High reaction heat positive electrode material for long time thermal battery and preparation method thereof

Abstract

The application discloses a high-reaction-heat positive electrode material for a long-time thermal battery, which comprises electrolyte, lithium oxide and conductive material, and further comprises oxide and disulfide. The most key effect of the patent is that, compared with the existing positive electrode material of the thermal battery, the basic components of the electrolyte, the lithium oxide and the conductive material are reserved, and then the oxide and the disulfide are simultaneously added. In the positive electrode material, the oxide releases a certain amount of heat in the discharge process, the heat can supplement the lost part of the heat of the thermal battery, the heat of the thermal battery is improved, and the thermal decomposition is reduced, so that the working time of the thermal battery is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of thermal battery technology, specifically relating to a high-reactivity thermal cathode material for long-term thermal batteries and its preparation method. Background Technology

[0002] A thermal battery is a thermally activated storage battery that relies on its own heating system to heat and melt a non-conductive solid salt electrolyte into an ionic conductor, thus entering its working state. Thermal batteries are characterized by arbitrary angle activation, rapid activation, long storage time, and strong resistance to environmental mechanical conditions. They have been widely used in weaponry. Furthermore, the application of thermal batteries in the civilian sector is also gaining attention, with research reports on their use as emergency power supplies for aircraft, fire alarms, and underground high-temperature mining power sources.

[0003] With the continuous development and upgrading of military equipment, the requirements for thermal battery performance are getting higher and higher, including longer working time, higher output power, higher specific characteristics, and faster activation time.

[0004] A thermal battery mainly consists of a substrate, positive electrode, negative electrode, electrolyte sheet (or separator), sheet-shaped current collector, heating system (electric igniter or spark plug, ignition paper, heating element), insulation pad, battery casing, and battery cover with terminals. Among these, the electrode materials of a thermal battery have the most critical impact on its electrochemical performance, such as output capacity and operating time. According to the working principle of a thermal battery, it relies on heat to bring the electrolyte to a molten state for discharge. During operation, a certain temperature needs to be maintained to keep the electrolyte in a molten state. Due to the temperature difference between the battery and the surrounding environment, heat is gradually lost over long periods of operation, causing the battery to stop discharging and affecting its effective capacity and operating time over extended periods.

[0005] Currently, extending battery operating time mainly relies on improving battery insulation performance. For example, CN113054213A discloses a method for reducing the surface temperature of a thermal battery. This method involves setting a heat insulation layer on the surface of the battery stack and / or the thermal battery casing. The heat insulation layer includes an aluminum foil heat insulation sleeve and SiO2 nanofiber aerogel from the inside out. This method can significantly reduce the surface temperature of the thermal battery. Essentially, it reduces heat loss from the thermal battery, thereby achieving the purpose of insulation. However, this method does not improve the positive electrode material; it only sets insulation material on the outer layer of the battery stack. This increases the battery volume, making it difficult to meet the current development needs for compact yet high-capacity thermal batteries.

[0006] Therefore, starting with improving the electrode materials of thermal batteries, it is particularly important to study a technology that can reduce heat loss and extend the working time of thermal batteries, in order to meet the current development needs of thermal batteries. Summary of the Invention

[0007] The present invention aims to provide a highly reactive thermal cathode material that helps to extend the working time of thermal batteries.

[0008] One of the high-reactivity thermal cathode materials for thermal batteries in this scheme includes components such as electrolyte, lithium oxide, and conductive materials, as well as oxides and disulfides.

[0009] Furthermore, the percentage content of each component in the high-reactivity thermal cathode material for the thermal battery is 2%–15% electrolyte, 2%–5% lithium oxide, 1%–5% conductive material, 5%–30% oxide, and 50%–90% disulfide.

[0010] Furthermore, the particle size of the disulfide, oxide, and lithium oxide raw materials is 50 nm to 50 μm.

[0011] Furthermore, the purity of the disulfide, oxide, and lithium oxide is >99.5%.

[0012] Furthermore, the oxide can be one of FeO, Fe2O3, Fe3O4, Cu2O, and CuO.

