Thermal battery positive electrode powder added with bimetallic sulfide as well as preparation method and application of thermal battery positive electrode powder

Abstract

The invention discloses thermal battery positive electrode powder added with bimetallic sulfide and a preparation method and application of the thermal battery positive electrode powder, and the bimetallic sulfide is used as a positive electrode additive to improve the conductivity of a positive electrode. The positive electrode material comprises the following components in percentage by mass: 65%-75% of a positive electrode active material, 15%-25% of eutectic salt, 2%-15% of bimetallic sulfide and 1%-3% of lithium oxide. The additive and the preparation method can effectively reduce the internal resistance of the thermal battery and improve the voltage and capacity of the thermal battery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of thermal batteries, and mainly relates to a thermal battery positive electrode powder added with a bimetallic sulfide as well as a preparation method and application thereof. BACKGROUND

[0002] Thermal batteries have the characteristics of high energy density, long service life, high temperature resistance, etc., and can provide high energy output in a short time. These characteristics make them mainly applied in the military. A typical thermal battery includes a positive electrode, a negative electrode, a non-conductive electrolyte at room temperature, and a heating agent. When the battery needs to be powered, the heating agent can be ignited by electric activation or mechanical activation, so that the electrolyte melts and conducts electricity.

[0003] Thermal battery materials are usually composed of powder particles. Each positive electrode, electrolyte, and heating agent is formed into a single layer sheet by pressing and combined into a single unit. The negative electrode material used in thermal batteries is usually an alkaline earth metal or an alkaline earth alloy, including lithium aluminum, lithium silicon, and lithium boron. The electrolyte material of the thermal battery usually includes eutectic salts of lithium fluoride, lithium chloride, and lithium bromide, and a binder (usually magnesium oxide). The positive electrode material of the thermal battery is usually a metal sulfide, including iron disulfide and cobalt disulfide. In order to improve the conductivity of the positive electrode material, additives are often added.

[0004] With the development of equipment, higher requirements are put forward for the power output of thermal batteries. The conductivity of the positive electrode is a key factor restricting the output power of the thermal battery, so there is a continuous demand for additives for the positive electrode. SUMMARY

[0005] The problem to be solved by the present application is to provide a thermal battery positive electrode powder added with a bimetallic sulfide as well as a preparation method and application thereof. Compared with traditional thermal battery positive electrode materials, the positive electrode of the present application has stronger conductivity, higher output voltage, and longer service life.

[0006] The technical scheme adopted by the present application is: a thermal battery positive electrode powder added with a bimetallic sulfide, including the following components in terms of mass percentage:

[0007]

[0008] Further, the bimetallic sulfide is one of FeNiS2 and CuFeS2.

[0009] Further, the positive electrode active material is a metal sulfide with a particle size of 100-300 mesh.

[0010] Further, the metal sulfide is iron disulfide or cobalt disulfide.

[0011] Further, the eutectic salt is one of LiF-LiCl-LiBr and LiCl-KCl.

[0012] The preparation method of the thermal battery cathode powder added with bimetallic sulfide comprises the following steps:

[0013] (1) high-temperature vacuum desulfurization of the cathode active material;

[0014] (2) weighing and uniformly mixing the desulfurized cathode active material, lithium oxide and bimetallic sulfide according to the proportion;

[0015] (3) high-temperature treatment of the mixture after step (2) at 300-450°C under argon atmosphere for 4h, and then cooling to room temperature;

[0016] (4) screening the mixture after step (3) through a 60-mesh sieve;

[0017] (5) weighing and uniformly mixing the material after step (4) and eutectic salt according to the proportion;

[0018] (6) high-temperature treatment of the material after step (5) at 320-400°C for 4h, and then cooling to room temperature;

[0019] (7) crushing the material after step (6), screening through a 60-mesh sieve, and obtaining the cathode powder.

[0020] Further, in step (1), the vacuum degree is 85-95kPa, and the temperature is 400-500°C.

[0021] A thermal battery, the cathode powder for preparing the cathode is the thermal battery cathode powder added with bimetallic sulfide or the thermal battery cathode powder added with bimetallic sulfide prepared by the preparation method.

[0022] The cathode material of the present application has stronger conductivity, higher output voltage and longer service life compared with the traditional thermal battery cathode material. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is the SEM image of the iron disulfide cathode in Example 1 of the present application.

[0024] Figure 2 is the SEM image of the iron disulfide cathode in Comparative Example 1 of the present application.

[0025] Figure 3 is the discharge data graph of 15 single batteries prepared by the cathode powder in Example 1 of the present application (constant current 7.5A, pulse 35A).

[0026] Figure 4 is the discharge data graph of 15 single batteries prepared by the cathode powder in Example 2 of the present application (constant current 7.5A, pulse 35A).

[0027] Figure 5 is a discharge data graph of 15 single batteries prepared by the positive electrode powder of Example 3 of the present application (constant current 7.5A, pulse 35A).

