33
1,000
B₂O₃
3.18

Note:

Except the parameters listed in Table G, other preparation processes in the examples are the same as those in Example 1.

TABLE 7

Product parameters of high-nickel active materials and performance of corresponding lithium-ion batteries in the examples

Shell

First shell layer

Total

mass

content

of

elements

Core

silicon

Content

and

of

aluminum
Transition
Second shell layer

Serial
Li_1+α[Ni_xCo_yMn_z
element
Li_αAl_xSi_yO₄
first shell
layer
Oxide
Content of element

No.
M_b]O₂
M/ppm
(Value of X:Y)
layer/ppm
Li_pR_qO_w
of R
R/ppm

E1
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
8,734
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E29
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
590
LiBO₂
B₂O₃
3,000

Mn_0.0495Ti_0.01]O₂

E30
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
7,869
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

E31
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
6,885
LiBO₂
B₂O₃
500

Mn_0.0495Ti_0.01]O₂

E32
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
17,469
LiBO₂

1,000

Mn_0.0495Ti_0.01]O₂

E33
Li_1.0[Ni_0.891Co_0.0495
5,000
LiAlSiO₄(1)
44
LiBO₂
B₂O₃
1,000

Mn_0.0495Ti_0.01]O₂

Mass

ratio
Mass

Battery performance parameters

of
ratio

Capacity

element
of

retention

Shell
lithium
element
Initial
Ex-
Surface
rate

layer
in core
silicon
discharge
pan-
impurity
during

thick-
layer
to
capacity/
sion/
lithium
cycling

Serial

ness/
and shell
element
(mAh/
(mL/
amount/
at

No.
Dv50/μm
μm
layer
R
g)
Ah)
ppm
25° C./%

E1
9.0
0.45
70
4.4
216
6.8
1,502
96.1

E29
9.0
0.21
625
0.1
213
7.3
1,568
96.5

E30
9.0
0.41
86
4
217
6.9
1,546
95.8

E31
9.0
0.37
103
7
214
7.5
1,659
95.6

E32
9.0
0.84
32
8.8
198
7.8
1,520
93.8

E33
9.0
0.06
4,806
0.022
210
13.9
2,108
92.8

It can be seen from Example 1, Examples 29-31 and Examples 32-33 in Table 7 that, when a mass ratio of the element Si to the element R is 0.1 to 7.0:1, and particularly 0.1 to 4.4:1, the surface impurity lithium amount of the positive electrode is reduced, the expansion amount inside the battery is improved, and the discharge capacity, safety performance and cycle performance are further improved.

TABLE H

Process parameters of high-nickel active materials in the examples

Step S1

Nickel-

containing

Step S2

Serial
Sodium
Sodium
NaOH
ternary
CO₂/
First

No.
metaaluminate/g
silicate/g
solution/L
precursor/g
(mL/min)
intermediate/g

E1
13.02
19.37
2.00
953.00
10.00
980.62

E34
13.02
19.37
2.00
953.00
10.00
980.62

E35
13.02
19.37
2.00
953.00
10.00
980.62

Step S2

Amount of
Step S3