A primary battery positive electrode material and a preparation method thereof

Abstract

The application discloses a primary battery positive electrode material and a preparation method thereof. α Cu β Mn γ O2 material; wherein, 0<=alpha<=0.15; 0<=beta<=0.4; when beta>0, 1<=beta+gamma<=1.2; when beta=0, gamma=1, and the volume expansion in the sodium ion embedding process during the battery discharging process can be reduced.

Description

Technical Field

[0001] This invention relates to the field of battery material preparation technology, specifically to a primary battery cathode material and its preparation method. Background Technology

[0002] Primary batteries are mainly used in various smart meters, intelligent transportation, intelligent security, medical devices, and other fields, with a wide range of market applications. Meanwhile, with the advent of the 5G era, the market demand for various smart meters, intelligent transportation, and intelligent security has increased significantly, indirectly driving the market demand for high-energy lithium primary batteries. The development prospects of China's high-energy lithium primary battery market are optimistic. According to data, the market size of China's lithium primary battery industry was approximately 6.26 billion yuan in 2022. In 2023, the market size of primary batteries reached 3.153 billion US dollars, with a compound annual growth rate of 4.3%. Therefore, how to independently develop environmentally friendly and highly sensitive sensing materials has become an urgent problem to be solved. The market is mainly composed of lithium manganese batteries, lithium thionyl chloride batteries, and lithium fluoride batteries. As people in the 21st century increasingly value environmental protection and system safety and reliability, further in-depth research on battery systems that are inexpensive, have high voltage, high energy density, wide operating temperature range, good high-rate discharge performance, long storage time, and are safe and environmentally friendly will become the focus of primary battery research.

[0003] Patent CN114497504B provides a manganese dioxide with small volume expansion, which can effectively reduce the expansion of the positive electrode during battery discharge. The positive electrode active material obtained by processing is used in lithium primary batteries, but it uses metal oxides such as titanium / vanadium, which is costly.

[0004] Patent CN115395035B discloses a water-activated magnesium primary battery and its positive electrode slurry preparation process. By utilizing the dispersibility of graphene in organic solvents in the positive electrode slurry formulation, a conductive and heat-dissipating network is constructed within the positive electrode material, effectively improving heat generation during battery use and mitigating the volume expansion problem of water-activated magnesium primary batteries. However, because magnesium in the negative electrode is highly reactive and reacts rapidly in strong electrolyte solutions, while the positive electrode reaction rate is low, it often results in low electrode utilization. Water-activated magnesium primary batteries release a large amount of heat during constant current discharge, leading to significant volume changes after discharge, even excessive expansion. Moreover, as the positive electrode reaction rate increases, the heat release and volume problems become more severe.

[0005] Patent CN103117384B describes a method that significantly improves the electrochemical performance of λ-MnO2 lithium-ion cathode materials by creating lattice defects through anion doping, thereby increasing carrier concentration. This preparation method is simple, requires no complex equipment, is clean and pollution-free, and has low cost, making it suitable for industrial-scale production. However, the material itself is a semiconductor with weak electronic and ionic conductivity, resulting in poor discharge performance and low actual specific capacity. This is especially true at higher current discharge rates, where the high-potential discharge specific capacity decreases significantly, greatly limiting its application as a Li / MnO2 lithium primary battery. Summary of the Invention

[0006] The purpose of this invention is to provide a positive electrode material for primary batteries and its preparation method. The method employs a simple and easy solid-state method, which involves pre-treating the raw materials by stirring, ultrasonication, heating, shearing, and dispersion to make the raw materials more uniformly mixed. The raw materials are then pressed into discs and calcined in an air atmosphere to embed the metal oxide into the manganese dioxide lattice at high temperature, thereby stabilizing the crystal structure and reducing the volume expansion during sodium ion insertion in the battery discharge process.

