Lithium primary battery positive electrode material and preparation method thereof

Abstract

The invention discloses a lithium primary battery positive electrode material and a preparation method thereof.The method comprises the steps that Ni oxide, Mn oxide, Co oxide and a sodium-containing compound are evenly mixed according to the proportion of the chemical formula and then subjected to calcination treatment, and P2 type sodium-containing layered oxide is prepared; and dispersing the P2 type sodium-containing layered oxide and Li salt in a mixed solvent of water and ethanol, and carrying out hydrothermal reaction to prepare the layered positive electrode material, and charging the layered positive electrode material to obtain the positive electrode material of the lithium primary battery, and the positive electrode material of the lithium primary battery is O2 type, T2 type or O6 type. According to the lithium primary battery prepared by the method, the rate capability of the battery is improved while the discharge capacity of the battery is not lost, so that the energy density and the discharge rate of the lithium primary battery are both considered, and the weight energy density and the volume energy density of the lithium primary battery are both considered.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium primary batteries, and relates to a lithium primary battery positive electrode material and a preparation method thereof. BACKGROUND

[0002] With the development of society, lithium primary batteries have been widely applied in the fields of energy internet and intelligent internet of things due to their advantages of convenient use, stable voltage and high specific energy. At present, commercialized lithium primary batteries are various, mainly including lithium / thionyl chloride batteries, lithium / manganese dioxide batteries, lithium / sulfur dioxide batteries, lithium / carbon fluoride batteries, lithium / iron disulfide batteries and lithium / chromium-based metal oxide batteries. The positive active material of the lithium / manganese dioxide battery generally uses heat-treated electrolytic manganese dioxide. Due to the difference in heat treatment process, the existing electrolytic manganese dioxide has problems of low capacity, large discharge volume expansion and poor pulse performance after heat treatment. Although the lithium / carbon fluoride battery can be discharged at a rate of about 1 C, the carbon fluoride itself has poor conductivity and low density, which causes a large amount of heat to be generated during high-rate discharge of the battery. At the same time, this characteristic also makes the volumetric energy density of the battery at a low level. The lithium / chromium-based oxide battery is not conducive to large-area popularization and use due to the high toxicity of the chromium oxide positive material.

[0003] Therefore, in the prior art, the lithium primary battery cannot balance the energy density and the discharge rate, especially under high current density, the discharge performance is greatly reduced, and it performs poorly under the requirement of continuous discharge at a rate of more than 1 C, which limits its application scenarios under many high-rate discharge conditions. Based on the above problems existing in the existing lithium primary battery system, it is of great significance to develop a lithium primary battery positive electrode material with high specific energy and high power. SUMMARY

[0004] In view of the problems in the prior art, the application provides a lithium primary battery positive electrode material and a preparation method thereof, so as to solve the technical problem that the lithium primary battery in the prior art cannot balance the energy density and the discharge rate.

[0005] The application is achieved by the following technical solutions: A preparation method of a lithium primary battery positive electrode material, comprising the following steps: S1: according to the chemical formula Na x Co y Ni z Mn (1-y-z) O2(0.4< x <1, 0.2 ≤ y ≤ 1, 0 ≤ zThe P2 type sodium-containing layered oxide is prepared by mixing the Ni oxide, the Mn oxide, the Co oxide and the sodium-containing compound in a ratio of 1:(0.2~0.5), and then performing calcination treatment. S2: dispersing the P2 type sodium-containing layered oxide and a Li salt in a mixed solvent of water and ethanol, and performing hydrothermal reaction to prepare a layered positive electrode material; S3: charging the layered positive electrode material to obtain the lithium primary battery positive electrode material, wherein the lithium primary battery positive electrode material is of an O2 type, a T2 type or an O6 type.

[0006] Preferably, in the step S1, the ratio of the molar amount of the sodium-containing compound to the sum of the molar amounts of the Ni oxide, the Mn oxide and the Co oxide is 1:(1.00~1.50).

[0007] Preferably, in the step S1, the calcination treatment is performed at a temperature of 800~850 ºC for 8~12 h, and the temperature rising rate is 3~10 ºC / min.

[0008] Preferably, in the step S2, the molar ratio of sodium ions in the sodium-containing compound to lithium ions in the Li salt is 1:(1.2~5).

[0009] Preferably, in the step S2, in the mixed solvent of water and ethanol, the volume ratio of water to ethanol is 1:(2~5).

[0010] Preferably, in the step S2, during the hydrothermal reaction, the temperature is 200~260 ºC, and the hydrothermal reaction is performed for 12~24 h.

[0011] Preferably, when the layered positive electrode material is charged, the initial voltage of the charging is the open circuit voltage, the cutoff voltage is 4.0 V, the obtained lithium primary battery positive electrode material is of a T2 type, the cutoff voltage is 4.5 V, the obtained lithium primary battery positive electrode material is of an O6 type, and the cutoff voltage is 4.6 V, the obtained lithium primary battery positive electrode material is of an O2 type.

