A method for producing a gold-doped sulfide material

Abstract

This invention relates to the field of manufacturing electrode materials for thermal batteries, specifically a method for preparing gold-doped sulfide materials. The invention employs a low-temperature hydrothermal method to construct a doped framework, forming a uniform and complete micron- and / or nano-scale Au dopant on the framework. Then, a sulfur-addition process is used to achieve a more stable embedding of the dopant within the FeS2 particles, resulting in excellent thermal stability and high effective discharge capacity when the product is used as a thermal battery. The product obtained by this invention has a discharge specific capacity greater than or equal to 361 mAh / g and an internal resistance less than or equal to 0.102 Ω. The process of this invention is simple and controllable, and the resulting product has excellent performance, facilitating industrial application.

Description

Technical Field

[0001] This invention relates to the field of manufacturing electrode materials for thermal batteries, specifically a method for preparing gold-doped sulfide materials. Background Technology

[0002] A thermal battery is a special type of battery that uses molten salt as the electrolyte. Thermal batteries are characterized by high power density, high energy density, long storage time, rapid and reliable activation, suitability for various harsh working conditions, and ease of use. Therefore, they are mainly used as power sources for high-tech weapons such as missiles, guided bombs, and torpedoes. In the civilian sector, thermal batteries also have broad application prospects as emergency power sources for aircraft, underground high-temperature mining equipment, and fire alarm power sources. Currently, the most widely used cathode material is pyrite-iron disulfide (FeS2). This material has moderate capacity, moderate discharge voltage, and is inexpensive. Its performance is dependent on the choice of ore deposit. Especially with the increasing activity of thermal battery anode materials (from Li-Al, Li-Si to Li-B alloys) and the application of all-lithium electrolytes, the operating temperature of thermal batteries has increased significantly, and the requirements for specific power and specific energy have also increased. Problems such as the low thermal decomposition temperature (550℃), high internal resistance, and severe self-discharge of iron disulfide have become extremely prominent.

[0003] Gurpreet Kaur et al. dissolved FeCl2·4H2O, Na2S2O3·5H2O, and HAuCl4·3H2O in an aqueous solution and reacted the mixture at 200℃ for 24 h. They synthesized a photocatalyst, Au@FeS2, for the degradation of textile dyes. Au@FeS2 exhibited good photocatalytic activity and reusability under visible light irradiation, but its thermal stability and effective discharge capacity were not discussed. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes for the first time to construct a doped framework using a hydrothermal method at a lower temperature, and then utilizes a sulfur replenishment process to achieve a more stable embedding of the dopant within the FeS2 particles, thereby enabling the product to exhibit excellent thermal stability and high effective discharge capacity when used as a thermal battery.

[0005] This invention is the first to propose a hydrothermal synthesis method at a lower temperature to prepare Au-containing iron-sulfur compound particles, and then introduce sulfur to form an Au-containing FeS2 composite with excellent thermal stability and high effective discharge capacity at a higher temperature.

[0006] This invention discloses a method for preparing a gold-doped sulfide material, the method comprising the following steps:

[0007] Step 1

[0008] Using an Au-containing solution as raw material; adding a sulfur source and an Fe source to the Au-containing solution and stirring; then placing it in a high-pressure reactor; reacting at 120–180°C, preferably 150–180°C, for at least 7 hours; cooling; solid-liquid separation; obtaining Au-doped iron-sulfur compound particles;

[0009] Step Two

[0010] In a sulfur-containing atmosphere, the Au-doped iron-sulfur compound particles obtained in step one are heated to 300-400°C and held at that temperature for at least 5 hours; then cooled in the furnace to obtain gold-doped sulfide material.

[0011] or

[0012] After uniformly mixing the Au-doped iron-sulfur compound particles obtained in step one with elemental sulfur, the mixture is heated to 350-440°C in a protective atmosphere and held at that temperature for at least 7 hours. The mixture is then cooled in the furnace to obtain the gold-doped sulfide material.

[0013] The sulfur source includes at least one of thiosulfate, sulfite, and sulfide ions.

