Porous silicon / 1T-phase MoS2 composite anode material, preparation method and application thereof

Abstract

The present invention belongs to the technical field related to negative electrode materials for lithium batteries, and discloses a porous silicon / 1T phase MoS2 composite negative electrode material and a preparation method and application thereof. The method comprises the following steps: (1) preparing an aluminum silicon alloy Al x Si 100‑x The present invention obtains a suspension by magnetically stirring the suspension at room temperature for etching, thereby obtaining porous silicon, wherein the porous silicon contains aluminum, where x=20 to 80; (2) the porous silicon is added to a 1T phase MoS2 precursor solution to obtain a suspension, and the suspension is first magnetically stirred and then hydrothermally treated to obtain a porous silicon / 1T phase MoS2 composite negative electrode material. x Si 100‑x (x=20-80) The method for preparing porous silicon is simple and safe. It uses dilute hydrochloric acid for etching without the need for hydrofluoric acid, and can realize the industrial preparation and production of porous silicon.

Description

Technical Field

[0001] The present invention belongs to the technical field related to anode materials for lithium batteries, and more specifically, relates to a porous silicon / 1T-phase MoS2 composite anode material, a preparation method thereof, and an application thereof. Background Art

[0002] Compared with traditional batteries, lithium-ion batteries (LIBs) have become the first choice for various energy storage devices due to their high energy conversion efficiency, no memory effect, good safety, environmental friendliness and other advantages. After several years of rapid development, lithium-ion batteries have occupied the vast majority of the market share in the battery industry, and their products are widely used in energy storage systems such as solar energy and wind energy, and various portable electronic devices and other fields. However, commercial LIBs mainly use graphite materials as the anode, and its theoretical specific capacity is only 372 mAh / g, which cannot meet the requirements of higher specific capacity batteries. Silicon has a higher theoretical specific capacity (4200 mAh / g) as an anode material for LIBs, and has advantages such as low lithium intercalation potential, low atomic mass, rich reserves, and low price. Silicon and silicon-based composite materials are regarded as the most promising anode materials to replace commercial graphite anodes for LIBs.

[0003] However, silicon will cause a huge volume expansion (~300%) during the process of lithium ion insertion and extraction. This volume expansion phenomenon will generate strong mechanical stress on the silicon surface, resulting in electrode swelling, silicon anode pulverization, and rupture of the solid electrolyte interface (SEI) film on the surface, thereby causing the loss of electrical contact between the silicon particles and the electrode and the continuous formation of an unstable solid electrolyte film on the silicon surface. In addition, the conductivity of silicon is relatively low, only 1.56×10 -3 S / cm, which has an adverse effect on its electrochemical performance. Therefore, the volume expansion phenomenon and low conductivity of silicon as the anode of lithium-ion batteries have hindered the application of silicon anodes.

[0004] Therefore, how to more simply and reasonably design and prepare a silicon anode material with high capacity, high stability, and low price has become one of the technical problems to be solved urgently in this field. Summary of the Invention

[0005] In view of the above deficiencies or improvement requirements of the prior art, the present invention provides a porous silicon / 1T-phase MoS2 composite anode material, its preparation method and application. By means of its key components, their electro-chemical reaction kinetics mechanism, MoS2 phase regulation, control of the microscopic morphology of silicon and MoS2, and ratio regulation, etc., a novel porous silicon / 1T-phase MoS2 composite anode system is obtained. Compared with existing products, porous silicon not only has a larger specific surface area, which is convenient for the insertion and extraction of lithium ions, but also the pores inside the porous silicon provide sufficient space for the volume expansion of silicon, effectively reducing the mechanical stress generated by volume expansion and preventing the pulverization of silicon. In addition, a small amount of elemental aluminum is contained in the porous silicon under the present invention, which can improve the conductivity and mechanical properties of silicon.

[0006] To achieve the above object, according to one aspect of the present invention, a preparation method of a porous silicon / 1T-phase MoS2 composite anode material is provided, and the preparation method mainly includes the following steps:

[0007] (1) Mix an aluminum-silicon alloy Al x Si 100-x with a hydrochloric acid solution to obtain a suspension, and magnetically stir the suspension at room temperature for etching to obtain porous silicon, and the porous silicon contains elemental aluminum, x = 20 - 80;

[0008] (2) Add the porous silicon to a 1T-phase MoS2 precursor solution to obtain a suspension, magnetically stir the current suspension first and then perform hydrothermal treatment to obtain a porous silicon / 1T-phase MoS2 composite anode material.