[0013] Furthermore, the disulfide is one of iron disulfide, cobalt disulfide, and nickel disulfide.

[0014] Furthermore, the conductive material is graphene or carbon nanotubes.

[0015] Furthermore, the electrolyte is one of LiF-LiCl-LiBr, LiCl-KCl, and LiCl-LiBr-KBr.

[0016] This application also provides a method for preparing the above-mentioned high-reactivity thermal cathode material for thermal batteries, which is prepared according to the following steps:

[0017] 1) First, place the oxides, disulfides, electrolytes, lithium oxides, and conductive material raw materials into an inert drying oven or vacuum drying oven at a temperature of 40℃~300℃ to remove moisture before use.

[0018] 2) Weigh out the disulfide, oxide, conductive material, electrolyte and lithium oxide according to the percentage content of each component. Put the disulfide, oxide, electrolyte and lithium oxide into a high-speed powder mixer and mix evenly. Transfer to an inert drying oven or vacuum drying oven at 350℃~500℃ for lithiation for 2h~48h. Take out the sample and cool it. Use mechanical pulverization and sieve to prepare 60 mesh~200 mesh powder.

[0019] 3) Finally, put the powder prepared in the second step and the weighed conductive material into the planetary mixer and mix them evenly.

[0020] The beneficial technical effects of this invention are:

[0021] 1. The most critical effect of this patent is that, compared with existing thermal battery cathode materials, it retains the basic components of electrolyte, lithium oxide and conductive materials, and then simultaneously adds oxides and disulfides. In this cathode material, the oxides react and release a certain amount of heat during the discharge process. This heat can supplement the heat lost by the thermal battery, thereby increasing the thermal battery's heat capacity and reducing thermal decomposition, thus extending the working time of the thermal battery.

[0022] 2. The high-reactivity thermal cathode material prepared by the method of the present invention has the dual functions of heating and cathode material. In addition to extending the working time of thermal battery, it also has the advantages of high specific characteristics, good electrochemical performance and strong stability, good conductivity, high calorific value, high output current density, and high safety. Attached Figure Description

[0023] Figure 1 Example 1: High-temperature discharge comparison of batteries using high-reactivity cathode materials and conventional cathode materials;

[0024] Figure 2 Example 1: Low-temperature discharge comparison of batteries with high-reaction-heat cathode materials and conventional cathode materials. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in further detail below, but the present invention is not limited to these embodiments. Any improvements or substitutions based on the basic spirit of these embodiments shall still fall within the scope of protection claimed by the claims of the present invention.

[0026] In the following examples, the disulfide, oxide, and lithium oxide are all powders in the range of 50 nm to 50 μm, and have a purity > 99.5%.

[0027] Example 1: Preparation of a high-reactivity cathode material, comprising the following steps:

[0028] 1) First, place the raw materials CoS2, CuO, LiCl-KCl, lithium oxide, and graphene into an inert drying oven or vacuum drying oven at 175℃ to remove moisture before use.

[0029] 2) Weigh 200g CoS2, 20g CuO, 6g Li2O, and 30g LiCl-KCl respectively. Put CoS2, CuO, Li2O, and LiCl-KCl into a high-speed powder mixer and mix evenly. Transfer the mixture to an inert drying oven at 450℃ for 8 hours. Take out the sample and cool it. Then, mechanically pulverize it and sieve it through a 120-mesh sieve to prepare the cathode material precursor.

[0030] 3) Finally, mix the cathode material precursor prepared in the second step with 2g of carbon nanotubes evenly.

[0031] The inert gas is either argon or helium; the synthesis process for all material tests was completed in a dry room with a humidity of less than 3%.

[0032] Example 2, preparation of a high-reaction-heat cathode material, includes the following steps:

[0033] 1) First, place FeS2, Cu2O, LiCl-KCl, lithium oxide, and graphene raw materials into an inert drying oven or vacuum drying oven at 175℃ to remove moisture before use.