[0012] Preferably, when the O2 type layered positive electrode material is charged, the charging rate is 1C.

[0013] A lithium primary battery positive electrode material is prepared by the above method.

[0014] A lithium primary battery comprises the above lithium primary battery positive electrode material, and the lithium primary battery has a first circle discharge capacity of 224 mAh / g under a condition of 1 C, and a first circle discharge capacity of 207 mAh / g under a condition of 3 C.

[0015] Compared with the prior art, the present application has the following beneficial technical effects: The application discloses a preparation method of a lithium primary battery positive electrode material. The method comprises the following steps: firstly, an intermediate sodium-containing layered oxide is synthesized by a high-temperature solid-phase method, a sodium ion framework is provided for subsequent Li + / Na + ion exchange, and a diffusion channel is provided for the lithium primary battery positive electrode material. + / Na + ion exchange reaction, and a layered positive electrode material is prepared. The unique ion exchange method is helpful to form a material structure beneficial to ion transmission and electron conduction. Finally, the layered positive electrode material is charged by adjusting a charging cutoff voltage, and an O2, T2 or O6 structure lithium primary battery positive electrode material is obtained. The O2, T2 or O6 structure lithium primary battery positive electrode material has excellent ion transmission channels and electron conduction characteristics, and provides a structural basis for improving the battery performance. Meanwhile, the lithium primary battery positive electrode material prepared has a particle size range of 5-10 microns, and the crystal particles are uniformly distributed, so that the transmission path of electrons and lithium ions is shortened, the hindrance of ions and electrons in the transmission process is reduced, the electrochemical performance of the battery is improved, and the energy density and the discharge rate are simultaneously improved. The lithium primary battery prepared by the method has a first circle discharge capacity of 224 mAh / g under the condition of 1 C, and a capacity of 207 mAh / g under the condition of 3 C, which indicates that the lithium primary battery prepared by the method improves the rate performance of the battery without losing the discharge capacity of the battery, and simultaneously realizes the energy density and the discharge rate of the lithium primary battery, and simultaneously realizes the double consideration of the weight energy density and the volume energy density of the lithium primary battery.

[0016] Further, in step S1, the ratio of the molar amount of the sodium-containing compound to the sum of the molar amounts of the Ni oxide, the Mn oxide and the Co oxide is 1:(1.00-1.50), so that the sodium-containing compound and the Ni, Mn and Co oxides can fully react.

[0017] Further, in step S1, the temperature of the calcination treatment is 800-850 DEG C, the time is 8-12 h, and the heating rate is 3-10 DEG C / min, so that the high-temperature reaction can be completed.

[0018] Further, in step S2, the molar ratio of the sodium ions in the sodium-containing compound to the lithium ions in the Li salt is 1:(1.2-5), so that the lithium ions and the sodium ions can fully exchange.

[0019] Further, in step S2, in the mixed solvent of water and ethanol, the volume ratio of water to ethanol is 1:(2-5), so that the ion exchange reaction can more easily occur.

[0020] Further, in the hydrothermal reaction process, the temperature is 200-260 DEG C, and the hydrothermal reaction is performed for 12-24 hours, so that the ion exchange reaction is complete.

[0021] Further, when the layered positive electrode material is charged, the initial voltage of the charging is the open circuit voltage, when the cut-off voltage is 4.0 V, the obtained lithium primary battery positive electrode material is T2 type, so that the power density of the lithium primary battery is improved; when the cut-off voltage is 4.5 V, the obtained lithium primary battery positive electrode material is O6 type, so that the power density of the lithium primary battery is improved; when the cut-off voltage is 4.6 V, the obtained lithium primary battery positive electrode material is O2 type, so that the energy density of the lithium primary battery is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 X-ray diffraction spectrum of the ternary layered oxide prepared in Example 1 of the present application; Figure 2 First discharge curve of the lithium primary battery positive electrode material prepared in Example 1 of the present application at 1 C rate; Figure 3 X-ray diffraction spectrum of the lithium primary battery positive electrode material prepared in Example 2 of the present application; Figure 4 First discharge curve of the lithium primary battery positive electrode material prepared in Example 2 of the present application at 1 C rate; Figure 5 X-ray diffraction spectrum of the ternary layered oxide prepared in Example 3 of the present application; Figure 6 X-ray diffraction spectrum of the lithium primary battery positive electrode material prepared in Example 3 of the present application; Figure 7 First discharge curve of the lithium primary battery positive electrode material prepared in Example 3 of the present application at 1 C rate; Figure 8 Scanning electron microscope image of the lithium primary battery positive electrode material prepared in Example 4 of the present application; Figure 9 First discharge curve of the lithium primary battery positive electrode material prepared in Example 4 of the present application at 3 C rate. DETAILED DESCRIPTION

[0024] To enable persons skilled in the art to understand the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have their usual meanings to those skilled in the art of the present application, and in the event of conflict, the definitions contained herein shall prevail.

