Sodium ion battery negative electrode material and preparation method thereof

Abstract

The invention provides a sodium ion battery negative electrode material and a preparation method thereof. The sodium ion battery negative electrode material is prepared by coating titanium oxide on the surface and in pores of a carbon material through a chemical vapor deposition method. The sodium ion battery negative electrode material disclosed by the invention is high in rate capability and good in cycling stability, and has a relatively good application prospect in the field of sodium ion battery negative electrode materials. The method disclosed by the invention has universality to carbon matrixes from various sources, and is suitable for large-scale preparation of the sodium ion battery negative electrode material.

Description

Technical Field

[0001] The present invention relates to the field of negative electrode materials for sodium ion batteries, and in particular to a negative electrode material for sodium ion batteries with a high rate and a long cycle and a preparation method thereof. Background Art

[0002] As an important electrochemical energy storage device, lithium-ion batteries have been mass-produced and widely used in 3C, automobiles, and energy storage. However, as the market demand on the consumer side, especially in the field of energy storage, continues to increase, the shortage of lithium resources and the uneven global distribution have become more prominent, which has brought about high battery costs, which has largely restricted the large-scale production and use of lithium-ion batteries. Therefore, it is imperative to find new energy storage devices to replace lithium-ion batteries.

[0003] Sodium-ion batteries work on the same principle as lithium-ion batteries, both of which are rocking-chair secondary batteries. At the same time, the raw materials used in sodium-ion batteries are abundant in resources, low in price, and have excellent safety performance, so they are likely to be favored by researchers as the next generation of new energy storage devices, and they also have great potential in large-scale energy storage scenarios such as smart grids.

[0004] The negative electrode material is one of the key components of secondary batteries. For sodium-ion batteries, the industry generally uses hard carbon as the negative electrode material. Compared with lithium-ion graphite, hard carbon has a disordered microcrystalline structure and a larger graphene layer spacing, resulting in more suitable thermodynamic properties and theoretical sodium storage capacity. It is considered to be an ideal negative electrode material for sodium-ion batteries. However, the existing hard carbon generally has a low sodium insertion potential, and sodium is easily precipitated during rate charging, which limits the application scenarios of the battery. In particular, the internal resistance of the battery increases after a long cycle, making sodium precipitation more likely to occur. Therefore, there is an urgent need in this field to improve the rate performance of hard carbon. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a sodium ion battery negative electrode material and a preparation method thereof. The preparation method uses a chemical vapor deposition method to uniformly deposit a titanium source on the surface and pores of a carbon matrix, and obtains a titanium oxide-coated carbon material as a sodium ion battery negative electrode through hydrolysis and carbonization. The prepared negative electrode material has a sodium ion rapid transport layer, which improves the rate performance and cycle stability of the negative electrode material.

[0006] To achieve the above technical objectives, the first aspect of the present invention is to provide a method for preparing a hard carbon negative electrode material for a sodium ion battery, comprising the following steps:

[0007] (1) introducing a vapor phase titanium source into a reactor and performing vapor phase deposition on a carbon substrate to obtain a carbon material on which the titanium source is deposited;

[0008] (2) passing water vapor through the carbon material obtained in step (1) to perform a hydrolysis reaction to obtain a carbon material with hydrated titanium oxide deposition;

[0009] (3) Sintering the carbon material obtained in step (3) to obtain a negative electrode material for a sodium ion battery.

[0010] According to the preparation method of the present invention, in step (1),

[0011] The raw material source of the carbon matrix includes biomass and biomass derivatives obtained by carbonization, such as lignin, cellulose, hemicellulose, starch, glucose, polyglucose, maltose, coconut shell, and carbon obtained by carbonization of bamboo;

[0012] The raw material source of the carbon matrix also includes that obtained by carbonization of artificial polymers, such as phenolic resin, epoxy resin, urea-formaldehyde resin, etc.;

[0013] The carbon matrix is ​​obtained by carbonizing the raw material at a temperature not lower than 1000°C, such as 1100°C, 1200°C, 1300°C, 1400°C, preferably 1000-1500°C;

[0014] Preferably, the carbon matrix is ​​obtained by carbonizing and crushing the aforementioned raw materials.