[0009] Further, the molar ratio of Al to HCl in the suspension in step (1) is 1:1 - 3.

[0010] Further, in step (1), mix Al x Si 100-x with a hydrochloric acid solution to obtain a suspension, magnetically stir the suspension at room temperature for more than 12 hours for sufficient etching; then, filter and wash the suspension with deionized water until neutral, and then vacuum dry at 60°C - 80°C to obtain the porous silicon.

[0011] Further, mix ammonium molybdate tetrahydrate, thiourea and deionized water or ammonium tetrathiomolybdate and deionized water, and then perform magnetic stirring to obtain a uniform 1T-phase MoS2 precursor solution.

[0012] Further, mix ammonium molybdate tetrahydrate, thiourea and deionized water or ammonium tetrathiomolybdate and deionized water and magnetically stir for 0.5 - 2 hours to obtain a uniform 1T-phase MoS2 precursor solution.

[0013] Furthermore, the hydrothermal treatment temperature of the suspension composed of the 1T-phase MoS2 precursor solution and porous silicon is 170-200 °C, and the hydrothermal treatment time is 10-14 hours; the vacuum drying temperature of the porous silicon / 1T-phase MoS2 composite material is 60-80 °C.

[0014] The present invention also provides a preparation method of a porous silicon / 1T-phase MoS2 composite anode material, and this composite anode material is prepared by using the preparation method of the porous silicon / 1T-phase MoS2 composite anode material as described above.

[0015] The present invention also provides an application of the porous silicon / 1T-phase MoS2 composite anode material, and the porous silicon / 1T-phase MoS2 composite anode material as described above is applied to the anode material of a lithium battery.

[0016] Furthermore, after the porous silicon / 1T-phase MoS2 composite anode material, a conductive agent, a binder, and deionized water are mixed evenly, the porous silicon / 1T-phase MoS2 composite anode material is coated onto a current collector copper foil by pressing to obtain a negative electrode sheet.

[0017] Furthermore, the conductive agent is at least one of Ketjen black, Super P, acetylene black, carbon black, carbon fiber, and carbon nanotube; the binder is at least one of sodium alginate, polyacrylic acid, and polyvinylidene fluoride; the mass ratio of the porous silicon / 1T-phase MoS2 composite anode material, the conductive agent, and the binder is (0.6-0.8):(0.1-0.2):(0.1-0.2).

[0018] Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the porous silicon / 1T-phase MoS2 composite anode material and its preparation method and application provided by the present invention mainly have the following beneficial effects:

[0019] 1. The method for preparing porous silicon by etching Al x Si 100-x (x = 20-80) is simple and safe. Dilute hydrochloric acid is used for etching, and hydrofluoric acid is not required, which can realize the industrial production of porous silicon.

[0020] 2. The prepared porous silicon contains a small amount of elemental aluminum, which can improve the mechanical properties and conductivity of the porous silicon.

[0021] 3. The porous silicon has a larger specific surface area, which is convenient for the insertion and extraction of lithium ions. And the pores inside the porous silicon provide sufficient space for the volume expansion of silicon, effectively reducing the mechanical stress generated by volume expansion and preventing the pulverization of silicon.

[0022] 4. In the porous silicon / 1T-phase MoS2 composite anode material prepared by the present invention, MoS2 is in the 1T phase. The 1T-phase MoS2 has an octahedral structure and can serve as an electron transport channel to achieve high Coulomb efficiency.

[0023] 5. The 1T-phase MoS2 supported on the surface of the porous silicon / 1T-phase MoS2 composite anode material prepared by the present invention is inert to the electrolyte, improving the stability of the surface SEI film, thereby preventing the loss of effective substances in the electrolyte.

[0024] 6. The preparation method of the porous silicon / 1T-phase MoS2 composite anode material prepared by the present invention is simple, convenient, green and environmentally friendly, and will not have any adverse effects on the environment, facilitating industrial production.

[0025] 7. The porous silicon / 1T-phase MoS2 composite anode material prepared by the simple hydrothermal method of the present invention is one of the ideal anode materials for lithium batteries, having excellent cycle stability and rate performance.

