Extreme-environment-resistant fluorine ion primary battery and preparation method thereof

Abstract

The invention discloses a fluorine ion primary battery resistant to an extreme environment and a preparation method thereof, the fluorine ion primary battery adopts a heating part, the internal temperature is kept at 300-600 DEG C, and a high-temperature environment is provided for battery discharge; magnesium oxide is adopted to adsorb fluorine-containing eutectic salt as an electrolyte, so that the ionic conductivity and extreme mechanical resistance of the battery at high temperature are improved; and an electron conductive agent and an ion conductive agent are adopted to improve a positive and negative electrode-electrolyte interface, so that the discharge capacity of the battery at extreme temperature is improved. The fluorine ion primary battery is high in extreme environment resistance and stable in discharge, and the preparation method is simple, convenient and reliable to operate and easy to manufacture in batches.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal batteries, and in particular relates to a fluorine ion primary battery resistant to extreme environments and a preparation method thereof. Background Art

[0002] In recent years, fluoride ion primary batteries based on anions have received extensive attention. Studies have shown that fluoride ion primary batteries are a new type of energy storage battery system and an important research and development direction for the next generation of ammunition power storage technology. Fluorine, as the element with the smallest mass among halogen anions, has the characteristics of high electronegativity, stable chemical properties, and good kinetic performance. Therefore, primary batteries based on fluoride ion systems have broad development prospects. In addition, the reserves of fluorine rank 13th in the earth's crust, and the global annual production is hundreds of times higher than that of lithium. Therefore, F- is very suitable as a carrier in chemical power sources.

[0003] At present, the development of fluoride ion batteries is still in its infancy, and most fluoride ion batteries use solid electrolytes. However, on the one hand, the solid-solid interface between the electrolyte and the electrode leads to insufficient contact, large interface resistance, and hindered ion / electron transmission, which greatly affects the electrochemical performance of fluoride ion batteries. On the other hand, due to the lower conductivity, fluoride ion batteries exhibit large electrochemical polarization at room temperature and low temperature environments, and the capacity decay is serious. In addition, fluoride ion batteries are currently unable to withstand large-scale mechanical vibrations and impacts, and the battery structure needs to be further optimized and improved.

[0004] Application No. CN202311243761.5 discloses a self-heating high-temperature all-solid-state fluoride ion battery and its preparation method. However, the invention uses active metals as the negative electrode (such as calcium foil, magnesium powder, lithium alloy, etc.), which are easy to react with electrolyte components at high temperatures to form surface films such as calcium fluoride, magnesium fluoride, and lithium fluoride. The essence is a metallurgical reaction between the negative electrode and the electrolyte, rather than an electrochemical reaction; the patent application No. CN202311196408.6 discloses a high-temperature fluorine-based thermal battery and its preparation method, which also has the above problems. In addition, porous solid fluorides are used as binders in the above inventions, but solid fluorides cannot adsorb inorganic molten salts well, so serious safety problems such as battery leakage will occur at high temperatures. In summary, it is necessary to construct high-conductivity electrolyte materials from the perspective of electrochemical material systems; to improve the wettability of the positive electrode-electrolyte interface from the perspective of interface chemistry; and to improve the stable discharge capacity of fluoride primary batteries under extreme environments (high temperature, low temperature, vibration, impact, etc.) from the perspective of battery structure. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a fluoride ion primary battery resistant to extreme environments and a preparation method thereof.

[0006] The technical scheme of the present invention is as follows: a method for preparing a fluoride ion primary battery resistant to extreme environments, wherein a heating material, a positive electrode material, an electrolyte, and a negative electrode material are pressed into sheets, and they are sequentially stacked and assembled into a single cell using a current collector, and multiple single cells are stacked together to form a battery stack, ignition paper is placed around, and a heat preservation material is wrapped on the outside, an ignition head is installed, and the battery is encapsulated in a battery shell and welded;

[0007] The electrolyte is a fluorine-containing eutectic salt electrolyte or a fluoride solid electrolyte;

[0008] The preparation method of the positive electrode material / negative electrode material is:

[0009] (1) Heating method: Add the electronic conductive agent and the ionic conductive agent to anhydrous ethanol and stir quickly to disperse them, then add the positive electrode active material / negative electrode active material, stir evenly, evaporate the anhydrous ethanol and vacuum dry; then place the mixture under a special atmosphere for heating treatment, and after cooling, grind, crush and sieve to obtain the final positive electrode material / negative electrode material; or

[0010] (2) Ball milling method: The positive electrode active material / negative electrode active material is uniformly mixed with the electronic conductive agent and the ionic conductive agent, placed in a ball mill and subjected to ball milling treatment under a special atmosphere, and the final positive electrode material / negative electrode material is obtained by grinding, crushing and sieving.

