Preparation method of gold-doped sulfide material

Abstract

The invention relates to the field of manufacturing of thermal battery electrode materials, in particular to a preparation method of a gold-doped sulfide material. According to the preparation method, a doping framework is constructed by adopting a hydrothermal method with relatively low temperature, and a uniform and complete micron and / or nano-scale Au doping agent is formed on the framework; and then the dopant is more stably embedded in the FeS2 particles by utilizing a sulfur supplementing process, so that the product has excellent thermal stability and relatively high effective discharge capacity when being used as a thermal battery. The specific discharge capacity of the obtained product is greater than or equal to 361mAh / g, and the internal resistance is less than or equal to 0.102 omega. The process is simple and controllable, the obtained product is excellent in performance, and industrial application is facilitated.

Description

Technical Field

[0001] The invention relates to the field of manufacturing thermal battery electrode materials, in particular to a method for preparing a gold-doped sulfide material. Background Art

[0002] Thermal battery is a special battery with molten salt as electrolyte. Thermal battery has the characteristics of high power density, high energy density, long storage time, rapid and reliable activation, suitable for various harsh working conditions, and simple and convenient use. Therefore, it is mainly used as a power source for high-tech weapons such as missiles, guided bombs, and torpedoes. In the civilian field, thermal batteries also have broad application prospects as aircraft emergency power supplies, underground high-temperature prospecting equipment power supplies, and fire alarm power supplies. At present, the widely used positive electrode material is mainly pyrite iron disulfide (FeS2). This material has moderate capacity, moderate discharge voltage, and low price. The problem is that the performance is related to the selection of the mine site. In particular, with the increase in the activity of the negative electrode material of the thermal battery (from Li-Al, Li-Si to Li-B alloy), the application of all-lithium electrolytes, the operating temperature of the thermal battery has been greatly increased, and the requirements for specific power and specific energy indicators have also been continuously improved. The problems of low thermal decomposition temperature (550℃) of iron disulfide, large internal resistance, and serious self-discharge have become extremely prominent.

[0003] Gurpreet Kaur et al. used FeCl2·4H2O, Na2S2O3·5H2O and HAuCl4·3H2O as raw materials, dissolved them in aqueous solution, and placed the mixed solution at 200℃ for 24h. A photocatalyst Au@FeS2 for the degradation of textile dyes was synthesized. Au@FeS2 showed good photocatalytic activity and good reusability under visible light irradiation, but it did not involve the thermal stability and effective discharge capacity of the product. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention proposes for the first time to use a relatively low-temperature hydrothermal method to construct a doping framework, and then utilizes a sulfur-supplementing process to achieve a more stable embedding of dopants in FeS2 particles, thereby enabling the product to have excellent thermal stability and a higher effective discharge capacity when used as a thermal battery.

[0005] The present invention proposes for the first time to prepare Au-containing iron sulfide compound particles by a relatively low temperature hydrothermal synthesis method, and then introduce sulfur to form an Au-containing FeS2 complex having excellent thermal stability and a relatively high effective discharge capacity at a relatively high temperature.

[0006] The present invention provides a method for preparing a gold-doped sulfide material, the preparation method comprising the following steps:

[0007] Step 1

[0008] The method comprises the following steps: using an Au-containing solution as a raw material; adding a sulfur source and an Fe source to the Au-containing solution and stirring the solution; placing the solution in a high-pressure reactor; reacting the solution at 120 to 180° C., preferably 150 to 180° C. for at least 7 hours; cooling the solution; performing solid-liquid separation; and obtaining Au-doped iron sulfide compound particles;

[0009] Step 2

[0010] In a sulfur-containing atmosphere, the Au-doped iron sulfide compound particles obtained in step 1 are heated to 300-400° C. and kept at this temperature for at least 5 hours; and cooled in the furnace to obtain a gold-doped sulfide material;

[0011] or

[0012] The Au-doped ferrosulfide particles obtained in step 1 are uniformly mixed with elemental sulfur; the temperature is raised to 350-440° C. in a protective atmosphere and kept warm for at least 7 hours; and the furnace is cooled to obtain the gold-doped sulfide material.

