A composite doped co-coated high-voltage cathode material, its preparation method and application

Abstract

The composite-doped co-coated high-voltage cathode material of this invention, based on traditional nickel-cobalt-manganese materials, adopts a composite modification method of multi-element co-doping and coating, with Ce2O as the main component. 12 Co-doping modification was performed using W3, MgWO4, AlF3, and θ-Al2O3, and Ce2O was used. 12 W3 and MgWO4 are used as coating agents for coating modification, and θ-Al2O3 with a more stable structure is further used to form a secondary coating. Through the synergistic effect of W / Mg / Ce / Al / F doping and coating and anion and cation doping, the structural stability, thermal stability, rate / cycle / storage performance, DCIR and other properties of high voltage ternary cathode materials are improved. It has the advantages of more stable layered structure, higher electronic conductivity, better rate, longer cycle performance and storage and lower DCIR.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, specifically relating to a composite doped co-coated high-voltage cathode material, and further discloses its preparation method and application. Background Technology

[0002] With the rapid development of new energy vehicles recently, the demand for lithium-ion batteries has also increased dramatically. Especially against the backdrop of a sharp rise in the prices of upstream raw materials such as lithium salts and cobalt salts, the cost-effectiveness of cathode materials has become an industry development trend and a key focus of R&D for various companies. Currently, the three major trends in the development of lithium-ion battery cathode materials, especially ternary cathodes, are single crystallization, high voltage, and high nickel content. Among them, high-nickel ternary cathode materials, due to their high energy density, meet the range requirements of high-end new energy vehicles and have a large market potential in the future. They are the key direction for the technological R&D and industrialization of various ternary cathode material manufacturers. In particular, medium-nickel high-voltage and high-nickel materials are the current competitive development direction for domestic companies.

[0003] The high-voltage approach is based on ternary materials with medium nickel or low cobalt content. By increasing the voltage plateau, the cathode material releases more lithium ions at higher voltages, thereby achieving higher specific capacity and average discharge voltage, ultimately increasing energy density. Looking at current mainstream applications, the actual energy density of a typical high-voltage Ni6 series product (Ni65) can reach 735.15 Wh / kg, which is very close to the 739.32 Wh / kg parameter of a typical Ni8 series product.

[0004] Currently, high-voltage cathode materials primarily utilize medium-nickel ternary materials, which offer advantages over high-nickel ternary materials in terms of raw materials, production processes, and processing costs. Furthermore, due to the relatively lower nickel content of high-voltage materials, their production processes are less complex than those of high-nickel ternary materials. Therefore, high-voltage cathode materials not only improve energy density but also offer certain safety enhancements. Thanks to their superior overall performance, the market for high-voltage ternary materials is gradually opening up. However, gradually increasing the voltage significantly impacts the structural performance and stability of the materials. Therefore, research on how to improve the various properties of these materials under high-voltage application conditions is an extremely urgent and complex research topic.

[0005] For example, Chinese patent CN113903907A discloses a tungsten-coated and doped single-crystal nickel-rich ternary cathode material. This material uses W for doping and coating, effectively enhancing the structural stability of the single-crystal nickel-rich ternary cathode material, reducing material polarization, and improving lithium-ion diffusion kinetics. Therefore, it simultaneously improves the battery's cycle stability and rate performance. However, simply using tungsten-containing elements for modification cannot better improve structural stability.

[0006] For example, Chinese patent CN111900401A discloses a method for coating lithium battery cathode materials with a composite of tungsten oxide and nitrogen-doped carbon. This method uses the polymerization of carbon precursors and the precipitation of tungsten precursors to form a coating layer on the surface of the lithium battery cathode material, followed by a calcination process to solidify and bond the coating layer. This method is characterized by low cost, low energy consumption, and simple operation, and the lithium battery cathode material exhibits excellent electronic conductivity and electrochemical stability. However, since this method mainly involves incorporating the precursor into the precursor end using a tungsten-containing solution, controlling the amount introduced and the parameters related to the co-precipitation reaction is difficult, thus limiting its effectiveness.

[0007] For example, Chinese patent CN112531154A discloses a ternary material with gradient doping of tungsten trioxide micro-nano particles. Tungsten doping is achieved through a wet synthesis stage of the precursor. Under normal temperature and pressure conditions, the surface of the material is activated by an aqueous solution of hydrogen peroxide. After tungsten doping, the material is sintered at low temperature to recrystallize. This can achieve a gradient distribution of tungsten elements from the surface to the interior of the ternary material at the atomic level. The crystal nuclei formed by tungsten elements and nickel, cobalt and manganese effectively fill the gaps in the secondary particle stacking of the ternary material, stabilize the composition and structure of the ternary material, and solve the problems of uneven tungsten doping caused by simultaneous lithium doping and tungsten doping in the high-temperature solid-state method and the high energy consumption caused by high sintering temperature.

[0008] For example, Chinese patent CN113764647A discloses a ternary cathode material precursor and ternary cathode material modified with zirconium and multiple anions, which provides a Zr and multiple anion co-doped ternary precursor scheme. It mainly uses compounds such as anions and cations to mix and add modified materials at the precursor solution end. However, it faces defects such as element interface fusion and grain boundary diffusion growth during high-temperature preparation. It still needs further modification during high-temperature calcination preparation.

[0009] For example, Chinese patent CN112811403A discloses a Mg / Ti co-doped Li3PO4-coated high-nickel ternary cathode material. Using a high-nickel precursor as raw material, nickel-cobalt-manganese precursors, a lithium source, magnesium compounds (magnesium carbonate and magnesium hydroxide), and titanium compounds (titanium oxide and titanium hydroxide) are added together in a high-speed mixer in a certain proportion and thoroughly mixed. The mixture is then pre-calcined at low temperature and then calcined at high temperature under an oxygen atmosphere to obtain a doped matrix material. The obtained doped matrix material and lithium phosphate compound are then thoroughly mixed in a mixer in a certain proportion and sintered a second time under an oxygen atmosphere to obtain a lithium phosphate-coated cathode material. This method is not only simple, but the layered distribution of the Mg / Ti dual dopants can simultaneously enhance surface stability and crystal structure stability. The Li3PO4 coating layer helps reduce electrochemical impedance and electrolyte side reactions, thereby improving the thermal stability and cycle performance of the high-nickel ternary cathode material.

