An amorphous SbPSe4 / C anode material, its preparation method and application

Abstract

The application discloses an amorphous SbPSe4 / C negative electrode material and a preparation method and application thereof, and belongs to the technical field of negative electrode materials.The Sb source, the P source and the Se source are subjected to one-time mechanical ball milling to obtain an SbPSe4 compound; the obtained SbPSe4 compound is subjected to second-time mechanical ball milling with a carbon material to obtain an SbPSe4 / C composite material; and the obtained SbPSe4 / C composite material is subjected to sealed heat treatment to obtain the amorphous SbPSe4 / C negative electrode material.The amorphous SbPSe4 / C negative electrode material prepared by the application is used as a negative electrode of a potassium ion battery, the introduction of the carbon material provides good conductivity, and effectively buffers the volume expansion and mechanical stress in the cycle process; in the preparation steps, the amorphous treatment is utilized, the volume change caused by ion insertion / extraction is converted into reversible local deformation instead of irreversible structure damage through the isotropic response of the disordered structure, and the cycle stability is improved.

Description

Technical Field

[0001] This invention relates to the field of anode materials, and in particular to an amorphous SbPSe4 / C anode material, its preparation method, and its applications. Background Technology

[0002] With the explosive growth in demand for electric vehicles and energy storage, the development of low-cost, reliable, high-energy-density energy storage systems for the efficient storage and output of renewable and clean energy is urgently needed. Potassium-ion batteries are considered an attractive alternative to lithium-ion batteries due to their abundant reserves and low cost. However, during the potassiumization / depotassiumization reaction, the large radius and significant volume change of potassium ions lead to slow reaction kinetics and rapid capacity decay. Therefore, it is necessary to develop electrode materials with high reversible capacity and long cycle life for potassium-ion battery applications.

[0003] Among the many anode materials for potassium-ion batteries, conversion-alloy type anode materials have attracted widespread attention due to their high theoretical specific capacity. However, high capacity implies huge volume changes and high chemimechanical stress, which can lead to pulverization and failure of the electrode material, thereby further deteriorating battery performance.

[0004] Therefore, how to achieve high capacity while maintaining long cycle performance is a technical problem that urgently needs to be solved in the development of potassium-ion batteries. Based on this problem, an amorphous SbPSe4 / C anode material, its preparation method and application are provided. Summary of the Invention

[0005] The purpose of this invention is to provide an amorphous SbPSe4 / C anode material, its preparation method, and its application, in order to solve the problems in the background art.

[0006] To achieve the above objectives, the present invention provides a method for preparing an amorphous SbPSe4 / C anode material, comprising the following steps: S1. The antimony source, phosphorus source and selenium source are subjected to mechanical ball milling under an inert atmosphere to obtain the SbPSe4 compound; S2. The obtained SbPSe4 compound and carbon material are subjected to secondary mechanical ball milling under an inert atmosphere to obtain SbPSe4 / C composite material. S3. The obtained SbPSe4 / C composite material is subjected to closed heat treatment in a reducing atmosphere and cooled to room temperature to obtain amorphous SbPSe4 / C anode material.

[0007] Preferably, in S1, the antimony source is antimony powder, the phosphorus source is red phosphorus, and the selenium source is selenium powder; the molar ratio of antimony powder, red phosphorus, and selenium powder is 1:1:4.

[0008] Preferably, in S1 and S2, the inert atmosphere is argon, and the mechanical ball milling is a planetary ball milling; the time for the first mechanical ball milling is 24~48h, the ball milling speed is 400~600rpm, and the ball-to-material ratio is 20~40:1; the time for the second mechanical ball milling is 30~60h, the ball milling speed is 300~500rpm, and the ball-to-material ratio is 10~20:1.