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

[0014] The present invention provides a method for preparing a gold-doped sulfide material, wherein the solute of the Au-containing solution is a soluble Au-containing substance. When used in industry, 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 ammonium 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 more preferably 12:1.

[0016] The present invention provides a method for preparing a gold-doped sulfide material, wherein in step 1,

[0017] According to the molar ratio, nAu:nFe=0.051~0.661:8333, prepare the Au source (soluble Au-containing substance) and the Fe source.

[0018] When used in industry, a soluble Au-containing substance and water-soluble divalent Fe are prepared, and the prepared soluble Au-containing substance is first dissolved in water to obtain an Au-containing solution; the Au-containing solution is used as a raw material; thiosulfate and the prepared Fe source are added to the Au-containing solution; the solution is stirred; the solution is then placed in a high-pressure reactor, heated to 130-180°C at a heating rate of 5-15°C / min, and kept warm for 10-22h; the solution is cooled; and solid-liquid separation is performed to obtain Au-doped ferrosulfide compound particles.

[0019] Preferably, in step 1 of the present invention, the cooling means that the product is cooled to 25-35° C. in the furnace.

[0020] In industrial applications, the product obtained in step 1 is washed with deionized water and then dried to obtain a precursor of the product, which is then mixed with elemental sulfur and sintered.

[0021] The present invention provides a method for preparing a gold-doped sulfide material. In step 2, the Au-doped sulfide compound particles obtained in step 1 are mixed evenly with elemental sulfur; the mixture is placed in a sintering furnace in a protective atmosphere, and the temperature is first increased to 300-350° C. at a heating rate of 5-15° C. / min and kept for 5-20 hours; the temperature is then increased to 350-440° C., preferably 390-400° C. and kept for 7-30 hours; the mixture is cooled with the furnace to obtain the gold-doped sulfide material. The protective atmosphere is nitrogen or an inert atmosphere.

[0022] As a further preference, the present invention provides a method for preparing a gold-doped sulfide material, wherein the mass ratio of Au-doped ferrosulfide compound particles: elemental sulfur is 2-10:0.8-4, preferably 3.1-8.2:1.4-3.6; the Au-doped ferrosulfide compound particles obtained in step 1 are uniformly mixed with elemental sulfur.

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

[0024] The present invention provides a method for preparing a gold-doped sulfide material. The particle size of the prepared gold-doped sulfide material is 1.5 to 34.5 microns, preferably 4.8 to 10.3 microns, and more preferably 8.2 to 9.9 microns.

[0025] The invention discloses a preparation method of a gold-doped sulfide material, wherein Li-B alloy is used as a negative electrode material, LiCl-LiBr-KBr is used as an electrolyte, and nano-MgO is used as an isolation powder; the obtained gold-doped sulfide material is used as a positive electrode material; after being assembled into a thermal battery, the thermal battery is operated at a temperature of 500°C, and the pulse test conditions are set as: at 200 mA cm -2 The battery was discharged at a current density of 100 mA cm for 12 seconds and then the current density was increased to 600 mA cm -2 Discharge for 1 second, and repeat this cycle 25 times. When the cut-off voltage is 1.4V, the discharge capacity is greater than or equal to 361mAh / g, and the internal resistance is less than or equal to 0.102Ω. After optimization, when the cut-off voltage is 1.4V, the discharge capacity is 361~379mAh / g, and the internal resistance is 0.085~0.102Ω.

[0026] The present invention discovered for the first time that a relatively low temperature hydrothermal method is used to construct a doping framework and form uniform and complete micrometer and / or nanometer-scale Au dopants on the framework; then a sulfur supplementation process is used to achieve a more stable embedding of the dopants in the FeS2 particles, thereby enabling the product to have excellent thermal stability and a higher effective discharge capacity when used as a thermal battery.