[0026] 8. By making targeted research and improvements on key components, electrochemistry reaction kinetics mechanism, the composite ratio of porous silicon and 1T-phase MoS2, etc., the present invention better solves problems such as volume expansion and poor conductivity of silicon anodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic flow chart of the preparation method and performance verification of the porous silicon / 1T-phase MoS2 composite anode material provided by Example 1 of the present invention;

[0028] Figure 2 is an XRD pattern of the porous silicon / 1T-phase MoS2 composite anode material prepared in Example 1 of the present invention;

[0029] Figure 3 is an SEM image of the porous silicon / 1T-phase MoS2 composite anode material prepared in Example 1 of the present invention;

[0030] Figure 4 is a graph showing the relationship between room temperature discharge capacity and rate of the lithium battery anode prepared from the porous silicon / 1T-phase MoS2 composite anode material prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] The present invention obtains a novel porous silicon / 1T-phase MoS2 composite anode system by means of key components of the anode material, their electrochemistry reaction kinetics mechanism, MoS2 phase regulation, control of the microscopic morphology of silicon and MoS2, and ratio regulation. Compared with existing products, porous silicon not only has a larger specific surface area, facilitating the insertion and extraction of lithium ions, but also the pores inside porous silicon provide sufficient space for the volume expansion of silicon, effectively reducing the mechanical stress generated by volume expansion and preventing silicon from pulverizing. In addition, a small amount of elemental aluminum is contained in the porous silicon of the present invention, which can improve the electrical conductivity and mechanical properties of silicon. The 1T-phase MoS2 is an octahedral structure with an electrical conductivity of 10-100 S / cm. The uniform loading of the 1T-phase MoS2 onto the surface of porous silicon can serve as an electron transport channel to achieve a high Coulombic efficiency of the silicon anode. Moreover, the 1T-phase MoS2 shows inertness to the electrolyte, and after the surface modification of the porous silicon by the 1T-phase MoS2, the stability of the surface SEI film is improved, thereby preventing the loss of effective substances in the electrolyte. The half-cell (with a lithium sheet as the anode) assembled with the porous silicon / 1T-phase MoS2 composite anode system exhibits excellent cycle stability and rate performance. At the same time, the porous silicon / 1T-phase MoS2 composite anode system can be coated on the negative current collector copper foil, with the advantages of simple operation, strong applicability, and good stability. Therefore, it is one of the ideal anode materials for constructing high-energy density secondary lithium batteries.

[0033] Please refer to Figure 1 , the present invention provides a preparation method of a porous silicon / 1T-phase MoS2 composite anode material, and the preparation method includes: using dilute hydrochloric acid and Al x Si 100-x to prepare porous silicon; using thiourea, ammonium molybdate tetrahydrate and deionized water or ammonium tetrathiomolybdate and deionized water to prepare a 1T-phase MoS2 precursor solution; using a hydrothermal method to load the 1T-phase MoS2 onto the surface of porous silicon to prepare a porous silicon / 1T-phase MoS2 composite anode material. Among them, the presence of a small amount of elemental aluminum in the porous silicon can improve the mechanical properties and electrical conductivity of the silicon anode, thereby improving the Coulombic efficiency and stability of the silicon anode. In addition, the pores in the porous silicon provide sufficient space for its volume expansion, effectively preventing the pulverization of the silicon anode. The / 1T-phase MoS2 in the porous silicon / 1T-phase MoS2 composite anode material has excellent electrical conductivity and shows inertness to the electrolyte, further improving the electrical conductivity of the silicon anode and enhancing the stability of the SEI film, ensuring high Coulombic efficiency and high stability of the anode of the porous silicon / 1T-phase MoS2 composite anode material.

[0034] The preparation method mainly includes the following sub-steps:

[0035] Step 1, the aluminum-silicon alloy Al x Si 100-xMix it with hydrochloric acid solution to obtain a suspension, and magnetically stir the suspension at room temperature for etching to obtain porous silicon. The porous silicon contains elemental aluminum, and x = 20 - 80.

[0036] Mix the aluminum-silicon alloy Al x Si 100-x (x = 20 - 80) with hydrochloric acid solution to obtain a suspension, and magnetically stir the suspension at room temperature for sufficient etching; then, filter and wash the mixed solution with deionized water until it is neutral, and then dry it to obtain porous silicon containing a small amount of elemental aluminum. The mass percentage of elemental aluminum in the porous silicon is 10% - 20%.

[0037] In this embodiment, mix Al x Si 100-x with hydrochloric acid solution to obtain a suspension. The molar ratio of Al to HCl is 1:1 - 3. Magnetically stir the suspension at room temperature for more than 12 hours for sufficient etching; then, filter and wash the suspension with deionized water until it is neutral, and vacuum dry it at 60°C - 80°C to obtain porous silicon containing a small amount of elemental aluminum.