[0014] This invention discloses a method for preparing gold-doped sulfide materials, wherein the solute in the Au-containing solution is a soluble Au-containing substance. In industrial applications, the soluble Au-containing substance includes at least one of gold(III) chloride, gold(III) chloride trihydrate, triphenylphosphine gold chloride, sodium gold thiosulfate, trisodium gold(I) disulfite, and triammonium gold(I) disulfite.

[0015] The molar ratio of the added sulfur source to the Au element in the Au-containing solution is 20 to 10:1, preferably 15 to 10:1, and even more preferably 12:1.

[0016] This invention discloses a method for preparing gold-doped sulfide materials. In step one,

[0017] Prepare a mixture of Au source (soluble Au-containing substance) and Fe source by molar ratio of nAu:nFe = 0.051–0.661:8333.

[0018] In industrial applications, a soluble Au-containing substance and water-soluble divalent Fe are prepared. First, the soluble Au-containing substance is dissolved in water to obtain an Au-containing solution. Using the Au-containing solution as a raw material, thiosulfate ions and the prepared Fe source are added to the Au-containing solution. The mixture is stirred and then placed in a high-pressure reactor. The temperature is increased to 130–180°C at a heating rate of 5–15°C / min and held for 10–22 hours. The mixture is then cooled, and the solid and liquid are separated to obtain Au-doped iron-sulfur compound particles.

[0019] Preferably, in step one of the present invention, the cooling refers to cooling the product with the furnace to 25-35°C.

[0020] In industrial applications, the product obtained in step one is washed with deionized water and then dried to obtain the precursor of the product. It is then mixed with elemental sulfur and sintered.

[0021] This invention discloses a method for preparing a gold-doped sulfide material. In step two, the Au-doped iron-sulfur compound particles obtained in step one are mixed uniformly with elemental sulfur; the mixture is then placed in a sintering furnace under a protective atmosphere, and the temperature is first raised to 300–350°C at a heating rate of 5–15°C / min and held for 5–20 hours; then the temperature is raised to 350–440°C, preferably 390–400°C, and held for 7–30 hours; the mixture is then cooled in the furnace to obtain the gold-doped sulfide material. The protective atmosphere is nitrogen or an inert atmosphere.

[0022] As a further preferred embodiment, the present invention provides a method for preparing a gold-doped sulfide material, wherein the mass ratio of Au-doped iron-sulfur compound particles to elemental sulfur is 2-10:0.8-4, preferably 3.1-8.2:1.4-3.6; and the Au-doped iron-sulfur compound particles obtained in step one are mixed evenly with elemental sulfur.

[0023] This invention discloses a method for preparing gold-doped sulfide materials, wherein the dopant in the prepared gold-doped sulfide materials is gold, and the main material is iron disulfide.

[0024] The present invention discloses a method for preparing gold-doped sulfide materials, wherein the prepared gold-doped sulfide materials have a particle size of 1.5 to 34.5 micrometers, preferably 4.8 to 10.3 micrometers, and more preferably 8.2 to 9.9 micrometers.

[0025] This invention discloses a method for preparing gold-doped sulfide materials, using a Li-B alloy as the negative electrode material, LiCl-LiBr-KBr as the electrolyte, and nano-MgO as the separating powder; the obtained gold-doped sulfide material is used as the positive electrode material; after being assembled into a thermal battery, the thermal battery operates at a temperature of 500°C, and the pulse test conditions are set at 200 mA cm⁻¹. -2 Discharged for 12 seconds at a current density, then the current density was increased to 600 mA cm⁻¹. -2 Discharge for 1 second, and repeat this cycle 25 times. At a cutoff voltage of 1.4V, its discharge specific capacity is greater than or equal to 361mAh / g, and its internal resistance is less than or equal to 0.102Ω. After optimization, at a cutoff voltage of 1.4V, its discharge specific capacity is 361~379mAh / g, and its internal resistance is 0.085~0.102Ω.

[0026] This invention is the first to discover a hydrothermal method at a lower temperature to construct a doped framework and form uniform and complete micron and / or nano-sized Au dopants on the framework; then, a sulfur replenishment process is used to make the dopants more stably embedded in the FeS2 particles, thereby enabling the product to have excellent thermal stability and high effective discharge capacity when used as a thermal battery.