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

[0028] The present invention adopts a hydrothermal reaction at a relatively low temperature. The hydrothermal method used in the early stage can improve the synthesis efficiency of Au-doped iron sulfide compound particles. After heat treatment, high-purity iron disulfide can be obtained, and the gold doping can be more stably attached to the iron disulfide bulk phase to form a doped composite material. The sulfurization heat treatment of the present invention makes the Au-doped FeS2 have a more stable crystal structure.

[0029] The doped material prepared by the present invention has significantly improved thermal stability. Compared with pure iron disulfide, the thermal decomposition temperature is increased from 569.4°C to 592.0°C to 612.2°C; the room temperature conductivity of the material is significantly improved. Compared with pure iron disulfide, the room temperature conductivity is doubled; when the material is discharged, the internal resistance of the thermal battery is reduced, and the specific power characteristics of the thermal battery are improved; when the material is discharged, the self-consumption of the thermal battery is reduced, and the discharge voltage platform characteristics are significantly improved. The effective discharge capacity of the battery is significantly improved. This preparation method is simple, easy to control, and suitable for large-scale production. It plays an important and key role in improving the cost performance of thermal battery materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the synthesis of Au-doped pyrite material.

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

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

[0033] Figure 4 The single cell composed of the doped composite material formed by iron disulfide and doped gold in Example 4 and the single cell composed of undoped Au were subjected to the conditions of 500°C and 200 mA / cm 2 Voltage-specific capacity discharge curve under current density conditions;

[0034] Figure 5 The single cell composed of the doped composite material formed by iron disulfide and doped gold in Example 4 and the single cell composed of undoped Au were tested at 500°C and 300 mA / cm 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 doped gold in Example 3.

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

[0037] from Figure 2 It can be seen that the dopant gold is generated.

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

[0039] from Figure 4 It can be seen that the effective discharge platform of the doped material is 5.2% longer than that of iron disulfide, and the specific capacity is increased by 31

[0040] mAh g-1, the internal resistance decreased by 22.5%.

[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 iron disulfide, the specific capacity is increased by 35mA h g-1, and the internal resistance is reduced by 24.1%.

[0042] from Figure 6 The thermal stability of doped sulfide materials and pure iron disulfide can be seen in the figure. DETAILED DESCRIPTION

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

[0044] Example 1

[0045] HAuCl4·3H2O was added to the deionized water solution, and the mixture was stirred thoroughly to ensure that the mixture was uniform. 20 g of a mixture consisting of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:1 was added thereto, and then an appropriate amount of deionized water was added, and then a solution containing a certain amount of HAuCl4·3H2O was added (at this time, the molar ratio of Au element to Na2S2O3 in the solution was nAu:nNa2S2O3=0.051:8333). The mixture was transferred to an autoclave, heated to 150°C at a heating rate of 10°C / min, and kept warm for 15 hours. After the warming, the sample was cooled to room temperature with the furnace to obtain Au-doped ferrosulfide particles. The Au-doped iron sulfide compound particles (26 g) were mixed evenly with 4 g of sulfur powder (the average particle size of the sulfur powder was about 16 microns), and placed in a nitrogen-protected reactor. During the reaction, the temperature was raised at a rate of 10°C / min to 300°C and kept for 15 hours. Then the temperature was raised to 400°C at a rate of 10°C / min and kept for 20 hours. Then the product was cooled to room temperature in the furnace to obtain a gold-doped sulfide material.

[0046] A single thermal battery cell was made using gold-doped sulfide material and iron disulfide as the positive electrode material, LiCl-LiBr-LiF as the electrolyte, and nano-MgO as the isolation powder. The cathode sheet and the electrolyte diaphragm 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 diaphragm sheet and the Li-B alloy anode sheet were stacked and pressed to form a stacked single cell. After the single cell was assembled, electrochemical tests were carried out at 500 ° C. To study the total polarization, the pulse test conditions were set as follows: at 200 mA cm -2 The battery was discharged at a current density of 100 mA cm for 12 seconds and then the current density was increased to 600 mA cm -2 Discharge for 1 second, and repeat this cycle 25 times. It is found that the effective discharge platform of gold-doped sulfide material is 5.2% longer than that of iron disulfide, and the specific capacity is 361mA hg at a cut-off voltage of 1.4V. -1 , compared with the specific capacity of FeS2 (348mA hg -1 ) increased by 13mA hg -1 The internal resistance is 0.102Ω, which is 9.74% lower than the internal resistance of FeS2 (0.113Ω).