[0025] Theories or mechanisms described and disclosed herein, whether correct or not, should not be considered limiting on the scope of the present application, i.e., the present application can be practiced without regard to any particular theory or mechanism.

[0026] Herein, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, amounts, contents and concentrations, are for the sake of brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0027] Herein, unless otherwise specified, "comprise", "include", "contain", "have" or similar words encompass the meaning of "consist of" and "consist essentially of", e.g., "A comprises a" encompasses the meaning of "A comprises a and other" and "A comprises only a".

[0028] Herein, for the sake of brevity, all possible combinations of the technical features in each embodiment or example are not described. Therefore, as long as there is no contradiction in the combination of the technical features, each technical feature in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope of the present specification.

[0029] The present application provides a preparation method of a lithium primary battery positive electrode material, comprising the following steps: S1: uniformly mixing Ni oxide, Mn oxide, Co oxide and a sodium-containing compound according to the ratio of Na x Co y Ni z Mn (1-y-z) O2(0.4 x <1, 0.2 ≤ y ≤ 1, 0 ≤ z ≤ 0.2) in a muffle furnace under normal pressure and air atmosphere, and naturally cooling to room temperature to obtain P2-type sodium-containing layered oxide (Na x Co y Ni z Mn (1-y-z) O2(0.4 x <1, 0.2 ≤ y ≤ 1, 0 ≤z ≤ 0.2)); the mixing mode can be ball milling or grinding; The ratio of the molar amount of the sodium-containing compound to the sum of the molar amounts of the Ni oxide, the Mn oxide and the Co oxide is 1:(1.00-1.50).

[0030] The temperature of the calcination treatment is 800-850°C, the time is 8-12 h, and the heating rate is 3-10°C / min.

[0031] The Mn oxide is one of MnO2, Mn3O4 and Mn2O3; The Co oxide is one of CoO, Co2O3 and Co3O4; The Ni oxide is NiO; The sodium-containing compound is one of Na2CO3, NaNO3, NaCl, NaCH3COO and NaOH; S2: dispersing the P2-type sodium-containing layered oxide and a Li salt in a mixed solvent of water and ethanol, performing a hydrothermal reaction, after the reaction, using deionized water to perform suction filtration until the filtrate is neutral, removing surface residual salt, when washing, the amount of solid and deionized water is 1 g:20 mL, and drying at 100°C to collect the obtained product, which is a layered positive electrode material; The molar ratio of sodium ions in the sodium-containing compound to lithium ions in the Li salt is 1:(1.2-5).

[0032] In the mixed solvent of water and ethanol, the volume ratio of water to ethanol is 1:(2-5).

[0033] During the hydrothermal reaction, the temperature is 200-260°C, and the hydrothermal reaction is performed for 12-24 h.

[0034] The water in the mixed solvent is preferably deionized water.

[0035] The amount ratio of the Li salt to the mixed solvent is 1 g:(10-30) mL.

[0036] The Li salt is at least one of LiNO3, LiOH, Li2CO3, LiCH3COO and LiCl; The amount of the Li salt is Li x Co y Ni z Mn (1-y-z) 1.1-2.5 times the stoichiometric ratio of O2; S3: charging the layered positive electrode material to obtain the lithium primary battery positive electrode material, the lithium primary battery positive electrode material is of O2 type, T2 type or O6 type.

[0037] The charging process includes preparation of the positive electrode sheet, assembly of the lithium primary battery and the charging process, in particular: The preparation of the positive electrode sheet is specifically: A certain amount of the prepared layered positive electrode material, acetylene black and the binder polyvinylidene fluoride (PVDF) are weighed, wherein the mass ratio of the layered positive electrode material, acetylene black and polyvinylidene fluoride is 8:1:1, then N-methyl pyrrolidone (NMP) is added, and the mixture is ground into a uniform slurry, the mass of NMP is 30 times the mass of PVDF, the slurry is uniformly coated on an aluminum foil, and vacuum dried at 80 °C for 12 h, then cut with a mold to prepare the positive electrode sheet, preferably the positive electrode sheet is a circular positive electrode sheet with a diameter of 12 mm.

[0038] The assembly of the lithium primary battery is specifically: The lithium primary battery adopts a negative electrode, the current collector is a copper foil, Celgard 2400 commercial polypropylene film is used as the separator, and the electrolyte is a 1 M LiPF6 ethylene carbonate / diethyl carbonate solution, i.e. an EC / DEC solution, the volume ratio of EC to DEC is 1:1, and the assembly of the battery is carried out in an argon-filled glove box.

