Sodium ion battery hard carbon negative electrode material and preparation method thereof, and sodium ion battery

Abstract

The application discloses a kind of sodium ion battery hard carbon negative electrode material and preparation method thereof, sodium ion battery, its preparation method includes the following steps: S1, the preparation of precursor suspension liquid: pitch and glucose are added in aqueous solution containing dispersant and stirred to be uniformly dispersed, then inorganic acid, graphitization inhibitor is formed into precursor suspension liquid;S2, the preparation of crosslinked precursor particle: precursor suspension liquid in step S1 is used spray drying granulation, and crosslinked precursor particle is obtained;S3, high-temperature carbonization: crosslinked precursor particle obtained in step S2 is high-temperature carbonized under protective atmosphere, and the solid-phase oxidized sodium ion battery negative electrode hard carbon material is obtained.The application has the characteristics of good uniformity, excellent electrochemical performance and simple process.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of sodium ion batteries, in particular to a sodium ion battery hard carbon negative electrode material and a preparation method thereof, and a sodium ion battery. BACKGROUND

[0002] At present, energy storage technologies mainly include physical energy storage, chemical energy storage and electrochemical energy storage. Among them, electrochemical energy storage technologies mainly include lithium ion batteries, sodium ion batteries and lead-acid batteries. Compared with lithium ion batteries, sodium ion batteries have the advantages of high abundance of sodium elements, low production cost, excellent high and low temperature performance and good safety, and are expected to become the main force of electrochemical energy storage.

[0003] In a sodium ion battery, the negative electrode material has a significant influence on the electrochemical performance of the sodium ion battery, therefore, developing a high-performance negative electrode material is of great significance to the commercialization of the sodium ion battery. Alloys, metal sulfides, metal oxides and carbon-based materials are common negative electrode materials for sodium ion batteries, which have attracted widespread attention. Among them, carbon-based materials have excellent comprehensive electrochemical performance and low cost, and have broad industrial application prospects. Carbon-based materials can be further divided into graphite and amorphous carbon (soft carbon and hard carbon), wherein hard carbon material has a complex structure, rich sodium storage sites and high capacity, and is one of ideal negative electrode materials.

[0004] However, the excessively complex and disordered microstructure of hard carbon and the relatively high cost compared with soft carbon hinder the further commercialization development of sodium ion batteries. Improving the sodium storage performance of hard carbon and reducing its production cost are important topics in the research of negative electrode materials for sodium ion batteries.

[0005] The structure of carbon material is closely related to the properties of the precursor. If the precursor is a thermoplastic macromolecule rich in H-deficient O, soft carbon material is easily formed by graphitization during carbonization, such as polyvinyl chloride (PVC), pitch, coal and aromatic compounds such as benzene. If it is a thermosetting material, the thermosetting precursor is rich in O-deficient H, and it is difficult to graphitize at high temperature and form hard carbon, such as glucose, sucrose and some biomass materials.

[0006] By contrast, the soft carbon precursor can be converted into hard carbon by pretreatment such as oxygenation or dehydrogenation during high-temperature calcination; and the soft and hard carbon precursors can be crosslinked in a certain proportion to prepare hard carbon with more excellent performance. The process of crosslinking soft and hard carbon has become a commonly used method in industry.

[0007] However, in the traditional process, there are a series of mixing steps before the soft and hard carbon cross-linking reaction, usually the powdery raw materials are first physically hot-pressed or isostatic pressed into blocks, then physically broken, and then cross-linked by fluidized bed oxidation reaction, the raw materials cannot achieve sufficient contact at the molecular or atomic level, resulting in that the subsequent cross-linking reaction only occurs locally between the surfaces of large particles of soft and hard carbon in the closely contacted areas. Moreover, the above-mentioned traditional process is complicated, the investment in hot-pressing or isostatic pressing and breaking equipment is large, and the energy consumption is also high, which brings high cost. Moreover, the cross-linking of the reaction raw materials is not sufficient, the areas not contacted by soft and hard carbon particles cannot occur sufficient cross-linking reaction, the uniformity and sufficiency of the cross-linking reaction are obviously insufficient, resulting in that in the subsequent high-temperature carbonization reaction, the soft carbon precursors not sufficiently cross-linked are carbonized to form a large number of graphitized regions, causing the specific capacity of the product to be low. SUMMARY

[0008] The purpose of the present application is to provide a sodium ion battery hard carbon negative material and a preparation method thereof, and a sodium ion battery, which have the characteristics of good uniformity, excellent electrochemical performance and simple process.