[0011] The positive electrode active material is MF x Transition metal fluoride, M is one element or a combination of multiple elements selected from Ni, Fe, Cu, Mn, Ti, V, Co, Sn, Ag, and Zn, and x is 1, 2, 3, or 4; the negative electrode active material is La, Al, or Mg metal powder.

[0012] The electronic conductive agent is one or more combinations of graphene, acetylene black, and carbon nanotubes, with a mass percentage content of 0.5%-5%; the ionic conductive agent is LiF-NaF-CsF eutectic salt, LiF-NaF-KF eutectic salt, and LiF-NaF-ZrF4 eutectic salt, with a mass percentage content of 5%-30%.

[0013] The fluorine-containing eutectic salt electrolyte uses flaky or spherical magnesium oxide as an adsorption carrier, and the fluorine-containing eutectic salt is one of LiF-NaF-CsF eutectic salt, LiF-NaF-KF eutectic salt, and LiF-NaF-ZrF4 eutectic salt; the fluoride solid electrolyte uses fluorcerite-type LaF3, CeF3, SmF3, or fluorite-type BaF2, SrF2, CaF2.

[0014] The heating method has a temperature of 500-700° C. and a heating time of 4 hours; the ball milling method has a rotation speed of 300-800 rpm; and the special atmosphere includes one of argon, hydrogen-argon mixed gas, and nitrogen.

[0015] The heating material is a mixture of iron powder and potassium perchlorate, and the mass fraction of the iron powder is 70%-90%.

[0016] The current collecting sheet is made of one or a composite sheet of two of corrosion-resistant stainless steel, graphite, carbon paper, nickel alloy and tungsten alloy.

[0017] The components of the ignition paper are zirconium powder and potassium dichromate.

[0018] The monomer structure assembled into a monomer battery is a single-layer sheet, a double-layer sheet, a three-layer sheet, or an integrated sheet.

[0019] The above-mentioned preparation method produces a fluoride ion primary battery resistant to extreme environments.

[0020] The beneficial effects of the present invention are:

[0021] (1) Fluoride ion primary batteries use a heating component to ignite the ignition paper and heating material to keep the internal temperature of the battery at 300-600°C, providing the battery with a high temperature environment suitable for discharge.

[0022] (2) Use electronic conductive agents and ionic conductive agents to prepare positive and negative electrode materials. When the temperature inside the battery rises, ion / electron conduction between active materials is achieved. Molten ionic conductors are also beneficial for improving the interface contact between positive and negative electrode materials and electrolytes, reducing interface impedance, and improving the discharge capacity of the battery at extreme temperatures.

[0023] (3) The electrolyte uses a fluorine-containing eutectic salt electrolyte or a fluoride solid electrolyte. The electrolyte adopts a solid-state design to improve the battery's ability to withstand extreme mechanical environments.

[0024] (4) The preparation method of the present invention requires that the positive and negative electrode materials, electrolyte materials, and heating materials are pressed into sheets and formed into single cells by stacking them in sequence. The single cells are stacked in sequence in the vertical direction, ignition paper is placed, insulation materials are wrapped, ignition heads are installed, and they are encapsulated in a battery shell and welded to form a fluoride ion primary battery. The preparation method is simple and reliable to operate and is easy to mass produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the discharge reaction mechanism of the fluoride ion primary battery of the present invention;

[0026] Figure 2 A schematic diagram of the structure of a fluoride ion primary battery monomer of the present invention;

[0027] Figure 3 Discharge curve of the fluoride ion primary battery prepared in Example 1 of the present invention;

[0028] Figure 4 Discharge curve of the fluoride ion primary battery prepared in Example 2 of the present invention;

[0029] Figure 5 Discharge curve of the fluoride ion primary battery prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. In addition, it should be understood that after reading the contents disclosed in the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope of protection defined by the present invention.