[0047] Example 2

[0048] HAuCl4·3H2O was added to the deionized water solution, and the mixture was stirred thoroughly to ensure that the mixture was uniform. 25 g of a mixture consisting of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:2 was added thereto, and then an appropriate amount of deionized water was added, and then a solution containing a certain amount of HAuCl4·3H2O was added (at this time, the molar ratio of Au element to Na2S2O3 in the solution was nAu:nNa2S2O3=0.254:16666). The mixture was transferred to an autoclave, heated to 160°C at a heating rate of 10°C / min, and kept warm for 15 hours. After the warming, the sample was cooled to room temperature with the furnace to obtain Au-doped ferrosulfide particles. The Au-doped iron sulfide compound particles (26 g) were mixed evenly with 4 g of sulfur powder (the average particle size of the sulfur powder was about 16 microns), and placed in a nitrogen-protected reactor. During the reaction, the temperature was raised at a rate of 10°C / min to 300°C and kept for 15 hours. Then the temperature was raised to 400°C at a rate of 10°C / min and kept for 20 hours. Then the product was cooled to room temperature in the furnace to obtain a gold-doped sulfide material.

[0049] A single thermal battery cell was made using gold-doped sulfide material and iron disulfide as the positive electrode material, LiCl-LiBr-LiF as the electrolyte, and nano-MgO as the isolation powder. The cathode sheet and the electrolyte diaphragm 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 diaphragm sheet and the Li-B alloy anode sheet were stacked and pressed to form a stacked single cell. After the single cell was assembled, electrochemical tests were carried out at 500 ° C. To study the total polarization, the pulse test conditions were set as follows: at 200 mA cm -2 The battery was discharged at a current density of 100 mA cm for 12 seconds and then the current density was increased to 600 mA cm -2 Discharge for 1 second, and repeat this cycle 25 times. When the cut-off voltage is 1.4V, it is found that the effective discharge platform of the gold-doped sulfide material is 6.4% longer than that of iron disulfide, and the specific capacity is 367mA hg -1 , compared with the specific capacity of FeS2 (348mA hg -1 ) increased by 19mA hg -1 The internal resistance is 0.095Ω, which is 15.9% lower than the internal resistance of FeS2 (0.113Ω).

[0050] Example 3

[0051] HAuCl4·3H2O was added to the deionized water solution, and the mixture was stirred thoroughly to ensure that the mixture was uniform. 30 g of a mixture consisting of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:3 was added thereto, and then an appropriate amount of deionized water was added, and then a solution containing a certain amount of HAuCl4·3H2O was added (at this time, the molar ratio of Au element to Na2S2O3 in the solution was nAu:nNa2S2O3=0.457:24999), and the mixture was transferred to an autoclave, heated to 170°C at a heating rate of 10°C / min, and kept warm for 15 hours. After the warming, the sample was cooled to room temperature with the furnace to obtain Au-doped ferrosulfide particles. The Au-doped iron sulfide compound particles (26 g) were mixed evenly with 4 g of sulfur powder (the average particle size of the sulfur powder was about 16 microns), and placed in a nitrogen-protected reactor. During the reaction, the temperature was raised at a rate of 10°C / min to 300°C and kept for 15 hours. Then the temperature was raised to 400°C at a rate of 10°C / min and kept for 20 hours. Then the product was cooled to room temperature in the furnace to obtain a gold-doped sulfide material.

