All-solid-state lithium-sulfur battery mxene-based monatomic-sulfur cathode and preparation method
By using MXene-based single-atom materials mixed with elemental sulfur, conductive agents, and solid electrolytes in all-solid-state lithium-sulfur batteries, the problem of slow solid sulfur conversion reaction kinetics was solved, achieving high utilization of active sulfur and improved battery performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN UNIV OF TECH
- Filing Date
- 2026-03-09
- Publication Date
- 2026-05-29
AI Technical Summary
In all-solid-state lithium-sulfur batteries, the solid-state sulfur conversion reaction kinetics are slow and the contact area of the three-phase boundary region is limited, resulting in poor battery performance and difficulty in achieving high sulfur utilization.
Using MXene-based single-atom materials as the positive electrode, and mixing them with elemental sulfur, conductive agents, and solid electrolytes, a positive electrode material with high adsorption energy and high catalytic activity is constructed to promote the conversion of active sulfur to Li2S.
It significantly improved the ratio and conversion of active sulfur, enhanced solid-state charge transfer behavior, and improved the performance of all-solid-state lithium-sulfur batteries.
Smart Images
Figure CN122117791A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of all-solid-state lithium-sulfur secondary battery technology, and relates to the MXene-based single-atom sulfur cathode of all-solid-state lithium-sulfur battery and its preparation method. Background Technology
[0002] Carbon-based MXene single-atom catalysts stand out due to their 100% atom utilization, high intrinsic activity, and excellent conductivity and charge transport capabilities. In lithium-sulfur catalysis, the functional groups (-O, -OH) and single-atom sites on the MXene surface exhibit strong chemisorption of lithium polysulfides, effectively "locking" sulfur species within the cathode. Furthermore, the performance of single-atom catalysts is closely related to their central metal atom. For example, the Mn atom has five electrons in its 3d orbital, enabling it to form stable Mn-S bonds with sulfur. This characteristic gives Mn / MXene single-atom catalysts exceptionally good ion / electron and catalytic activity, significantly improving the active sulfur ratio and conversion rate. The Fe atom has six electrons in its 3d orbital, providing a suitable adsorption energy for sulfur. This energy not only blocks the shuttle of polysulfides but also prevents catalyst performance degradation due to "poisoning," resulting in the excellent catalytic performance of Fe / MXene single-atom catalysts.
[0003] All-solid-state lithium-sulfur batteries (ASSBs) that use solid-state electrolytes (SSEs) instead of traditional liquid electrolytes offer numerous advantages, including high energy density, safety, and durability. By transforming the interfacial phase transition from a "solid-liquid-solid" to a "solid-solid-solid" structure, they effectively suppress polysulfide formation and eliminate harmful shuttle effects. However, the solid-state sulfur conversion reaction kinetics are slow and primarily limited by the three-phase boundary region composed of sulfur, carbon, and the solid-state electrolyte. Due to the inherent properties of the materials, the contact area in this region is inherently limited, resulting in poor battery performance and difficulty in achieving high sulfur utilization. Therefore, there is an urgent need to design and develop cathode materials with high ionic / electronic conductivity and high catalytic activity to promote the complete conversion of active sulfur to Li₂S and improve sulfur utilization. Summary of the Invention
[0004] The first objective of this invention is to provide an MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries, in order to solve the problems of poor performance and difficulty in achieving high sulfur utilization in existing batteries.
[0005] The second objective of this invention is to provide a method for preparing MXene-based single-atom materials, which features high adsorption energy and high catalytic activity with metal atoms as active sites.
[0006] The third objective of this invention is to provide a method for preparing an MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries, which significantly improves the active sulfur ratio and conversion rate.
[0007] The technical solution of the MXene-based single-atom sulfur cathode for the all-solid-state lithium-sulfur battery of the present invention includes MXene-based single-atom material, elemental sulfur, conductive agent and solid electrolyte.