[0038] Step 2: Add the porous silicon to the 1T-phase MoS2 precursor solution to obtain a suspension. First, magnetically stir the current suspension and then perform hydrothermal treatment to obtain a porous silicon / 1T-phase MoS2 composite anode material.

[0039] Mix ammonium molybdate tetrahydrate, thiourea, and deionized water or ammonium tetrathiomolybdate and deionized water, and magnetically stir to obtain a uniform 1T-phase MoS2 precursor solution.

[0040] In this embodiment, mix ammonium molybdate tetrahydrate, thiourea, and deionized water or ammonium tetrathiomolybdate and deionized water and magnetically stir for 0.5 - 2 hours to obtain a uniform 1T-phase MoS2 precursor solution; then, add the porous silicon to the 1T-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate, thiourea, deionized water, and porous silicon is 0.25 - 0.35 g: 0.2 - 0.3 g: 60 - 80 ml: 0.6 - 0.8 g; or the dosage ratio of ammonium tetrathiomolybdate, deionized water, and porous silicon is 0.45 - 0.55 g: 60 - 80 ml: 0.6 - 0.8 g. Magnetically stir the suspension for another 0.5 - 2 hours; then, hydrothermally treat the suspension at 170 - 200°C for 10 - 14 hours; then filter and wash the suspension with deionized water, and then vacuum dry it at 60 - 80°C to obtain a porous silicon / 1T-phase MoS2 composite anode material.

[0041] The obtained porous silicon / 1T-phase MoS2 composite anode material is applied to the anode material of a lithium battery. Specifically: the prepared porous silicon / 1T-phase MoS2 composite anode material, conductive agent, binder and deionized water are mixed evenly, and then the porous silicon / 1T-phase MoS2 composite anode material is coated on the current collector copper foil by pressing to obtain the anode sheet. Among them, the conductive agent is at least one of Ketjen black, Super P, acetylene black, carbon black, carbon fiber, and carbon nanotube; the binder is at least one of sodium alginate, polyacrylic acid, and polyvinylidene fluoride; the dosage ratio of the porous silicon / 1T-phase MoS2 composite anode material, conductive agent, binder and deionized water is 0.6 - 0.8 g: 0.1 - 0.2 g: 0.1 - 0.2 g: 5 - 8 ml.

[0042] The following takes several specific examples to further elaborate on the present invention in detail.

[0043] Example 1

[0044] Please refer to Figure 2 、 Figure 3 and Figure 4 In this example, the porous silicon / 1T-phase MoS2 composite anode material includes porous silicon and 1T-phase MoS2. Among them, the porous silicon / 1T-phase MoS2 composite anode is prepared by a pressing process; the molar ratio of Al in Al60Si40 to HCl in the hydrochloric acid solution is 1:2; the molar ratio of the porous silicon to 1T-phase MoS2 is 1:1.

[0045] The process operation steps of this example are as follows:

[0046] (1) Mix Al60Si40 with the hydrochloric acid solution to obtain a suspension. The molar ratio of Al to HCl is 1:2. The suspension is magnetically stirred at room temperature for 12 hours for sufficient etching; then, the suspension is filtered and washed with deionized water until neutral, and vacuum dried at 60°C to obtain porous silicon containing a small amount of aluminum.

[0047] (2) Mix ammonium molybdate tetrahydrate, thiourea and deionized water and magnetically stir for 1 hour to obtain a uniform 1T-phase MoS2 precursor solution; then, add the porous silicon to the 1T-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate, thiourea, deionized water and porous silicon is 0.35 g: 0.3 g: 70 ml: 0.7 g. The suspension is continuously magnetically stirred for 1 hour; then, the suspension is hydrothermally treated at 180°C for 12 hours; then the suspension is filtered and washed with deionized water, and then vacuum dried at 60°C to obtain the porous silicon / 1T-phase MoS2 composite anode material.

[0048] (3) The prepared porous silicon / 1T-phase MoS2 composite anode material, Ketjen black, and sodium alginate are mixed evenly with deionized water, and then the porous silicon / 1T-phase MoS2 composite anode material is coated onto the current collector copper foil by pressing to obtain the anode plate. Among them, the dosage ratio of the porous silicon / 1T-phase MoS2 composite anode material, Ketjen black, sodium alginate, and deionized water is 0.6 g: 0.2 g: 0.2 g: 5 ml.