[0052] A single thermal battery cell was made using gold-doped sulfide material and iron disulfide as the positive electrode material, LiCl-LiBr-LiF as the electrolyte, and nano-MgO as the isolation powder. The cathode sheet and the electrolyte diaphragm 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 diaphragm sheet and the Li-B alloy anode sheet were stacked and pressed to form a stacked single cell. After the single cell was assembled, electrochemical tests were carried out at 500 ° C. To study the total polarization, the pulse test conditions were set as follows: at 200 mA cm -2 The battery was discharged at a current density of 100 mA cm for 12 seconds and then the current density was increased to 600 mA cm -2 Discharge for 1 second, and repeat this cycle 25 times. When the cut-off voltage is 1.4V, it is measured that the effective discharge platform of the gold-doped sulfide material is 5.2% longer than that of iron disulfide, and the specific capacity is 375mA hg -1 , compared with FeS2 (348mA hg -1 ) increased by 27mA hg -1 The internal resistance is 0.089Ω, which is 21.2% lower than the internal resistance of FeS2 (0.113Ω).

[0053] Example 4

[0054] HAuCl4·3H2O was added to the deionized water solution, and the mixture was stirred thoroughly to ensure that the mixture was uniform. 40 g of a mixture consisting of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:3 was added thereto, and then an appropriate amount of deionized water was added, and then a solution containing a certain amount of HAuCl4·3H2O was added (at this time, the molar ratio of Au element to Na2S2O3 in the solution was nAu:nNa2S2O3=0.659:24999), and the mixture was transferred to an autoclave, heated to 180°C at a heating rate of 10°C / min, and kept warm for 15 hours. After the heat preservation, the sample was cooled to room temperature with the furnace to obtain Au-doped ferrosulfide particles. The Au-doped iron sulfide compound particles (26 g) were mixed evenly with 4 g of sulfur powder (the average particle size of the sulfur powder was about 16 microns), and placed in a nitrogen-protected reactor. During the reaction, the temperature was raised at a rate of 10°C / min to 300°C and kept for 15 hours. Then the temperature was raised to 440°C at a rate of 10°C / min and kept for 20 hours. Then the product was cooled to room temperature in the furnace to obtain a gold-doped sulfide material.

[0055] The cathode sheet and electrolyte separator were placed in a mold and pressed into a sheet with a diameter of 17 mm at a pressure of 20 MPa. In addition, the cathode separator particles and the Li-B alloy anode sheet were stacked and pressed to form a stacked single cell. After the single cell was assembled, electrochemical testing was performed at 500 °C. To study the total polarization, the pulse test conditions were set as follows: -2The battery was discharged at a current density of 100 mA cm for 12 seconds and then the current density was increased to 600 mA cm -2 Discharge for 1 second, and repeat this cycle 25 times. When the cut-off voltage is 1.4V, it is found that the effective discharge platform of the gold-doped sulfide material is 7.5% longer than that of iron disulfide, and the specific capacity is 379mA hg -1 , compared with FeS2 (348mA hg -1 ) increased by 31mA hg -1 The internal resistance is 0.085Ω, which is 24.7% lower than the internal resistance of FeS2 (0.113Ω).

[0056] Comparative Example 1

[0057] HAuCl4·3H2O was added to the deionized water solution, and the mixture was stirred thoroughly to ensure that the mixture was uniform. 20 g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:1 was added thereto, and then an appropriate amount of deionized water was added, and then a solution containing a certain amount of HAuCl4·3H2O was added (at this time, the molar ratio of Au element to Na2S2O3 in the solution was nAu:nNa2S2O3=0.051:8333). The mixture was transferred to an autoclave, heated to 110°C at a heating rate of 10°C / min, and kept warm for 10 hours. After the warming, the sample was cooled to room temperature with the furnace. The Au-doped iron sulfide compound particles were obtained, and the Au-doped iron sulfide compound particles (26 g) were mixed with 4 g of sulfur powder (the average particle size of the sulfur powder was about 16 microns), and placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10°C / min to 300°C and kept for 15 hours. Then the temperature was increased at a rate of 10°C / min to 350°C and kept for 5 hours. Then the product was cooled to room temperature with the furnace to obtain a gold-doped sulfide material.