[0008] The technical solution adopted in the preparation method of the MXene-based single-atom material of the present invention is implemented according to the following steps:
[0009] Step 1: Weigh concentrated hydrochloric acid and solvent and mix them in a reaction vessel. After the first stirring, add LiF powder and Ti3AlC2 powder. After the second stirring, perform the first centrifugation. Transfer the centrifuged solvent to a three-necked flask, introduce inert gas and sonicate. After the second centrifugation, obtain the MXene solution. Step 2: Add a metal source to the MXene solution, mix and stir for 4-6 hours, then add a reducing agent. After mixing and separation, freeze-dry the mixture to obtain MXene-based single-atom precursor powder. Step 3: The MXene-based single-atom precursor powder is pyrolyzed at high temperature under an inert atmosphere to obtain MXene-based single-atom materials.
[0010] The invention is further characterized in that: in step 1, the volume of concentrated hydrochloric acid is 15 mL and the mass fraction is 30%–35%; the solvent is deionized water and the volume is 5 mL; the first stirring time is 10 min–20 min; the amount of LiF powder added is 1.5 g–2.5 g, and the amount of Ti3AlC2 powder added is 0.6 g–1.2 g; the temperature of the second stirring is 25℃–60℃, the stirring speed is 400 r / min–500 r / min, and the stirring time is 24–48 h; the centrifugation rate of the first and second centrifugations is 8000 r / min–10000 r / min, and the number of centrifugations is 8–10; the temperature of the ultrasonic treatment is 5℃–15℃, and the ultrasonic treatment time is 1 h–1.5 h; the inert gas is argon or nitrogen.
[0011] In step 2, the volume of the MXene solution is 15 mL to 45 mL, the concentration of the metal source is 0.5 mg / mL to 2.5 mg / mL, and the metal source is one of FeCl3, CoCl2, NiCl2, MnCl2, MoCl2, ZnCl2, CeCl2, NbCl2, RuCl2, and TcCl2. The concentration of the reducing agent is 1.5 mg / mL to 5.5 mg / mL, and the reducing agent is one of sodium borohydride, ethylene glycol, hydrazine hydrate, sodium citrate, and tannic acid. The mixing and separation process is as follows: stirring at 300 r / min to 800 r / min for 6 h to 12 h at a temperature of 25℃ to 50℃, followed by centrifugation at 6000 r / min to 10000 r / min for 6 h to 12 h. The freeze-drying process is as follows: freeze-drying at a pressure of 50 Pa to 300 Pa and a temperature of -75℃ to -35℃ for 24 h to 48 h.
[0012] The specific process of high-temperature pyrolysis in step 3 is as follows: the powder is transferred to a tube furnace and heated to 300℃~600℃ in an inert gas atmosphere at a heating rate of 5℃ / min~20℃ / min. The temperature is held for 2h~6h and then cooled to room temperature with the furnace. The inert gas is one of N2, NH3 and Ar.
[0013] The technical solution adopted in the preparation method of the MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries of the present invention is implemented according to the following steps: Step 1. The conductive agent and MXene-based single atoms are placed in a zirconium oxide crucible containing ZrO2 balls at a mass ratio of 1:3 to 1:6 and mechanically ball-milled to obtain precursor powder. Step 2. Mix the precursor powder and sublimed sulfur at a mass ratio of 1:2 to 1:4, and perform a second mechanical ball milling process to obtain precursor powder mixed with sulfur powder. Step 3. Mix the precursor powder containing sulfur powder and the solid electrolyte at a mass ratio of 3:1 to 6:1, and continue to add 0.12g of solid electrolyte. Then, put it into a sealed ZrO2 container and ball mill the ZrO2 container in an argon-filled glove box at a speed of 400r / min to 800r / min for 36 to 48 revolutions to obtain the MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries.