[0039] The charging process is specifically: The charging rate is 1C, the initial voltage of charging is the open circuit voltage, when the cutoff voltage is 4.0 V, the obtained lithium primary battery positive electrode material is T2 type; when the cutoff voltage is 4.5 V, the obtained lithium primary battery positive electrode material is O6 type; and when the cutoff voltage is 4.6 V, the obtained lithium primary battery positive electrode material is O2 type.

[0040] The application also discloses a lithium primary battery positive electrode material prepared by the above method, and the chemical general formula of the lithium primary battery positive electrode material is: x Co y Ni z Mn (1-y-z) O2, wherein 0.4 x <1, 0.5 ≤ y ≤ 1, 0 ≤ z ≤ 0.2. The lithium primary battery positive electrode material is O2 type, T2 or O6 type, is composed of micron-sized single crystal particles, the grain size distribution is between 5-10 μm, and the particle size is controllable. The first circle discharge specific capacity of the lithium primary battery positive electrode material is as high as 224 mAh / g, and the lithium primary battery positive electrode material has the advantages of high energy density and high power density.

[0041] wherein T2, O2 and O6 refer to different stacking sequences of oxygen atoms and transition metal atom layers in the prepared layered cathode material. "T" and "O" represent the coordination environment of lithium ions between the layers, and "2" and "6" represent the repeat period of the stacking sequence in the crystal. c The number of oxygen atom layers contained in one complete structural repeat unit in the axial direction reflects the repeat period of the stacking sequence. Herein, "T" represents tetrahedral coordination, i.e. the lithium ions are located in tetrahedral voids formed by oxygen atoms, and "O" represents octahedral coordination, i.e. the position of lithium ions in the commonly known layered oxides.

[0042] Specifically, the stacking sequence of the T2 type structure is AB AB AB..., i.e. the stacking sequence repeats once every 2 layers of oxygen atoms, and the lithium ions are located in the tetrahedral voids formed between adjacent two oxygen layers.

[0043] The stacking sequence of the O2 type structure is AB AB AB..., i.e. the stacking sequence repeats once every 2 layers of oxygen atoms, and the lithium ions are located in the octahedral voids formed between adjacent two oxygen layers.

[0044] The stacking sequence of the O6 type structure is ABC ACB ABC ACB..., i.e. the stacking sequence repeats once every 6 layers of oxygen atoms, and the lithium ions are located in the octahedral voids.

[0045] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not used to limit the scope of the present application. Furthermore, it should be understood that after reading the content taught by the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0046] The following examples use the instruments and equipment that are conventional in the art. The experimental methods in the following examples, for which no specific conditions are indicated, are generally carried out under conventional conditions, or under the conditions recommended by the manufacturers. The following examples use various raw materials, unless otherwise specified, all of which are conventional commercially available products, and the specifications thereof are conventional in the art. In the specification of the present application and in the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.

[0047] Example 1 A preparation method of a lithium primary battery cathode material, the chemical formula of the cathode material is Li 0.9 Co 0.8 Ni 0.1 Mn 0.1 O2.

[0048] Step 1. Weighing: According to the chemical formula Na 0.9 Co 0.8 Ni 0.1 Mn 0.1 O2, the ratio of the mixture of Ni, Mn, Co oxides, sodium-containing compounds, etc. is weighed and mixed uniformly.

[0049] Step 2. Calcination: The mixed sample in step 1 is placed in a muffle furnace and calcined at 800 °C under normal pressure and air atmosphere for 12 h, with a heating rate of 5 °C / min, and naturally cooled to room temperature to obtain P2-type sodium-containing layered oxide Na 0.9 Co 0.8 Ni 0.1 Mn 0.1 O2.

[0050] Step 3. Ion exchange: According to the molar ratio of Na + and Li + is 1:1.2, a specific amount of Li salt is weighed, and the Li salt and P2-type sodium-containing layered oxide prepared in step 2 are dispersed in a deionized water-ethanol mixed solvent in a sealed reaction kettle. The ratio of Li salt to deionized water-ethanol is 1:10 g / ml. The reaction temperature is controlled at 240 °C, and the reaction time is 12 h. After the hydrothermal reaction is completed, the surface residual salt is removed by suction filtration and washing, and the obtained product ternary layered oxide is dried and collected. The XRD of the ternary layered oxide obtained here is tested, and the test results are shown in Figure 1 The characteristic diffraction peak of the ternary layered oxide is 1.33 Å -1 , corresponding to the O2-type layered structure, and the crystallinity of the crystal is good.