[0010] For another example, Chinese Patent CN108550810A discloses a cerium-doped and carbon-coated modified ternary cathode material. The cathode material precursor is obtained from NiSO4, MnSO4, CoSO4, and Ce(NO3)3. Then, a matrix containing cerium elements is prepared by solid-phase high-temperature calcination, and the ternary cathode material is modified by combining doping and carbon coating, effectively stabilizing the layered structure of the ternary cathode material, suppressing cation mixing, and improving the rate capacity, cycle performance, electron conductivity, and other properties of the ternary cathode material. Summary of the Invention

[0011] To this end, the technical problem to be solved by the present invention is to provide a composite-doped and co-coated high-voltage cathode material. The ternary material has the advantages of stable structure, low DCIR value, and good rate performance, cycle performance, and storage performance. The lithium-ion battery prepared therefrom has the advantages of high specific capacity per gram, low DCIR growth, and excellent comprehensive long-cycle performance.

[0012] The second technical problem to be solved by the present invention is to provide a preparation method and application of the above-mentioned composite-doped and co-coated high-voltage cathode material.

[0013] To solve the above technical problems, a composite-doped and co-coated high-voltage cathode material described in the present invention has a general formula as shown in LiNi x Co y Mn z W a Al b Ce c Mg d Zr e F n O 2-n and x + y + z + a + b + c + d + e + n = 1.

[0014] In the composite-doped and co-coated high-voltage cathode material described in the present invention, the total molar amount of each metal element is 1, and the specific molar content of each element can be conventionally selected according to the ratio of the required material.

[0015] Preferably, in the composite-doped and co-coated high-voltage cathode material, the molar ratio of Ni x is 0.5 ≤ x < 1.0, the molar ratio of Co y is 0 < y ≤ 0.30, the molar ratio of Mn z is 0 < z ≤ 0.30, and x + y + z = 1; the molar ratio of Li: (x + y + z) is preferably 0.98 - 1.16:1.0, more preferably 0.99 - 1.12:1.0.

[0016] The present invention also discloses a method for preparing the composite-doped and co-coated high-voltage cathode material, including the following steps:

[0017] (1) Take Ni, the precursor of ternary cathode material, according to the selected content ratio. x Co y Mn z (OH)2, lithium source material and tungsten-cerium dopant are mixed and subjected to a first sintering treatment to obtain a ternary cathode material doped matrix;

[0018] (2) According to the selected content ratio, the ternary cathode material doped matrix is ​​mixed with the zirconium-containing coating agent and subjected to a second sintering treatment to obtain the ternary cathode material coated matrix;

[0019] (3) According to the selected content ratio, the ternary cathode material coating matrix is ​​mixed with aluminum-containing additives and subjected to a third sintering treatment to obtain the desired composite doped co-coated high voltage cathode material.

[0020] Specifically, in the preparation method of the composite doped co-coated high-voltage cathode material, step (1) includes:

[0021] The ternary cathode material precursor Ni x Co y Mn z (OH)2, the lithium source material (in Li) + The molar ratio of the tungsten-cerium dopant (based on the total amount of doping elements) is 1:(0.96-1.30):(0.02-0.6).

[0022] Preferably, the ternary cathode material precursor Ni x Co y Mn z (OH)2, the lithium source material (in Li) + The molar ratio of the tungsten-cerium dopant (based on the total amount of dopant elements) is 1:(0.98-1.16):(0.02-0.6), more preferably 1:(0.99-1.12):(0.05-0.6);

[0023] The tungsten-cerium dopant includes Ce2O 12 A mixture of W3, MgWO4, AlF3 and θ-Al2O3;

[0024] Preferably, the ternary cathode material precursor Ni x Co y Mn z (OH)2 and the Ce2O 12 The mass ratio of W3 is 100:(0.05-0.8), preferably 100:(0.1-0.6), and more preferably 100:(0.25-0.50);

[0025] Preferably, the dopant Ce2O 12 W3 has a purity of 99.9%, and its D 50 The particle size is 0.5μm-20μm, preferably 1μm-10μm, and more preferably 2μm-6μm;

[0026] Preferably, the ternary cathode material precursor Ni x Co y Mn z The mass ratio of (OH)2 to MgWO4 is 100:(0.02-0.8), preferably 100:(0.04-0.6), and more preferably 100:(0.06-0.45;

[0027] Preferably, the dopant MgWO4 has a purity of 99.0% and its D 50 The particle size is 0.5μm-15μm, preferably 1μm-10μm, and more preferably 3μm-8μm;

[0028] Preferably, the ternary cathode material precursor Ni x Co y Mn z The mass ratio of (OH)2 to AlF3 is 100:(0.01-0.6), preferably 100:(0.05-0.4), and more preferably 100:(0.08-0.25;

[0029] Preferably, the dopant AlF3 has a purity of 99.0% and its D 50 The particle size is 0.5μm-15μm, preferably 1μm-10μm, and more preferably 3μm-8μm;

[0030] Preferably, the ternary cathode material precursor Ni x Co y Mn z The mass ratio of (OH)2 to θ-Al2O3 is 100:(0.01-0.5), preferably 100:(0.04-0.4), and more preferably 100:(0.05-0.30);

[0031] Preferably, the dopant θ-Al2O3 has a purity of 99.9% and its D 50 The particle size is 1μm-50μm, preferably 2μm-30μm, and more preferably 3μm-20μm;

[0032] Preferably, the lithium source material is a lithium-containing compound, including one or a mixture of several of LiOH, LiOH·H2O, Li2CO3, or LiNO3. In application, the coarse lithium source particles can be mechanically ground to 3-12 μm or commercially available lithium sources of this size can be selected, preferably 4-8 μm; the ternary lithium source is preferably LiOH·H2O or Li2CO3.