[0058] The thermal battery cells were made of gold-doped sulfide positive electrode materials, LiCl-LiBr-LiF as electrolyte, and nano-MgO as isolation powder. The cathode sheet and electrolyte separator 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 separator particles and Li-B alloy anode sheets were stacked and pressed to form a stacked single cell. After the single cell was assembled, electrochemical tests were carried out at 500 ° C. To study the total polarization, the pulse test conditions were set as follows: at 200 mA cm -2 The battery was discharged at a current density of 100 mA cm for 12 seconds and then the current density was increased to 600 mA cm -2 Discharge for 1 second, and repeat this cycle 25 times. When the cut-off voltage is 1.4V, compared with the gold-doped sulfide material in Example 1, the effective discharge platform of the gold-doped sulfide is reduced by 9.2%, and the effective discharge specific capacity is 321mA hg -140mA hg lower than Example 1 -1 The internal resistance is 0.125Ω, which is 22.55% higher than that of Example 1.

[0059] Comparative Example 2

[0060] HAuCl4·3H2O was added to the deionized water solution and stirred thoroughly to ensure that the mixture was uniform. 20 g of a mixture of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:2 was added thereto, and then an appropriate amount of deionized water was added, and then a solution containing a certain amount of HAuCl4·3H2O was added (at this time, the molar ratio of Au element to Na2S2O3 in the solution was nAu:nNa2S2O3=0.254:16666). The mixture was transferred to an autoclave and heated to 100°C at a heating rate of 10°C / min, and kept warm for 15 hours. After the warming, the sample was cooled to room temperature with the furnace. The Au-doped iron sulfide compound particles were obtained, and the Au-doped iron sulfide compound particles (26 g) were mixed with 4 g of sulfur powder (the average particle size of the sulfur powder was about 16 microns), and placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10°C / min to 300°C and kept for 15 hours. Then the temperature was increased at a rate of 10°C / min to 350°C and kept for 5 hours. Then the product was cooled to room temperature with the furnace to obtain a gold-doped sulfide material.

[0061] The gold-doped sulfide material was used to make a thermal battery cell with LiCl-LiBr-LiF as the electrolyte and nano-MgO as the separator powder. The cathode sheet and the electrolyte membrane were placed in a mold and pressed into a sheet with a diameter of 17 mm at a pressure of 20 MPa. In addition, the cathode electrolyte membrane sheet and the Li-B alloy anode sheet were stacked and pressed to form a stacked single cell. After the single cell was assembled, electrochemical tests were carried out at 500°C. To study the total polarization, the pulse test conditions were set as follows: at 200 mA cm -2 The battery was discharged at a current density of 100 mA cm for 12 seconds and then the current density was increased to 600 mA cm -2 Discharge for 1 second, and repeat this cycle 25 times. When the cut-off voltage is 1.4V, compared with the gold-doped sulfide material in Example 2, the effective discharge platform of the gold-doped sulfide is reduced by 11.4%, and the effective discharge specific capacity is 324mA hg -1 43 mA hg lower than Example 2 -1 The internal resistance is 0.129Ω, which is 35.78% higher than that of Example 2.

[0062] Comparative Example 3

[0063] Other conditions are the same as those in Example 3, except that:

[0064] HAuCl4·3H2O was added to the deionized water solution, and the mixture was stirred thoroughly to ensure that the mixture was uniform. 20 g of a mixture consisting of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:3 was added thereto, and then an appropriate amount of deionized water was added, and then a solution containing a certain amount of HAuCl4·3H2O was added (at this time, the molar ratio of Au element to Na2S2O3 in the solution was nAu:nNa2S2O3=0.457:24999), and the mixture was transferred to an autoclave, heated to 200°C at a heating rate of 10°C / min, and kept warm for 15 hours. After the heat preservation, the sample was cooled to room temperature with the furnace to obtain Au-doped ferrosulfide particles. The Au-doped iron sulfide compound particles were obtained, and the Au-doped iron sulfide compound particles (26 g) were mixed with 4 g of sulfur powder (the average particle size of the sulfur powder was about 16 microns), and placed in a nitrogen-protected reactor. During the reaction, the temperature was increased at a rate of 10°C / min to 300°C and kept for 15 hours. Then the temperature was increased at a rate of 10°C / min to 350°C and kept for 5 hours. Then the product was cooled to room temperature with the furnace to obtain a gold-doped sulfide material.