[0049] The cyclic and rate performances of the lithium battery anode assembled with the porous silicon / 1T-phase MoS2 composite anode material are tested. The discharge specific capacity at 0.1C is 1242.07 mAh g at room temperature. -1 。

[0050] Example 2

[0051] The porous silicon / 1T-phase MoS2 composite anode material in this example includes porous silicon and 1T-phase MoS2. Among them, the porous silicon / 1T-phase MoS2 composite anode is prepared by a pressing process; the molar ratio of Al in Al60Si40 to HCl in the hydrochloric acid solution is 1:1; the molar ratio of the porous silicon to 1T-phase MoS2 is 1:1.

[0052] The process operation steps of this example are as follows:

[0053] (1) Al60Si40 is mixed with the hydrochloric acid solution to obtain a suspension. The molar ratio of Al to HCl is 1:1. The suspension is magnetically stirred at room temperature for 12 hours for sufficient etching; then, the suspension is filtered and washed with deionized water until neutral, and vacuum dried at 60°C to obtain porous silicon containing a small amount of aluminum.

[0054] (2) Ammonium molybdate tetrahydrate, thiourea, and deionized water are mixed and magnetically stirred for 1 hour to obtain a uniform 1T-phase MoS2 precursor solution; then, the porous silicon is added to the 1T-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate, thiourea, deionized water, and porous silicon is 0.35 g: 0.3 g: 70 ml: 0.7 g. The suspension is continuously magnetically stirred for 1 hour; then, the suspension is hydrothermally treated at 180°C for 12 hours; then the suspension is filtered and washed with deionized water, and then vacuum dried at 60°C to obtain the porous silicon / 1T-phase MoS2 composite anode material.

[0055] (3) The prepared porous silicon / 1T-phase MoS2 composite anode material, Ketjen black, and sodium alginate are mixed evenly with deionized water, and then the porous silicon / 1T-phase MoS2 composite anode material is coated onto the current collector copper foil by pressing to obtain the anode plate. The dosage ratio of the porous silicon / 1T-phase MoS2 composite anode material, Ketjen black, sodium alginate, and deionized water is 0.6 g: 0.2 g: 0.2 g: 5 ml.

[0056] Testing the cycling and rate performance of the lithium battery negative electrode assembled with the porous silicon / 1T-phase MoS2 composite negative electrode material into Li / / porous silicon / 1T-phase MoS2. The discharge specific capacity at 0.1C at room temperature is 1084.15 mAh g -1 。

[0057] Example 3

[0058] The porous silicon / 1T-phase MoS2 composite negative electrode material in this example includes porous silicon and 1T-phase MoS2. Among them, the negative electrode of the porous silicon / 1T-phase MoS2 composite negative electrode material is prepared by a tablet pressing process; the molar ratio of Al in Al80Si20 to HCl in the hydrochloric acid solution is 1:3; the molar ratio of the porous silicon to 1T-phase MoS2 is 1:1.

[0059] The process operation steps of this example are as follows:

[0060] (1) Mix Al80Si20 with the hydrochloric acid solution to obtain a suspension. The molar ratio of Al to HCl is 1:3. The suspension is magnetically stirred at room temperature for 12 hours for sufficient etching; then, the suspension is filtered and washed with deionized water until neutral, and vacuum dried at 60°C to obtain porous silicon containing a small amount of aluminum.

[0061] (2) Mix ammonium molybdate tetrahydrate, thiourea and deionized water and magnetically stir for 1 hour to obtain a uniform 1T-phase MoS2 precursor solution; then, add the porous silicon to the 1T-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate, thiourea, deionized water and porous silicon is 0.35 g: 0.3 g: 70 ml: 0.7 g. The suspension is continuously magnetically stirred for 1 hour; then, the suspension is hydrothermally treated at 180°C for 12 hours; then the suspension is filtered and washed with deionized water, and then vacuum dried at 60°C to obtain the porous silicon / 1T-phase MoS2 composite negative electrode material.

[0062] (3) Mix the prepared porous silicon / 1T-phase MoS2 composite negative electrode material, Ketjen black and sodium alginate with deionized water evenly, and then use tablet pressing to coat the porous silicon / 1T-phase MoS2 composite negative electrode material on the current collector copper foil to obtain the negative electrode plate. The dosage ratio of the porous silicon / 1T-phase MoS2 composite negative electrode material, Ketjen black, sodium alginate and deionized water is 0.6 g: 0.2 g: 0.2 g: 5 ml.