[0033] Preferably, the selection of the ternary cathode material precursor involves small-particle ternary precursors with a particle size D. 50 (2-6μm), preferably 3.0-5.0μm; its large-particle ternary precursor particle size D 50 (9-16μm), preferably 10-14μm.

[0034] Preferably, the mixing step uses a ball mill, can mill, plow mixer, or high-speed mixer to mix the materials evenly, then the mixture is placed in a small dry pot or sagger, shaken evenly, cut into pieces, and then sintered once; the mixing equipment is preferably a ball mill, plow mixer, or high-speed mixer.

[0035] Specifically, in the preparation method of the composite doped co-coated high voltage cathode material, the first sintering step in step (1) includes: a first heating to 400-500℃ and holding for 2-6 hours in an oxygen-containing atmosphere, a second heating to 580-740℃ and holding for 2-5 hours, and a third heating to 740-1000℃ and holding for 6-18 hours;

[0036] As a preferred embodiment, in step (1), the first sintering step includes: a first heating to 420-480℃ and holding for 3-5 hours in an oxygen-containing atmosphere, a second heating to 680-740℃ and holding for 3-4 hours, and a third heating to 740-100℃ and holding for 8-16 hours.

[0037] As a preferred embodiment, in step (1), the first sintering step includes: a first heating to 460-480℃ and holding for 4 hours in an oxygen-containing atmosphere, a second heating to 680-740℃ and holding for 3-4 hours, and a third heating to 740-1000℃ and holding for 9-14 hours.

[0038] Preferably, when the first sintering step is carried out in a muffle furnace or tube furnace mode, the heating rate of the first heating step, the second heating step, and the third heating step are controlled to be independent of each other at 1-5℃ / min, preferably at 2-4℃ / min, and more preferably at 3℃ / min.

[0039] Preferably, when the first sintering step is carried out in an atmosphere roller kiln or rotary kiln mode, the heating rates of the first, second, and third heating steps are controlled independently to be 1-30℃ / h, preferably 5-20℃ / h, and more preferably 10℃ / h.

[0040] The atmosphere used in the first sintering process is oxygen with a concentration ≥95%. After the first sintering, the material undergoes coarse crushing, fine crushing, sieving, and demagnetization to obtain a ternary cathode material doped matrix for subsequent coating. Preferably, the large particle size D of the ternary cathode material doped matrix after crushing and sieving is... 50 The particle size is 9-16 μm, preferably 10-14 μm; the particle size of the small particle matrix D 50 The thickness is 2.5-6.0 μm, preferably 3.0-5.0 μm.

[0041] Specifically, in the preparation method of the composite doped co-coated high-voltage cathode material, step (2) includes:

[0042] The molar ratio of the ternary cathode material doped matrix to the zirconium-containing coating agent (based on the total amount of coating elements) is 1:(0.02-0.3);

[0043] The zirconium-containing coating agent includes Ce2O 12 A mixture of W3, MgWO4 and ZrO2;

[0044] Preferably, the ternary cathode material doped matrix and the Ce2O 12 The mass ratio of W3 is 100:(0.05-0.25), preferably 100:(0.08-0.20), and more preferably 100:(0.10-0.15);

[0045] Preferably, the coating agent Ce2O 12 W3 has a purity of 99.9%, and its D 50 Particle size 30nm-60nm;

[0046] Preferably, the mass ratio of the ternary cathode material doped matrix to the MgWO4 is 100:(0.08-0.3), more preferably 100:(0.10-0.22), and even more preferably 100:(0.12-0.18);

[0047] Preferably, the coating agent is MgWO4 with a purity of 99.0%, and its D 50 Particle size 20nm-100nm;

[0048] Preferably, the mass ratio of the ternary cathode material doped matrix to the ZrO2 is 100:(0.02-0.20), more preferably 100:(0.05-0.18), and even more preferably 100:(0.06-0.15);

[0049] Preferably, the coating agent is ZrO2 with a purity of 99.0%, and its D 50 Particle size: 20nm-150nm;

[0050] Specifically, in the preparation method of the composite doped co-coated high voltage cathode material, step (2) includes a second sintering step of heating to 400-780℃ for calcination and holding for 1-20h; preferably, the calcination temperature is 440-760℃ and the holding time is 3-14h; more preferably, the calcination temperature is 460-720℃ and the holding time is 6-11h.

[0051] Preferably, in the second sintering step, the heating rate is controlled to be 1-20℃ / h;

[0052] Preferably, in step (2), when the molar content of Ni element x in the ternary cathode material doped matrix is ​​≥0.8, before adding the boron-containing coating agent, the step further includes dispersing, washing and drying the ternary cathode material doped matrix.

[0053] The preparation method of the ternary cathode material of the present invention, when the Ni content x in the ternary cathode material is 0.5≤x<0.8, can directly coat the ternary cathode material doped matrix; while when the molar content of Ni element x in the ternary cathode material doped matrix is ​​≥0.8 (i.e., it is a high-nickel cathode material), before adding the coating agent, the method further includes the steps of dispersing, washing and drying the ternary cathode material doped matrix.

[0054] Specifically, in its water washing process, the ratio of material to water is controlled at 1:0.5-3.0, and the washing time is 10-120s; preferably, the ratio of material to water is 1:1.0-2.0, and the washing time is 20-60s; more preferably, the ratio of material to water is 1:1.5, and the washing time is 30s. During the water washing process, the material is gradually injected into a plate and frame filter press for pre-dehydration. After pre-dehydration, nitrogen gas is introduced for purging for 1-4 hours, preferably 2-3 hours, and the moisture content of the filter cake is controlled to be ≤7%. Subsequently, the filter cake is put into a vacuum oven or a double cone dryer for drying and dehydration. The drying temperature is 120-200℃, and the drying time is 1-12 hours; preferably 130-180℃, 3-10 hours; more preferably 150-160℃, 4-8 hours. A ternary water-washed and dried doped matrix is ​​obtained.