[0009] Preferably, the specific steps of S1 are as follows: antimony powder, red phosphorus, and selenium powder are added to the ball mill jar in a glove box filled with argon gas, and then the ball mill jar is sealed in the glove box; After removing the sealed ball mill jar from the glove box, it was installed on a planetary ball mill to mill the mixture in the jar. After milling, the ball mill jar was removed and disassembled in the glove box. The sample was then taken out and subjected to shaking and sieving to obtain the SbPSe4 compound.

[0010] Preferably, in S2, the carbon material is carbon nanotubes, and the mass ratio of SbPSe4 to carbon nanotubes is 1:0.2~1.

[0011] Preferably, the specific steps of S2 are as follows: the SbPSe4 compound and carbon nanotubes are added to the ball mill jar in an argon-filled glove box, and then the ball mill jar is sealed in the glove box; After removing the sealed ball mill jar from the glove box, it was installed on a planetary ball mill to mill the mixture in the jar. After milling, the ball mill jar was removed and disassembled in the glove box. The sample was then taken out and subjected to vibration sieving to obtain the SbPSe4 / C composite material.

[0012] Preferably, in step S3, the reducing atmosphere is a mixture of argon and hydrogen, with hydrogen accounting for 1% to 5% of the volume.

[0013] Preferably, in step S3, the heat treatment is carried out in a closed reactor with an initial pressure of 2~20MPa, a reaction temperature of 230~320℃, a heating rate of 1~5℃ / min, and a reaction time of 8~24h.

[0014] The present invention also provides an amorphous SbPSe4 / C anode material, which is prepared by the above-described preparation method.

[0015] This invention also provides an application of the amorphous SbPSe4 / C anode material, which is used as a negative electrode in potassium-ion batteries.

[0016] Preferably, the negative electrode preparation steps are as follows: amorphous SbPSe4 / C negative electrode material, conductive carbon black and binder are mixed evenly, then N-methylpyrrolidone is added and ground into a slurry, which is then coated on copper foil and vacuum dried at 120°C for 12 hours to obtain the negative electrode.

[0017] Preferably, the ratio of amorphous SbPSe4 / C anode material, conductive carbon black, and binder is 8:1:1; The conductive carbon black is one of Super-P carbon black, Ketjen black, and acetylene black, and the binder is one of polyvinylidene fluoride and polytetrafluoroethylene.

[0018] Preferably, the potassium-ion battery assembly process is as follows: the negative electrode material is cut into a 12mm diameter circular piece as the negative electrode sheet, a 10mm diameter metallic potassium is used as the counter electrode, a Whatman GF-A glass fiber separator is used, and 1~5mol / L potassium salt is dissolved in a solvent as the electrolyte, and the battery is assembled under the protection of argon gas.

[0019] Preferably, the potassium salt is one of potassium bis(trifluoromethylsulfonyl)imide, potassium hexafluorophosphate, and potassium bis(trifluoromethylsulfonyl)imide; the solvent of the potassium salt solution is one or more of methyl ethyl carbonate, dimethyl carbonate, ethylene glycol dimethyl ether, diethyl carbonate, and ethylene carbonate.

[0020] Therefore, the amorphous SbPSe4 / C anode material, its preparation method, and its application, as disclosed in this invention, have the following beneficial effects: (1) The amorphous SbPSe4 / C composite material prepared in this invention is used as the negative electrode of potassium-ion battery. The introduction of carbon material not only provides good conductivity, but also effectively buffers the volume expansion and mechanical stress during cycling.

[0021] (2) The preparation steps of the present invention utilize amorphization treatment, which transforms the volume change caused by ion insertion / extraction into reversible local deformation rather than irreversible structural destruction through the isotropic response of disordered structure, thereby improving cycle stability.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a SEM image of Embodiment 1 of the present invention; Figure 2 This is the XRD pattern of Embodiment 1 of the present invention; Figure 3 This is a cyclic performance diagram of an application embodiment of the present invention; Figure 4 This is a rate performance diagram of an application embodiment of the present invention; Figure 5The diagram shows the cyclic performance of the application of this invention. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0026] Example 1 This embodiment prepares an amorphous SbPSe4 / C anode material, and the specific steps are as follows: S1. Add 0.4g antimony powder, 0.1g red phosphorus, 1g selenium powder and 60g grinding beads to a ball milling jar in an argon-filled glove box and seal the glove box. Remove the sealed ball milling jar from the glove box and install it on a planetary ball mill. Grind the mixture in the ball milling jar at 450 rpm for 40 hours. Then remove the ball milling jar and disassemble it in an argon-filled glove box. Take out the sample and sieve it by shaking to obtain crystalline SbPSe4.