[0028] Figure 6 is a discharge data graph of 15 single batteries prepared by the positive electrode powder of Comparative Example 1 of the present application (constant current 7.5A, pulse 35A). DETAILED DESCRIPTION

[0029] The specific embodiments of the present application are further described in detail below, but the present application is not limited to these embodiments, any improvement or replacement of the basic scheme of the present embodiments still belongs to the scope of protection claimed by the present application.

[0030] The following lists examples and comparative examples:

[0031] Example 1

[0032] A preparation method of a hot battery positive electrode powder added with a bimetallic sulfide, the formula according to mass percentage, including 65% of iron disulfide, 20% of full lithium eutectic salt (LiF-LiCl-LiBr), 14% of iron disulfide nickel and 1% of lithium oxide. The specific preparation method of the positive electrode powder in this embodiment mainly includes iron disulfide pretreatment, preparation of the positive electrode, eutectic salt coating and firing of the positive electrode.

[0033] The preparation process is as follows:

[0034] (1) The iron disulfide is desulfurized at high temperature under vacuum, the vacuum degree is 90kPa, and the temperature is 450℃;

[0035] (2) The desulfurized iron disulfide, lithium oxide and iron disulfide nickel are weighed and mixed according to the proportion, wherein the weight of the iron disulfide is 650g, the weight of the lithium oxide is 10g, and the weight of the iron disulfide nickel is 140g;

[0036] (3) The mixed material in step (2) is treated at high temperature under argon atmosphere at 400℃ for 4h, and then cooled to room temperature;

[0037] (4) The iron disulfide mixture treated in step (3) is passed through a 60 mesh sieve;

[0038] (5) 800g of the material treated in step (4) is mixed with 200g of eutectic salt;

[0039] (6) The material treated in step (5) is treated at high temperature at 400℃ for 4h, and then cooled to room temperature;

[0040] (7) The material treated in step (6) is crushed and passed through a 60-mesh sieve to obtain the positive electrode powder of the bimetallic sulfide composite iron disulfide for thermal batteries.

[0041] Example 2

[0042] A positive electrode powder of a bimetallic sulfide composite iron disulfide for thermal batteries is prepared according to the following method. The formulation is 70% iron disulfide, 20% eutectic lithium salt (LiF-LiCl-LiBr), 8% iron nickel disulfide, and 2% lithium oxide, by mass percentage. The specific preparation method of the positive electrode in this embodiment mainly includes iron disulfide pretreatment, positive electrode preparation, and eutectic salt coating and firing of the positive electrode.

[0043] The preparation process is as follows:

[0044] (1) The iron disulfide is desulfurized at high temperature under vacuum, with a vacuum degree of 90 kPa and a temperature of 450°C;

[0045] (2) The desulfurized iron disulfide, lithium oxide, and iron nickel disulfide are weighed and mixed according to the proportions, with the weight of the iron disulfide being 700 g, the weight of the lithium oxide being 20 g, and the weight of the iron nickel disulfide being 80 g;

[0046] (3) The mixture from step (2) is treated at high temperature under an argon atmosphere at 400°C for 4 h, and then cooled to room temperature;

[0047] (4) The iron disulfide mixture from step (3) is passed through a 60-mesh sieve;

[0048] (5) 800 g of the material from step (4) is mixed with 200 g of eutectic salt;

[0049] (6) The material from step (5) is treated at high temperature at 400°C for 4 h, and then cooled to room temperature;

[0050] (7) The material from step (6) is crushed and passed through a 60-mesh sieve to obtain the positive electrode powder of the bimetallic sulfide composite iron disulfide for thermal batteries.

[0051] Example 3

[0052] A positive electrode powder of a bimetallic sulfide composite iron disulfide for thermal batteries is prepared according to the following method. The formulation is 75% iron disulfide, 20% eutectic lithium salt (LiF-LiCl-LiBr), 2% copper iron disulfide, and 3% lithium oxide, by mass percentage. The specific preparation method of the positive electrode in this embodiment mainly includes iron disulfide pretreatment, positive electrode preparation, and eutectic salt coating and firing of the positive electrode.

[0053] The preparation process is as follows:

[0054] (1) The iron disulfide is high-temperature vacuum desulfurized at a vacuum degree of 90 kPa and a temperature of 450°C;

[0055] (2) The desulfurized iron disulfide, lithium oxide and copper-iron disulfide are weighed and mixed according to the proportion, wherein the weight of the iron disulfide is 750 g, the weight of the lithium oxide is 20 g, and the weight of the copper-iron disulfide is 20 g;

[0056] (3) The mixed substance in step (2) is high-temperature treated at 400°C in an argon atmosphere for 4 h, and then cooled to room temperature;

[0057] (4) The iron disulfide mixture treated in step (3) is sieved through a 60-mesh sieve;

[0058] (5) 800 g of the material treated in step (4) is uniformly mixed with 200 g of eutectic salt;

[0059] (6) The material treated in step (5) is high-temperature treated at 400°C for 4 h, and then cooled to room temperature;

[0060] (7) The material treated in step (6) is crushed and sieved through a 60-mesh sieve to obtain a hot battery iron disulfide positive electrode powder.