[0055] Specifically, in the preparation method of the composite doped co-coated high voltage cathode material, in step (3), the aluminum-containing additive includes θ-Al2O3;

[0056] Preferably, the mass ratio of the ternary cathode material coating matrix to the θ-Al2O3 is 100:(0.02-0.25), more preferably 100:(0.04-0.20), and even more preferably 100:(0.05-0.18);

[0057] Preferably, the coating agent θ-Al2O3 has a purity of 99.9% and its D 50 Particle size should be selected between 10nm and 100nm.

[0058] Specifically, in the preparation method of the composite doped co-coated high voltage cathode material, step (3) includes the third sintering step, which involves heating to 200-400℃ for calcination and holding for 1-10 hours; preferably, the calcination temperature is 240-385℃ and the holding time is 3-8 hours; more preferably, the calcination temperature is 300-380℃ and the holding time is 4-7 hours.

[0059] Preferably, in the third sintering step, the heating rate is controlled to be 1-20℃ / h;

[0060] Specifically, the equipment used for the coating operation can be a high-speed mixer or a mechanical fusion machine, with a high-speed mixer being preferred;

[0061] Preferably, step (3) further includes crushing, sieving, and demagnetizing the obtained composite doped co-coated high-voltage cathode material; and it can be mixed evenly in a batch mixing tank and protected by introducing dry gas (dehydration and decarbonization) or inert gas.

[0062] Preferably, in step (3), the large particle size D of the matrix of the composite doped co-coated high-voltage cathode material is... 50 The particle size D of the small particle matrix is ​​9-16 μm. 50 The range is 2.5-6.0 μm.

[0063] Preferably, in step (3), the particle size D of the large particle matrix of the ternary cathode material is... 50 The particle size is 9-16 μm, preferably 10-14 μm; the particle size of the small particle matrix D 50 The micrometer size is 2.5-6.0 μm, preferably 3.0-5.0 μm, and more preferably 3.5-4.5 μm.

[0064] Preferably, the batch mixing equipment can be a ribbon batch mixer or a high-speed mixer.

[0065] The present invention also discloses the use of the composite doped co-coated high-voltage cathode material or the composite doped co-coated high-voltage cathode material prepared by the method for preparing secondary battery cathode sheets or secondary batteries;

[0066] Preferably, the secondary battery includes a lithium-ion battery.

[0067] The present invention also discloses a secondary battery positive electrode sheet or a secondary battery prepared from the composite doped co-coated high-voltage positive electrode material or the composite doped co-coated high-voltage positive electrode material prepared by the method.

[0068] The composite doped co-coated high-voltage cathode material of this invention, based on traditional nickel-cobalt-manganese materials, uses Ce2O 12 Co-doping modification was performed using W3, MgWO4, AlF3, and θ-Al2O3; among which, Ce2O 12 W3 and MgWO4 dopants introduce fluxing effects, and Ce2O is used. 12 The low melting point and elemental bonding characteristics of W3 and MgWO4 promote grain growth, improve crystallinity and particle strength, enhance compaction resistance, and lower calcination temperature to reduce energy consumption. The introduction of AlF3 as anion and cation co-doping, combined with fluxing agents, better facilitates the inward diffusion of Ce / W / Mg / Al / Li, inhibiting cation mixing, increasing interlayer spacing, and improving ion migration. This is especially true through the use of Ce2O... 12 The invention utilizes tetragonal W3, tetragonal monoclinic MgWO4, and tetragonal AlF3 ionic crystals to enhance structural stability, along with the structural stability exhibited during low-temperature treatment with θ-Al2O3 and the structural evolution characteristic of transforming into a stable α-phase at high temperatures. These features further improve the structure and thermal stability of the nickel-cobalt-manganese ternary material. The composite-doped co-coated high-voltage cathode material of this invention uses Ce2O3 as a base. 12 Co-doping with W3, MgWO4, AlF3, and θ-Al2O3 followed by high-temperature sintering solid-state reaction results in a W / Ce / Al / Mg / F co-doped structure, effectively increasing particle strength and reversible capacity. This reduces side reactions at the interface between the active material and the electrolyte, lowers the solubility of manganese in organic electrolytes, and effectively improves the material's cycle performance under high voltage. Furthermore, it widens ion channels and interlayer distances, improving discharge efficiency and rate capability. It also enhances the material's high-temperature electrochemical performance, reduces Li / Ni mixing, and ensures the performance of battery products.

[0069] The composite doped co-coated high-voltage cathode material of this invention further utilizes Ce2O. 12 W3 and MgWO4 were used as coating agents for coating modification; among them, Ce2O was used...12 W3 and MgWO4 coating improve the surface conductivity of ternary cathode materials, repair surface particle morphology, enhance particle surface corrosion resistance, and reduce cell DCIR and cycle impedance growth; it can effectively improve the material's surface resistance to electrolyte corrosion, rate capability, surface conductivity, and ion migration ability; while simultaneously using ZrO2 and Ce2O 12 W3 composite coating can improve the particle surface's resistance to hydrofluoric acid corrosion, inhibit the generation and initiation of microcracks, improve high-temperature oxidation resistance, reduce surface impedance, improve surface electronic conductivity, improve first discharge efficiency and cycle performance, and ensure the application performance of battery products.

[0070] The composite doped co-coated high-voltage cathode material of this invention further employs a secondary coating by mixing θ-Al2O3, which has an evolutionary structure and is more stable, with a matrix containing Ni / Co / Mn / Ce / W / F / Zr / Al / Mg oxides. This results in a surface gradient coating structure, which further improves surface conductivity, reduces surface residual alkali, suppresses interfacial side reactions, effectively enhances the surface gradient coating protective layer, and increases the Li ion migration induction ability, thereby improving the material's cycle performance.