[0014] The invention is further characterized in that: the conductive agent in step 1 is one of acetylene black, Super P, and Ketjen black; the size and quantity of ZrO2 balls are selected as 10-20 balls with a diameter of 3mm, 6-12 balls with a diameter of 5mm, and 4-8 balls with a diameter of 10mm; the ball milling speed of the mechanical ball milling process is 500r / min-800r / min; the ball milling cycle of the mechanical ball milling process is 48-72 cycles; and each ball milling cycle includes 15 minutes of ball milling and 5 minutes of rest.
[0015] The sublimed sulfur in step 2 has a mass of 0.12–0.48 g, the ball milling speed for the secondary mechanical ball milling is 500 r / min–800 r / min, and the ball milling cycle for the secondary mechanical ball milling is 48–72 cycles.
[0016] The mass of the solid electrolyte in step 3 is 0.12g, and the inert gas is argon.
[0017] The beneficial effects of this invention are: The MXene-based single-atom sulfur cathode of the all-solid-state lithium-sulfur battery of this invention uses carbon-based MXene as a substrate and metal atoms with high adsorption energy and high catalytic activity as active sites. After being mixed with elemental sulfur, a conductive agent, and a solid electrolyte, it constructs a novel hybrid ion-electron conductor. This material possesses superior electronic and ion conductivity, enhancing solid-state charge transfer behavior and achieving interfacial sulfur conversion and kinetic acceleration. Its application in all-solid-state lithium-sulfur batteries forms a solid-solid two-phase interface, significantly improving the active sulfur ratio and conversion degree. Furthermore, the preparation method of the MXene-based single-atom sulfur cathode of the all-solid-state lithium-sulfur battery of this invention provides a novel carbon-based single-atom cathode material for sulfur cathode materials in all-solid-state lithium-sulfur batteries. Attached Figure Description
[0018] Figure 1 This is a transmission electron microscope image of MXene-based single atoms in the MXene-based single-atom sulfur cathode and its preparation method for the all-solid-state lithium-sulfur battery of this invention. Figure 2 This is the XRD pattern of the MXene-based single atom in the MXene-based single-atom sulfur cathode and its preparation method for the all-solid-state lithium-sulfur battery of this invention; Figure 3 This is the XPS image of Mn-MXene-based single atoms in the MXene-based single-atom sulfur cathode and its preparation method for the all-solid-state lithium-sulfur battery of this invention; Figure 4 This is an XPS image of the MXene-based single atom in the MXene-based single-atom sulfur cathode and its preparation method for the all-solid-state lithium-sulfur battery of this invention; Figure 5 This is a graph showing the long-cycle performance of the MXene-based single-atom sulfur cathode of the all-solid-state lithium-sulfur battery of this invention in a solid-state battery; Figure 6 This is a graph showing the first charge-discharge performance of the MXene-based single-atom sulfur cathode of the all-solid-state lithium-sulfur battery of this invention in a solid-state battery. Detailed Implementation
[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0020] The first technical solution adopted in this invention is, as follows: Figure 1 As shown, the MXene-based single-atom sulfur cathode of the all-solid-state lithium-sulfur battery specifically includes MXene-based single-atom material, elemental sulfur, conductive agent and solid electrolyte. The MXene-based single-atom material serves as the sulfur host, and elemental sulfur is the positive electrode active material. Elemental sulfur is uniformly dispersed and loaded inside the sulfur host.