[0027] The main advantages of this technical solution are:

[0028] This invention employs a low-temperature hydrothermal reaction. The initial hydrothermal method improves the synthesis efficiency of Au-doped iron disulfide particles. After heat treatment, high-purity iron disulfide is obtained, and the gold dopant is more firmly attached to the bulk iron disulfide phase, forming a doped composite material. The sulfidation heat treatment of this invention results in a more stable crystal structure for Au-doped FeS2.

[0029] The doped material prepared by this invention exhibits significantly improved thermal stability, with the thermal decomposition temperature increasing from 569.4℃ to 592.0℃~612.2℃ compared to pure iron disulfide. The material also shows significantly improved room-temperature conductivity, with the room-temperature conductivity increasing several times compared to pure iron disulfide. During discharge, the material reduces the internal resistance of the thermal battery, improving its specific power characteristics. Furthermore, the material reduces self-loss during discharge, significantly improving the discharge voltage plateau characteristics. The effective discharge capacity of the battery is thus significantly increased. This preparation method is simple, easy to control, and suitable for large-scale production, playing a crucial role in improving the cost-effectiveness of thermal battery materials. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the synthesis of Au-doped pyrite materials.

[0031] Figure 2 XRD pattern of a doped composite material formed by iron disulfide and doped pyrite.

[0032] Figure 3 SEM image of the doped composite material formed by iron disulfide and gold doping in Example 4.

[0033] Figure 4 In Example 4, a single-cell battery composed of a doped composite material formed by iron disulfide and gold doping, and a single-cell battery composed of undoped Au, were tested at 500°C and 200 mA / cm². 2 Voltage-specific capacity discharge curve under current density conditions;

[0034] Figure 5 In Example 4, a single-cell battery composed of a doped composite material formed by iron disulfide and gold doping, and a single-cell battery composed of undoped Au, were tested at 500°C and 300 mA / cm². 2 Voltage-specific capacity discharge curve under current density conditions;

[0035] Figure 6 TG curve of the sulfide composite material formed by iron disulfide and gold doping in Example 3.

[0036] from Figure 1The synthesis process of the doped material can be seen from this.

[0037] from Figure 2 The presence of gold dopant can be observed.

[0038] from Figure 3 The improved and optimized morphology and structure of gold-doped iron disulfide can be seen.

[0039] from Figure 4 It can be seen that the effective discharge platform of the doped material is extended by 5.2% compared with iron disulfide, and the specific capacity increases by 31%.

[0040] The internal resistance was reduced by 22.5% to mAh g⁻¹.

[0041] from Figure 5 It can be seen that the effective discharge platform of the doped sulfide material is extended by 6.4% compared with that of iron disulfide, the specific capacity is increased by 35 mA h g-1, and the internal resistance is reduced by 24.1%.

[0042] from Figure 6 The results show the thermal stability of doped sulfide materials compared to pure iron disulfide. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0044] Example 1

[0045] HAuCl4·3H2O was added to a deionized aqueous solution and stirred thoroughly to ensure homogeneity. 20g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:1 was added, followed by an appropriate amount of deionized water. Then, a solution containing a certain amount of HAuCl4·3H2O was added (at this point, the molar ratio of Au to Na2S2O3 in the solution was nAu:nNa2S2O3 = 0.051:8333). The mixture was transferred to an autoclave and heated to 150℃ at a heating rate of 10℃ / min, and held at this temperature for 15h. After holding, the sample was cooled to room temperature with the furnace to obtain Au-doped iron-sulfur compound particles. 26g of Au-doped iron-sulfur compound particles were mixed evenly with 4g of sulfur powder (the average particle size of the sulfur powder was approximately 16 micrometers). The mixture was placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10℃ / min, reaching 300℃ and held for 15 hours. Then, the temperature was increased to 400℃ at a rate of 10℃ / min and held for 20 hours. The mixture was then cooled to room temperature in the furnace to obtain the product, which was a gold-doped sulfide material.

