A sodium-ion battery negative electrode pre-sodium agent, a preparation method and application thereof

Abstract

The application belongs to the technical field of sodium ion batteries, and particularly relates to a sodium ion battery negative electrode pre-sodium agent and a preparation method and application thereof. x M alloy, 0 < x < 5; M is an element simple substance capable of forming an alloy with sodium in III, IV and V main groups, such as tin, phosphorus, antimony and indium. The preparation method is as follows: after sodium is melted, III, IV and V main group element simple substance powder is added, stirring is carried out in an inert atmosphere, and a solid-liquid two-phase alloying reaction is carried out, so that a sodium-rich alloy Na x M material is prepared. x The Na x M alloy is used as the sodium ion battery negative electrode pre-sodium agent, and for example, the first circle coulomb efficiency of a composite negative electrode can reach 100%. The alloy material after sodium removal can be used as an active substance to participate in battery circulation, and the specific capacity of the electrode is improved. Finally, by adjusting the proportion of the negative electrode active material and the pre-sodium agent, the customization of different first circle coulomb efficiencies can be realized, so as to play a role in different application requirements.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sodium ion batteries, and particularly relates to a sodium-ion battery negative electrode pre-sodium agent and a preparation method and application thereof. BACKGROUND

[0002] Under the background of the double carbon strategy, developing safe and environmentally friendly clean energy is an important national policy to ensure the sustainable development of China's economy. In the fields of wind power generation, hydroelectric power generation, and solar power generation, electrochemical energy storage is a key technology for clean energy storage, transportation, and efficient utilization. Sodium resources are abundant (2.7% in the earth's crust and 11 g / L in seawater), widely distributed, and have similar physical and chemical properties to lithium, making high-performance, low-cost sodium ion batteries an ideal substitute for lithium ion batteries. Therefore, the development of key technologies for sodium ion electrodes is a research hotspot in today's cutting-edge technology and industrial applications.

[0003] Similar to lithium ion batteries, sodium ion batteries also have sodium loss problems during charging and discharging cycles, resulting in low first-cycle coulombic efficiency and cycle performance deterioration. The main reasons for the irreversible capacity loss in secondary ion batteries are as follows: (1) electrolyte decomposition to form a solid electrolyte interface (SEI film); (2) capture of ions (Li + , Na + ) by structural defects, such as hard carbon materials randomly stacked by a large number of disordered microcrystalline carbon layers, which have a large number of structural defects, some of which irreversibly capture ions, causing irreversible loss of the first capacity; (3) active ion consumption caused by side reactions.

[0004] Currently, the industry mainly uses pre-lithiation technology to solve the problem of capacity reduction and life reduction of lithium ion batteries caused by irreversible loss. There are mainly three methods: (1) negative electrode lithium supplement: patent CN111384428B describes a method of pre-lithiating the negative electrode of the battery with lithium-silicon alloy Li 15 Si4. The lithium-silicon alloy is coated with an organic-inorganic composite to isolate air and release lithium source after battery liquid injection. (2) positive electrode lithium supplement: in 2021, Guoxuan High-tech proposed a method of synthesizing graphene-tetracobalt trioxide composite by hydrothermal method, and then mixing and calcining with metallic lithium to obtain an oxidized graphene-cobalt-lithium oxide positive electrode lithium supplement [CN112290022A]. (3) electrolyte and separator lithium supplement: additional lithium sources can be attached to the separator or doped in the electrolyte. For example, patent CN109888392A describes a composite electrolyte with pre-lithiation function, which pre-adds dihydroxy cyclopropenyl ketone lithium salt, etc. in the electrolyte, which can be decomposed into Li +, electron and gas, through the exhaust process can effectively play the role of pre-lithiation and limit the negative impact. In summary, after the introduction of the pre-lithiation process, the first circle coulomb efficiency of the battery can be improved by more than ten percentage points, and the cycle life can be effectively prolonged.