[0034] 2) Weigh 200g FeS2, 20g Cu2O, 6g Li2O, and 4g LiCl-KCl respectively. Put FeS2, Cu2O, Li2O, and LiCl-KCl into a high-speed powder mixer and mix them evenly. Transfer the mixture to an inert drying oven at 450℃ for 8 hours. Take out the sample and cool it. Then, mechanically pulverize it and sieve it through an 80-mesh sieve to prepare the precursor of the integrated heating cathode material.

[0035] 3) Finally, mix the cathode material precursor prepared in the second step with 2g of carbon nanotubes evenly.

[0036] The inert gas is either argon or helium; the synthesis process for all material tests was completed in a dry room with a humidity of less than 3%.

[0037] Example 3: Preparation of a high-reaction-heat cathode material, comprising the following steps:

[0038] 1) First, put NiS2, Fe2O3, LiCl-KCl, lithium oxide, and graphene raw materials into an inert drying oven or vacuum drying oven at 175℃ to remove moisture and set aside for later use.

[0039] 2) Weigh 200g NiS2, 20g Fe2O3, 6g Li2O, and 4g LiCl-KCl respectively. Put NiS2, Fe2O3, Li2O, and LiCl-KCl into a high-speed powder mixer and mix evenly. Transfer the mixture to an inert drying oven at 450℃ for 8 hours. Take out the sample and cool it. Then, mechanically pulverize it and sieve it through an 80-mesh sieve to prepare the precursor of the integrated heating cathode material.

[0040] 3) Finally, mix the cathode material precursor prepared in the second step with 2g of carbon nanotubes evenly.

[0041] The inert gas is either argon or helium; the synthesis process for all material tests was completed in a dry room with a humidity of less than 3%.

[0042] Example 4

[0043] The preparation of high-reactivity cathode materials includes the following steps:

[0044] 1) First, place the raw materials CoS2, Fe3O4, LiCl-KCl, lithium oxide, and graphene into an inert drying oven or vacuum drying oven at 175℃ to remove moisture before use.

[0045] 2) Weigh 200g CoS2, 30g Fe3O4, 6g Li2O, and 4g LiCl-KCl respectively. Put CoS2, Fe3O4, Li2O, and LiCl-KCl into a high-speed mixer and mix them evenly. Transfer the mixture to an inert drying oven at 450℃ for 8 hours. Take out the sample and cool it. Then, mechanically pulverize it and sieve it through an 80-mesh sieve to prepare the precursor of the integrated heating cathode material.

[0046] 3) Finally, mix the cathode material precursor prepared in the second step with 2g of carbon nanotubes evenly.

[0047] Example 5: Preparation of a high-reaction-heat cathode material, comprising the following steps:

[0048] 1) First, place the raw materials CoS2, FeO, LiCl-KCl, lithium oxide, and graphene into an inert drying oven or vacuum drying oven at 175℃ to remove moisture before use.

[0049] 2) Weigh 200g CoS2, 20g FeO, 6g Li2O, and 20g LiCl-KCl respectively. Put CoS2, FeO, Li2O, and LiCl-KCl into a high-speed powder mixer and mix evenly. Transfer the mixture to an inert drying oven at 450℃ for 8 hours. Take out the sample and cool it. Then, mechanically pulverize it and sieve it through an 80-mesh sieve to prepare the precursor of the integrated heating cathode material.

[0050] 3) Finally, mix the cathode material precursor prepared in the second step with 2g of carbon nanotubes evenly.

[0051] The inert gas is either argon or helium; the synthesis process for all material tests was completed in a dry room with a humidity of less than 3%.

[0052] Example 5: Preparation of a high-reaction-heat cathode material, comprising the following steps:

[0053] 1) First, put NiS2, CuO, LiCl-KCl, lithium oxide, and graphene raw materials into an inert drying oven or vacuum drying oven at 175℃ to remove moisture and set aside for later use.

[0054] 2) Weigh 200g NiS2, 20g CuO, 6g Li2O, and 20g LiCl-KCl respectively. Put NiS2, CuO, Li2O, and LiCl-KCl into a high-speed powder mixer and mix evenly. Transfer the mixture to an inert drying oven at 450℃ for 8 hours. Take out the sample and cool it. Then, mechanically pulverize it and sieve it through a 200-mesh sieve to prepare the precursor of the integrated heating cathode material.