[0046] A single thermal battery cell was fabricated using gold-doped sulfide and iron disulfide as cathode materials, LiCl-LiBr-LiF as electrolyte, and nano-MgO as separator powder, respectively. The cathode sheet and electrolyte separator were placed in a mold and pressed into a 17mm diameter sheet under a pressure of 20MPa. Furthermore, the cathode separator sheet and Li-B alloy anode sheet were stacked and pressed together to form a stacked single cell. After assembling the single cell, electrochemical tests were performed at 500℃. To study the total polarization, the pulse test conditions were set at 200mA cm⁻¹. -2 Discharged for 12 seconds at a current density, then the current density was increased to 600 mA cm⁻¹. -2 Discharge for 1 second, this cycle is repeated 25 times. The effective discharge plateau of the gold-doped sulfide material was measured to be 5.2% longer than that of iron disulfide, and the specific capacitance at a cutoff voltage of 1.4V was 361 mA hg. -1 The specific capacity of FeS2 (348 mA hg) -1 ) Increased by 13mA hg -1 Its internal resistance is 0.102Ω, which is 9.74% lower than that of FeS2 (0.113Ω).

[0047] Example 2

[0048] HAuCl4·3H2O was added to a deionized aqueous solution and stirred thoroughly to ensure homogeneity. 25g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:2 was added, followed by an appropriate amount of deionized water. Then, a solution containing a certain amount of HAuCl4·3H2O was added (at this point, the molar ratio of Au to Na2S2O3 in the solution was nAu:nNa2S2O3 = 0.254:16666). The mixture was transferred to an autoclave and heated to 160℃ at a heating rate of 10℃ / min, and held at this temperature for 15 hours. After holding, the sample was cooled to room temperature with the furnace to obtain Au-doped iron-sulfur compound particles. 26g of Au-doped iron-sulfur compound particles were mixed evenly with 4g of sulfur powder (the average particle size of the sulfur powder was approximately 16 micrometers). The mixture was placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10℃ / min, reaching 300℃ and held for 15 hours. Then, the temperature was increased to 400℃ at a rate of 10℃ / min and held for 20 hours. The mixture was then cooled to room temperature in the furnace to obtain the product, which was a gold-doped sulfide material.

[0049] A single thermal battery cell was fabricated using gold-doped sulfide and iron disulfide as cathode materials, LiCl-LiBr-LiF as electrolyte, and nano-MgO as separator powder, respectively. The cathode sheet and electrolyte separator were placed in a mold and pressed into a 17mm diameter sheet under a pressure of 20MPa. Furthermore, the cathode separator sheet and Li-B alloy anode sheet were stacked and pressed together to form a stacked single cell. After assembling the single cell, electrochemical tests were performed at 500℃. To study the total polarization, the pulse test conditions were set at 200mA cm⁻¹. -2 Discharged for 12 seconds at a current density, then the current density was increased to 600 mA cm⁻¹. -2 Discharge for 1 second, this cycle is repeated 25 times. At a cutoff voltage of 1.4V, the effective discharge plateau of the gold-doped sulfide material was measured to be 6.4% longer than that of iron disulfide, and the specific capacity was 367 mA hg. -1 Compared to the specific capacity of FeS2 (348 mA hg) -1 ) Increased by 19mA hg -1 Its internal resistance is 0.095Ω, which is 15.9% lower than that of FeS2 (0.113Ω).

[0050] Example 3

[0051] HAuCl4·3H2O was added to a deionized aqueous solution and stirred thoroughly to ensure homogeneity. 30g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:3 was added, followed by an appropriate amount of deionized water. Then, a solution containing a certain amount of HAuCl4·3H2O was added (at this point, the molar ratio of Au to Na2S2O3 in the solution was nAu:nNa2S2O3 = 0.457:24999). The mixture was transferred to an autoclave and heated to 170℃ at a heating rate of 10℃ / min, and held at this temperature for 15 hours. After holding, the sample was cooled to room temperature with the furnace to obtain Au-doped iron-sulfur compound particles. 26g of Au-doped iron-sulfur compound particles were mixed evenly with 4g of sulfur powder (the average particle size of the sulfur powder was approximately 16 micrometers). The mixture was placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10℃ / min, reaching 300℃ and held for 15 hours. Then, the temperature was increased to 400℃ at a rate of 10℃ / min and held for 20 hours. The mixture was then cooled to room temperature in the furnace to obtain the product, which was a gold-doped sulfide material.