[0005] Researchers have done a lot of work from material and electrolyte design to reduce the irreversible loss in sodium-ion batteries, but sodium consumption is difficult to completely eliminate. Therefore, the pre-sodium of sodium-ion battery electrode material has become an important emerging solution. However, the current development of lithium supplement is mainly concentrated in the field of lithium-ion batteries, and the related research in the field of sodium-ion batteries is relatively scarce. Therefore, it is urgent to provide a pre-sodium agent with excellent comprehensive performance for improving the first circle coulomb efficiency of sodium-ion battery and prolonging the overall life of the battery. SUMMARY

[0006] In view of the above-mentioned blank of sodium ion battery field sodium supplement additive related patent, the purpose of the present application is to provide a sodium ion battery negative electrode pre-sodium agent and its preparation method and application. Including providing a sodium supplement additive for sodium ion battery negative electrode sheet, aiming to improve the reversible capacity and coulomb efficiency during the first charge and discharge process of sodium ion battery, and then improve the overall cycle performance and prolong the service life of the battery.

[0007] The sodium ion battery negative electrode pre-sodium agent provided by the present application is an alloy type sodium supplement additive, specifically Na x M alloy powder, 0

[0008] After the sodium supplement additive is compounded with the traditional commercial negative electrode material, the first circle coulomb efficiency is improved from about 60% to more than 85%. By adjusting the ratio of negative electrode active material and pre-sodium agent, different first circle coulomb efficiency can be customized.

[0009] Preferably, the Na x The particle size of the M alloy pre-sodium agent is controllable, ranging from 0.2 to 1.5 microns.

[0010] Preferably, the M element is one or more of Sn powder, P powder, Sb powder, In powder, Pb powder, Bi powder or Ge powder.

[0011] Preferably, the sodium element and the M element are in a molar ratio of (n Na : n M ) = 0.1-5:1.

[0012] In particular, the molar ratio of Na to Sn, P, Sb, In, Pb, Bi, and Ge is 1.0-4.5, 0.5-3.5, 0.5-3.5, 0.5-2.5, 1.0-4.5, 0.5-3.5, and 0.1-2, respectively.

[0013] The application also provides a preparation method of the sodium-ion battery negative electrode pre-sodium agent, which comprises the following steps: setting the reaction temperature above the melting point of sodium metal, adding another alloy element element, and performing a solid-liquid two-phase alloy reaction to prepare a series of sodium-rich alloy pre-sodium agents.

[0014] The sodium block and the M element element are added into a stainless steel reaction tank in a proportion, sealed in an inert environment, heated to a temperature above the melting point of sodium metal, stirred, and then the alloying reaction of sodium and the M element element is performed. x The M-type alloy powder is obtained.

[0015] Preferably, the reaction temperature is 100-300 DEG C, and the reaction time is 24-96 h. More preferably, the reaction temperature is 150-200 DEG C, and the reaction time is 48-72 h.

[0016] Preferably, the inert environment is an argon environment.

[0017] The above-mentioned pre-sodium agent can be used in a sodium-ion battery negative electrode material, and specifically, the sodium-ion battery composite negative electrode is prepared by stirring the negative electrode material, the pre-sodium agent, the conductive agent, and the binder in a certain proportion.

[0018] Preferably, the addition amount of the negative electrode pre-sodium agent is 1-20% of the mass of the negative electrode active material.

[0019] Preferably, the negative electrode active material is one or more of hard carbon, graphite, tin, phosphorus, germanium, or antimony material.

[0020] Preferably, the conductive agent is Super P conductive carbon black, and the binder is polyvinylidene fluoride.

[0021] Preferably, the mass ratio of the negative electrode material, the pre-sodium agent, the conductive agent, and the binder is 60-80:4-20:3-10:3-10.

[0022] In a preferred embodiment of the application, the above-mentioned sodium-ion battery negative electrode pre-sodium agent Na x The specific preparation method of the Na M alloy is as follows: in an argon glove box (H2O, O2< 0.1 ppm), 10 mmol of nano Sn powder and 37.5 mmol of sodium metal block are weighed and added into a stainless steel tank, sealed, heated to 150 DEG C, and then adjusted to a rotation speed of 300 r / min after 10 min, and the reaction is continued for 72 h to obtain Nax Sn alloy pre-sodiation agent. Hard carbon material, Na x Sn pre-sodiation agent, Super conductive carbon black and polyvinylidene fluoride are mixed according to the mass ratio of 68:12:10:10, and the pre-sodiation hard carbon negative electrode is prepared by coating after stirring into a uniform slurry.