[0051] Step 4. Preparation of positive electrode sheet and assembly of lithium primary battery: A certain amount of prepared ternary layered oxide, acetylene black, and binder PVDF are weighed, with a mass ratio of 8:1:1, and NMP is added. The mixture is ground into a uniform slurry, and the mass of NMP is 30 times the mass of PVDF. The slurry is uniformly coated on an aluminum foil. Vacuum drying is performed at 80 °C for 12 h, and then the positive electrode sheet with a diameter of 12 mm is cut by a mold. A negative electrode is not used, the current collector is a copper foil, Celgard 2400 commercial polypropylene membrane is used as a separator, and the electrolyte is a 1 M LiPF6 EC / DEC (volume ratio 1:1) solution. The battery is assembled in an argon-filled glove box.

[0052] Step 5. Charging treatment The assembled lithium primary battery is charged to 4.6 V at 1 C to obtain a lithium primary battery positive electrode material. The lithium primary battery positive electrode material is in the O2 configuration.

[0053] Performance test: After charging, the discharge test was carried out, and the results are shown in Figure 2 The figure shows that the first circle discharge specific capacity of the lithium primary battery positive electrode material is 224 mAh / g.

[0054] Example 2 A preparation method of a lithium primary battery positive electrode material, the chemical formula of the positive electrode material is Li 2 / 3Co 0.8 Ni 0.1 Mn 0.1 O2.

[0055] Step 1. Weighing: According to the chemical formula Na 2 / 3 Co 0.8 Ni 0.1 Mn 0.1 O2, the Ni, Mn, Co-containing oxides, sodium-containing compounds, etc. were weighed according to the ratio, and they were mixed uniformly.

[0056] Step 2. Calcination: The mixed sample in step 1 was placed in a muffle furnace, calcined at 800 °C for 12 h under normal pressure and air atmosphere, the heating rate was 5 °C / min, and naturally cooled to room temperature, to obtain P2 type sodium-containing layered oxide Na 2 / 3 Co 0.8 Ni 0.1 Mn 0.1 O2.

[0057] Step 3. Ion exchange: According to the molar ratio of Na + and Li + is 1:1.2, a specific content of Li salt was weighed, the Li salt and the P2 type sodium-containing layered oxide prepared in step 2 were dispersed in deionized water-ethanol mixed solvent, and placed in a sealed reaction kettle, the ratio of Li salt to deionized water-ethanol is 1:10 g / ml. The reaction temperature was controlled at 240 °C, and the reaction time was 12 h. After the hydrothermal reaction was completed, the surface residual salt was removed by suction filtration and washing, and the obtained product was dried to collect the ternary layered oxide.

[0058] Step 4. Preparation of positive electrode sheet and assembly of lithium primary battery: A certain amount of prepared ternary layered oxide, acetylene black and binder PVDF were weighed, with a mass ratio of 8:1:1, NMP was added, and the mixture was ground into a uniform slurry. The mass of NMP was 30 times the mass of PVDF. The slurry was uniformly coated on an aluminum foil. The coated aluminum foil was vacuum dried at 80 °C for 12 h, and then cut into positive electrode sheets with a diameter of 12 mm using a mold. The batteries were assembled in an argon-filled glove box using no negative electrode, copper foil as the current collector, Celgard 2400 commercial polypropylene membrane as the separator, and 1 M LiPF6 solution in EC / DEC (volume ratio 1:1) as the electrolyte.

[0059] The assembled lithium primary battery was charged to 4.0 V at 1 C to obtain a lithium primary battery positive electrode material.

[0060] The lithium primary battery positive electrode material prepared in this example was subjected to XRD test, and the results are shown in FIG. 1. Figure 3 As can be seen from the figure, the characteristic diffraction peak of the lithium primary battery positive electrode material is 1.24 Å -1 Therefore, the lithium primary battery positive electrode material prepared in this example has a T2 type layered structure, and the crystallinity of the crystal is good.

[0061] Performance test: After charging, the discharge test was performed, and the results are shown in FIG. 2. Figure 4 As can be seen from the figure, the first circle discharge specific capacity of the lithium primary battery positive electrode material is 105 mAh / g.

[0062] Example 3 A method for preparing a lithium primary battery positive electrode material, the chemical formula of the positive electrode material is Li 2 / 3Co 0.8 Ni 0.1 Mn 0.1 O2.

[0063] Step 1. Weighing: According to the ratio of the chemical formula Na 2 / 3 Co 0.8 Ni 0.1 Mn 0.1 O2, Ni-, Mn- and Co-containing oxides, sodium-containing compounds, etc. were weighed and mixed uniformly.

[0064] Step 2. Calcination: The mixed sample in step 1 was placed in a muffle furnace and calcined at 800 °C for 12 h under normal pressure and air atmosphere, with a heating rate of 5 °C / min, and naturally cooled to room temperature to obtain P2 type sodium-containing layered oxide Na 2 / 3 Co 0.8 Ni 0.1 Mn 0.1 O2.

