A method for preparing a negative electrode material for a sulfide all-solid-state battery

Abstract

The application discloses a kind of preparation methods of negative electrode material for sulfide all-solid-state battery, belong to negative electrode material technical field, the method is first by ball milling, silicon and sulfide electrolyte are mixed, and silicon material is obtained;Then the silicon material and carbon nanotube, graphene oxide are combined, and composite material is obtained;Again, the composite material is immersed into linear macromolecular crosslinking agent, and after a period of time, the negative electrode material for sulfide all-solid-state battery is obtained by drying after reaction.The carbon nanotube and graphene oxide in the application not only can provide conductive network for negative electrode material, but also can use its one-dimensional and two-dimensional structure active hydroxyl to form skeleton with linear macromolecule, and bind the composite large-capacity silicon material in its interior, accommodate the volume expansion after silicon lithiation, and relieve the instability of silicon negative electrode material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of negative electrode materials, and particularly relates to a preparation method of a negative electrode material for a sulfide full-solid-state battery. BACKGROUND

[0002] Lithium ion batteries have become the first choice for consumer electronic batteries and new energy vehicle power batteries due to their high energy density, long cycle life, no memory effect and other advantages. Under the background of rapid development of new energy vehicles, the market has higher requirements for the comprehensive performance of power batteries, and the development of new materials with high capacity, high rate and high stability has become the key to the development of power batteries. Among them, the development of negative electrode materials is crucial to improving battery performance. In the field of negative electrode materials, graphite materials are the mainstream, but graphite negative electrode materials have reached the theoretical specific capacity limit.

[0003] Among the new generation of materials, silicon-based negative electrode materials are developing rapidly, and the industrialization process is accelerating. Silicon negative electrodes have received widespread attention from the scientific research community and the industry due to their high specific capacity. However, silicon undergoes a large volume change during lithiation, which leads to cracking of large silicon particles and poor contact at the interface, resulting in low stability of the silicon negative electrode material, thereby limiting the practical application of the silicon negative electrode. In addition, the poor conductivity of silicon also limits the performance of the electrode.

[0004] Therefore, it is urgent to propose a preparation method of a negative electrode material for a sulfide full-solid-state battery to solve the above problems. SUMMARY

[0005] The present application discloses a preparation method of a negative electrode material for a sulfide full-solid-state battery, which can effectively solve at least one technical problem involved in the background art.

[0006] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0007] A preparation method of a negative electrode material for a sulfide full-solid-state battery, comprising the following steps:

[0008] Step S1: mixing nano-silicon and sulfide electrolyte by ball milling to obtain a silicon material;

[0009] Step S2: combining the silicon material with carbon nanotubes and graphene oxide to obtain a composite material;

[0010] Step S3: immersing the composite material in a linear macromolecular crosslinking agent, and drying after a period of reaction to obtain a negative electrode material for a sulfide full-solid-state battery.

[0011] As a preferred improvement of the present application, in step S1, the mass ratio of the nano-silicon to the sulfide electrolyte is 1:0.1-1.

[0012] As a preferred improvement of the present application, in step S1, the ball milling speed is 200-500 rpm, and the ball milling time is 1-10 h.

[0013] As a preferred improvement of the present application, in step S2, the silicon material and the carbon nanotube and the graphene oxide are mixed by ball milling, the ball milling speed is 200-500 rpm, and the ball milling time is 30-120 min.

[0014] As a preferred improvement of the present application, in step S2, the mass ratio of the silicon material to the carbon nanotube and the graphene oxide is 100:1-5, and the mass ratio of the carbon nanotube to the graphene oxide is 1-3:1.

[0015] As a preferred improvement of the present application, in step S3, the drying temperature is 120℃, and the drying time is 1-8 h.

[0016] As a preferred improvement of the present application, the carbon nanotube is a hydroxylated carbon nanotube with a diameter greater than 1 nm.

[0017] As a preferred improvement of the present application, the concentration of the linear macromolecular crosslinking agent is 2 g / L.

[0018] As a preferred improvement of the present application, the linear macromolecular crosslinking agent has an amine end group or an acyl chloride end group, the amine end group is polyethyleneimine, and the acyl chloride end group is acetyl chloride.

[0019] The beneficial effects of the present application are as follows:

[0020] The present application constructs a strong combination conductive network by one-dimensional carbon nanotubes and two-dimensional graphene oxide and linear macromolecular crosslinking, improves the conductive performance, and can use the active hydroxyl groups on the one-dimensional and two-dimensional structures to form a skeleton with linear macromolecules to bind the large capacity silicon material in its interior, absorb the volume expansion after silicon lithiation, and relieve the instability of the silicon negative electrode material. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] It should be noted that all the directionality indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture, and if the certain posture changes, the directionality indications will also change accordingly.

[0023] In addition, the descriptions such as "first", "second" and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can be explicitly or implicitly included at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0024] In the present application, unless otherwise explicitly specified and limited, the terms "connection", "fixation" and the like should be understood in a broad sense, for example, "fixation" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through intermediate medium; can be internal communication of two elements or interaction relationship between two elements, unless otherwise explicitly limited. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0025] In addition, the technical solutions of various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary skilled in the art can realize it, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0026] The present application provides a kind of negative electrode material preparation method for sulfide full solid battery, specifically comprising the following steps:

[0027] Step S1, nano-silicon and sulfide electrolyte are mixed by ball milling to obtain silicon material;

[0028] Wherein, the mass ratio of the nano-silicon and the sulfide electrolyte is 1:0.1-1;The rate of ball milling is 200-500rpm, and the ball milling time is 1-10h.