[0052] A single thermal battery cell was fabricated using gold-doped sulfide and iron disulfide as cathode materials, LiCl-LiBr-LiF as electrolyte, and nano-MgO as separator powder, respectively. The cathode sheet and electrolyte separator were placed in a mold and pressed into a 17mm diameter sheet under a pressure of 20MPa. Furthermore, the cathode separator sheet and Li-B alloy anode sheet were stacked and pressed together to form a stacked single cell. After assembling the single cell, electrochemical tests were performed at 500℃. To study the total polarization, the pulse test conditions were set at 200mA cm⁻¹. -2 Discharged for 12 seconds at a current density, then the current density was increased to 600 mA cm⁻¹. -2 Discharge for 1 second, this cycle is repeated 25 times. At a cutoff voltage of 1.4V, the effective discharge plateau of the gold-doped sulfide material was measured to be 5.2% longer than that of iron disulfide, and the specific capacity was 375 mA hg. -1 Compared to FeS2 (348mA hg) -1 ) Increased by 27mA hg -1 Its internal resistance is 0.089Ω, which is 21.2% lower than that of FeS2 (0.113Ω).

[0053] Example 4

[0054] HAuCl4·3H2O was added to a deionized aqueous solution and stirred thoroughly to ensure homogeneity. 40g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:3 was added, followed by an appropriate amount of deionized water. Then, a solution containing a certain amount of HAuCl4·3H2O was added (at this point, the molar ratio of Au to Na2S2O3 in the solution was nAu:nNa2S2O3 = 0.659:24999). The mixture was transferred to an autoclave and heated to 180℃ at a heating rate of 10℃ / min, and held at this temperature for 15 hours. After holding, the sample was cooled to room temperature with the furnace, yielding Au-doped iron-sulfur compound particles. 26g of Au-doped iron-sulfur compound particles were mixed evenly with 4g of sulfur powder (the average particle size of the sulfur powder was approximately 16 micrometers). The mixture was placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10℃ / min, reaching 300℃ and held for 15 hours. Then, the temperature was increased to 440℃ at a rate of 10℃ / min and held for 20 hours. The mixture was then cooled to room temperature in the furnace to obtain the product, which was a gold-doped sulfide material.

[0055] The cathode sheet and electrolyte membrane were placed in a mold and pressed into a sheet with a diameter of 17 mm under a pressure of 20 MPa. Furthermore, cathode membrane particles and Li-B alloy anode sheets were stacked and pressed together to form a stacked single cell. After assembling the single cell, electrochemical tests were performed at 500 °C. To study the total polarization, the pulse test conditions were set at 200 mA cm⁻¹. -2Discharged for 12 seconds at a current density, then the current density was increased to 600 mA cm⁻¹. -2 Discharge for 1 second, this cycle is repeated 25 times. At a cutoff voltage of 1.4V, the effective discharge plateau of the gold-doped sulfide material was measured to be 7.5% longer than that of iron disulfide, and the specific capacity was 379 mA hg. -1 Compared to FeS2 (348mA hg) -1 ) Increased by 31mA hg -1 Its internal resistance is 0.085Ω, which is 24.7% lower than that of FeS2 (0.113Ω).

[0056] Comparative Example 1

[0057] Add HAuCl4·3H2O to the deionized water solution and stir thoroughly to ensure homogeneity. Add 20g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:1, then add an appropriate amount of deionized water, followed by a solution containing a certain amount of HAuCl4·3H2O (at this point, the molar ratio of Au to Na2S2O3 in the solution is nAu:nNa2S2O3 = 0.051:8333). Transfer the mixture to an autoclave and heat to 110℃ at a heating rate of 10℃ / min, holding at this temperature for 10 hours. After holding, cool the sample to room temperature with the autoclave. Au-doped iron sulfide compound particles were obtained. 26g of these particles were mixed evenly with 4g of sulfur powder (the average particle size of the sulfur powder was approximately 16 micrometers). The mixture was placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10℃ / min, reaching 300℃ and held for 15 hours. Then, the temperature was increased again at 10℃ / min to 350℃ and held for 5 hours. The mixture was then cooled to room temperature in the furnace to obtain the product, which was a gold-doped sulfide material.