[0065] Step 3. Ion exchange: According to the molar ratio of Na + and Li + 1:1.2, a certain amount of Li salt was weighed, and the Li salt and the P2-type sodium-containing layered oxide prepared in step 2 were dispersed in a deionized water-ethanol mixed solvent, and placed in a sealed reaction kettle. The ratio of Li salt to deionized water-ethanol was 1:10 g / ml. The reaction temperature was controlled at 240 °C, and the reaction time was 12 h. After the hydrothermal reaction was completed, the surface residual salt was removed by suction filtration and washing, and the obtained product was dried to obtain the ternary layered oxide. The ternary layered oxide prepared in this step was subjected to XRD test, and the results are shown in Figure 5 As can be seen from the figure, the characteristic diffraction peak of the ternary layered oxide is 18.64º, and the ternary layered oxide prepared in this step has an O2-type layered structure, and the crystallinity of the crystal is good.

[0066] Step 4. Preparation of positive electrode sheet and assembly of lithium primary battery: A certain amount of the prepared ternary layered oxide, acetylene black and binder PVDF were weighed, and the mass ratio was 8:1:1. NMP was added, and the mixture was ground into a uniform slurry. The mass of NMP was 30 times the mass of PVDF. The slurry was uniformly coated on an aluminum foil. Vacuum drying was performed at 80 °C for 12 h, and then the positive electrode sheet with a diameter of 12 mm was cut by a mold. A negative electrode was not used, the current collector was a copper foil, Celgard 2400 commercial polypropylene membrane was used as a separator, and the electrolyte was a 1 M LiPF6 EC / DEC (volume ratio 1:1) solution. The battery was assembled in an argon-filled glove box.

[0067] The assembled lithium primary battery was charged to 4.5 V at 1 C to prepare a lithium primary battery positive electrode material.

[0068] The lithium primary battery positive electrode material prepared in this example was subjected to XRD test, and the results are shown in Figure 6 As can be seen from the figure, the characteristic diffraction peak of the lithium primary battery positive electrode material is 1.29 Å -1 Therefore, the lithium primary battery positive electrode material prepared in this example has an O6-type layered structure, and the crystallinity of the crystal is good.

[0069] Performance test: After charging, the discharge test was performed, and the results are shown in Figure 7 As can be seen from the figure, the first circle discharge specific capacity of the lithium primary battery positive electrode material is 180 mAh / g.

[0070] Example 4 A preparation method of a lithium primary battery positive electrode material, the chemical formula of the positive electrode material is Li 0.9 CoO2.

[0071] Step 1. Weighing: According to the chemical formula Na 0.9 CoO2, the Co-containing oxide, lithium salt, sodium-containing compound, etc. were weighed and mixed uniformly.

[0072] Step 2. Calcination: The mixed sample in step 1 was placed in a muffle furnace and calcined at 800 ºC for 12 h under normal pressure and air atmosphere, with a heating rate of 5 ºC / min, and then naturally cooled to room temperature to obtain P2-type sodium-containing layered oxide Na 0.9 CoO2.

[0073] Step 3. Ion exchange: According to the molar ratio of Na + and Li + 1:1.2, a specific amount of Li salt (LiOH and LiCl) was weighed, and the Li salt and P2-type sodium-containing layered oxide prepared in step 2 were dispersed in a deionized water-ethanol mixed solvent in a sealed reaction kettle. The ratio of Li salt to deionized water-ethanol was 1:10 g / ml. The reaction temperature was controlled at 240 ºC, and the reaction time was 12 h. After the hydrothermal reaction was completed, the surface residual salt was removed by suction filtration and washing to obtain a layered oxide, which was O2-type.

[0074] Step 4. Preparation of positive electrode sheet and assembly of lithium primary battery: A certain amount of prepared layered oxide, acetylene black, and binder PVDF were weighed with a mass ratio of 8:1:1, added to NMP, and ground into a uniform slurry. The mass of NMP was 30 times the mass of PVDF. The slurry was uniformly coated on an aluminum foil. Vacuum drying was performed at 80 ºC for 12 h, and then the positive electrode sheet with a diameter of 12 mm was cut by a mold. A negative electrode-free lithium primary battery was assembled in an argon-filled glove box using copper foil as the current collector, Celgard 2400 commercial polypropylene membrane as the separator, and 1 M LiPF6 EC / DEC (volume ratio 1:1) solution as the electrolyte. The assembled lithium primary battery was charged to 4.6 V at 3 C to prepare a lithium primary battery positive electrode material.

[0075] The SEM results of the lithium primary battery positive electrode material are shown in Figure 8 The figure shows that the particle size of the sheet-like particles is 5-10 μm.

[0076] Performance test: After charging, the discharge test was performed, and the results are shown in Figure 9 The figure shows that the first cycle discharge specific capacity of the lithium primary battery positive electrode material is 207 mAh / g.