[0015] The crushing method is mechanical crushing or air flow crushing, which is carried out in common equipment in the industry, such as jaw crusher, roll crusher, mechanical crusher, ball mill, air flow mill, etc.

[0016] Preferably, the carbon matrix is ​​crushed to a Dv50 of 2-15 μm.

[0017] According to the preparation method of the present invention, in step (1),

[0018] The gas phase titanium source includes vapor of at least one of titanium tetrafluoride (TiF4), titanium tetrachloride (TiCl4), titanium tetraiodide (TiI4), tetrabutyl titanate (Ti(OEt)4), and titanium tetraisopropoxide (Ti(i-OPr)4);

[0019] The reaction temperature of the vapor deposition is 150-600°C, for example, 150°C, 160°C, 170°C, 180°C, 200°C, 300°C, 400°C, 500°C, 600°C; preferably 150-200°C, for example, 150°C, 160°C, 170°C; the reaction time is preferably 1-2 hours.

[0020] The titanium source deposition amount is 0.1-5% of the mass of the carbon matrix, such as 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%; preferably 0.1-1%, such as 0.1%, 0.5%, 1%.

[0021] The reactor is a commonly used reactor in the industry, such as a tubular fixed bed reactor, a rotary kiln, a fluidized bed, etc.;

[0022] According to the preparation method of the present invention, in step (2),

[0023] The hydrolysis reaction temperature is 150-600°C, for example, 150°C, 160°C, 170°C, 180°C, 200°C, 300°C, 400°C, 500°C, 600°C; preferably 150-300°C, for example, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 220°C, 250°C, 270°C, 280°C, 300°C; the hydrolysis reaction time is preferably 1-2 hours.

[0024] According to the preparation method of the present invention, in step (3),

[0025] The sintering temperature is 500-800°C, for example, 500°C, 600°C, 700°C, 800°C; preferably 700-800°C, for example, 700°C, 750°C, 800°C; the sintering time is preferably 1-2 hours.

[0026] The second aspect of the present invention is to provide a sodium ion battery negative electrode material, wherein, at a voltage of 0-1.5V, the sodium ion battery negative electrode material is charged and discharged at a current density of 0.1C in a button half cell, and the reversible capacity (first charge capacity) of the sodium ion battery negative electrode material is 290-330mAh / g, and the first coulombic efficiency is 82-94%.

[0027] According to the sodium ion battery negative electrode material of the present invention, at a voltage of 0-1.5V, when charged and discharged at a current density of 0.1C in a button half-cell, the reversible discharge capacity of >0.1V accounts for 32-42%.

[0028] According to the sodium ion battery negative electrode material of the present invention, at a voltage of 0-1.5V, the capacity retention rate is 40-75% when charged and discharged at a current density of 5C in a button-type half-cell.

[0029] The third aspect of the present invention is to provide the use of the above-mentioned sodium ion battery negative electrode material in the preparation of a sodium ion battery.

[0030] A fourth aspect of the present invention is to provide a sodium ion battery negative electrode, wherein the sodium ion battery negative electrode is prepared using the sodium ion battery negative electrode material raw material of the present invention.

[0031] The fifth aspect of the present invention is to provide a sodium ion battery, comprising the sodium ion battery negative electrode material described in the present invention.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention coats titanium oxide on the surface and in the pores of a carbon matrix as a rapid sodium ion transport layer by vapor deposition. The resulting sodium ion battery negative electrode material can effectively improve the rate performance and cycle stability of the sodium ion battery, and has considerable application prospects in this field.

[0034] (2) The present invention prepares titanium oxide-coated composite carbon materials by chemical vapor deposition, which is universal to carbon matrices from various sources and is suitable for large-scale preparation of negative electrode materials for sodium ion batteries. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0036] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0037] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0038] Unless otherwise specified, all reagents and raw materials used in the present invention are commercially available products or products that can be prepared by known methods.