[0071] The boron-coated fluorine-zirconium co-doped ternary cathode material of this invention employs a multi-element co-doping and coating composite modification method. Through the synergistic effect of W / Mg / Ce / Al / F doping and coating, as well as anion and cation doping, it effectively improves the Li / Ni mixing and particle surface band effect in the cathode material, enhancing the structural stability, thermal stability, rate / cycle / storage performance, and DCIR of the high-voltage ternary cathode material. It exhibits advantages such as a more stable layered structure, higher electronic conductivity, better rate capability, longer cycle life, and lower DCIR. Lithium-ion batteries prepared from the ternary cathode material provided by this invention possess high specific capacity, rate capability, cycle life, and application effectiveness, demonstrating excellent comprehensive performance advantages including high specific capacity, low DCIR growth, and long cycle life. Attached Figure Description

[0072] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0073] Figure 1 The image shows the XRD characterization of cerium tungstate (cerium tungstate).

[0074] Figure 2 This is a process flow diagram for the preparation of the high-voltage ternary cathode material of the present invention;

[0075] Figure 3In the middle (a)-(c), the SEM morphology characteristics of the ternary cathode materials prepared in Examples 1-3 are respectively.

[0076] Figure 4 Figures (a)-(c) are the cycling curves of the high-voltage ternary cathode materials in Examples 1-3 and Comparative Examples 1-3, respectively.

[0077] Figure 5 The full-cell cycling curves at 25°C for the high-voltage ternary cathode materials in Example 1 and Comparative Example 1 are shown.

[0078] Figure 6 The full-cell cycling curves at 45°C for the high-voltage ternary cathode materials in Example 1 and Comparative Example 1 are shown. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0080] In the following embodiments of the present invention, Ce2O is selected. 12 W3 can be purchased commercially from raw materials of the same specifications, or it can be prepared using traditional synthesis methods. For example, Ce2O3 can be prepared by heating a mixture of Ce2O3, CeO2, and WO3. 12 W3 can also be prepared using a high-temperature solid-state method. This involves dissolving ammonium tungstate and cerium oxalate in distilled water, ball milling for 1 hour, drying, grinding, pressing into tablets, sintering at 600℃ for 8 hours, grinding again, pressing into tablets, and sintering at 900℃ for 9 hours to obtain the final product. Ce2O of the desired particle size can then be obtained through further grinding. 12 W3 is an additive raw material. The XRD characterization pattern of the cerium tungstate (cerium tungstate) is attached. Figure 1 As shown.

[0081] In the following embodiments of the present invention, the MgWO4 used can be commercially available in the same specifications, or it can be prepared according to conventional synthesis methods. For example, tungsten trioxide and magnesium oxide are mixed in a molar ratio of 1:1.4 and calcined at 1000°C to obtain a magnesium tungstate matrix, which is then ground to obtain the additive raw material with the required particle size.

[0082] Example 1

[0083] like Figure 2 The flowchart shown illustrates the preparation method of the composite-doped co-coated high-voltage cathode material described in this embodiment, which includes the following steps:

[0084] (1) Prepare the precursor Ni according to conventional methods. 0.6 Co 0.1 Mn0.3 (OH)2(D 50 (4.0±0.5μm), Li2CO3(D) 50 (6±2 μm) with dopant Ce2O 12 W3(D 50 (4.0±1.0μm), MgWO4 (D 50 (4.0±1.0μm), AlF3(D) 50 (4.0±1.0μm), θ-Al2O3(D) 50 The raw material is 5.0±2.0μm. Ni was weighed separately. 0.6 Co 0.1 Mn 0.3 (OH)2(2000g), Li2CO3(845.54g), Ce2O 12 W3 (4.5494g), MgWO4 (5.5638g), AlF3 (3.1441g), and θ-Al2O3 (4.5395g) were mixed. The materials were transferred to a high-speed mixer and mixed uniformly using a three-stage mixing process: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min. The mixture was then placed in a crucible and transferred to an atmosphere muffle furnace. Under a slightly positive pressure oxygen atmosphere, the temperature was increased to 480℃ at a rate of 2℃ / min for 4.0 h, then increased to 770℃ for 3.2 h, and then increased to 960℃ for 12.4 h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0085] (2) Take 1600g of the obtained doped substrate and mix it with the coating agent Ce2O 12 W3(D 50 (45.0±15.0nm)(1.4270g), MgWO4(D) 50 (60.0±20.0nm)(2.6894g), ZrO2(D) 50 The three powders (80.0±20.0nm) (2.1634g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. The mixture was then placed in a crucible and sintered at 640℃ for 8.6h in an oxygen atmosphere. After cooling, the mixture was crushed and then demagnetized by sieving to obtain the positive electrode material coating matrix.

[0086] (3) Take 1500g of the obtained substrate and mix it with the additive θ-Al2O3 (D 50The three powders (80.0±20.0nm) (1.8158g) were added to a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. The mixture was then placed in a crucible and sintered at 360℃ for 6.0h in dry air or oxygen-air (5:5) atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism. The resulting ternary cathode material was then added to a batch mixing tank and mixed for 2h. The discharged material was then sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were then tested.