[0007] According to the present invention, a primary battery positive electrode material is provided, wherein the battery positive electrode material comprises Nb α Cu β Mn γ Materials containing O2; where 0 ≤ α ≤ 0.15; 0 ≤ β ≤ 0.4;

[0008] When β>0, 1≤β+γ≤1.2; when β=0, γ=1.

[0009] This invention also provides a method for preparing a primary battery cathode material, comprising the following steps:

[0010] S1: Manganese dioxide and metal oxide are mixed and ultrasonically treated to obtain a mixed powder;

[0011] S2: The mixed powder after stirring and ultrasonication is heated, sheared and dispersed to obtain a uniform mixed powder;

[0012] S3: Press the uniformly mixed powder into small round tablets with a diameter of 0.5-5 cm and a thickness of 0.5-5 cm using a tablet press;

[0013] S4: Place the small discs in a crucible, calcine them, cool them to room temperature, remove them, grind them into powder, and pass them through a 250-mesh sieve to obtain a high-specific-capacity modified manganese oxide cathode material.

[0014] Furthermore, in step S1, the ultrasonic stirring treatment has an ultrasonic power of 10-15KHz, a stirring speed of 0.5-5Kr / min, and a duration of 0.5-2 hours.

[0015] Furthermore, the metal oxide mixture includes copper oxide and / or niobium pentoxide.

[0016] Furthermore, the heating, shearing, and dispersion in step S2 are carried out in air at 120–200°C, with a shearing linear velocity of 10–40 m / s, for a time of 0.5–2 hours.

[0017] Furthermore, in step S4, "the small disc is placed in a crucible and calcined," the calcination is carried out in an air or oxygen atmosphere at a temperature of 500–900°C for 6–12 hours.

[0018] Furthermore, in step S4, calcination is carried out in a muffle furnace or a tube furnace.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. A simple and easy-to-implement solid-state method is adopted to pre-treat the raw materials by stirring, ultrasonication, heating, shearing and dispersion, so that the raw materials are mixed more evenly. Then, the raw materials are pressed into discs and then calcined in an air atmosphere to embed the metal oxide into the manganese dioxide lattice at high temperature, stabilize the crystal structure, and reduce the volume expansion of sodium ion insertion during battery discharge. Attached Figure Description

[0021] Figure 1 The specific capacity test diagram for niobium manganese oxide discharge (cutoff voltage 1.5V).

[0022] Figure 2 This is a comparison diagram of the impedance of niobium manganese oxide before and after discharge.

[0023] Figure 3 The specific capacity test diagram for niobium manganese oxide discharge (cutoff voltage 1.0V).

[0024] Figure 4 The specific capacitance test diagram for copper manganese oxide discharge (cutoff voltage 1.5V).

[0025] Figure 5 The specific capacitance test diagram for niobium copper manganese oxide discharge (cutoff voltage 1.5V). Detailed Implementation

[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0027] This invention provides a primary battery cathode material, the cathode material comprising Nb α Cu β Mn γ Materials containing O2; where 0 ≤ α ≤ 0.15; 0 ≤ β ≤ 0.4;

[0028] When β>0, 1≤β+γ≤1.2; when β=0, γ=1.

[0029] This invention also provides a method for preparing a primary battery cathode material, comprising the following steps:

[0030] S1: Manganese dioxide and metal oxide are mixed and ultrasonically treated to obtain a mixed powder;

[0031] S2: The mixed powder after stirring and ultrasonication is heated, sheared and dispersed to obtain a uniform mixed powder;

[0032] S3: Press the uniformly mixed powder into small round tablets with a diameter of 0.5-5 cm and a thickness of 0.5-5 cm using a tablet press;

[0033] S4: Place the small discs in a crucible, calcine them, cool them to room temperature, remove them, grind them into powder, and pass them through a 250-mesh sieve to obtain a high-specific-capacity modified manganese oxide cathode material.

[0034] The ultrasonic stirring treatment in step S1 has an ultrasonic power of 10-15KHz, a stirring speed of 0.5-5Kr / min, and a duration of 0.5-2 hours.