[0039] Example 1

[0040] (1) Crushing coconut shell charcoal to a Dv50 of 5 μm to obtain a carbon matrix.

[0041] (2) at 150° C., passing titanium tetrachloride gas into a carbon matrix in a reactor for vapor deposition, wherein the deposition amount is 1% of the mass of the carbon matrix, to obtain a carbon material with titanium tetrachloride deposition;

[0042] (3) introducing water vapor into the deposited carbon material obtained in step (2) at 300° C. for 2 hours to carry out a hydrolysis reaction to obtain a carbon material deposited with hydrated titanium oxide;

[0043] (4) Sintering the deposited carbon material obtained in step (3) at 800° C. for 2 hours to obtain a negative electrode material for a sodium ion battery.

[0044] Example 2

[0045] (1) The phenolic resin carbon is crushed to a Dv50 of 5 μm to obtain a carbon matrix.

[0046] (2) at 150° C., passing titanium tetrachloride gas into the carbon matrix in a reactor for vapor deposition, with the deposition amount accounting for 0.5% of the mass of the carbon matrix, to obtain a carbon material with titanium tetrachloride deposition;

[0047] (3) introducing water vapor into the deposited carbon material obtained in step (2) at 170° C. for 2 hours to carry out a hydrolysis reaction to obtain a carbon material deposited with hydrated titanium oxide;

[0048] (4) Sintering the deposited carbon material obtained in step (3) at 800° C. for 2 hours to obtain a negative electrode material for a sodium ion battery.

[0049] Example 3

[0050] (1) The bamboo charcoal is crushed to a Dv50 of 5 μm to obtain a carbon matrix.

[0051] (2) at 200° C., introducing tetrabutyl titanate gas into a carbon matrix in a reactor for vapor deposition, with the deposition amount accounting for 3% of the mass of the carbon matrix, to obtain a carbon material with titanium tetrachloride deposition;

[0052] (3) introducing water vapor into the deposited carbon material obtained in step (2) at 170° C. for 1 hour to carry out a hydrolysis reaction to obtain a carbon material deposited with hydrated titanium oxide;

[0053] (4) Sintering the deposited carbon material obtained in step (3) at 800° C. for 2 hours to obtain a negative electrode material for a sodium ion battery.

[0054] Example 4

[0055] (1) Crushing coconut shell charcoal to a Dv50 of 8 μm to obtain a carbon matrix.

[0056] (2) at 200° C., introducing titanium tetraiodide gas into a carbon matrix in a reactor for vapor deposition, with the deposition amount accounting for 0.1% of the mass of the carbon matrix, to obtain a carbon material with titanium tetrachloride deposition;

[0057] (3) introducing water vapor into the deposited carbon material obtained in step (2) at 200° C. for 1 hour to carry out a hydrolysis reaction to obtain a carbon material deposited with hydrated titanium oxide;

[0058] (4) Sintering the deposited carbon material obtained in step (3) at 700° C. for 2 hours to obtain a negative electrode material for a sodium ion battery.

[0059] Example 5

[0060] (1) Crushing coconut shell charcoal to a Dv50 of 5 μm to obtain a carbon matrix.

[0061] (2) at 170° C., passing titanium tetrachloride gas into a carbon matrix in a reactor for vapor deposition, with the deposition amount accounting for 1% of the mass of the carbon matrix, to obtain a carbon material with titanium tetrachloride deposition;

[0062] (3) introducing water vapor into the deposited carbon material obtained in step (2) at 300° C. for 1 hour to carry out a hydrolysis reaction to obtain a carbon material deposited with hydrated titanium oxide;

[0063] (4) Sintering the deposited carbon material obtained in step (3) at 500° C. for 2 hours to obtain a negative electrode material for a sodium ion battery.