[0087] Example 2

[0088] like Figure 2 The flowchart shown illustrates the preparation method of the composite-doped co-coated high-voltage cathode material described in this embodiment, which includes the following steps:

[0089] (1) Prepare the precursor Ni according to conventional methods. 0.7 Co 0.1 Mn 0.2 (OH)₂ (D50: 3.9±0.5μm), LiOH·H₂O (D50: 6±2μm) and dopant Ce₂O 12 W3(D 50 (4.0±1.0μm), MgWO4 (D 50 (4.0±1.0μm), AlF3(D) 50 (4.0±1.0μm), θ-Al2O3(D) 50 The raw material is 5.0±2.0μm. Ni was weighed separately. 0.7 Co 0.1 Mn 0.2 (OH)2 (2000g), LiOH·H2O (955.95g), Ce2O 12 W3 (4.6823g), MgWO4 (4.5231g), AlF3 (1.8864g), and θ-Al2O3 (5.6744g) were mixed. The materials were transferred to a high-speed mixer and mixed uniformly using a three-stage mixing process: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min. The mixture was then placed in a crucible and transferred to a muffle furnace under a slightly positive pressure oxygen atmosphere. The temperature was increased to 480℃ at a rate of 2℃ / min and held for 4.0 h. The temperature was then increased to 760℃ and sintered for 3.2 h. Finally, the temperature was increased to 926℃ and sintered for 12.4 h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0090] (2) Take 1600g of the obtained doped substrate and mix it with the coating agent Ce2O 12 W3(D 50 (45.0±15.0nm)(1.4270g), MgWO4(D)50 (60.0±20.0nm)(2.6894g), ZrO2(D) 50 The three powders (80.0±20.0nm) (2.5861g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. The mixture was then placed into a crucible and sintered at 640℃ for 8.6h in an oxygen atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism, thus obtaining the positive electrode material coating matrix.

[0091] (3) Take 1500g of the obtained substrate and mix it with the additive θ-Al2O3 (D 50 The three powders (80.0±20.0nm) (1.8158g) were added to a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. The mixture was then placed in a crucible and sintered at 360℃ for 6.0h in dry air or oxygen-air (5:5) atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism. The resulting ternary cathode material was then added to a batch mixing tank and mixed for 2h. The discharged material was then sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were then tested.

[0092] Example 3

[0093] like Figure 2 The flowchart shown illustrates the preparation method of the composite-doped co-coated high-voltage cathode material described in this embodiment, which includes the following steps:

[0094] (1) Prepare the precursor Ni according to conventional methods. 0.67 Co 0.08 Mn 0.25 (OH)2 (D50: 3.8±0.5μm), Li2CO3 (D50: 6±2μm) and dopant Ce2O 12 W3(D 50 (4.0±1.0μm), MgWO4 (D 50 (4.0±1.0μm), AlF3(D) 50 (4.0±1.0μm), θ-Al2O3(D) 50 The raw material is 5.0±2.0μm. Ni was weighed separately. 0.67 Co 0.08 Mn 0.25 (OH)2(2000g), Li2CO3(843.35g), Ce2O 12W3 (5.1283g), MgWO4 (5.0884g), AlF3 (2.5113g), and θ-Al2O3 (5.6744g) were mixed. The materials were transferred to a high-speed mixer and mixed uniformly using a three-stage mixing process: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min. The mixture was then placed in a crucible and transferred to a muffle furnace. Under a slightly positive pressure oxygen atmosphere, the temperature was increased at a rate of 2℃ / min to 480℃ for 4.0 h, then increased to 770℃ for 3.2 h, and then increased to 940℃ for 12.4 h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0095] (2) Take 1600g of the obtained doped substrate and mix it with the coating agent Ce2O 12 W3(D 50 (45.0±15.0nm)(1.4270g), MgWO4(D) 50 (60.0±20.0nm)(2.6894g), ZrO2(D) 50 The three powders (80.0±20.0nm) (2.5861g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. The mixture was then placed in a crucible and sintered at 640℃ for 8.6h in an oxygen atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism, thus obtaining the positive electrode material coating matrix.

[0096] (3) Take 1500g of the obtained coating substrate and mix it with the additive θ-Al2O3 (D 50 The three powders (80.0±20.0nm) (1.8158g) were added to a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. The mixture was then placed in a crucible and sintered at 360℃ for 6.0h in dry air or oxygen-air (5:5) atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism. The resulting ternary cathode material was then added to a batch mixing tank and mixed for 2h. The discharged material was then sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were then tested.

[0097] Comparative Example 1

[0098] The method for preparing the cathode material described in this comparative example includes the following steps:

[0099] (1) Prepare the precursor Ni according to conventional methods. 0.6 Co 0.1 Mn 0.3 (OH)2 (D50: 4.0±0.5μm), Li2CO3 (D50: 6±2μm) and dopant θ-Al2O3 (D 50The raw material is 5.0±2.0μm. Ni was weighed separately. 0.6 Co 0.1 Mn 0.3 (OH)2 (2000g), Li2CO3 (845.5435g), and θ-Al2O3 (9.079g) were mixed uniformly in a high-speed mixer using a three-stage mixing process: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min. The mixture was then placed in a crucible and transferred to a muffle furnace. Under a slightly positive pressure oxygen atmosphere, the temperature was increased to 480℃ at a rate of 3℃ / min and sintered for 4.0 h, then increased to 770℃ and sintered for 3.2 h, and finally increased to 980℃ and sintered for 12.4 h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0100] (2) Take 1600g of the obtained doped substrate and mix it with the coating agent ZrO2 (D 50 The three powders (80.0±20.0nm) (2.6134g) were put into a high-speed mixer and mixed in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. After the three powders were mixed evenly, they were put into a crucible and sintered at 640℃ for 8.6h in an oxygen atmosphere. After cooling, they were crushed and then sieved to remove magnetism, thus obtaining the positive electrode material coating matrix.

[0101] (3) Take 1500g of the obtained coating substrate and mix it with the additive θ-Al2O3 (D 50 The three powders (80.0±20.0nm) (1.8158g) were added to a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. The mixture was then placed in a crucible and sintered at 360℃ for 6.0h in dry air or oxygen-air (5:5) atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism. The resulting ternary cathode material was then added to a batch mixing tank and mixed for 2h. The discharged material was then sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were then tested.