[0023] The main advantage of the present application is:

[0024] (1) The series of alloy type pre-sodiation agents prepared by the present application have a sodium content of more than 400 mAh / g (such as Na x Sn, Na x P alloy, more than 600 mAh / g), which is much higher than the specific capacity of the negative electrode of the current common sodium ion battery (hard carbon, soft carbon, etc., ~200 mAh / g);

[0025] (2) The present application uses sodium metal and other high commercial degree nano powders as raw materials, and the resources of sodium, tin and phosphorus are abundant, widely distributed and low in cost, without development bottleneck;

[0026] (3) The preparation process of the present application is simple, and the equipment requirement is low. The simple process is conducive to reducing cost and large-scale production.

[0027] The beneficial effects of the present application are:

[0028] The present application develops a synthesis method of alloy type pre-sodiation agent for the low first circle coulomb efficiency of the negative electrode in sodium ion battery, and a series of pre-sodiation agents with a first sodium removal capacity of more than 400 mAh / g (part of the pre-sodiation agent is more than 600 mAh / g), which is a high-capacity negative electrode pre-sodiation additive. Add the pre-sodiation agent to the hard carbon material, and the sodium ions removed in the first cycle form SEI film on the surface of the negative electrode, which relieves the consumption of sodium ions and improves the first circle coulomb efficiency. When the proportion of the composite negative electrode is adjusted to 80:20 (hard carbon: Na x Sn), the first circle coulomb efficiency is more than 100%, and the initial specific capacity of the composite negative electrode is 292 mAh / g, which is increased by 52% compared with the original hard carbon negative electrode (~192 mAh / g). BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is the first sodium removal capacity graph of the Na x Sn alloy pre-sodiation agent prepared in example 1.

[0030] Figure 2 is the XRD graph of the Na x Sn alloy pre-sodiation agent prepared in example 1.

[0031] Figure 3 is the Nax SEM image of Sn alloy pre-sodiation agent.

[0032] Figure 4 Long cycle curve of different ratio of hard carbon: NaxSn composite anode in Example 1. x First cycle charge-discharge curve of Sn composite anode.

[0033] Figure 5 Long cycle curve of different ratio of hard carbon: NaxSn composite anode in Example 1.

[0034] Figure 6 First sodiation capacity of Na x First sodiation capacity of P alloy pre-sodiation agent.

[0035] Figure 7 First sodiation capacity of Na x XRD image of P alloy pre-sodiation agent.

[0036] Figure 8 First sodiation capacity of Na x SEM image of P alloy pre-sodiation agent. DETAILED DESCRIPTION

[0037] The specific steps of the present application are illustrated below by examples, but are not limited by the examples.

[0038] The terms used in the present application have the meanings generally understood by those of ordinary skill in the art, unless otherwise specified.

[0039] The present application is further described in detail below with reference to specific examples and data. It should be understood that the examples are only intended to illustrate the present application, and do not limit the scope of the present application in any way.

[0040] In the following examples, various processes and methods not described in detail are conventional methods known in the art.

[0041] The present application is further described below with reference to specific examples.

[0042] Comparative Example

[0043] S1, Preparation of electrode sheet

[0044] Hard carbon, super P conductive carbon black, and polyvinylidene fluoride were dispersed in tetrahydrofuran at a mass ratio of 8:1:1, and a uniform electrode slurry was obtained by stirring. The slurry was coated on a copper or aluminum foil, the solvent was dried, and a hard carbon electrode sheet was obtained after rolling.

[0045] S2, Assembly of battery

[0046] The above obtained hard carbon electrode sheet and sodium metal electrode sheet were assembled into a CR2032 type button cell, the electrolyte was 1 M NaClO4 (EC: PC = 1:1 Vol% + 5% FEC), and the separator was glass fiber. After standing for 6 h, the required sodium ion battery was obtained, numbered A1.

[0047] Example 1

[0048] S1, Preparation of pre-sodium agent

[0049] In an argon glove box (H2O, O2< 0.1 ppm), 10 mmol of nano-tin powder (~50 nm) and 37.5 mmol of bulk metal sodium were weighed together into a stainless steel tank, sealed, and heated to 150 ℃. After waiting for 10 min, the rotation speed was adjusted to 300 r / min, and the reaction was continued for 72 h to obtain a Na x Sn pre-sodium agent. Figure 2 The XRD pattern of the Na x Sn pre-sodium agent was analyzed by phase analysis, and it can be seen that the Na x Sn phase is mainly Na 15 Sn4 phase, which is the phase with the highest sodium content in the Na-Sn alloy. In addition, the Na x Sn alloy particle size is controllable, and by adjusting the size of the raw tin particles, pre-sodium agents with different particle size distributions can be prepared. Figure 3 The two Na x Sn pre-sodium agents were analyzed by SEM, and it can be seen that Figure 3 The particle sizes in (a) and (b) are ~400 nm and ~1.2 µm, respectively.