[0035] The metal oxide mixture includes copper oxide and / or niobium pentoxide.

[0036] The purpose of step S1 is to mix manganese dioxide and metal oxide evenly to form a precursor of modified manganese oxide.

[0037] The heating, shearing, and dispersion in step S2 are carried out in air at 120–200°C, with a shearing linear velocity of 10–40 m / s and a duration of 0.5–2 hours.

[0038] Step S2 further ensures the uniform mixing of raw materials and prepares them for subsequent processes.

[0039] Step S3, tableting, makes the particles more closely connected, increasing the reaction area.

[0040] In step S4, "place the small discs in the crucible and calcine them." Calcination is carried out in an air or oxygen atmosphere at a temperature of 500–900°C for 6–12 hours.

[0041] In step S4, calcination is carried out in a muffle furnace or a tube furnace.

[0042] Metal oxides are embedded in the manganese dioxide lattice at high temperatures, stabilizing the crystal structure and reducing the volume expansion of sodium ions during battery discharge.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] 1. A simple and easy-to-implement solid-state method is adopted to pre-treat the raw materials by stirring, ultrasonication, heating, shearing and dispersion, so that the raw materials are mixed more evenly. Then, the raw materials are pressed into discs and then calcined in an air atmosphere to embed the metal oxide into the manganese dioxide lattice at high temperature, stabilize the crystal structure, and reduce the volume expansion of sodium ion insertion during battery discharge.

[0045] Example 1

[0046] S1: Mix 1585g of manganese dioxide (CAS No.: 1313-13-9, Kermei 85%) with 206g of Nb2O5 niobium pentoxide (CAS No.: 1313-96-8, Shanghai high purity 99.5%) and stir and ultrasonically treat to form a mixed powder. The ultrasonic power is 10-15KHz, the stirring speed is 3Kr / min, and the time is 0.5 hours.

[0047] S2: The mixed powder after stirring and ultrasonication is heated and sheared to disperse it. It is heated and sheared in air at 140°C to obtain a uniform mixed powder with a shearing linear velocity of 14m / s for 1 hour.

[0048] S3: The uniformly mixed powder obtained in step S2 is pressed into small round tablets with a diameter of 2.5 cm and a thickness of 2 cm using a tablet press, with a pressure of 10 KN;

[0049] S4: Place the small discs obtained in step S3 into a crucible and calcine them in a muffle furnace at 700℃ for 9 hours. After cooling to room temperature, remove them, grind them into powder, and pass them through a 250-mesh sieve to obtain the high-specific-capacity modified manganese oxide cathode material MnNb. 0.1 O2.

[0050] Example 2

[0051] S1: Mix 1585g of manganese dioxide (CAS: 1313-13-9, Kermei 85%) with 103g of Nb2O5 (CAS: 1313-96-8, Shanghai high purity 99.5%) and stir and ultrasonically treat to form a mixed powder. The ultrasonic power is 10-15KHz, the stirring speed is 3Kr / min, and the time is 0.5 hours.

[0052] S2: The mixed powder after stirring and ultrasonication is heated and sheared to disperse it. It is heated and sheared in air at 140℃ to obtain a uniform mixed powder with a shearing linear velocity of 14m / s for 1 hour.

[0053] S3: The uniformly mixed powder obtained in step S2 is pressed into small round tablets with a diameter of 2.5 cm and a thickness of 2 cm using a tablet press, with a pressure of 10 KN;

[0054] S4: Place the small discs obtained in step S3 into a crucible and calcine them at 700℃ for 9 hours in a tube furnace. After cooling to room temperature, remove them, grind them into powder, and pass them through a 250-mesh sieve to obtain the high-specific-capacity modified manganese oxide cathode material MnNb. 0.05 O2.