[0021] This invention relates to a method for preparing MXene-based single-atom materials, specifically implemented according to the following steps: Step 1: Weigh 15 mL of concentrated hydrochloric acid (30%–35% by mass) and 5 mL of deionized water, mix them, and place them in a reaction vessel. After the first stirring for 10–20 min, add 1.5 g–2.5 g of LiF powder and 0.6 g–1.2 g of Ti3AlC2 powder. After a second stirring at a temperature of 25°C–60°C, a stirring speed of 400–500 r / min, and a stirring time of 24–48 h, perform a first centrifugation. Transfer the centrifuged material to a three-necked flask, introduce Ar or N2 inert gas, and sonicate at 5–15°C for 1–1.5 h. After a second centrifugation, obtain an MXene solution. The centrifugation rates for both the first and second centrifugations are 8000–10000 r / min, and the number of centrifugations is 8–10. Step 2: Take 15 mL to 45 mL of the above MXene solution, add a metal source, mix and stir for 4 to 6 hours, then add a reducing agent. First, stir for 10 to 12 hours at 25℃ to 50℃ and 300 r / min to 800 r / min for mixing treatment. Then, centrifuge 6 to 8 times at 6000 r / min to 10000 r / min to complete the separation treatment. Finally, freeze-dry for 24 to 48 hours at 50 Pa to 300 Pa pressure and -75℃ to -35℃ to obtain MXene-based single-atom precursor powder. The metal source concentration is 0.5 mg / mL to 2.5 mg / mL, and the metal source is FeCl3, CoCl2, NiCl2, MnCl2, MoCl2, or ZnC. l2 One of CeCl2, NbCl2, RuCl2, and TcCl2, with a reducing agent concentration of 1.5 mg / mL to 5.5 mg / mL, and one of sodium borohydride, ethylene glycol, hydrazine hydrate, sodium citrate, and tannic acid; Step 3: The precursor powder obtained in Step 2 is subjected to high-temperature pyrolysis under an inert atmosphere. The specific process of high-temperature pyrolysis is as follows: the powder is transferred to a tube furnace and heated to 300℃~600℃ at a heating rate of 5℃ / min~20℃ / min under an inert gas atmosphere, held at that temperature for 3h~3.5h, and then cooled to room temperature with the furnace. The inert gas is one of N2, NH3, and Ar, to obtain MXene-based single-atom materials.
[0022] The preparation method of MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries is implemented according to the following steps: Step 1. Place the conductive agent and MXene-based single atoms in a ZrO2 crucible at a mass ratio of 1:3 to 1:6. The crucible contains a certain amount of ZrO2 balls, which are then mechanically ball-milled at a certain speed to obtain the precursor powder. The conductive agent is one of acetylene black, Super P, or Ketjen black. The size and number of ZrO2 balls are selected as follows: 10-20 balls with a diameter of 3 mm, 6-12 balls with a diameter of 5 mm, and 4-8 balls with a diameter of 10 mm. The ball milling speed is 500-800 r / min, and the ball milling cycle is 48-72 cycles, with each cycle including 15 minutes of ball milling and 5 minutes of rest. Step 2. Mix the precursor powder and sublimed sulfur at a mass ratio of 1:2 to 1:4, with the sublimed sulfur weighing 0.12 g to 0.48 g. The ball milling speed is 500 r / min to 800 r / min, and the ball milling cycle is 48 to 72 cycles to obtain the precursor powder mixed with sulfur powder. Step 3. The precursor powder mixed with sulfur powder and solid electrolyte are mixed at a mass ratio of 3:1 to 6:1. A certain amount of solid electrolyte (LPS) is then added, and the mixture is placed in a sealed ZrO2 container. These containers are operated in a glove box filled with inert gas. Finally, the mixture is milled for 36 to 48 revolutions at a certain rotation speed to obtain the MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries. The mass of the solid electrolyte is 0.12 g, the inert gas is argon, and the ball milling speed is 400 to 800 r / min.
[0023] Example 1 MXene-based single-atom sulfur cathodes for all-solid-state lithium-sulfur batteries, such as Figure 1 As shown, it specifically includes MXene-based single-atom materials, elemental sulfur, conductive agents, and solid electrolytes. MXene-based single-atom materials serve as sulfur hosts, elemental sulfur is the positive electrode active material, and elemental sulfur is uniformly dispersed and loaded inside the sulfur host.