[0050] S2, Preparation of electrode sheet

[0051] Hard carbon and Na x Sn pre-sodium agent were ground and mixed in a mass ratio of 90:10, 85:15 and 80:20, respectively, to obtain a composite electrode material. The composite electrode material, Super P conductive carbon black and polyvinylidene fluoride were dispersed in tetrahydrofuran in a mass ratio of 8:1:1, and a uniform electrode slurry was obtained after stirring. The electrode slurry was coated on a copper foil with a diameter of 12 mm, the solvent was dried, and three different proportions of pre-sodium hard carbon electrode sheets were obtained after rolling.

[0052] S3, Assembly of battery

[0053] The above obtained hard carbon / Na xSn composite electrode sheet and sodium metal electrode sheet were assembled into CR2032 type button cell, electrolyte was 1 M NaClO4(EC: PC = 1:1 Vol% + 5% FEC), separator was glass fiber. After standing for 6h, the required sodium ion battery was obtained, numbered B1, B2, B3 respectively.

[0054] Table 1 Specific preparation parameters and battery performance data of comparative example and example 1

[0055] .

[0056] As shown in Table 1 and Figure 4 , 5 , the first coulombic efficiency and cycle performance of sodium ion batteries in example 1 and comparative example can be seen: because the hard carbon material in comparative example (battery A1) consumes a large amount of sodium ions in the first formation of solid electrolyte membrane, the first coulombic efficiency of battery A1 is only 61.94%. In the example, due to the addition of different proportions of pre-sodium agent, the sodium ions discharged in the first charge can make up for the irreversible sodium loss, so the first coulombic efficiency is obviously increased, and when the mass ratio of hard carbon: Na x Sn in the composite negative electrode material is 80:20, the first coulombic efficiency reaches 100%. In addition, due to the too high content of pre-sodium agent, although the specific capacity of the battery is high in the early stage of cycle, but in the long cycle test, due to the volume expansion effect of Sn material, the capacity attenuation is relatively fast. Therefore, preferably, the mass ratio of hard carbon: Na x Sn in the composite negative electrode material is 85:15, at this time, the first cycle coulombic efficiency is 88.00%, and the specific capacity after 100 cycles is 222 mAh / g.

[0057] Example 2

[0058] S1, preparation of pre-sodium agent

[0059] In an argon glove box (H2O, O2< 0.1 ppm), 10 mmol of red phosphorus powder and 30 mmol of sodium metal block were weighed and added to a stainless steel tank, sealed, and heated to 150 ℃. After waiting for 10 min, the rotation speed was adjusted to 300 r / min, and the reaction was continued for 48 h to obtain Na x P pre-sodium agent. Figure 7 The XRD pattern of Na x P pre-sodium agent, through phase analysis, it can be seen that Na x P is mainly Na3P phase, which is the phase with the highest sodium content in Na-P alloy. Figure 8 The SEM image of Na x P pre-sodium agent, it can be seen that the particle size is ~400 nm.

[0060] S2, Preparation of electrode sheet

[0061] Hard carbon and Na x The P presodiation agent was mixed uniformly by grinding in a certain mass ratio. The obtained composite electrode material was dispersed in tetrahydrofuran in a mass ratio of 8:1:1 with Super P conductive carbon black and polyvinylidene fluoride. After stirring, a uniform electrode slurry was obtained. The slurry was coated on a copper foil with a diameter of 12 mm. The solvent was dried, and a presodiated hard carbon electrode sheet was obtained after rolling.

[0062] S3, Assembly of battery

[0063] The different proportions of hard carbon / Na x P obtained above were assembled into CR2032 type button cells with a sodium metal electrode sheet. The electrolyte was 1 M NaClO4(EC: PC = 1:1 Vol% + 5% FEC), and the separator was glass fiber. The required sodium ion battery was obtained after standing for 6 h. The battery was tested according to Example 1. By adjusting the proportion of hard carbon and Na x P presodiation agent, the sodium supplement effect obtained was the same as that of Na x Sn presodiation agent in Example 1.