[0063] Testing the cycling and rate performance of the lithium battery negative electrode assembled with the porous silicon / 1T-phase MoS2 composite negative electrode material into Li / / porous silicon / 1T-phase MoS2. The discharge specific capacity at 0.1C at room temperature is 1032.42 mAh g -1 。

[0064] Example 4

[0065] The porous silicon / 1T-phase MoS2 composite anode material in this example includes porous silicon and 1T-phase MoS2. Among them, the porous silicon / 1T-phase MoS2 composite anode is prepared by a tablet pressing process; the molar ratio of Al in Al60Si40 to HCl in the hydrochloric acid solution is 1:2; the molar ratio of the porous silicon to 1T-phase MoS2 is 1:0.5.

[0066] The process operation steps of this example are as follows:

[0067] (1) Mix Al60Si40 with the hydrochloric acid solution to obtain a suspension. The molar ratio of Al to HCl is 1:2. The suspension is magnetically stirred at room temperature for 12 hours for sufficient etching; then, the suspension is filtered by suction and washed with deionized water until neutral, and vacuum dried at 60 °C to obtain porous silicon containing a small amount of aluminum.

[0068] (2) Mix ammonium molybdate tetrahydrate, thiourea, and deionized water and magnetically stir for 1 hour to obtain a uniform 1T-phase MoS2 precursor solution; then, add the porous silicon to the 1T-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate, thiourea, deionized water, and porous silicon is 0.35 g: 0.3 g: 70 ml: 1.4 g. The suspension is continuously magnetically stirred for 1 hour; then, the suspension is hydrothermally treated at 180 °C for 12 hours; then the suspension is filtered by suction and washed with deionized water, and then vacuum dried at 60 °C to obtain the porous silicon / 1T-phase MoS2 composite anode material.

[0069] (3) Mix the prepared porous silicon / 1T-phase MoS2 composite anode material, Ketjen black, and sodium alginate with deionized water evenly, and then use tablet pressing to coat the porous silicon / 1T-phase MoS2 composite anode material onto the current collector copper foil to obtain the negative electrode sheet. The dosage ratio of the porous silicon / 1T-phase MoS2 composite anode material, Ketjen black, sodium alginate, and deionized water is 0.6 g: 0.2 g: 0.2 g: 5 ml.

[0070] Test the cycling and rate performance of the porous silicon / 1T-phase MoS2 composite anode material assembled into the Li / / porous silicon / 1T-phase MoS2 lithium battery anode. The discharge specific capacity at 0.1C at room temperature is 1042.14 mAh g -1 .

[0071] Example 5

[0072] The porous silicon / 1T-phase MoS2 composite anode material in this embodiment includes porous silicon and 1T-phase MoS2. Among them, the porous silicon / 1T-phase MoS2 composite anode material is prepared by a tablet pressing process; the molar ratio of Al in Al60Si40 to HCl in the hydrochloric acid solution is 1:2; the molar ratio of porous silicon to 1T-phase MoS2 is 1:2.

[0073] The process operation steps of this embodiment are as follows:

[0074] (1) Mix Al60Si40 with the hydrochloric acid solution to obtain a suspension. The molar ratio of Al to HCl is 1:2. The suspension is magnetically stirred at room temperature for 12 hours for sufficient etching; then, the suspension is filtered and washed with deionized water until neutral, and vacuum dried at 60 °C to obtain porous silicon containing a small amount of aluminum.

[0075] (2) Mix ammonium molybdate tetrahydrate, thiourea, and deionized water and magnetically stir for 1 hour to obtain a uniform 1T-phase MoS2 precursor solution; then, add porous silicon to the 1T-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate, thiourea, deionized water, and porous silicon is 0.35 g: 0.3 g: 70 ml: 0.35 g. The suspension is continuously magnetically stirred for 1 hour; then, the suspension is hydrothermally treated at 180 °C for 12 hours; then the suspension is filtered and washed with deionized water, and then vacuum dried at 60 °C to obtain the porous silicon / 1T-phase MoS2 composite anode material.

[0076] (3) Mix the prepared porous silicon / 1T-phase MoS2 composite anode material, Ketjen black, and sodium alginate with deionized water evenly, and then use tablet pressing to coat the porous silicon / 1T-phase MoS2 composite anode material on the current collector copper foil to obtain the anode electrode sheet. The dosage ratio of the porous silicon / 1T-phase MoS2 composite anode material, Ketjen black, sodium alginate, and deionized water is 0.6 g: 0.2 g: 0.2 g: 5 ml.