[0024] Example 2 Preparation methods of MXene-based single-atom materials, such as Figures 2-4 As shown, please follow these steps: Step 1: Weigh 15 mL of 30% concentrated hydrochloric acid and 5 mL of deionized water and mix them in a reaction vessel. After stirring for 10 min, add 1.5 g of LiF powder and 0.6 g of Ti3AlC2 powder. After stirring for 24 h at 35℃ and 400 r / min, perform the first centrifugation. Transfer the material after the first centrifugation to a three-necked flask, introduce Ar gas, and sonicate at 5℃. After the second centrifugation, obtain the MXene solution. The centrifugation rate for both the first and second centrifugations is 8000 r / min, and the number of centrifugations for both is 8. Step 2: Take 15 mL of the above MXene solution, add the metal source FeCl3 to it, mix and stir for 4 h, then add the reducing agent sodium borohydride. First, stir for 12 h at 25 °C and 300 r / min for mixing treatment, then centrifuge 6 times at 10000 r / min to complete the separation treatment, and then freeze dry at 50 Pa pressure and -75 °C for 24 h to obtain MXene-based single-atom precursor powder with a metal source concentration of 1 mg / mL and a reducing agent concentration of 3.5 mg / mL. Step 3: The MXene-based single-atom precursor powder obtained in Step 2 is subjected to high-temperature pyrolysis under an inert atmosphere. The specific process of high-temperature pyrolysis is as follows: the powder is transferred to a tube furnace and heated to 300°C at a heating rate of 5°C / min under an inert gas N2 atmosphere, held at that temperature for 2 hours, and then cooled to room temperature with the furnace to obtain high-purity Fe-MXene-based single-atom material. The XRD of the high-purity Fe-MXene-based single-atom material is then analyzed. Figure 2 The absence of impurity peaks in the test results indicates that the layered crystal structure of MXene remains intact, and the Fe metal in the Fe-MXene-based single-atom material is in a single-atom state.
[0025] Example 3 Preparation methods of MXene-based single-atom materials, such as Figures 2-4 As shown, please follow these steps: Step 1: Weigh 15 mL of 35% concentrated hydrochloric acid and 5 mL of deionized water and mix them in a reaction vessel. After stirring for 15 min, add 2 g of LiF powder and 0.8 g of Ti3AlC2 powder. After stirring for 48 h at a temperature of 40 °C and a speed of 500 r / min, the mixture is centrifuged for the first time. The material after the first centrifugation is transferred to a three-necked flask, inert gas N2 is introduced, and the mixture is sonicated at 15 °C for 1.5 h. After a second centrifugation, an MXene solution is obtained. The centrifugation rate for both the first and second centrifugations is 10000 r / min, and the number of centrifugations is 9 times for each. Step 2: Take 30 mL of the above MXene solution, add the metal source NiCl2 to it, mix and stir for 6 h, then add the reducing agent hydrazine hydrate, stir for 10 h at 30 °C and 400 r / min for mixing treatment, then centrifuge 8 times at 8000 r / min to complete the separation treatment, and then freeze dry at 100 Pa pressure and -60 °C for 36 h to obtain MXene-based single-atom precursor powder, with the concentration of metal source NiCl2 being 1.5 mg / mL and the concentration of reducing agent hydrazine hydrate being 4 mg / mL; Step 3: The precursor powder obtained in Step 2 is transferred to a tube furnace. Under an Ar atmosphere, it is heated to 450°C at a heating rate of 10°C / min and held at that temperature for 3 hours for high-temperature pyrolysis. The powder is then cooled to room temperature with the furnace to obtain high-purity Ni-MXene-based single-atom material. XRD of the high-purity Ni-MXene-based single-atom material (…) Figure 2 The absence of impurity peaks in the test results indicates that the layered crystal structure of MXene remains intact, and the Ni metal in the high-purity Ni-MXene-based single-atom material is in a single-atom state.