[0064] Example 3

[0065] S1, Preparation of presodiation agent

[0066] In an argon glove box (H2O, O2< 0.1 ppm), 10 mmol of nano-antimony powder and 30 mmol of sodium metal were weighed and added to a stainless steel tank. After sealing, the temperature was raised to 150°C. After waiting for 10 min, the rotation speed was adjusted to 300 r / min. After continuing the reaction for 48 h, a Na x Sb presodiation agent was obtained. Through phase analysis, it can be seen that the Na x Sb mainly exists in the form of Na3Sb phase.

[0067] S2, Preparation of electrode sheet

[0068] Hard carbon and Na x Sb presodiation agent was mixed uniformly by grinding in a certain mass ratio. The obtained composite electrode material was dispersed in tetrahydrofuran in a mass ratio of 8:1:1 with Super P conductive carbon black and polyvinylidene fluoride. After stirring, a uniform electrode slurry was obtained. The slurry was coated on a copper foil with a diameter of 12 mm. The solvent was dried, and a presodiated hard carbon electrode sheet was obtained after rolling.

[0069] S3, Assembly of battery

[0070] The different proportions of hard carbon / Na xSb pre-sodium agent. By phase analysis, it can be seen that Na x The effect of the Sb pre-sodium agent is the same as that of Na x The effect of the Sn pre-sodium agent is the same as that of Na

[0071] Example 4

[0072] S1, Preparation of pre-sodium agent

[0073] In an argon glove box (H2O, O2< 0.1 ppm), 10 mmol of nano-indium powder and 20 mmol of sodium metal block were weighed and added to a stainless steel tank together, sealed, and heated to 150°C. After waiting for 10 min, the rotation speed was adjusted to 300 r / min, and the reaction was continued for 48 h to obtain Na x In pre-sodium agent. By phase analysis, it can be seen that Na x In is mainly in the form of Na2In phase.

[0074] S2, Preparation of electrode sheet

[0075] Hard carbon and Na x In pre-sodium agent was ground and mixed according to a certain mass ratio, and the obtained composite electrode material was dispersed in tetrahydrofuran according to a mass ratio of 8:1:1 with Super P conductive carbon black and polyvinylidene fluoride. After stirring, a uniform electrode slurry was obtained, which was coated on a copper foil with a diameter of 12 mm. The solvent was dried and rolled to obtain a pre-sodium hard carbon electrode sheet.

[0076] S3, Assembly of battery

[0077] The different proportions of hard carbon / Na x In pre-sodium agent were assembled into CR2032 type button cells with sodium metal electrode sheets, and the electrolyte was 1 M NaClO4 (EC: PC = 1:1 Vol% + 5% FEC), and the separator was glass fiber. After standing for 6 h, the required sodium ion battery was obtained. The battery was tested according to Example 1, and the sodium supplement effect was obtained by adjusting the proportion of hard carbon and Na x In pre-sodium agent. The effect of the Sb pre-sodium agent is the same as that of Na x The effect of the Sn pre-sodium agent is the same as that of Na

[0078] Example 5

[0079] S1, Preparation of pre-sodium agent

[0080] In an argon glove box (H2O, O2< 0.1 ppm), 10 mmol of nano-lead powder and 37.5 mmol of sodium metal block were weighed and added into a stainless steel tank, sealed, and heated to 150 ℃. After waiting for 10 min, the rotation speed was adjusted to 300 r / min, and the reaction was continued for 48 h to obtain Na x Pb pre-sodium agent. Through phase analysis, it can be seen that Na x Pb is mainly Na 15 Pb4 phase.

[0081] S2, Preparation of electrode sheet

[0082] Hard carbon and Na x Pb pre-sodium agent was ground and mixed according to a certain mass ratio. The obtained composite electrode material was dispersed in tetrahydrofuran according to a mass ratio of 8:1:1 with Super P conductive carbon black and polyvinylidene fluoride. After stirring, a uniform electrode slurry was obtained, which was coated on a copper foil with a diameter of 12 mm. The solvent was dried and rolled to obtain a pre-sodium hard carbon electrode sheet.

[0083] S3, Assembly of battery

[0084] The different proportion of hard carbon / Na x Pb composite electrode sheet and sodium metal electrode sheet were assembled into CR2032 type button cell, and the electrolyte was 1 M NaClO4 (EC: PC = 1:1 Vol% + 5% FEC), and the separator was glass fiber. After standing for 6 h, the required sodium ion battery was obtained. The battery was tested according to Example 1, and the sodium supplement effect obtained by adjusting the proportion of hard carbon and Na x Pb pre-sodium agent in Example 1 was the same. x Sn pre-sodium agent.