[0102] Comparative Example 2

[0103] The method for preparing the cathode material described in this comparative example includes the following steps:

[0104] (1) Prepare the precursor Ni according to conventional methods. 0.7 Co 0.1 Mn 0.2 (OH)2 (D50: 3.9±0.5μm), LiOH·H2O (D50: 6±2μm) and dopant θ-Al2O3 (D 50 The raw material is 5.0±2.0μm. Ni was weighed separately. 0.7 Co 0.1 Mn0.2 (OH)2 (2000g), LiOH·H2O (955.959g), θ-Al2O3 (9.079g); the materials were transferred to a high-speed mixer and mixed evenly using a three-stage mixing process: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min. The mixture was then placed in a crucible and transferred to an atmosphere muffle furnace. Under a slightly positive pressure oxygen atmosphere, the temperature was increased to 480℃ at a rate of 2℃ / min and sintered for 4.0 h, then increased to 760℃ and sintered for 3.2 h, and then increased to 940℃ and sintered for 12.4 h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0105] (2) Take 1600g of the obtained doped substrate and mix it with the coating agent ZrO2 (D 50 The three powders (80.0±20.0nm) (2.5861g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. The mixture was then placed into a crucible and sintered at 640℃ for 8.6h in an oxygen atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism, thus obtaining the positive electrode material coating matrix.

[0106] (3) Take 1500g of the obtained coating substrate and mix it with the additive θ-Al2O3 (D 50 The three powders (80.0±20.0nm) (1.8158g) were added to a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. The mixture was then placed in a crucible and sintered at 360℃ for 6.0h in dry air or oxygen-air (5:5) atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism. The resulting ternary cathode material was then added to a batch mixing tank and mixed for 2h. The discharged material was then sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were then tested.

[0107] Comparative Example 3

[0108] The method for preparing the cathode material described in this comparative example includes the following steps:

[0109] (1) Prepare the precursor Ni according to conventional methods. 0.67 Co 0.08 Mn 0.25 (OH)2 (D50: 4.0±0.5μm), Li2CO3 (D50: 6±2μm) and dopant θ-Al2O3 (D 50 The raw material is 5.0±2.0μm. Ni was weighed separately. 0.67 Co 0.08 Mn 0.25(OH)2 (2000g), Li2CO3 (845.5435g), and θ-Al2O3 (9.079g) were mixed in a high-speed mixer using a three-stage mixing process: 200 rpm / 2 min, 800 rpm / 20 min, and 100 rpm / 3 min. The mixture was then placed in a crucible and transferred to a muffle furnace. Under a slightly positive pressure oxygen atmosphere, the temperature was increased to 480℃ at a rate of 3℃ / min and sintered for 4.0 h, then increased to 770℃ and sintered for 3.2 h, and finally increased to 960℃ and sintered for 12.4 h. After cooling, the mixture was crushed and sieved to obtain the ternary cathode material doped matrix.

[0110] (2) Take 1600g of the obtained doped substrate and mix it with the coating agent ZrO2 (D 50 The three powders (80.0±20.0nm) (2.6134g) were put into a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1200rpm / 30min, and 200rpm / 3min. The mixture was then placed in a crucible and sintered at 640℃ for 8.6h in an oxygen atmosphere. After cooling, the mixture was crushed and then demagnetized by sieving to obtain the positive electrode material coating matrix.

[0111] (3) Take 1500g of the obtained coating substrate and mix it with the additive θ-Al2O3 (D 50 The three powders (80.0±20.0nm) (1.8158g) were added to a high-speed mixer and mixed evenly in three stages: 100rpm / 2min, 1000rpm / 30min, and 200rpm / 3min. The mixture was then placed in a crucible and sintered at 360℃ for 6.0h in dry air or oxygen-air (5:5) atmosphere. After cooling, the mixture was crushed and then sieved to remove magnetism. The resulting ternary cathode material was then added to a batch mixing tank and mixed for 2h. The discharged material was then sieved to remove magnetism and packaged to obtain the finished ternary cathode material. The relevant physicochemical data were then tested.

[0112] Experimental Example

[0113] 1. Physicochemical Indicators

[0114] The physicochemical properties of the ternary cathode materials prepared in Examples 1-3 and Comparative Examples 1-3 were analyzed using equipment familiar to technicians, such as scanning electron microscopes, laser particle size analyzers, and automatic titration instruments from Metrohm, Switzerland. The test results are shown in Table 1 below.

[0115] SEM images of the ternary cathode materials prepared in Examples 1-3 are attached. Figure 3 As shown in (a)-(c).

[0116] Table 1. Physicochemical properties of ternary cathode materials in Examples 1-3 and Comparative Examples 1-3

[0117]

[0118] As can be seen from the test data of the basic material physicochemical properties of Ni613, Ni712, and Ni6708 ternary cathode single crystal materials in Examples 1-3, the tap and residual alkali related performance indicators have been improved, and they have superior performance advantages.

[0119] 2. Cyclic performance test

[0120] Using methods well known to those skilled in the art, the cathode materials prepared in Examples 1-3 and Comparative Examples 1-3 will be used to prepare lithium-ion batteries (active material: PVDF:CNT:SP = 97.2:1.1:0.8:0.9, solid content 73.5%), and the obtained cathode materials will be assembled into coin cells.

[0121] Using the Blue Electric testing system, the initial charge-discharge specific capacity and discharge performance at 0.2C / 0.5C / 1.0C / 2.0C rates were measured at 25℃ and 0.1C under the voltage range of 3.0-4.40V. The results are shown in Table 2 below.

[0122] Table 2 Results of Discharge Performance Tests at Higher Rates

[0123]

[0124] The cycle retention rate after 100 cycles was tested under 1C charge / discharge conditions, and the test results are shown below. Figure 4 As shown, where, Figure 4 (a) shows the results of Example 1 and Comparative Example 1, (b) shows the results of Example 2 and Comparative Example 2, and (c) shows the results of Example 3 and Comparative Example 3.