[0031] The method for preparing the extreme environment resistant fluoride ion primary battery of the present invention specifically comprises the following steps:

[0032] The positive and negative electrode materials, electrolyte materials, and heating materials are pressed into sheets, and then stacked in sequence using current collectors to assemble into single cells. The single cells are stacked in sequence in the vertical direction, ignition paper is placed, insulation materials are wrapped, ignition heads are installed, and they are encapsulated in the battery shell and welded.

[0033] The heating material is a mixture of iron powder and potassium perchlorate, and the mass fraction of the iron powder is 70%-90%.

[0034] The current collecting sheet is made of corrosion-resistant metal material, specifically one or a composite sheet of two of stainless steel, nickel alloy and tungsten alloy.

[0035] The monomer structure includes a single-layer sheet, a double-layer sheet, a three-layer sheet, and an integrated sheet.

[0036] The ingredients of the ignition paper are zirconium powder and potassium dichromate.

[0037] In the above-mentioned fluoride ion primary battery preparation method, the positive and negative electrodes use electronic conductive agents and ionic conductive agents to form electronic and ionic conductor coating layers on the positive and negative electrode surfaces. The positive electrode active material is MF x (x=1,2,3,4) transition metal fluoride, M is one element or a combination of multiple elements selected from Ni, Fe, Cu, Mn, Ti, V, Co, Sn, Ag, and Zn; the negative electrode active material is La, Al, or Mg metal powder. The electronic conductive agent is one or more combinations of graphene, acetylene black, and carbon nanotubes; the ionic conductive agent is LiF-NaF-CsF eutectic salt, LiF-NaF-KF eutectic salt, or LiF-NaF-ZrF4 eutectic salt.

[0038] The heating method comprises the following steps:

[0039] The electronic conductive agent and the ionic conductive agent are added to anhydrous ethanol and quickly stirred and dispersed, and then the positive / negative electrode active material is added, and after stirring evenly, the anhydrous ethanol is evaporated and vacuum dried; the mixture is then placed in a special atmosphere for heating treatment, and after cooling, it is ground, crushed, and sieved to obtain the final positive electrode material.

[0040] The heating temperature is 500-700°C and the heating time is 4 hours.

[0041] Alternatively, a ball milling method is used, which specifically includes the following steps:

[0042] The positive / negative electrode active materials, the electronic conductive agent and the ionic conductive agent are uniformly mixed, placed in a ball mill, and subjected to ball milling treatment under a special atmosphere, and the final positive electrode material is obtained by grinding, crushing and sieving.

[0043] The ball milling speed is 300-800 rpm.

[0044] The added amount of the electronic conductive agent accounts for 0.5%-5% of the total material mass.

[0045] The added amount of the ion conductive agent accounts for 5%-30% of the total material mass.

[0046] The special atmosphere includes one of argon, hydrogen-argon mixed gas and nitrogen. The preferred special gas is argon with a purity greater than 99%.

[0047] like Figure 1 As shown, in the above-mentioned fluoride ion primary battery preparation method, the electrolyte adopts a fluorine-containing eutectic salt electrolyte or a fluoride solid electrolyte. Among them, the fluorine-containing eutectic salt electrolyte adopts magnesium oxide as an adsorption carrier. The fluorine-containing eutectic salt is LiF-NaF-CsF eutectic salt, LiF-NaF-KF eutectic salt, LiF-NaF-ZrF4 eutectic salt. The fluoride solid electrolyte adopts fluorcerite-type LaF3, CeF3 and SmF3 and their modified materials, fluorite-type BaF2, SrF2 and CaF2 and their modified materials. Fluorine-containing eutectic salt electrolytes are mainly used in discharge environments with large current and high power output, and fluoride solid electrolytes are mainly used in discharge environments with long time and small current output.

[0048] The invention uses a heating component to heat the thermal battery, achieving a battery internal temperature range of 300-600°C. The heating component includes an ignition head, ignition paper, and heating material. The ignition head is activated by an external signal to ignite the ignition paper and heating material, which burn instantly to generate heat, melt the electrolyte, and achieve electrical performance output.

[0049] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the reagents and materials used in the following examples are all commercially available unless otherwise specified.