[0026] Example 4 Preparation methods of MXene-based single-atom materials, such as Figures 2-4 As shown, please follow these steps: Step 1: Weigh 15 mL of 32% concentrated hydrochloric acid and 5 mL of deionized water and mix them in a reaction vessel. After the first stirring for 20 min, add 2.5 g of LiF powder and 1.2 g of Ti3AlC2 powder. After a second stirring at 60℃, 500 r / min, and 36 h, centrifuge for the first time. Transfer the centrifuged material to a three-necked flask, introduce N2 gas, and sonicate at 15℃ for 1.5 h. After a second centrifugation, obtain the MXene solution. The centrifugation rate for both the first and second centrifugations is 90,000 r / min, and the number of centrifugations is 10 each time. Step 2: Take 45 mL of the above MXene solution, add MnCl2 as the metal source, mix and stir for 5 h, then add the reducing agent, stir for 12 h at 50 °C and 800 r / min for mixing treatment, then centrifuge 7 times at 9000 r / min to complete the separation treatment, and then freeze dry at 80 Pa pressure and -68 °C for 28 h to obtain MXene-based single-atom precursor powder. The metal source concentration is 1.2 mg / mL, the reducing agent concentration is 3.8 mg / mL, and the reducing agent is tannic acid. Step 3: The precursor powder obtained in Step 2 is subjected to high-temperature pyrolysis under an inert atmosphere. The specific process of high-temperature pyrolysis is as follows: the powder is transferred to a tube furnace and heated to 600°C at a heating rate of 20°C / min under an inert gas atmosphere, held at that temperature for 6 hours, and then cooled to room temperature with the furnace. The inert gas is NH3. High-purity Mn-MXene-based single-atom material is obtained. XRD pattern of high-purity Mn-MXene-based single-atom material (…) Figure 2 The absence of impurity peaks in the test results indicates that the layered crystal structure of MXene remains intact, and the Mn metal in the high-purity Mn-MXene-based single-atom material is in a single-atom state.
[0027] Example 5 Preparation method of MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries, such as Figure 5 and Figure 6 As shown, please follow these steps: Step 1. Place acetylene black and MXene-based single-atom particles into a ZrO2 crucible at a mass ratio of 1:3. Select the following ZrO2 balls in the crucible: 10 balls with a diameter of 3 mm, 6 balls with a diameter of 5 mm, and 4 balls with a diameter of 10 mm. Perform mechanical ball milling at a speed of 800 r / min for 48 cycles. Each cycle includes 15 minutes of ball milling and 5 minutes of rest to obtain the precursor powder. Step 2. Mix the precursor powder and sublimed sulfur at a mass ratio of 1:2, and then ball mill at a speed of 500 r / min for 48 cycles to obtain precursor powder mixed with sulfur powder. Step 3. The precursor powder mixed with sulfur powder and solid electrolyte were mixed at a mass ratio of 3:1. 0.12 g of solid electrolyte (LPS) was then added, and the mixture was placed into a sealed ZrO2 container. These containers were operated in a glove box filled with inert gas. Finally, the mixture was ball-milled at 400 rpm for 36 revolutions to obtain the MXene-based single-atom sulfur cathode for the all-solid-state lithium-sulfur battery.
[0028] Example 6 Preparation method of MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries, such as Figure 5 and Figure 6 As shown, please follow these steps: Step 1. Place Super P and MXene-based single atoms into a ZrO2 crucible at a mass ratio of 1:6. The crucible contains ZrO2 balls of different sizes and quantities: 10 balls with a diameter of 3 mm, 6 balls with a diameter of 5 mm, and 4 balls with a diameter of 10 mm. Perform mechanical ball milling at a speed of 600 r / min for 48 cycles, with each cycle consisting of 15 minutes of ball milling and 5 minutes of rest, to obtain the precursor powder.
[0029] Step 2. Mix the precursor powder with 0.12 g of sublimed sulfur at a mass ratio of 1:2, and then ball mill at a speed of 500 r / min for 48 cycles to obtain precursor powder mixed with sulfur powder.