[0027] S2. Add 1.2g of SbPSe4, 1.2g of carbon nanotubes, and 24g of grinding beads to a grinding jar, and then seal the grinding jar in an argon-filled glove box. After removing the sealed grinding jar from the glove box, install it on a planetary ball mill and grind the mixture in the grinding jar at 400rpm for 50h. Remove the grinding jar and disassemble it in the glove box, take out the sample, and oscillate and sieve it to obtain the crystalline SbPSe4 / C composite material.

[0028] S3. The crystalline SbPSe4 / C composite material was added to the reactor and heated in a closed atmosphere under Ar / H2 mixed atmosphere (volume ratio of 99:1) with an initial pressure of 2 MPa. The temperature was increased to 320°C at a rate of 5°C / min and held for 12 hours. Then it was naturally cooled to room temperature to obtain the amorphous SbPSe4 / C anode material.

[0029] The obtained negative electrode material was examined using scanning electron microscopy, such as... Figure 1 As shown, SbPSe4 nanoparticles are uniformly dispersed within a carbon nanotube framework. X-ray diffraction was used to analyze the material, as... Figure 2 As shown, no crystal diffraction peaks were observed, indicating the successful preparation of amorphous SbPSe4 / C.

[0030] Example 2 This embodiment prepares an amorphous SbPSe4 / C anode material, and the specific steps are as follows: S1. Add 0.6g antimony powder, 0.15g red phosphorus, 1.5g selenium powder, and 45g grinding beads to a ball milling jar in an argon-filled glove box and seal the glove box. Remove the sealed ball milling jar from the glove box and install it on a planetary ball mill. Grind the mixture in the ball milling jar at 500 rpm for 35 hours. Then remove the ball milling jar and disassemble it in an argon-filled glove box. Take out the sample and sieve it by shaking to obtain crystalline SbPSe4.

[0031] S2. Add 2g of SbPSe4, 1g of carbon nanotubes, and 45g of grinding beads to a grinding jar, and then seal the grinding jar in an argon-filled glove box. After removing the sealed grinding jar from the glove box, install it on a planetary ball mill and grind the mixture in the grinding jar at 450 rpm for 48 hours. Remove the grinding jar and disassemble it in the glove box, take out the sample, and oscillate and sieve it to obtain the crystalline SbPSe4 / C composite material.

[0032] S3. The crystalline SbPSe4 / C composite material was added to the reactor and heated in a closed atmosphere of Ar / H2 (volume ratio of 98:2) with an initial pressure of 8 MPa. The temperature was increased to 250°C at a rate of 3°C / min and held for 16 hours. Then it was naturally cooled to room temperature to obtain the amorphous SbPSe4 / C anode material.

[0033] Example 3 This embodiment prepares an amorphous SbPSe4 / C anode material, and the specific steps are as follows: S1. Add 0.8g antimony powder, 0.2g red phosphorus, 2g selenium powder, and 75g grinding beads to a ball milling jar in an argon-filled glove box, and seal the glove box. Remove the sealed ball milling jar from the glove box and install it on a planetary ball mill. Grind the mixture in the ball milling jar at 550 rpm for 30 hours. Then remove the ball milling jar and disassemble it in an argon-filled glove box. Take out the sample and sieve it by shaking to obtain crystalline SbPSe4.