[0050] Example 1

[0051] Preparation of positive electrode: Weigh 10g of graphene and 180g of LiF-NaF-KF eutectic salt and fully disperse them in anhydrous ethanol to form a suspension; add 1kg of NiF2 to the suspension and stir evenly, then transfer to a 60℃ oven and vacuum dry for 6 hours to obtain a mixture; place the mixture in an argon atmosphere, calcine at 600℃ for 4 hours, cool to room temperature, grind, crush and sieve to obtain the final positive electrode material.

[0052] Negative electrode preparation: 25 g of graphene, 200 g of LiF-NaF-KF eutectic salt, and 1 kg of La were weighed and mixed evenly, placed in a ball mill and ball milled at 800 rpm under a nitrogen atmosphere, and ground, crushed, and sieved to obtain the final negative electrode material.

[0053] Electrolyte preparation: LiF-NaF-KF was used as the electrolyte material, and magnesium oxide was the adsorption carrier.

[0054] Preparation of primary battery: Weigh iron powder and potassium perchlorate in a mass ratio of 80:20 and mix them evenly. Then press the positive and negative electrode materials, electrolyte materials, and heating materials into Φ28mm single-layer sheets respectively. Use stainless steel current collectors and press Figure 2 The single cell structure shown is stacked and assembled in sequence. Subsequently, 15 single cells are stacked together, ignition strips are placed, insulation materials are wrapped, ignition heads are installed, and they are encapsulated in a battery casing and welded to obtain a primary battery.

[0055] Figure 3 The discharge curve of the primary battery prepared in Example 1 at room temperature.

[0056] Example 2

[0057] Positive electrode preparation: Weigh 50g of acetylene black, 50g of LiF-NaF-CsF eutectic salt, and 1kg of NiF2, mix them evenly, place them in a ball mill and perform ball milling at 500 rpm under a nitrogen atmosphere, grind, crush, and sieve to obtain the final positive electrode material.

[0058] Negative electrode preparation: Weigh 20g of acetylene black and 80g of LiF-NaF-CsF eutectic salt and fully disperse them in anhydrous ethanol to form a suspension; add 1kg of Al to the suspension and stir evenly, then transfer to a 60°C oven and vacuum dry for 6 hours to obtain a mixture; place the mixture in an argon atmosphere, calcine at 500°C for 4 hours, cool to room temperature, grind, crush, and sieve to obtain the final negative electrode material.

[0059] Electrolyte preparation: LiF-NaF-CsF was used as the electrolyte material, and magnesium oxide was used as the adsorption carrier.

[0060] Preparation of primary battery: Weigh iron powder and potassium perchlorate in a mass ratio of 70:30 and mix them evenly. Then press the positive and negative electrode materials, electrolyte materials, and heating materials into Φ50mm integrated sheets. Use stainless steel and graphite composite current collectors. Figure 2 The single cell structure shown is stacked and assembled in sequence. Subsequently, 15 single cells are stacked together, ignition strips are placed, insulation materials are wrapped, ignition heads are installed, and they are encapsulated in a battery casing and welded to obtain a primary battery.

[0061] Figure 4 This is the discharge curve of the primary battery prepared in Example 2 at -20°C.

[0062] Example 3

[0063] Positive electrode preparation: Weigh 15g carbon nanotubes, 100g LiF-NaF-ZrF4 eutectic salt, and 1kg NiF2, mix them evenly, place them in a ball mill and perform ball milling at 300 rpm under a nitrogen atmosphere, grind, crush, and sieve to obtain the final positive electrode material.

[0064] Negative electrode preparation: Weigh 30 g of carbon nanotubes, 300 g of LiF-NaF-ZrF4 eutectic salt, and 1 kg of Mg, mix them evenly, place them in a ball mill and perform ball milling at 400 rpm under a nitrogen atmosphere, grind, crush, and sieve to obtain the final negative electrode material.

[0065] Electrolyte preparation: LiF-NaF-ZrF4 was used as the electrolyte material, and magnesium oxide was used as the adsorption carrier.

[0066] Preparation of primary battery: Weigh iron powder and potassium perchlorate in a mass ratio of 88:12 and mix them evenly. Then press the positive and negative electrode materials and electrolyte materials into Φ42mm three-layer sheets, press the heating materials into Φ42mm single-layer sheets, and use stainless steel, graphite, and carbon paper composite current collectors. Figure 2 The single cell structure shown is stacked and assembled in sequence. Subsequently, 15 single cells are stacked together, ignition strips are placed, insulation materials are wrapped, ignition heads are installed, and they are encapsulated in a battery casing and welded to obtain a primary battery.