[0065] The gold-doped sulfide material was used to make a thermal battery cell with LiCl-LiBr-LiF as the electrolyte and nano-MgO as the separator powder. The cathode sheet and the electrolyte membrane were placed in a mold and pressed into a sheet with a diameter of 17 mm at a pressure of 20 MPa. In addition, the cathode electrolyte membrane sheet and the Li-B alloy anode sheet were stacked and pressed to form a stacked single cell. After the single cell was assembled, electrochemical tests were carried out at 500°C. To study the total polarization, the pulse test conditions were set as follows: at 200 mA cm -2 The battery was discharged at a current density of 100 mA cm for 12 seconds and then the current density was increased to 600 mA cm -2 Discharge for 1 second, and repeat this cycle 25 times. When the cut-off voltage is 1.4V, compared with the gold-doped sulfide material in Example 3, the effective discharge platform of the gold-doped sulfide is reduced by 10.9%, and the effective discharge specific capacity is 322mA hg -1 53 mA hg lower than Example 3 -1 The internal resistance is 0.124Ω, which is 39.33% higher than that of Example 3.

[0066] Comparative Example 4

[0067] Other conditions are the same as those in Example 4, except that:

[0068] HAuCl4·3H2O was added to the deionized water solution, and the mixture was stirred thoroughly to ensure that the mixture was uniform. 20 g of a mixture consisting of FeCl2·4H2O and Na2S2O3·5H2O in a molar ratio of 1:3 was added thereto, and then an appropriate amount of deionized water was added, and then a solution containing a certain amount of HAuCl4·3H2O was added (at this time, the molar ratio of Au element to Na2S2O3 in the solution was nAu:nNa2S2O3=0.659:24999), and the mixture was transferred to an autoclave, heated to 200°C at a heating rate of 10°C / min, and kept warm for 15 hours. After the heat preservation, the sample was cooled to room temperature with the furnace to obtain Au-doped ferrosulfide compound particles. The Au-doped iron sulfide compound particles (26 g) were mixed evenly with 4 g of sulfur powder (the average particle size of the sulfur powder was about 16 microns), and placed in a nitrogen-protected reactor. During the reaction, the temperature was raised at a rate of 10°C / min to 300°C and kept for 15 hours. Then the temperature was raised to 440°C at a rate of 10°C / min and kept for 20 hours. Then the product was cooled to room temperature in the furnace to obtain a gold-doped sulfide material.

[0069] The gold-doped sulfide material was used to make a thermal battery cell with LiCl-LiBr-LiF as the electrolyte and nano-MgO as the separator powder. The cathode sheet and the electrolyte membrane were placed in a mold and pressed into a sheet with a diameter of 17 mm at a pressure of 20 MPa. In addition, the cathode electrolyte membrane sheet and the Li-B alloy anode sheet were stacked and pressed to form a stacked single cell. After the single cell was assembled, electrochemical tests were carried out at 500°C. To study the total polarization, the pulse test conditions were set as follows: at 200 mA cm -2 The battery was discharged at a current density of 100 mA cm for 12 seconds and then the current density was increased to 600 mA cm -2 Discharge for 1 second, and repeat this cycle 25 times. When the cut-off voltage is 1.4V, compared with the gold-doped sulfide material in Example 4, the effective discharge platform of the gold-doped sulfide is reduced by 15.3%, and the effective discharge specific capacity is 342mA hg -1 37 mA hg lower than Example 4 -1 The internal resistance is 0.129Ω, which is 51.76% higher than that of Example 4.

[0070] During the technical development process, the hydrothermal intermediate product was mixed with sulfur, and then heated to below 350°C for sulfurization protection sintering. However, the resulting composite material also contained other phases composed of Fe and S. At the same time, after assembling it into a thermal battery, the performance was worse than that of the present invention.