[0058] A single thermal cell was fabricated using gold-doped sulfide cathode material, LiCl-LiBr-LiF as electrolyte, and nano-MgO as separator powder. The cathode sheet and electrolyte separator were placed in a mold and pressed into a 17mm diameter sheet under a pressure of 20MPa. Furthermore, cathode separator particles and Li-B alloy anode sheets were stacked and pressed to form a stacked single cell. After assembly, electrochemical tests were performed at 500℃. To study the total polarization, the pulse test conditions were set at 200mA cm⁻¹. -2 Discharged for 12 seconds at a current density, then the current density was increased to 600 mA cm⁻¹. -2 Discharge for 1 second, and this cycle is repeated 25 times. At a cutoff voltage of 1.4V, compared to the gold-doped sulfide material in Example 1, this gold-doped sulfide exhibits a 9.2% reduction in effective discharge plateau and an effective discharge specific capacity of 321 mA hg. -140 mA hg lower than in Example 1 -1 The internal resistance is 0.125Ω, which is 22.55% higher than that of Example 1.

[0059] Comparative Example 2

[0060] Add HAuCl4·3H2O to the deionized water solution and stir thoroughly to ensure homogeneity. Add 20g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:2, then add an appropriate amount of deionized water, followed by a solution containing a certain amount of HAuCl4·3H2O (at this point, the molar ratio of Au to Na2S2O3 in the solution is nAu:nNa2S2O3 = 0.254:16666). Transfer the mixture to an autoclave and heat to 100℃ at a heating rate of 10℃ / min, holding at this temperature for 15 hours. After holding, cool the sample to room temperature with the autoclave. Au-doped iron sulfide compound particles were obtained. 26g of these particles were mixed evenly with 4g of sulfur powder (the average particle size of the sulfur powder was approximately 16 micrometers). The mixture was placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10℃ / min, reaching 300℃ and held for 15 hours. Then, the temperature was increased again at 10℃ / min to 350℃ and held for 5 hours. The mixture was then cooled to room temperature in the furnace to obtain the product, which was a gold-doped sulfide material.

[0061] Using the gold-doped sulfide material, LiCl-LiBr-LiF as the electrolyte, and nano-MgO as the separator, single thermal cells were fabricated. The cathode sheet and electrolyte membrane were placed in a mold and pressed into a sheet with a diameter of 17 mm under a pressure of 20 MPa. Furthermore, the cathode electrolyte membrane sheet and Li-B alloy anode sheet were stacked and pressed together to form a stacked single cell. After assembling the single cells, electrochemical tests were performed at 500 °C. To study the total polarization, the pulse test conditions were set at 200 mA cm⁻¹. -2 Discharged for 12 seconds at a current density, then the current density was increased to 600 mA cm⁻¹. -2 Discharge for 1 second, and this cycle is repeated 25 times. At a cutoff voltage of 1.4V, compared to the gold-doped sulfide material in Example 2, this gold-doped sulfide exhibits an 11.4% reduction in effective discharge plateau and an effective discharge specific capacity of 324 mA hg. -1 43 mA hg lower than in Example 2 -1 The internal resistance is 0.129Ω, which is 35.78% higher than that of Example 2.

[0062] Comparative Example 3

[0063] All other conditions are the same as in Example 3, except that:

[0064] HAuCl4·3H2O was added to a deionized aqueous solution and stirred thoroughly to ensure homogeneity. 20g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:3 was added, followed by an appropriate amount of deionized water. Then, a solution containing a certain amount of HAuCl4·3H2O was added (at this point, the molar ratio of Au to Na2S2O3 in the solution was nAu:nNa2S2O3 = 0.457:24999). The mixture was transferred to an autoclave and heated to 200℃ at a heating rate of 10℃ / min, and held at this temperature for 15 hours. After holding, the sample was cooled to room temperature with the furnace to obtain Au-doped iron-sulfur compound particles. Au-doped iron sulfide compound particles were obtained. 26g of these particles were mixed evenly with 4g of sulfur powder (the average particle size of the sulfur powder was approximately 16 micrometers). The mixture was placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10℃ / min, reaching 300℃ and held for 15 hours. Then, the temperature was increased again at 10℃ / min to 350℃ and held for 5 hours. The mixture was then cooled to room temperature in the furnace to obtain the product, which was a gold-doped sulfide material.