[0034] S2. Add 2.5g of SbPSe4, 0.5g of carbon nanotubes, and 60g of grinding beads to a grinding jar, and then seal the grinding jar in an argon-filled glove box. After removing the sealed grinding jar from the glove box, install it on a planetary ball mill and grind the mixture in the grinding jar at 500rpm for 30h. Remove the grinding jar and disassemble it in the glove box, take out the sample, and oscillate and sieve it to obtain the crystalline SbPSe4 / C composite material.

[0035] S3. The crystalline SbPSe4 / C composite material was added to the reactor and heated in a closed atmosphere of Ar / H2 (volume ratio of 97:3) with an initial pressure of 12 MPa. The temperature was increased to 300°C at a rate of 1°C / min and held for 20 hours. Then it was naturally cooled to room temperature to obtain the amorphous SbPSe4 / C anode material.

[0036] Example 4 This embodiment prepares an amorphous SbPSe4 / C anode material, and the specific steps are as follows: S1. Add 0.4g antimony powder, 0.1g red phosphorus, 1g selenium powder and 45g grinding beads to a ball milling jar in an argon-filled glove box and seal the glove box. Remove the sealed ball milling jar from the glove box and install it on a planetary ball mill. Grind the mixture in the ball milling jar at 400 rpm for 48 hours. Then remove the ball milling jar and disassemble it in an argon-filled glove box. Take out the sample and sieve it by shaking to obtain crystalline SbPSe4.

[0037] S2. Add 1g of SbPSe4, 0.25g of carbon nanotubes, and 25g of grinding beads to a grinding jar, and then seal the grinding jar in an argon-filled glove box. After removing the sealed grinding jar from the glove box, install it on a planetary ball mill and grind the mixture in the grinding jar at 350rpm for 40h. Remove the grinding jar and disassemble it in the glove box, take out the sample, and oscillate and sieve it to obtain the crystalline SbPSe4 / C composite material.

[0038] S3. The crystalline SbPSe4 / C composite material was added to the reactor and heated in a closed atmosphere of Ar / H2 (volume ratio of 96:4) with an initial pressure of 16 MPa. The temperature was increased to 280°C at a rate of 4°C / min and held for 24 hours. Then it was naturally cooled to room temperature to obtain the amorphous SbPSe4 / C anode material.

[0039] Example 5 This embodiment prepares an amorphous SbPSe4 / C anode material, and the specific steps are as follows: S1. Add 0.4g antimony powder, 0.1g red phosphorus, 1g selenium powder and 50g grinding beads to a ball milling jar in an argon-filled glove box and seal the glove box. Remove the sealed ball milling jar from the glove box and install it on a planetary ball mill. Grind the mixture in the ball milling jar at 600 rpm for 24 hours. Then remove the ball milling jar and disassemble it in an argon-filled glove box. Take out the sample and sieve it to obtain crystalline SbPSe4.

[0040] S2. Add 1g of SbPSe4, 0.4g of carbon nanotubes, and 25g of grinding beads to a grinding jar, and then seal the grinding jar in an argon-filled glove box. After removing the sealed grinding jar from the glove box, install it on a planetary ball mill and grind the mixture in the grinding jar at 300rpm for 60h. Remove the grinding jar and disassemble it in the glove box, take out the sample, and oscillate and sieve it to obtain the crystalline SbPSe4 / C composite material.

[0041] S3. The crystalline SbPSe4 / C composite material was added to the reactor and heated in a closed atmosphere of Ar / H2 (volume ratio of 95:5) with an initial pressure of 20 MPa. The temperature was increased to 230°C at a rate of 2°C / min and held for 8 hours. Then it was naturally cooled to room temperature to obtain the amorphous SbPSe4 / C anode material.

[0042] Comparative Example 1 The comparative example follows the same steps as in Example 1, except that step S1 is modified to have a ball milling time of 16 hours and a ball milling speed of 300 rpm. Due to the reduction in ball milling speed and time, the reaction is incomplete, ultimately yielding an amorphous Sb₂Se₃ / P / C anode material.