[0030] Step 3. The precursor powder mixed with sulfur powder and the solid electrolyte are mixed at a mass ratio of 4:1, and then placed into sealed ZrO2 containers. These containers are operated in an argon-filled glove box. Finally, the mixture is ball-milled at 600 r / min for 48 revolutions to obtain the MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries.
[0031] Example 6 A method for preparing an MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries, characterized by the following specific steps: Step 1. Place acetylene black and MXene-based single-atom particles into a ZrO2 crucible at a mass ratio of 1:6. The crucible contains ZrO2 balls of different sizes and quantities: 15 balls with a diameter of 3 mm, 8 balls with a diameter of 5 mm, and 6 balls with a diameter of 10 mm. Perform mechanical ball milling at a speed of 600 r / min for 60 cycles, with each cycle consisting of 15 minutes of ball milling and 5 minutes of rest, to obtain the precursor powder. Step 2. Mix the precursor powder with 0.12 g of sublimed sulfur, and then ball mill it at 500 r / min for 42 cycles to obtain precursor powder mixed with sulfur powder. Step 3. The precursor powder mixed with sulfur powder and the solid electrolyte are mixed at a mass ratio of 3:1, and then placed into sealed ZrO2 containers. These containers are operated in an argon-filled glove box. Finally, the mixture is ball-milled at 600 r / min for 60 revolutions to obtain the MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries.
[0032] Example 7 Preparation method of MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries, such as Figure 5 and Figure 6 As shown, please follow these steps: Step 1. Place Ketjen black and MXene-based single atoms into a ZrO2 crucible at a mass ratio of 1:6. The crucible contains ZrO2 balls of different sizes and quantities: 20 balls with a diameter of 3 mm, 12 balls with a diameter of 5 mm, and 8 balls with a diameter of 10 mm. Perform mechanical ball milling at a speed of 800 r / min for 72 cycles, with each cycle consisting of 15 minutes of ball milling and 5 minutes of rest, to obtain the precursor powder. Step 2. Mix the precursor powder with 0.12g of sublimed sulfur at a mass ratio of 1:4, and then ball mill at 800r / min for 72 cycles to obtain precursor powder mixed with sulfur powder. Step 3. The precursor powder mixed with sulfur powder and the solid electrolyte are mixed at a mass ratio of 6:1, and then placed into sealed ZrO2 containers. These containers are operated in an argon-filled glove box. Finally, the mixture is ball-milled at 800 r / min for 72 revolutions to obtain the MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries.
Claims
1. An MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries, characterized in that, The cathode material specifically includes MXene-based single-atom materials, elemental sulfur, conductive agents, and solid electrolytes.
2. A method for preparing MXene-based single-atom materials, using the MXene-based single-atom sulfur cathode of the all-solid-state lithium-sulfur battery as described in claim 1, characterized in that, The specific steps are as follows: Step 1: Weigh concentrated hydrochloric acid and solvent and mix them in a reaction vessel. After the first stirring, add LiF powder and Ti3AlC2 powder. After the second stirring, perform the first centrifugation. Transfer the centrifuged material to a three-necked flask, introduce inert gas and sonicate. After the second centrifugation, obtain the MXene solution. Step 2: Add a metal source to the MXene solution, mix and stir for 4-6 hours, then add a reducing agent. After mixing and separation, freeze-dry the mixture to obtain MXene-based single-atom precursor powder. Step 3: The MXene-based single-atom precursor powder is pyrolyzed at high temperature under an inert atmosphere to obtain MXene-based single-atom materials.