[0065] Using the gold-doped sulfide material, LiCl-LiBr-LiF as the electrolyte, and nano-MgO as the separator, single thermal cells were fabricated. The cathode sheet and electrolyte membrane were placed in a mold and pressed into a sheet with a diameter of 17 mm under a pressure of 20 MPa. Furthermore, the cathode electrolyte membrane sheet and Li-B alloy anode sheet were stacked and pressed together to form a stacked single cell. After assembling the single cells, electrochemical tests were performed at 500 °C. To study the total polarization, the pulse test conditions were set at 200 mA cm⁻¹. -2 Discharged for 12 seconds at a current density, then the current density was increased to 600 mA cm⁻¹. -2 Discharge for 1 second, and this cycle is repeated 25 times. At a cutoff voltage of 1.4V, compared to the gold-doped sulfide material in Example 3, this gold-doped sulfide exhibits a 10.9% reduction in effective discharge plateau and an effective discharge specific capacity of 322 mA hg. -1 53 mA hg lower than in Example 3 -1 The internal resistance is 0.124Ω, which is 39.33% higher than that of Example 3.

[0066] Comparative Example 4

[0067] All other conditions are the same as in Example 4, except that:

[0068] HAuCl4·3H2O was added to a deionized aqueous solution and stirred thoroughly to ensure homogeneity. 20g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:3 was added, followed by an appropriate amount of deionized water. Then, a solution containing a certain amount of HAuCl4·3H2O was added (at this point, the molar ratio of Au to Na2S2O3 in the solution was nAu:nNa2S2O3 = 0.659:24999). The mixture was transferred to an autoclave and heated to 200℃ at a heating rate of 10℃ / min, and held at this temperature for 15 hours. After holding, the sample was cooled to room temperature with the furnace to obtain Au-doped iron-sulfur compound particles. 26g of Au-doped iron-sulfur compound particles were mixed evenly with 4g of sulfur powder (the average particle size of the sulfur powder was approximately 16 micrometers). The mixture was placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10℃ / min, reaching 300℃ and held for 15 hours. Then, the temperature was increased to 440℃ at a rate of 10℃ / min and held for 20 hours. The mixture was then cooled to room temperature in the furnace to obtain the product, which was a gold-doped sulfide material.

[0069] Using the gold-doped sulfide material, LiCl-LiBr-LiF as the electrolyte, and nano-MgO as the separator, single thermal cells were fabricated. The cathode sheet and electrolyte membrane were placed in a mold and pressed into a sheet with a diameter of 17 mm under a pressure of 20 MPa. Furthermore, the cathode electrolyte membrane sheet and Li-B alloy anode sheet were stacked and pressed together to form a stacked single cell. After assembling the single cells, electrochemical tests were performed at 500 °C. To study the total polarization, the pulse test conditions were set at 200 mA cm⁻¹. -2 Discharged for 12 seconds at a current density, then the current density was increased to 600 mA cm⁻¹. -2 Discharge for 1 second, and this cycle is repeated 25 times. At a cutoff voltage of 1.4V, compared to the gold-doped sulfide material in Example 4, this gold-doped sulfide exhibits a 15.3% reduction in effective discharge plateau and an effective discharge specific capacity of 342 mA hg. -1 37 mA hg lower than in Example 4 -1 The internal resistance is 0.129Ω, which is 51.76% higher than that of Example 4.

[0070] During the technology development process, we also studied mixing sulfur with hydrothermal intermediates and then heating the mixture to below 350°C for sulfurization protection sintering. However, the resulting composite material contained other phases composed of Fe and S. Furthermore, when assembled into a thermal battery, its performance was inferior to that of this invention.