[0043] Comparative Example 2 The steps in this comparative example are the same as in Example 2, except that in step S3, the volume percentage of H2 in the mixed atmosphere is modified to 6%. Due to the increase in H2 concentration, a strong reduction reaction is triggered, which leads to the chemical decomposition of SbPSe4, ultimately yielding a multiphase anode material composed of metallic Sb nanocrystals, residual amorphous selenium phosphate compounds, and carbon nanotubes.

[0044] Comparative Example 3 The steps in this comparative example are the same as in Example 3, except that in step S3, the filling atmosphere in the reactor is changed to pure Ar. The presence of H2 inhibits the volatilization and oxidation of Se at high temperatures. Without the inhibition of H2, the atoms in the material are more likely to migrate and rearrange under thermal drive, thereby crystallizing and finally obtaining crystalline SbPSe4 / C anode material.

[0045] Comparative Example 4 The steps in this comparative example are the same as in Example 4, except that the initial pressure in the reactor in step S3 is changed to 1 MPa. Due to the reduced initial pressure, the constraint on atomic diffusion is lessened. Driven by thermal energy, the material is more prone to structural relaxation, nucleation, and growth, ultimately yielding a crystalline SbPSe4 / C anode material.

[0046] Comparative Example 5 The steps in this comparative example are the same as in Example 5, except that in step S3, the holding time during the sealed heating treatment of the reactor is modified to 6 hours. Due to the reduction in the holding time, the amorphous relaxation process is insufficient, ultimately resulting in a crystalline SbPSe4 / C anode material.

[0047] Comparative Example 6 The steps in this comparative example are the same as in Example 5, except that in step S3, the heating rate during the sealed heating treatment of the reactor is modified to 6°C / min. Due to the increased heating rate, when the material reaches the 230°C holding point, it still retains a higher concentration of non-equilibrium defects and higher internal energy. The entire system is in a metastable state further away from equilibrium, ultimately yielding a crystalline SbPSe4 / C anode material.

[0048] Application Examples This application example utilizes the amorphous SbPSe4 / C anode material obtained in Example 1 in a potassium-ion battery, as detailed below: The prepared amorphous SbPSe4 / C anode material, Super-P and PVDF were mixed evenly in a ratio of 8:1:1, and then N-methylpyrrolidone (NMP) was added and ground into a slurry. The slurry was coated on copper foil with a thickness of 200 μm and dried under vacuum at 120 °C for 12 h to obtain the anode sheet.

[0049] The obtained negative electrode sheet was cut into a 12mm diameter disc as the working electrode, and a 10mm diameter potassium metal was used as the counter electrode. Whatman GF-A was used as the separator. The electrolyte was 1 mol / L potassium bis(trifluoromethanesulfonyl)imide dissolved in methyl ethyl carbonate. The cells were assembled into a button cell in a glove box (where the water and oxygen content were both below 0.01 ppm).

[0050] In 25 Its cycle performance and rate performance were measured in an environment of 1℃, with an operating voltage of 0.01~3V.

[0051] The cycle performance of the obtained amorphous SbPSe4 / C‖K half-cell is as follows: Figure 3 As shown, at a current density of 2000 mAg -1 The material can be stably cycled 200 times, indicating that the prepared material has excellent cycle stability.

[0052] Its rate performance is as follows Figure 4 As shown, the current density ranges from 100, 200, 400, 600, and 800 mAg. -1 It dropped back to 100mAg -1 .

[0053] As the current density increases, the discharge specific capacity gradually decreases, at a current density of 800 mAg. -1At that time, the discharge specific capacity reached as high as 170mAhg. -1 When the current density drops back to 100 mAg -1 At that time, the discharge specific capacity recovered to 230mAhg -1 This indicates that the amorphous SbPSe4 / C anode has good rate performance.