[0055] 3) Finally, mix the cathode material precursor prepared in the second step with 2g of carbon nanotubes evenly.

[0056] The inert gas is either argon or helium; the synthesis process for all material tests was completed in a dry room with a humidity of less than 3%.

[0057] Comparative example: Conventional cathode material, whose composition and percentage content are 80% cobalt disulfide + 18% electrolyte + 1% lithium oxide + 1% carbon nanotubes.

[0058] The high-reaction-heat cathode material was prepared according to Example 1. Simultaneously, the high-reaction-heat cathode material was pressed into sheets and assembled into 16 single-cell series-connected cell units for electrical performance testing. The test results are as follows: Figure 1 and Figure 2 As shown in the figure, the unit thermal battery has a small thermal shock, good thermal stability, a stable discharge platform, and excellent discharge performance. The voltage platform is high in the later stage of discharge, and the electrical performance is significantly improved in the later stage. The battery's high current carrying capacity is significantly improved in the later stage.

Claims

1. A high-reactivity thermal cathode material for long-term thermal batteries, characterized in that, The raw materials include disulfides, oxides, electrolytes, lithium oxide, and conductive materials, in the following weight percentages: disulfides 50%–90%, oxides 5%–30%, electrolytes 2%–15%, and lithium oxide 2%–5%. The oxides are one of FeO, Fe2O3, Fe3O4, Cu2O, and CuO. The disulfides are one of iron disulfide, cobalt disulfide, and nickel disulfide. The positive electrode material is prepared according to the following steps: 1) First, place the oxides, disulfides, electrolytes, lithium oxides, and conductive material raw materials into an inert drying oven or vacuum drying oven at a temperature of 40℃~300℃ to remove moisture before use. 2) Weigh out the disulfide, oxide, conductive material, electrolyte and lithium oxide according to the percentage content of each component. Put the disulfide, oxide, electrolyte and lithium oxide into a high-speed powder mixer and mix evenly. Transfer to an inert drying oven or vacuum drying oven at 350℃~500℃ for lithiumation for 2h~48h. Take out the sample and cool it. Use mechanical pulverization and sieve to prepare 60 mesh~200 mesh powder. 3) Finally, put the powder prepared in the second step and the weighed conductive material into the planetary mixer and mix them evenly.

2. The high-reactivity cathode material for long-term thermal batteries according to claim 1, characterized in that: The particle size of the disulfide, oxide, and lithium oxide raw materials is 50 nm to 50 μm.

3. The high-reactivity cathode material for a long-term thermal battery according to claim 1, characterized in that: The purity of the disulfide, oxide, and lithium oxide is >99.5%.

4. The high-reactivity cathode material for a long-term thermal battery according to claim 1, characterized in that: The conductive material is graphene or carbon nanotubes.

5. The high-reactivity cathode material for a long-term thermal battery according to claim 4, characterized in that: The electrolyte is one of LiF-LiCl-LiBr, LiCl-KCl, and LiCl-LiBr-KBr.

6. A method for preparing a high-reactivity thermal cathode material for a long-term thermal battery according to any one of claims 1 to 5, characterized in that, Prepare according to the following steps: 1) First, place the oxides, disulfides, electrolytes, lithium oxides, and conductive material raw materials into an inert drying oven or vacuum drying oven at a temperature of 40℃~300℃ to remove moisture before use. 2) Weigh out the disulfide, oxide, conductive material, electrolyte and lithium oxide according to the percentage content of each component. Put the disulfide, oxide, electrolyte and lithium oxide into a high-speed powder mixer and mix evenly. Transfer to an inert drying oven or vacuum drying oven at 350℃~500℃ for lithiumation for 2h~48h. Take out the sample and cool it. Use mechanical pulverization and sieve to prepare 60 mesh~200 mesh powder. 3) Finally, put the powder prepared in the second step and the weighed conductive material into the planetary mixer and mix them evenly.

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