[0077] Example 5 A preparation method of a lithium primary battery positive electrode material, comprising the following steps: S1: mixing Na x Co y Ni z Mn (1-y-z) O2(0.4 x <1, 0.2 ≤ y ≤ 1, 0 ≤ z ≤ 0.2) in a ratio of 1:1:1:1, and then uniformly mixing NiO, MnO2, CoO and Na2CO3, and then placing the mixture in a muffle furnace, and then heating to 800 °C at a heating rate of 3 °C / min in an air atmosphere, and then performing calcination treatment for 12 h, and then naturally cooling to room temperature, to obtain a P2 type sodium-containing layered oxide (Na x Co y Ni z Mn (1-y-z) O2(0.4 x <1, 0.2 ≤ y ≤ 1, 0 ≤ z ≤ 0.2) in a ratio of 1:1:1:1, and then uniformly mixing NiO, MnO2, CoO and Na2CO3, and then placing the mixture in a muffle furnace, and then heating to 800 °C at a heating rate of 3 °C / min in an air atmosphere, and then performing calcination treatment for 12 h, and then naturally cooling to room temperature, to obtain a P2 type sodium-containing layered oxide (Na

[0078] S2: dispersing the P2 type sodium-containing layered oxide and a Li salt in a mixed solvent of water and ethanol in a volume ratio of 1:2, and then performing hydrothermal reaction at 200 °C for 24 h, and then, after the reaction is completed, using deionized water to perform suction filtration until the filtrate is neutral, and then removing surface residual salt, and then, when washing, using 1 g of the solid and 20 mL of deionized water, and then drying the obtained product at 100 °C to collect the product, to obtain a layered positive electrode material. The molar ratio of sodium ions in the sodium-containing compound to lithium ions in the Li salt is 1:1.2. The amount ratio of the Li salt to the mixed solvent is 1 g:10 mL. The Li salt is LiNO3.

[0079] S3: charging the layered positive electrode material, and, when charging, the charging rate is 1C, the initial voltage of charging is the open circuit voltage, and the cutoff voltage is 4.0 V, to obtain a T2 type lithium primary battery positive electrode material.

[0080] Example 6 A preparation method of a lithium primary battery positive electrode material, comprising the following steps: S1: mixing Na x Co y Ni z Mn (1-y-z) O2(0.4 x <1, 0.2 ≤y ≤ 1, 0 ≤ z ≤ 0.2) in a ratio of 1:1.5, and then the Ni oxide, the Mn oxide, the Co oxide, and the sodium-containing compound are mixed uniformly, and then the mixture is placed in a muffle furnace, calcination treatment is performed in an air atmosphere at normal pressure, and then the mixture is naturally cooled to room temperature, thereby obtaining a P2-type sodium-containing layered oxide (Na x Co y Ni z Mn (1-y-z) O2(0.4 x <1, 0.2 ≤ y ≤ 1, 0 ≤ z ≤ 0.2) in a ratio of 1:1.5, and then the Ni oxide, the Mn oxide, the Co oxide, and the sodium-containing compound are mixed uniformly, and then the mixture is placed in a muffle furnace, calcination treatment is performed in an air atmosphere at normal pressure, and then the mixture is naturally cooled to room temperature, thereby obtaining a P2-type sodium-containing layered oxide (Na The ratio of the molar amount of the sodium-containing compound to the sum of the molar amounts of the Ni oxide, the Mn oxide, and the Co oxide is 1:1.5. The temperature of the calcination treatment is 850 °C, the time of the calcination treatment is 8 h, and the temperature increase rate is 10 °C / min. The Mn oxide is Mn3O4, the Co oxide is Co2O3, the Ni oxide is NiO, and the sodium-containing compound is NaNO3. S2: The P2-type sodium-containing layered oxide is dispersed with a Li salt in a mixed solvent of water and ethanol in a volume ratio of 1:5, and then hydrothermal reaction is performed at 260 °C for 12 h. After the reaction is completed, deionized water is used to perform suction filtration until the filtrate is neutral, and then surface residual salt is removed. When washing, the amount of the solid and the deionized water is 1 g:20 mL, and then the obtained product is collected after drying at 100 °C, thereby obtaining a layered positive electrode material. The molar ratio of sodium ions in the sodium-containing compound to lithium ions in the Li salt is 1:5. The amount ratio of the Li salt to the mixed solvent is 1 g:30 mL. The Li salt is LiOH. S3: The layered positive electrode material is charged, and when charging, the charging rate is 1C, the initial voltage of the charging is the open circuit voltage, and the cutoff voltage is 4.5 V, thereby obtaining an O6-type lithium primary battery positive electrode material.