[0077] Test the cycle and rate performance of the porous silicon / 1T-phase MoS2 composite anode material assembled into the Li / / porous silicon / 1T-phase MoS2 lithium battery anode. The discharge specific capacity at 0.1C at room temperature is 952.34 mAh g -1 。

[0078] Example 6

[0079] The porous silicon / 1T-phase MoS2 composite anode material in this embodiment includes porous silicon and 1T-phase MoS2. Among them, the porous silicon / 1T-phase MoS2 composite anode material is prepared by a tablet pressing process; the molar ratio of Al in Al60Si40 to HCl in the hydrochloric acid solution is 1:2; the molar ratio of porous silicon to 1T-phase MoS2 is 1:1.

[0080] The process operation steps of this embodiment are as follows:

[0081] (1) Mix Al60Si40 with hydrochloric acid solution to obtain a suspension. The molar ratio of Al to HCl is 1:2. The suspension is magnetically stirred at room temperature for 12 hours for sufficient etching. Then, the suspension is filtered by suction and washed with deionized water until neutral, and vacuum dried at 60 °C to obtain porous silicon containing a small amount of elemental aluminum.

[0082] (2) Mix ammonium tetrathiomolybdate and deionized water and magnetically stir for 1 hour to obtain a uniform 1T-phase MoS2 precursor solution. Then, add the porous silicon to the 1T-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium tetrathiomolybdate, deionized water and porous silicon is 0.5 g: 70 ml: 0.7 g. The suspension is continuously magnetically stirred for 1 hour. Then, the suspension is hydrothermally treated at 180 °C for 12 hours. Then, the suspension is filtered by suction and washed with deionized water, and then vacuum dried at 60 °C to obtain a porous silicon / 1T-phase MoS2 composite anode material.

[0083] (3) Mix the prepared porous silicon / 1T-phase MoS2 composite anode material, Ketjen black and sodium alginate with deionized water evenly, and then use tabletting to coat the porous silicon / 1T-phase MoS2 composite anode material onto the current collector copper foil to obtain a negative electrode sheet. The dosage ratio of the porous silicon / 1T-phase MoS2 composite anode material, Ketjen black, sodium alginate and deionized water is 0.6 g: 0.2 g: 0.2 g: 5 ml.

[0084] Test the cycle and rate performance of the lithium battery negative electrode assembled with the porous silicon / 1T-phase MoS2 composite anode material, Li / / porous silicon / 1T-phase MoS2. The discharge specific capacity at 0.1C at room temperature is 1224.15 mAh g -1 .

[0085] Example 7

[0086] The porous silicon / 1T-phase MoS2 composite anode material in this embodiment includes porous silicon and 1T-phase MoS2. Among them, the porous silicon / 1T-phase MoS2 composite anode is prepared by a tabletting process; the molar ratio of Al in the Al60Si40 to HCl in the hydrochloric acid solution is 1:2; the molar ratio of the porous silicon to the 1T-phase MoS2 is 1:1.

[0087] The process operation steps of this embodiment are as follows:

[0088] (1) Mix Al60Si40 with hydrochloric acid solution to obtain a suspension. The molar ratio of Al to HCl is 1:2. The suspension is magnetically stirred at room temperature for 12 hours for sufficient etching. Then, the suspension is filtered by suction and washed with deionized water until neutral, and vacuum dried at 60 °C to obtain porous silicon containing a small amount of elemental aluminum.

[0089] (2) Mix ammonium molybdate tetrahydrate, thiourea and deionized water and magnetically stir for 1 hour to obtain a uniform 1T-phase MoS2 precursor solution. Then, add the porous silicon into the 1T-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate, thiourea, deionized water and porous silicon is 0.35 g: 0.3 g: 70 ml: 0.7 g. The suspension is continuously magnetically stirred for 1 hour. Then, the suspension is hydrothermally treated at 180 °C for 12 hours. Then, the suspension is filtered by suction and washed with deionized water, and then vacuum dried at 60 °C to obtain a porous silicon / 1T-phase MoS2 composite anode material.

[0090] (3) Mix the prepared porous silicon / 1T-phase MoS2 composite anode material, acetylene black, polyacrylic acid and deionized water evenly, and then use pressing to coat the porous silicon / 1T-phase MoS2 composite anode material onto the current collector copper foil to obtain a negative electrode sheet. The dosage ratio of the porous silicon / 1T-phase MoS2 composite anode material, acetylene black, polyacrylic acid and deionized water is 0.8 g: 0.1 g: 0.1 g: 6 ml.