[0125] The finished products obtained in Example 1 and Comparative Example 1 were used to prepare soft-pack battery cells, and their cycling performance was evaluated at room temperature and high temperature. The test results at different temperatures are shown in the attached figure. Figure 5-6 As shown in Table 3 below, the cyclic DCIR test data of the product in Example 1 are as follows.

[0126] Table 3. Results of Cyclic DCIR Test of Products in Example 1

[0127]

[0128] It is evident that the ternary cathode material prepared based on this doping and coating formulation and process system exhibits excellent low DCIR performance and long-cycle performance at both room temperature and high temperature. In Example 1, the high-voltage cathode material maintains 100% capacity with no significant decay after continuous 500-day cycling at room temperature under 1C / 1C-100% DOD (2.75V-4.40V); and maintains over 96.5% capacity with low DCIR growth after 500-day cycling at high temperature.

[0129] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A composite doped co-coated high-voltage cathode material, characterized in that, The positive electrode material has a general formula as shown in LiNi x Co y Mn z W a Al b Ce c Mg d Zr e F n O 2-n x+y+z+a+b+c+d+e+n=1; The preparation method of the composite doped co-coated high-voltage positive electrode material comprises the following steps: (1) according to the selected content ratio, taking the positive material precursor Ni x Co y Mn z (OH)2, lithium source material and tungsten-containing cerium dopant are mixed, and a first sintering treatment is performed to obtain a positive material doped base; (2) The positive electrode material doping matrix and the zirconium-containing coating agent are mixed according to the selected content ratio, and a second sintering treatment is performed to obtain a positive electrode material coating matrix; (3) The positive electrode material coating matrix and the aluminum-containing additive are mixed according to the selected content ratio, and a third sintering treatment is performed to obtain the required composite doped co-coated high-voltage positive electrode material; The positive electrode material precursor Ni x Co y Mn z The molar ratio of the positive electrode material precursor Ni (OH)2, the lithium source material, and the tungsten-containing cerium dopant is 1:(0.96-1.30):(0.02-0.6). The tungsten-containing cerium dopant includes Ce2O 12 a mixture of W3, MgWO4, AlF3, and θ-Al2O3 The molar ratio of the positive electrode material doping matrix to the zirconium-containing coating agent is 1: (0.02-0.3); The zirconium-containing coating agent includes Ce2O 12 a mixture of W3, MgWO4, and ZrO2 In the step (3), the aluminum-containing additive includes θ-Al2O3; The mass ratio of the positive electrode material coating matrix to the θ-Al2O3 is 100: (0.05-0.20).

2. The composite doped co-coated high-voltage cathode material of claim 1, wherein, In the step (1): The positive electrode material precursor Ni x Co y Mn z (OH)2 and the Ce2O 12 The mass ratio of W3 is 100: (0.05-0.8); The positive electrode material precursor Ni x Co y Mn z The mass ratio of (OH)2 to the MgWO4 is 100: (0.02-0.8); The positive electrode material precursor Ni x Co y Mn z The mass ratio of (OH)2 to AlF3 is 100: (0.01-0.6); The positive electrode material precursor Ni x Co y Mn z The mass ratio of (OH)2 to the θ-Al2O3 is 100: (0.01-0.5); The lithium source material includes one or a mixture of several of LiOH, LiOH·H2O, Li2CO3 or LiNO3.

3. The composite doped co-coated high-voltage cathode material of claim 2, wherein, In the step (1), the first sintering step includes the following steps: a first temperature rising step of rising to 400-500°C under an oxygen-containing atmosphere and maintaining for 2-6h, a second temperature rising step of rising to 580-740°C and maintaining for 2-5h, and a third temperature rising step of rising to 740-1000°C and maintaining for 6-18h; When the first sintering step is performed in a muffle furnace or a tube furnace mode, the temperature rising rate of the first temperature rising step, the second temperature rising step and the third temperature rising step is independently controlled to be 1-5°C / min; When the first sintering step is performed in an atmosphere roller kiln or a rotary furnace mode, the temperature rising rate of the first temperature rising step, the second temperature rising step and the third temperature rising step is independently controlled to be 1-30°C / h.

4. The composite doped co-coated high-voltage cathode material according to any one of claims 1-3, characterized in that, In the step (2): The positive electrode material doped matrix and the Ce2O 12 The mass ratio of W3 is 100:(0.05-0.25). The mass ratio of the positive electrode material doping matrix to the MgWO4 is 100: (0.08-0.3); The mass ratio of the positive electrode material doping matrix to the ZrO2 is 100: (0.02-0.20).

5. The composite-doped co-coated high-voltage cathode material according to claim 4, characterized in that, In the step (2), the second sintering step includes a calcination and maintaining step of rising to 400-780°C and maintaining for 1-20h; In the second sintering step, the temperature rising rate is controlled to be 1-20°C / h; In the step (2), when the molar content x of Ni element in the positive electrode material doping matrix is ≥0.8, before the zirconium-containing coating agent is added, the positive electrode material doping matrix is further subjected to a dispersion water washing and drying step.

6. The composite doped co-coated high-voltage cathode material of claim 1, wherein, In the step (3), the third sintering step includes a calcination and maintaining step of rising to 200-400°C and maintaining for 1-10h; In the third sintering step, the temperature rising rate is controlled to be 1-20°C / h; In the step (3), further comprising a step of crushing, sieving and demagnetizing the obtained composite doped co-coated high-voltage positive electrode material; In the step (3), the large particle base particle size D of the composite doped co-coated high-voltage positive electrode material is 9-16 μm 50 The small particle base particle size D is 2.5-6.0 μm. 50 The small particle base particle size D is 2.5-6.0 μm.

7. Use of the composite doped co-coated high-voltage positive electrode material of claim 1 for preparing a positive electrode sheet of a secondary battery or a secondary battery; the secondary battery includes a lithium ion battery.

8. A secondary battery cathode sheet or a secondary battery prepared from the composite doped co-coated high-voltage cathode material of claim 1.

Images