[0067] Figure 5 This is the discharge curve of the primary battery prepared in Example 3 at -50°C.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a fluoride ion primary battery resistant to extreme environments, characterized in that: The heating material, positive electrode material, electrolyte and negative electrode material are pressed into sheets, and then stacked in sequence using current collectors to form a single cell. Multiple single cells are stacked together to form a battery stack, ignition paper is placed around them, and insulation material is wrapped on the outside. The ignition head is installed, and the battery is encapsulated in a battery shell and welded; The electrolyte is a fluorine-containing eutectic salt electrolyte or a fluoride solid electrolyte; The preparation method of the positive electrode material / negative electrode material is: (1) Heating method: Add the electronic conductive agent and the ionic conductive agent to anhydrous ethanol and stir quickly to disperse them, then add the positive electrode active material / negative electrode active material, stir evenly, evaporate the anhydrous ethanol and vacuum dry; then place the mixture under a special atmosphere for heating treatment, and after cooling, grind, crush and sieve to obtain the final positive electrode material / negative electrode material; or (2) Ball milling method: The positive electrode active material / negative electrode active material is uniformly mixed with the electronic conductive agent and the ionic conductive agent, placed in a ball mill and subjected to ball milling treatment under a special atmosphere, and the final positive electrode material / negative electrode material is obtained by grinding, crushing and sieving.

2. The method for preparing a fluoride ion primary battery resistant to extreme environments according to claim 1, characterized in that: The positive electrode active material is MF x Transition metal fluoride, M is one element or a combination of multiple elements selected from Ni, Fe, Cu, Mn, Ti, V, Co, Sn, Ag, and Zn, and x is 1, 2, 3, or 4; the negative electrode active material is La, Al, or Mg metal powder.

3. The method for preparing a fluoride ion primary battery resistant to extreme environments according to claim 1 or 2, characterized in that: The electronic conductive agent is one or more combinations of graphene, acetylene black, and carbon nanotubes, with a mass percentage content of 0.5%-5%; the ionic conductive agent is LiF-NaF-CsF eutectic salt, LiF-NaF-KF eutectic salt, and LiF-NaF-ZrF4 eutectic salt, with a mass percentage content of 5%-30%.

4. The method for preparing a fluoride ion primary battery resistant to extreme environments according to claim 1, characterized in that: The fluorine-containing eutectic salt electrolyte uses flaky or spherical magnesium oxide as an adsorption carrier, and the fluorine-containing eutectic salt is one of LiF-NaF-CsF eutectic salt, LiF-NaF-KF eutectic salt, and LiF-NaF-ZrF4 eutectic salt; the fluoride solid electrolyte uses fluorcerite-type LaF3, CeF3, SmF3, or fluorite-type BaF2, SrF2, CaF2.

5. The method for preparing a fluoride ion primary battery resistant to extreme environments according to claim 1, characterized in that: The heating method has a temperature of 500-700° C. and a heating time of 4 hours; the ball milling method has a rotation speed of 300-800 rpm; and the special atmosphere includes one of argon, hydrogen-argon mixed gas, and nitrogen.

6. The method for preparing a fluoride ion primary battery resistant to extreme environments according to claim 1, characterized in that: The heating material is a mixture of iron powder and potassium perchlorate, and the mass fraction of the iron powder is 70%-90%.

7. The method for preparing a fluoride ion primary battery resistant to extreme environments according to claim 1, characterized in that: The current collecting sheet is made of one or a composite sheet of two of corrosion-resistant stainless steel, graphite, carbon paper, nickel alloy and tungsten alloy.

8. The method for preparing a fluoride ion primary battery resistant to extreme environments according to claim 1, characterized in that: The components of the ignition paper are zirconium powder and potassium dichromate.

9. The method for preparing a fluoride ion primary battery resistant to extreme environments according to claim 1, characterized in that: The monomer structure assembled into a monomer battery is a single-layer sheet, a double-layer sheet, a three-layer sheet, or an integrated sheet.

10. A fluoride ion primary battery resistant to extreme environments prepared by the preparation method according to any one of claims 1 to 9.

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