[0085] Example 6

[0086] S1, Preparation of pre-sodium agent

[0087] In an argon glove box (H2O, O2< 0.1 ppm), 10 mmol of nano-lead powder and 37.5 mmol of sodium metal block were weighed and added into a stainless steel tank, sealed, and heated to 150 ℃. After waiting for 10 min, the rotation speed was adjusted to 300 r / min, and the reaction was continued for 48 h to obtain Na x Bi pre-sodium agent. Through phase analysis, it can be seen that Na x Bi is mainly Na3Bi phase.

[0088] S2, Preparation of electrode sheet

[0089] Hard carbon and Na xBi pre-sodiation agent was mixed with Super P conductive carbon black and polyvinylidene fluoride (PVDF) in a mass ratio of 8:1:1 in tetrahydrofuran (THF) to obtain a uniform electrode slurry. The slurry was coated on a copper foil with a diameter of 12 mm, and the solvent was dried by baking. After rolling, a pre-sodiated hard carbon electrode sheet was obtained.

[0090] S3, Assembly of the battery

[0091] The different proportions of hard carbon / Na x The Bi composite electrode sheet and sodium metal electrode sheet were assembled into a CR2032 type button cell, and the electrolyte was 1 M NaClO4(EC: PC = 1:1 Vol% + 5% FEC), and the separator was glass fiber. The required sodium ion battery was obtained after standing for 6 h. The battery was tested according to Example 1, and the sodiation effect of the hard carbon / Na x Bi pre-sodiation agent was mixed with Super P conductive carbon black and polyvinylidene fluoride (PVDF) in a mass ratio of 8:1:1 in tetrahydrofuran (THF) to obtain a uniform electrode slurry. The slurry was coated on a copper foil with a diameter of 12 mm, and the solvent was dried by baking. After rolling, a pre-sodiated hard carbon electrode sheet was obtained. x The effect of Sn pre-sodiation agent was the same as that of Bi

Claims

1. A sodium-ion battery anode presodiation agent, characterized in that, NaxM alloy powder, 0 < x < 5; it has a sodium supplement capacity of more than 600 mAh / g; M is an element single substance in the III, IV and V main groups which can form an alloy with sodium, wherein: The NaxM particle size is 0.2-1.5 microns; The M element single substance is one or more of Sn, P, Sb, In, Pb, Bi, Ge powder; The sodium single substance and the M single substance are in a molar ratio of (0.1-5):1; The molar ratio of Na and Sn, P, Sb, In, Pb, Bi, Ge is 1.0-4.5, 0.5-3.5, 0.5-3.5, 0.5-2.5, 1.0-4.5, 0.5-3.5 and 0.1-2, respectively; The sodium ion battery negative electrode pre-sodium agent is prepared by the following method: setting the reaction temperature above the sodium metal melting point, adding another alloy element single substance, and carrying out a solid-liquid two-phase alloy reaction in an inert environment to prepare a series of sodium-rich alloy pre-sodium agents; the specific steps are as follows: The metal sodium block and the M element single substance are added to a stainless steel reaction tank in proportion, sealed in an inert environment, heated to a temperature above the sodium metal melting point, stirred, and the alloying reaction of sodium and M elements is carried out, after the reaction is completed, NaxM type alloy powder is obtained; The alloying reaction temperature is 100-300℃, and the reaction time is 24-96h.

2. The sodium-ion battery anode presodiation agent of claim 1, wherein, The inert environment is an argon environment.

3. The application of the sodium ion battery negative electrode pre-sodium agent of claim 1 as a sodium supplement additive for a sodium ion battery negative electrode material, specifically a sodium ion battery composite negative electrode material is prepared by stirring the negative electrode material, the pre-sodium agent, the conductive agent and the binder uniformly; the addition amount of the negative electrode pre-sodium agent is 1-20% of the mass of the negative electrode active material.

4. Use according to claim 3, wherein the compound is ###0002### The negative electrode active material is one or more of hard carbon, graphite, tin, phosphorus, germanium or antimony material; the conductive agent is one or more of acetylene black, SuperP, conductive graphite, Ketjen black or carbon nanotubes, and the binder is polyvinylidene fluoride.

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