Claims

1. An application of a gold-doped sulfide material, characterized in that: Using gold-doped sulfide material as the positive electrode material, LiCl-LiBr-LiF as the electrolyte, and nano-MgO as the separator powder, a single thermal battery cell was made. The cathode sheet and electrolyte membrane were placed in a mold and pressed into a sheet with a diameter of 17 mm under a pressure of 20 MPa. In addition, the cathode membrane sheet and Li-B alloy anode sheet were stacked and pressed to form a stacked single cell. The gold-doped sulfide material was prepared by the following process: HAuCl4·3H2O was added to a deionized aqueous solution and stirred thoroughly to ensure a homogeneous mixture. 20g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:1 was added, followed by an appropriate amount of deionized water. Then, a solution containing a certain amount of HAuCl4·3H2O was added. At this point, the molar ratio of Au to Na2S2O3 in the solution was nAu:nNa2S2O3 = 0.051:8333. The mixture was transferred to an autoclave and heated to 150℃ at a heating rate of 10℃ / min, and held at this temperature for 15 h. After holding, the sample was cooled to room temperature with the furnace to obtain Au-doped iron-sulfur compound particles. 26g of the obtained Au-doped iron-sulfur compound particles were mixed evenly with 4g of sulfur powder, the average particle size of which was 16g. The micrometers were placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10 °C / min, and the temperature was raised to 300 °C and held for 15 h. Then the temperature was increased to 400 °C at a rate of 10 °C / min and held for 20 h. The product was then cooled to room temperature with the furnace to obtain the gold-doped sulfide material.

2. An application of a gold-doped sulfide material, characterized in that: Using gold-doped sulfide material as the positive electrode material, LiCl-LiBr-LiF as the electrolyte, and nano-MgO as the separator powder, a thermal battery single cell is made. The cathode sheet and electrolyte membrane are placed in a mold and pressed into a sheet with a diameter of 17 mm under a pressure of 20 MPa. In addition, the cathode membrane sheet and Li-B alloy anode sheet are stacked and pressed to form a stacked single cell. The gold-doped sulfide material is prepared by the following process: Add HAuCl4·3H2O to the deionized water solution and stir thoroughly to ensure a homogeneous mixture. Then add 25g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:

2. Add an appropriate amount of deionized water, then add a solution containing a certain amount of HAuCl4·3H2O. At this point, the molar ratio of Au to Na2S2O3 in the solution is nAu:nNa2S2O3 = 0.254:16666. Transfer the mixture to an autoclave and heat it to 160℃ at a heating rate of 10 ℃ / min. Hold the temperature for 15 h. After holding, cool the sample to room temperature with the furnace to obtain Au-doped iron-sulfur compound particles. Mix 26 g of the obtained Au-doped iron-sulfur compound particles with 4 g of sulfur powder evenly. The average particle size of the sulfur powder is 16 micrometers. Place the mixture in a nitrogen-protected reactor. During the reaction, the heating rate is 10 ℃ / min. Heat to 300 ℃ and hold for 15 h, then heat to 400 ℃ at 10 ℃ / min and hold for 20 h. Then cool to room temperature with the furnace to obtain the product, which is a gold-doped sulfide material.

3. An application of a gold-doped sulfide material, characterized in that: Using gold-doped sulfide material as the positive electrode material, LiCl-LiBr-LiF as the electrolyte, and nano-MgO as the separator powder, a thermal battery single cell is made. The cathode sheet and electrolyte membrane are placed in a mold and pressed into a sheet with a diameter of 17 mm under a pressure of 20 MPa. In addition, the cathode membrane sheet and Li-B alloy anode sheet are stacked and pressed to form a stacked single cell. Add HAuCl4·3H2O to the deionized water solution and stir thoroughly to ensure a homogeneous mixture. Then add 30g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:

3. Add an appropriate amount of deionized water, then add a solution containing a certain amount of HAuCl4·3H2O. At this point, the molar ratio of Au to Na2S2O3 in the solution is nAu:nNa2S2O3 = 0.457:24999. Transfer the mixture to an autoclave and heat it to 170℃ at a heating rate of 10 ℃ / min. Hold the temperature for 15 h. After holding, cool the sample to room temperature with the furnace to obtain Au-doped iron-sulfur compound particles. Mix 26 g of the obtained Au-doped iron-sulfur compound particles with 4 g of sulfur powder evenly. The average particle size of the sulfur powder is 16 micrometers. Place the mixture in a nitrogen-protected reactor. During the reaction, the heating rate is 10 ℃ / min. Heat to 300 ℃ and hold for 15 h, then heat to 400 ℃ at 10 ℃ / min and hold for 20 h. Then cool to room temperature with the furnace to obtain the product, which is a gold-doped sulfide material.

Images