[0091] Test the cycling and rate performance of the porous silicon / 1T-phase MoS2 composite anode material assembled into a Li / / porous silicon / 1T-phase MoS2 lithium battery anode. The discharge specific capacity at 0.1C at room temperature is 1204.15 mAh g -1 。

[0092] The present invention also provides a preparation method of a porous silicon / 1T-phase MoS2 composite anode material. The composite anode material is prepared by using the preparation method of the porous silicon / 1T-phase MoS2 composite anode material as described above.

[0093] The present invention also provides an application of a porous silicon / 1T-phase MoS2 composite anode material. The porous silicon / 1T-phase MoS2 composite anode material as described above is applied to a lithium battery anode material.

[0094] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A preparation method of a porous silicon / 1T-phase MoS2 composite anode material, characterized in that, The method comprises the following steps: (1) Mix the aluminum-silicon alloy Al x Si 100-x with a hydrochloric acid solution to obtain a suspension, and magnetically stir the suspension at room temperature for etching to obtain porous silicon containing elemental aluminum, where x = 20 - 80; (2) Adding the porous silicon into a 1T-phase MoS2 precursor solution to obtain a suspension, magnetically stirring the current suspension first and then performing hydrothermal treatment to obtain a porous silicon / 1T-phase MoS2 composite anode material; wherein, the molar ratio of the porous silicon to the 1T-phase MoS2 is 1:1 or 1:0.5 or 1:

2.

2. The preparation method of the porous silicon / 1T-phase MoS2 composite anode material according to claim 1, characterized in that: The molar ratio of Al to HCl in the suspension in step (1) is 1:1 - 3.

3. The preparation method of the porous silicon / 1T-phase MoS2 composite anode material according to claim 2, characterized in that: In step (1), Al x Si 100-x is mixed with a hydrochloric acid solution to obtain a suspension, and the suspension is magnetically stirred at room temperature for more than 12 hours for sufficient etching; then, the suspension is suction filtered and washed with deionized water to neutrality, and then vacuum dried at 60 °C to 80 °C to obtain the porous silicon.

4. The preparation method of the porous silicon / 1T-phase MoS2 composite anode material according to claim 1, characterized in that: Mixing ammonium molybdate tetrahydrate, thiourea and deionized water or ammonium tetrathiomolybdate and deionized water, and then magnetically stirring to obtain a uniform 1T-phase MoS2 precursor solution.

5. The preparation method of the porous silicon / 1T-phase MoS2 composite anode material according to claim 4, characterized in that: Mixing ammonium molybdate tetrahydrate, thiourea and deionized water or ammonium tetrathiomolybdate and deionized water and magnetically stirring for 0.5 - 2 hours to obtain a uniform 1T-phase MoS2 precursor solution.

6. The preparation method of the porous silicon / 1T-phase MoS2 composite anode material according to any one of claims 1-5, characterized in that: The temperature of the hydrothermal treatment of the suspension composed of the 1T-phase MoS2 precursor solution and the porous silicon is 170 - 200 °C, and the hydrothermal treatment time is 10 - 14 hours; the vacuum drying temperature of the porous silicon / 1T-phase MoS2 composite material is 60 - 80 °C.

7. A porous silicon / 1T-phase MoS2 composite anode material, characterized in that: The composite anode material is prepared by using the preparation method of the porous silicon / 1T-phase MoS2 composite anode material according to any one of claims 1 - 6.

8. An application of a porous silicon / 1T-phase MoS2 composite anode material, characterized in that: Applying the porous silicon / 1T-phase MoS2 composite anode material according to claim 7 to a lithium battery anode material.

9. The application of the porous silicon / 1T-phase MoS2 composite anode material according to claim 8, characterized in that: Mixing the porous silicon / 1T-phase MoS2 composite anode material, a conductive agent, a binder and deionized water evenly, and then using tabletting to coat the porous silicon / 1T-phase MoS2 composite anode material onto a current collector copper foil to obtain a negative electrode sheet.

10. The application of the porous silicon / 1T-phase MoS2 composite anode material according to claim 9, characterized in that: The conductive agent is at least one of Ketjen black, Super P, acetylene black, carbon black, carbon fiber, carbon nanotubes; the binder is at least one of sodium alginate, polyacrylic acid and polyvinylidene fluoride; the mass ratio of the porous silicon / 1T-phase MoS2 composite anode material, the conductive agent and the binder is (0.6 - 0.8):(0.1 - 0.2):(0.1 - 0.2).

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