[0061] Comparative Example

[0062] The iron disulfide positive electrode material widely used in the current hot battery products adopts the following specific steps in the preparation technology:

[0063] (1) The iron disulfide is high-temperature vacuum desulfurized at a vacuum degree of 90 kPa and a temperature of 450°C;

[0064] (2) The desulfurized iron disulfide and lithium oxide are weighed and mixed according to the proportion, wherein the weight of the iron disulfide is 790 g, and the weight of the lithium oxide is 10 g;

[0065] (3) The mixed substance in step (2) is high-temperature treated at 400°C in an argon atmosphere for 4 h, and then cooled to room temperature;

[0066] (4) The iron disulfide mixture treated in step (3) is sieved through a 60-mesh sieve;

[0067] (5) 800 g of the material treated in step (4) is uniformly mixed with 200 g of eutectic salt;

[0068] (6) The material treated in step (5) is high-temperature treated at 400°C for 4 h, and then cooled to room temperature;

[0069] (7) The material treated in step (6) is crushed and sieved through a 60-mesh sieve to obtain a hot battery iron disulfide positive electrode powder.

[0070] Comparative analysis of test results

[0071] (Please refer to) Figures 1-6 This includes what experiments were conducted, the results of which were analyzed, and a detailed description in language, including ***see Figure 1 (Descriptions such as, etc., and the effects of comparing data, and conclusions)

[0072] Figure 1 SEM images of a bimetallic sulfide composite iron disulfide cathode are shown, compared to Figure 2 Traditional SEM images of iron disulfide cathodes show that the composite cathode particles are relatively aggregated, with a large number of circular or near-circular pores distributed on the surface. The morphology is relatively loose and porous, with a certain fluffy feel, which is conducive to establishing ion transport channels with the electrolyte.

[0073] Figure 3 , Figure 4 , Figure 5 , Figure 6 The voltage curves of four thermal batteries, each consisting of 15 cells, are shown. A basic load of 7.5A was applied to each battery, with a 35A pulse applied every 40 seconds for 500ms.

[0074] Figure 3 The battery is composed of positive electrode powder prepared in Example 1, all-lithium molten salt electrolyte, lithium-boron alloy negative electrode, and iron powder heating agent; Figure 4 The battery is composed of positive electrode powder prepared in Example 2, all-lithium molten salt electrolyte, lithium-boron alloy negative electrode, and iron powder heating agent; Figure 5 The battery is composed of positive electrode powder prepared in Example 3, all-lithium molten salt electrolyte, lithium-boron alloy negative electrode, and iron powder heating agent; Figure 6 The battery consists of positive electrode powder prepared in Comparative Example 1, all-lithium molten salt electrolyte, lithium-boron alloy negative electrode, and iron powder heating agent.

[0075] By comparison Figures 3-6 The discharge curves of Examples 1, 2, and 3 show working times of 473s, 480s, and 406s, respectively, which are significantly improved compared to the working time of 361s in the comparative example.

[0076] The embodiments of the present invention have been described in detail above, but the content described is only an embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A thermal battery cathode powder with added bimetallic sulfide, characterized in that, By weight percentage, it includes the following ingredients: Positive electrode active material 65%–75% Eutectic salt 15%–25% Bimetallic sulfides 2%–15% Lithium oxide 1-3%.

2. The thermal battery cathode powder with added bimetallic sulfide according to claim 1, characterized in that, The bimetallic sulfide is one of FeNiS2 and CuFeS2.

3. The thermal battery cathode powder with added bimetallic sulfide according to claim 1, characterized in that, The positive electrode active material is a metal sulfide with a mesh size of 100-300.

4. The thermal battery cathode powder with added bimetallic sulfide according to claim 3, characterized in that, The metal sulfide is iron disulfide or cobalt disulfide.

5. The thermal battery cathode powder with added bimetallic sulfide according to claim 1, characterized in that, The eutectic salt is one of LiF-LiCl-LiBr and LiCl-KCl.

6. The method for preparing the thermal battery cathode powder with added bimetallic sulfide as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) High-temperature vacuum desulfurization of positive electrode active material; (2) Weigh and mix the desulfurized positive electrode active material, lithium oxide, and bimetallic sulfide in proportion; (3) The mixture after step (2) is subjected to high temperature treatment in an argon atmosphere at 300℃~450℃ for 4 hours, and then cooled to room temperature; (4) Pass the mixture after step (3) through a 60-mesh sieve; (5) Weigh and mix the materials and eutectic salt processed in step (4) according to the proportion; (6) Place the material processed in step (5) at 320℃~400℃ for 4 hours and then cool it to room temperature; (7) The material processed in step (6) is crushed and passed through a 60-mesh sieve to obtain positive electrode powder.

7. The method for preparing the thermal battery cathode powder with added bimetallic sulfide according to claim 6, characterized in that, In step (1), the vacuum degree is 85 kPa to 95 kPa and the temperature is 400℃ to 500℃.

8. A thermal battery, characterized in that, The positive electrode powder used to prepare the positive electrode is the thermal battery positive electrode powder with added bimetallic sulfide as described in any one of claims 1-5 or the thermal battery positive electrode powder with added bimetallic sulfide prepared by the preparation method described in claim 6.

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