3. The method for preparing MXene-based single-atom materials according to claim 2, characterized in that, In step 1, the volume of concentrated hydrochloric acid is 15 mL and the mass fraction is 30%–35%, and the solvent is deionized water with a volume of 5 mL; the first stirring time is 10 min–15 min; the amount of LiF powder added is 1.5 g–2 g, and the amount of Ti3AlC2 powder added is 0.8 g–1 g; the temperature of the second stirring is 35℃–40℃, the stirring speed is 400 r / min–500 r / min, and the stirring time is 24–48 h; the centrifugation rate of the first and second centrifugations is 8000 r / min–10000 r / min, and the number of centrifugations is 8–10 times; the temperature of the ultrasonic treatment is 5℃–15℃, and the ultrasonic treatment time is 1 h–1.5 h; the inert gas is Ar or N2.
4. The method for preparing MXene-based single-atom materials according to claim 2, characterized in that, In step 2, the volume of the MXene solution is 25 mL to 30 mL, the concentration of the metal source is 1 mg / mL to 1.5 mg / mL, and the metal source is one of FeCl3, CoCl2, NiCl2, MnCl2, MoCl2, ZnCl2, CeCl2, NbCl2, RuCl2, and TcCl2. The concentration of the reducing agent is 3.5 mg / mL to 4 mg / mL, and the reducing agent is one of sodium borohydride, ethylene glycol, hydrazine hydrate, sodium citrate, and tannic acid. The mixing and separation process is carried out at a temperature of 25℃ to 30℃ and a stirring speed of 400 r / min to 500 r / min for 10 h to 12 h, followed by centrifugation at a speed of 8000 r / min to 10000 r / min 6 to 8 times. The freeze-drying process is carried out at a pressure of 50 Pa to 100 Pa and a temperature of -75℃ to -60℃ for 24 to 36 h.
5. The method for preparing MXene-based single-atom materials according to claim 2, characterized in that, The specific process of high-temperature pyrolysis in step 3 is as follows: the powder is transferred to a tube furnace and heated to 450℃~500℃ at a heating rate of 5℃ / min~10℃ / min under an inert gas atmosphere, held at that temperature for 3h~3.5h, and then cooled to room temperature with the furnace. The inert gas is one of N2, NH3, and Ar.
6. A method for preparing an MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries, characterized in that, The specific steps are as follows: Step 1. The conductive agent and MXene-based single atoms are placed in a zirconium oxide crucible containing ZrO2 balls at a mass ratio of 1:3 to 1:6 and mechanically ball-milled to obtain precursor powder. Step 2. Mix the precursor powder and sublimed sulfur at a mass ratio of 1:2 to 1:4, and perform a second mechanical ball milling process to obtain precursor powder mixed with sulfur powder. Step 3. Mix the precursor powder containing sulfur powder and the solid electrolyte at a mass ratio of 3:1 to 6:1, and continue to add 0.12g of solid electrolyte. Then, put it into a sealed ZrO2 container and ball mill the ZrO2 container in an argon-filled glove box at a speed of 400r / min to 800r / min for 36 to 48 revolutions to obtain the MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries.
7. The method for preparing an MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries according to claim 6, characterized in that, The conductive agent in step 1 is one of acetylene black, Super P, or Ketjen black. The size and quantity of the ZrO2 balls are selected as follows: 10-20 balls with a diameter of 3 mm, 6-12 balls with a diameter of 5 mm, or 4-8 balls with a diameter of 10 mm. The ball milling speed of the mechanical ball milling process is 500 r / min to 800 r / min. The ball milling cycle of the mechanical ball milling process is 48-72 cycles, and each ball milling cycle includes 15 minutes of ball milling and 5 minutes of rest.
8. The method for preparing an MXene-based single-atom sulfur cathode for an all-solid-state lithium-sulfur battery according to claim 6, characterized in that, The sublimed sulfur in step 2 has a mass of 0.12g, the ball milling speed of the secondary mechanical ball milling process is 500r / min to 800r / min, and the ball milling cycle of the secondary mechanical ball milling process is 48 to 72 cycles.
9. The method for preparing an MXene-based single-atom sulfur cathode for all-solid-state lithium-sulfur batteries according to claim 6, characterized in that, The solid electrolyte in step 3 has a mass of 0.12g, and the inert gas is argon.