Claims

1. A method for preparing a gold-doped sulfide material, characterized in that: The preparation method comprises the following steps: Step 1 The method comprises the following steps: using an Au-containing solution as a raw material; adding a sulfur source and an Fe source to the Au-containing solution and stirring the solution; placing the solution in a high-pressure reactor; reacting the solution at 120 to 180° C., preferably 150 to 180° C. for at least 7 hours; cooling the solution; performing solid-liquid separation; and obtaining Au-doped iron sulfide compound particles; Step 2 In a sulfur-containing atmosphere, the Au-doped iron sulfide compound particles obtained in step 1 are heated to 300-440° C. and kept at this temperature for at least 5 hours; and cooled in the furnace to obtain a gold-doped sulfide material; or The Au-doped ferrosulfide particles obtained in step 1 are uniformly mixed with elemental sulfur; the mixture is heated to 350-440° C. in a protective atmosphere and kept warm for at least 7 hours; the mixture is cooled in the furnace to obtain the gold-doped sulfide material; The sulfur source includes at least one of thiosulfate, sulfite, and sulfide ion.

2. The method for preparing a gold-doped sulfide material according to claim 1, characterized in that: The solute of the Au-containing solution is a soluble Au-containing substance, and 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 ammonium gold (I) disulfite.

3. The method for preparing a gold-doped sulfide material according to claim 1, characterized in that: 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 more preferably 12:

1.

4. The method for preparing a gold-doped sulfide material according to claim 1, characterized in that: In step 1, prepare Au source and Fe source at a molar ratio of nAu:nFe=0.051-0.661:8333.

5. The method for preparing a gold-doped sulfide material according to claim 1, characterized in that: Prepare a soluble Au-containing substance and water-soluble divalent Fe, first dissolve the prepared soluble Au-containing substance in water to obtain an Au-containing solution; use the Au-containing solution as a raw material; add thiosulfate and the prepared Fe source to the Au-containing solution; stir; then place in a high-pressure reactor, heat to 120-180°C at a heating rate of 5-15°C / min, and keep warm for 10-22h; cool; separate the solid and liquid; and obtain Au-doped ferrosulfide compound particles.

6. The method for preparing a gold-doped sulfide material according to claim 1, characterized in that: In step 1, the product is cooled to 25-35°C in the furnace.

7. The method for preparing a gold-doped sulfide material according to claim 1, characterized in that: In step 2, the Au-doped sulfide compound particles obtained in step 1 are uniformly mixed with elemental sulfur; placed in a sintering furnace in a protective atmosphere, heated to 300-350° C. at a heating rate of 5-15° C. / min and kept warm for 5-20 hours; then heated to 350-440° C. and kept warm for 7-30 hours; cooled in the furnace to obtain the gold-doped sulfide material; the protective atmosphere is nitrogen or an inert atmosphere.

8. The method for preparing a gold-doped sulfide material according to claim 1, characterized in that: According to the mass ratio, Au-doped ferrosulfide compound particles: elemental sulfur = 2-10: 0.8-4, preferably 3.1-8.2: 1.4-3.6; the Au-doped ferrosulfide compound particles obtained in step 1 are uniformly mixed with elemental sulfur.

9. The method for preparing a gold-doped sulfide material according to claim 1, characterized in that: The dopant in the prepared gold-doped sulfide material is gold, and the main material is iron disulfide; The prepared gold-doped sulfide material has a particle size of 1.5 to 34.5 microns, preferably 4.8 to 10.3 microns, and more preferably 8.2 to 9.9 microns.

10. The method for preparing a gold-doped sulfide material according to claim 1, characterized in that: Li-B alloy was used as the negative electrode material, LiCl-LiBr-KBr was used as the electrolyte, and nano-MgO was used as the isolation powder; the obtained gold-doped sulfide material was used as the positive electrode material; after being assembled into a thermal battery, the thermal battery was operated at 500°C, and the pulse test conditions were set as: at 200mAcm -2 The battery was discharged at a current density of 100 mA cm for 12 seconds and then the current density was increased to 600 mA cm -2 Discharge for 1 second, repeat this cycle 25 times. When the cut-off voltage is 1.4V, the discharge capacity is greater than or equal to 361mAh / g.

Images