[0055] Example 3

[0056] S1: 865g of manganese dioxide (CAS: 1313-13-9 McLean, β phase ≥ 99%) and 297g of CuO (CAS: 1313-96-8, Shanghai Titan Technology high purity 99.5%) were mixed and ultrasonically treated to form a mixed powder. The ultrasonic power was 10-15KHz, the stirring speed was 3Kr / min, and the time was 0.5 hours.

[0057] S2: The mixed powder after stirring and ultrasonication is heated and sheared to disperse it. It is heated and sheared in air at 100°C to obtain a uniform mixed powder with a shearing linear velocity of 8m / s and a time of 0.5 hours.

[0058] S3: The uniformly mixed powder obtained in step S2 is pressed into small round tablets with a diameter of 2 cm and a thickness of 2 cm using a tablet press, with a pressure of 10 KN.

[0059] S4: Place the small discs obtained in step S3 into a crucible and calcine them in a muffle furnace at 800℃ for 9 hours. After cooling to room temperature, remove them, grind them into powder, and pass them through a 250-mesh sieve to obtain Cu, a high-specific-capacity modified manganese oxide cathode material. 0.3 Mn 0.8 O2.

[0060] Example 4

[0061] S1: 757g of manganese dioxide (CAS: 1313-13-9 McLean, β phase ≥ 99%) and 297g of CuO (CAS: 1313-96-8, Shanghai Titan Technology high purity 99.5%) were mixed and ultrasonically treated to form a mixed powder. The ultrasonic power was 10-15KHz, the stirring speed was 3Kr / min, and the time was 0.5 hours.

[0062] S2: The mixed powder after stirring and ultrasonication is heated and sheared to disperse it. It is heated and sheared in air at 100°C to obtain a uniform mixed powder with a shearing linear velocity of 10m / s for 1 hour.

[0063] S3: The uniformly mixed powder obtained in step S2 is pressed into small round tablets with a diameter of 2 cm and a thickness of 2 cm using a tablet press, with a pressure of 10 KN.

[0064] S4: Place the small discs obtained in step S3 into a crucible and calcine them at 800℃ for 9 hours in a tube furnace. After cooling to room temperature, remove them, grind them into powder, and pass them through a 250-mesh sieve to obtain high-specific-capacity modified manganese oxide cathode material Cu. 0.3 Mn 0.7 O2.

[0065] It is worth noting that the names of the aforementioned companies such as Comio, Shanghai Test High Purity, and McLean simply represent the names of the manufacturers of the reagents used, and have no other special meaning.

[0066] This invention also provides a method for preparing a positive electrode, comprising the following steps:

[0067] T1: Provide calcined positive electrode material powder, conductive carbon black powder, and 20 mg / ml PVDF NMP solution, weighed in a ratio of 7:2:1.

[0068] T2: Place the weighed positive electrode material powder, conductive carbon black powder and binder PVDF powder into a mortar and grind until fine;

[0069] T3: Apply the positive electrode material slurry to the current collector using a 250μm thick scraper to wet the electrode sheet;

[0070] T4: First, place the coated wet electrode prototype into a forced-air drying oven at 110℃ for two hours, then place it into a vacuum drying oven at 120℃ for 10 hours to make a dry electrode.

[0071] T5: Cut the dry electrode into small round pieces with a diameter of 12mm, and use a tablet press to process them into tablets. Press them with a pressure of 117.8kg / cm2 to produce the finished electrode.

[0072] It is worth noting that the above-mentioned PVDF NMP solution refers to the homogeneous mixture formed by dissolving PVDF in NMP, where PVDF is polyvinylidene fluoride, a high-performance fluoropolymer; and NMP is the abbreviation for N-methylpyrrolidone, a polar organic solvent.

[0073] Battery assembly

[0074] A1: Select qualified electrode sheets and weigh them using a high-precision balance. Weigh each sheet three times and take the average value.