[0054] Application of comparative examples The crystalline SbPSe4 / C anode material prepared in Comparative Example 5 was used to assemble a potassium-ion battery using the method described in the application examples.

[0055] Cyclic performance testing was performed on it, and the results are as follows: Figure 5 As shown, compared to the amorphous SbPSe4 / C anode material prepared in Example 1, the crystalline SbPSe4 / C anode material used in this comparative application exhibits better performance at 2000 mAg. -1 At the initial current density, the capacity begins to decay rapidly during the initial cycling phase, and after 44 cycles, the capacity retention rate is only 10%, exhibiting poor cycling stability.

[0056] Therefore, this invention provides an amorphous SbPSe4 / C anode material, its preparation method, and its application. The prepared amorphous SbPSe4 / C anode material can effectively alleviate volume changes during battery cycling and improve cycle stability. It has great guiding significance for the application of potassium-ion battery anodes, and this method is conducive to the large-scale application of high-performance potassium-ion battery anodes.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing an amorphous SbPSe4 / C anode material, characterized in that, Includes the following steps: S1. The antimony source, phosphorus source and selenium source are subjected to mechanical ball milling under an inert atmosphere to obtain crystalline SbPSe4 compound; the mechanical ball milling time is 24~48h, the ball milling speed is 400~600rpm, and the ball-to-material ratio is 20~40:

1. S2. The obtained crystalline SbPSe4 compound and carbon material are subjected to secondary mechanical ball milling under an inert atmosphere to obtain a crystalline SbPSe4 / C composite material; the carbon material is carbon nanotubes, and the mass ratio of SbPSe4 to carbon nanotubes is 1:0.2~1; the secondary mechanical ball milling time is 30~60h, the ball milling speed is 300~500rpm, and the ball-to-material ratio is 10~20:1; S3. The obtained crystalline SbPSe4 / C composite material is subjected to closed heat treatment in a reducing atmosphere and cooled to room temperature to obtain amorphous SbPSe4 / C anode material. The heat treatment is carried out in a closed reactor with an initial pressure of 2~20MPa, a reaction temperature of 230~320℃, a heating rate of 1~5℃ / min, and a reaction time of 8~24h.

2. The preparation method of the amorphous SbPSe4 / C negative electrode material according to claim 1, characterized in that: In S1, the antimony source is antimony powder, the phosphorus source is red phosphorus, and the selenium source is selenium powder; the molar ratio of antimony powder, red phosphorus, and selenium powder is 1:1:

4.

3. The method for preparing an amorphous SbPSe4 / C anode material according to claim 1, characterized in that: In both S1 and S2, the inert atmosphere is argon, and the mechanical ball milling is planetary ball milling.

4. The method for preparing an amorphous SbPSe4 / C anode material according to claim 1, characterized in that: In step S3, the reducing atmosphere is a mixture of argon and hydrogen, with hydrogen accounting for 1% to 5% of the volume.

5. An amorphous SbPSe4 / C anode material, characterized in that: The amorphous SbPSe4 / C anode material is prepared by the preparation method according to any one of claims 1-4.

6. An application of an amorphous SbPSe4 / C anode material, characterized in that: The amorphous SbPSe4 / C anode material obtained in claim 5 is used as an anode sheet in potassium-ion batteries.

7. Use according to claim 6, characterized in that, The negative electrode preparation steps are as follows: Amorphous SbPSe4 / C negative electrode material, conductive carbon black and binder are mixed evenly, then N-methylpyrrolidone is added and ground into a slurry, which is then coated on copper foil and vacuum dried at 120°C for 12 hours to obtain the negative electrode.

8. Use according to claim 7, characterized in that: The ratio of amorphous SbPSe4 / C anode material, conductive carbon black, and binder is 8:1:1; The conductive carbon black is one of Super-P carbon black, Ketjen black, and acetylene black, and the binder is one of polyvinylidene fluoride and polytetrafluoroethylene.

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