[0064] Comparative Example 1

[0065] (1) Crushing coconut shell charcoal to a Dv50 of 5 microns to obtain a carbon matrix.

[0066] (2) Sintering the carbon matrix obtained in step (1) at 800° C. for 2 hours to obtain a negative electrode material for a sodium ion battery.

[0067] Using the metallic sodium sheet as the negative electrode and the hard carbon material prepared in each embodiment and comparative example as the positive electrode, button cells were assembled in an argon-protected glove box, and charged and discharged at a voltage of 0-1.5V and a current density of 0.1C. The first discharge specific capacity and reversible capacity were measured, and the first coulombic efficiency was calculated. The charge and discharge capacity retention rate at a current density of 5C was also measured. The results are shown in the table below.

[0068]

[0069] It can be seen from the examples and comparative example 1 that the titanium-coated sodium ion battery negative electrode material can effectively improve the initial efficiency of the battery, thereby exhibiting a higher reversible capacity; at a 5C rate, the titanium-coated negative electrode material has a higher capacity retention rate.

[0070] The embodiments and comparative examples of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for preparing a negative electrode material for a sodium ion battery, comprising the following steps: (1) introducing a vapor phase titanium source into a reactor and performing vapor phase deposition on a carbon substrate to obtain a carbon material on which the titanium source is deposited; (2) passing water vapor through the carbon material obtained in step (1) to perform a hydrolysis reaction to obtain a carbon material with hydrated titanium oxide deposition; (3) Sintering the carbon material obtained in step (3) to obtain a negative electrode material for a sodium ion battery.

2. The preparation method according to claim 1, characterized in that: In step (1), The carbon matrix is ​​obtained by carbonizing biomass, biomass derivatives, and artificial polymers, preferably a carbon matrix obtained by carbonizing at least one of lignin, cellulose, hemicellulose, starch, glucose, polyglucose, maltose, coconut shell, and bamboo, or at least one of phenolic resin, epoxy resin, and urea-formaldehyde resin.

3. The preparation method according to claim 1, characterized in that: In step (1), The gas phase titanium source includes titanium source vapor of at least one of titanium tetrafluoride, titanium tetrachloride, titanium tetraiodide, tetrabutyl titanate, and titanium tetraisopropoxide; The vapor deposition reaction temperature is 150-600°C, preferably 150-200°C; Preferably, the deposition amount of the titanium source is 0.1-5% of the mass of the carbon matrix, more preferably 0.1-1%.

4. The preparation method according to claim 1, characterized in that: In step (2), the hydrolysis reaction temperature is 150-600°C, preferably 150-200°C; Preferably, the hydrolysis reaction time is 1-2 hours.

5. The preparation method according to claim 1, characterized in that: In step (3), the sintering temperature is 500-800°C, preferably 700-800°C; Preferably, the sintering time is 1-2 hours.

6. A sodium ion battery negative electrode material prepared according to the preparation method according to any one of claims 1 to 5, characterized in that: At a voltage of 0-1.5V, the sodium ion battery negative electrode material is charged and discharged at a current density of 0.1C in a button-type half-cell, and the reversible capacity is 290-330mAh / g, and the first coulombic efficiency is 82%-94%.

7. The negative electrode material for sodium ion battery according to claim 6, characterized in that: At a voltage of 0-1.5V, the reversible discharge capacity >0.1V accounted for 32-42% when charged and discharged at a current density of 0.1C in a button half-cell.

8. The sodium ion battery negative electrode material according to claim 6 or 7, characterized in that: At a voltage of 0-1.5V, the capacity retention rate was 40-75% when charged and discharged at a current density of 5C in a button half-cell.

9. A sodium ion battery negative electrode, characterized in that: The sodium ion battery negative electrode is prepared using the sodium ion battery negative electrode material obtained by the preparation method according to any one of claims 1 to 5 or the sodium ion battery negative electrode material according to any one of claims 6 to 8 as a raw material.

10. A sodium ion battery, comprising the sodium ion battery negative electrode according to claim 9.

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