[0075] A2: Place the positive electrode shell flat on an insulated platform, place the test electrode in the center of the positive electrode shell, use a pipette to add a drop of electrolyte to wet the surface of the test electrode, use insulated tweezers to place the diaphragm on top of the test electrode, with the active material side of the test electrode in contact with the diaphragm, use a pipette to add an appropriate amount of electrolyte to the surface of the diaphragm, then use insulated tweezers to place the sodium sheet on top of the diaphragm, and then place the gasket, spring, and negative electrode shell on top of the sodium sheet in sequence.

[0076] A3: Using insulated tweezers, place the button cell battery with the negative terminal facing up on the button cell sealing machine mold, and adjust the pressure to 50 kg / cm². 2 Press for 5 seconds to complete the assembly of the button cell, remove it with insulated tweezers, observe whether the appearance is complete, and wipe it clean with a paper towel;

[0077] A4: Battery testing includes constant current discharge testing and EIS testing.

[0078] The constant current discharge tests were performed on the above Examples 1-4, and the results are shown in the attached figures.

[0079] Figures 1 to 5 The results of specific capacity tests for niobium manganese oxide discharge (cutoff voltage 1.5V), impedance comparison before and after niobium manganese oxide discharge, specific capacity test graphs for niobium manganese oxide discharge (cutoff voltage 1.0V), specific capacity test results for copper manganese oxide discharge (cutoff voltage 1.5V), and specific capacity test results for niobium copper manganese oxide discharge (cutoff voltage 1.5V) are presented respectively.

[0080] Figure 1 The comparison between Example 1 and Example 2 is shown. When niobium manganese oxide is used as the positive electrode material, the doping of niobium element effectively stabilizes the manganese dioxide lattice and reduces the volume expansion during sodium ion insertion / extraction. The higher the niobium element content, the higher the specific capacity under the same voltage.

[0081] Figure 2 This indicates that doping with niobium can improve electronic / ionic conductivity.

[0082] Figure 3 and Figure 1 In comparison, the cutoff voltage is different. Figure 3 The capacity is higher at the cutoff voltage, and sodium ions are removed more completely.

[0083] Figure 4 The study demonstrates the effect of copper (Cu) doping compared to niobium manganese oxide. Copper doping may improve conductivity by introducing impurity energy levels, and its capacity may be slightly lower than that of niobium-doped materials, but it is also cheaper.

[0084] Figure 5 comprehensive Figure 1 and Figure 4 The results validate the advantages of bimetallic synergistic doping: niobium stabilizes the lattice, copper enhances conductivity, and the capacity may be further improved, while maintaining good cycle stability.

[0085] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A primary battery, characterized in that, The primary battery includes a positive electrode, a separator, and a sodium sheet. The positive electrode material includes a material with the chemical formula NbαCuβMnγO2, wherein 0.05≤α≤0.15; 0.3≤β≤0.4; 1≤β+γ≤1.

2. The positive electrode material is prepared by the following steps: S1: Manganese dioxide and a metal oxide mixture are stirred and ultrasonically treated to obtain a mixed powder, wherein the metal oxide mixture includes copper oxide and niobium pentoxide; S2: The stirred and ultrasonically treated mixed powder is subjected to air at 120°C. Heating and shearing dispersion are carried out at ~200℃ with a shearing linear velocity of 10-40m / s for 0.5-2 hours to obtain a uniformly mixed powder; S3: The uniformly mixed powder is pressed into small round discs with a diameter of 0.5-5 cm and a thickness of 0.5-5 cm using a tablet press; S4: The small round discs are placed in a crucible and calcined in an air or oxygen atmosphere at a temperature of 500-900℃ for 6-12 hours. After cooling to room temperature, they are taken out, ground into powder, and passed through a 250-mesh sieve to obtain the positive electrode material.

2. The primary battery according to claim 1, characterized in that, The ultrasonic stirring treatment in step S1 has an ultrasonic power of 10-15KHz, a stirring speed of 0.5-5Kr / min, and a duration of 0.5-2 hours.

3. The primary battery according to claim 1, characterized in that, In step S4, calcination is carried out in a muffle furnace or a tube furnace.

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