[0029] Step S2, the silicon material and carbon nanotube, graphene oxide are combined to obtain a composite material;

[0030] Specifically, the silicon material and the carbon nanotube and graphene oxide are mixed by ball milling, and the ball milling rate is 200-500rpm, and the ball milling time is 30-120min.

[0031] The mass ratio of the silicon material to the carbon nanotube and graphene oxide is 100:1-5, and the mass ratio of the carbon nanotube to the graphene oxide is 1-3:1.

[0032] Preferably, the carbon nanotube is a hydroxylated carbon nanotube with a diameter greater than 1 nm.

[0033] Step S3, the composite material is immersed in a linear macromolecular crosslinking agent to complete the skeleton construction, and then dried at 120 DEG C for 8h to obtain a negative electrode material for a sulfide all-solid-state battery.

[0034] The linear macromolecular crosslinking agent is 2g / L of an amine end group or an acyl chloride end group, the amine end group is polyethyleneimine, and the acyl chloride end group is acetyl chloride.

[0035] The preparation method of the negative electrode material for the sulfide all-solid-state battery provided by the application is described in detail below with specific examples 1-3.

[0036] Example 1 provides a preparation method of a negative electrode material for a sulfide all-solid-state battery, comprising the following steps:

[0037] Step S1, 90wt% of nano-silicon (0.9g) and 10wt% of Li6PS5Cl electrolyte (0.1g) are weighed and mixed using a planetary ball mill at a medium speed to obtain a mixture; wherein the ball milling speed is 450rpm and the ball milling time is 3h;

[0038] Step S2, 0.02g of carbon nanotubes and 0.01g of graphene oxide are weighed and added to the ball mill tank of step S1, and the mixture is secondarily ball-mixed at 450rpm for 30min to obtain a composite material;

[0039] Step S3, acetyl chloride is added to a n-hexane solvent and heated to 30 DEG C, then the composite material is immersed in the heated solution for 30s, and after drying, a negative electrode material for a sulfide all-solid-state battery is obtained.

[0040] Example 2 provides a preparation method of a negative electrode material for a sulfide all-solid-state battery, comprising the following steps:

[0041] Step S1, 50wt% of nano-silicon (0.5g) and 50wt% of Li6PS5Cl electrolyte (0.5g) are weighed and mixed using a planetary ball mill at a medium speed to obtain a mixture; wherein the ball milling speed is 400rpm and the ball milling time is 5h;

[0042] Step S2, 0.02 g of carbon nanotubes and 0.02 g of graphene oxide were weighed and added to the ball mill tank of step S1, and the mixture was secondarily ball-mixed at 350 rpm for 30 min to obtain a composite material;

[0043] Step S3, polyethyleneimine was added to an ethanol solvent and heated to 60°C, then the composite material was immersed in the heated solution for 1 h, and after drying, a negative electrode material for a sulfide all-solid-state battery was obtained.

[0044] Example 3 provides a method for preparing a negative electrode material for a sulfide all-solid-state battery, comprising the following steps:

[0045] Step S1, 75 wt% of nano-silicon (0.75 g) and 25 wt% of Li6PS5Cl electrolyte (0.25 g) were weighed and mixed using a planetary ball mill at a medium speed to obtain a mixture; wherein the ball milling speed was 500 rpm and the ball milling time was 5 h;

[0046] Step S2, 0.015 g of carbon nanotubes and 0.015 g of graphene oxide were weighed and added to the ball mill tank of step S1, and the mixture was secondarily ball-mixed at 350 rpm for 30 min to obtain a composite material;

[0047] Step S3, polyethyleneimine was added to an ethanol solvent and heated to 60°C, then the composite material was immersed in the heated solution for 1 h, and after drying, a negative electrode material for a sulfide all-solid-state battery was obtained.

[0048] The negative electrode materials prepared in Examples 1 to 3 were applied to all-solid-state lithium batteries, and the performance of the all-solid-state lithium batteries was tested, and the results are shown in Table 1 below. Specifically, the all-solid-state lithium battery comprises a positive electrode, a negative electrode, and a sulfide electrolyte between the positive electrode and the negative electrode, the positive electrode is nickel-cobalt-manganese lithium (NCM811), the sulfide electrolyte is Li6PS5Cl, and the negative electrode is prepared from the negative electrode material prepared by the example.

[0049] Table 1 Performance test results

[0050]

[0051] As can be seen from Table 1, the batteries prepared by the modified silicon negative electrode are much better than the batteries including the unmodified silicon negative electrode.

[0052] The application constructs a strong combination conductive network by cross-linking one-dimensional carbon nanotubes and two-dimensional graphene with linear macromolecules, improves the conductive performance, and can also use the active hydroxyl groups on the one-dimensional and two-dimensional structures to form a skeleton with linear macromolecules to bind the large-capacity phosphorus-silicon material composite in the inside, and absorb the volume expansion after the lithiumation of the phosphorus-silicon, and relieve the instability of the silicon negative electrode material.

[0053] Although the embodiments of the present application have been disclosed as above, they are not limited to the use listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present application, and additional modifications can be easily realized by those skilled in the art, and therefore the present application is not limited to specific details, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A method for preparing a negative electrode material for a sulfide all-solid-state battery, characterized by, The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery.

2. The method of claim 1, wherein the method is characterized by: The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery.

3. The method of claim 1, wherein the method is characterized by: The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery.

4. The method of claim 1, wherein the method is characterized by: The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery.

5. The method of claim 1, wherein the method is a method of preparing a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery.

6. The method of claim 1, wherein the method is a method of preparing a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery.

7. The method of claim 1, wherein the method is a method of preparing a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery.

8. The method of claim 1, wherein the method is a method of preparing a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery.

9. The method of claim 8, wherein the method is a method of preparing a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a negative electrode material for a sulfide all-solid-state battery. The application relates to a preparation method of a

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