[0081] Example 7 A method for preparing a lithium primary battery positive electrode material includes the following steps: S1: A sodium-containing layered oxide (Na x Co y Ni z Mn (1-y-z) O2(0.4 x <1, 0.2 ≤ y ≤ 1, 0 ≤ zIn a mixture with a ratio of ≤ 0.2%, Ni oxide, Mn oxide, Co oxide, and a sodium-containing compound were thoroughly mixed and placed in a muffle furnace for calcination under normal pressure and air atmosphere. The mixture was then naturally cooled to room temperature to obtain P2-type sodium-containing layered oxide (Na). x Co y Ni z Mn (1-y-z) O2(0.4< x <1, 0.2 ≤ y ≤ 1, 0 ≤ z ≤ 0.2); The mixing method here can be ball milling or grinding; The molar ratio of the sodium-containing compound to the sum of the molar amounts of Ni oxide, Mn oxide, and Co oxide is 1:1.2. The calcination treatment is performed at a temperature of 830 ºC for 10 h at a heating rate of 7 ºC / min. The Mn oxide is Mn₂O₃; the Co oxide is Co₃O₄; the Ni oxide is NiO; and the sodium-containing compound is NaCl. S2: The P2 type sodium-containing layered oxide and Li salt are dispersed in a mixed solvent of water and ethanol with a volume ratio of 1:(2~5), and hydrothermal reaction is carried out at 230 ºC for 20 h. After the reaction is completed, deionized water is used to filter the filtrate until it is neutral to remove residual dissolved salts on the surface. During washing, the amount of solid to deionized water is 1 g:20 mL. The product is dried at 100 ºC and collected, which is the layered cathode material. In this embodiment, the molar ratio of sodium ions in the sodium-containing compound to lithium ions in the Li salt is 1:2.5. The volume ratio of Li salt to the mixed solvent is 1 g:20 mL. The Li salt is Li₂CO₃. S3: Charge the layered cathode material at a charging rate of 1C, with the starting voltage being the open-circuit voltage and the cutoff voltage being 4.6V, to obtain an O2-type lithium primary battery cathode material.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a lithium primary battery cathode material, characterized by, The method comprises the following steps: S1: a mixture of Na x Co y Ni z Mn (1-y-z) O2 (0.4 < x < 0.6, 0 < y < 0.2, 0 < z < 0.2) x < 1, 0.2 ≤ x < 0.4 y ≤ 1, 0 ≤ y < 0.2 z ≤ 0.2) is calcined to obtain a P2-type sodium-containing layered oxide; S2: dispersing the P2 type sodium-containing layered oxide and a Li salt in a mixed solvent of water and ethanol, and performing a hydrothermal reaction to obtain a layered positive electrode material; S3: charging the layered positive electrode material to obtain the lithium primary battery positive electrode material, wherein the lithium primary battery positive electrode material is of an O2 type, a T2 type or an O6 type.

2. The method for preparing a lithium primary battery cathode material according to claim 1, characterized in that, In step S1, the ratio of the molar amount of the sodium-containing compound to the sum of the molar amounts of the Ni oxide, the Mn oxide and the Co oxide is 1:(1.00-1.50).

3. The method according to claim 1, wherein the method is characterized by, In step S1, the temperature of the calcination treatment is 800-850 °C, the time is 8-12 h, and the temperature rising rate is 3-10 °C / min.

4. The method for preparing a lithium primary battery cathode material according to claim 1, characterized in that, In step S2, the molar ratio of sodium ions in the sodium-containing compound to lithium ions in the Li salt is 1:(1.2-5).

5. The method for preparing a lithium primary battery cathode material according to claim 1, characterized in that, In step S2, in the mixed solvent of water and ethanol, the volume ratio of water to ethanol is 1:(2-5).

6. A method for preparing a lithium primary battery cathode material according to claim 1, characterized in that, In step S2, during the hydrothermal reaction, the temperature is 200-260 °C, and the hydrothermal reaction is performed for 12-24 h.

7. The method according to claim 1, wherein the method is characterized by, When the layered positive electrode material is charged, the initial voltage of the charging is the open circuit voltage, the cutoff voltage is 4.0 V, the obtained lithium primary battery positive electrode material is of a T2 type, the cutoff voltage is 4.5 V, the obtained lithium primary battery positive electrode material is of an O6 type, and the cutoff voltage is 4.6 V, the obtained lithium primary battery positive electrode material is of an O2 type.

8. The method for preparing a lithium primary battery cathode material according to claim 1, characterized in that, When the O2 type layered positive electrode material is charged, the charging rate is 1C.

9. A lithium primary battery cathode material, characterized by, The lithium primary battery positive electrode material is prepared by the method.

10. A lithium primary battery characterized by comprising: The lithium primary battery comprises the lithium primary battery positive electrode material, and has a first circle discharge capacity of 224 mAh / g under a condition of 1 C and a first circle discharge capacity of 207 mAh / g under a condition of 3 C.

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