[0009] The present application can be realized by the following technical solutions:

[0010] The present application discloses a preparation method of a sodium ion battery hard carbon negative material, comprising the following steps:

[0011] S1, preparation of a precursor suspension: add pitch and glucose into an aqueous solution containing a dispersant and stir until they are uniformly dispersed, then add inorganic acid and graphitization inhibitor to form a precursor suspension;

[0012] S2, preparation of cross-linked precursor particles: use spray drying granulation on the precursor suspension in step S1, adjust the outlet temperature to a temperature interval, adjust the gas speed, make the mixed particles continuously rotate in high-speed and high-temperature air, and realize solid-phase oxidation of pitch and glucose by using oxygen in the air to obtain cross-linked precursor particles;

[0013] S3, high-temperature carbonization: carbonize the cross-linked precursor particles obtained in step S2 under a protective atmosphere to obtain solid-phase oxidized sodium ion battery negative hard carbon material.

[0014] In step S1, the mass ratio of asphalt in the two precursors is 10%-90%. If the asphalt ratio is higher than 90%, it will increase the difficulty of cross-linking, resulting in soft carbon with poor sodium storage capacity after high-temperature calcination; if the ratio is lower than 10%, the material cost is too high, which is not conducive to industrial production. The mass ratio of dispersant in the precursor suspension is 1-10%. If the dispersant ratio is higher than 10%, its organic structure will hinder the cross-linking of the precursor; if the ratio is lower than 1%, the asphalt cannot be uniformly dispersed, resulting in uneven cross-linking. The mass ratio of inorganic acid in the precursor suspension is 0.1-10%. If the inorganic acid ratio is higher than 10%, it will erode the structure of the carbon material, reducing the sodium storage capacity of the material; if the ratio is lower than 0.1%, it cannot provide an effective acidic environment to complete the cross-linking. The mass ratio of graphitization inhibitor in the precursor suspension is 0.1-10%. If the graphitization inhibitor ratio is higher than 10%, it will result in fewer graphitic domains in the final material, and will cause serious ash problems, reducing the sodium ion insertion capacity of the material; if the ratio is lower than 0.1%, the inhibition effect is weak, and soft carbon material is easily formed.

[0015] Further, in step S2, the conditions for spray drying are: outlet temperature 90-150℃, mixed particle rotation time 0.5-2h. If the outlet temperature is higher than 150℃, the precursor will carbonize during the spraying process, sticking to the instrument and causing loss of raw materials; if it is lower than 90℃, the material cannot form a spherical structure. If the rotation time is higher than 2h, the cross-linking effect will not be significantly improved, increasing the processing cost; if it is lower than 0.5h, the cross-linking cannot be fully carried out.

[0016] Further, in step S3, the conditions for high-temperature carbonization are: carbonization temperature 1000-1400℃, carbonization time 1-3h. If the carbonization temperature is higher than 1400℃ and the time is longer than 3h, it will result in too low interlayer spacing of the graphitic domain carbon layer, hindering the insertion of sodium ions; if the temperature is lower than 1000℃ and the time is shorter than 1h, it cannot form a stable carbon structure.

[0017] Further, in step S3, the protective atmosphere is one or more of argon, hydrogen, carbon monoxide, and nitrogen, and the gas flow range of the protective atmosphere is 50-150sccm. If the gas flow is greater than 150sccm, the material will be lost with the gas flow during high-temperature sintering due to the lightness of the carbon material; if the gas flow is less than 50sccm, it cannot provide an effective inert gas environment, and the carbon material is easily oxidized.

[0018] Further, the dispersant is one or more of polyvinyl alcohol, F127 polyether ester, and dextran.

[0019] Further, the inorganic acid is one or more of phosphoric acid solution, nitric acid solution, and boric acid particles.

[0020] Further, the graphitization inhibitor is a substance containing one or more of the elements of Nb, W, Mn, S, Cr, V, Mg, Ce, B, Al, Si, Ti.

[0021] Another aspect of the present application is to protect a sodium ion battery hard carbon anode material prepared by the above preparation method.

[0022] Another aspect of the present application is to protect a sodium ion battery using the above hard carbon anode material as the anode.

[0023] The present application is a sodium ion battery hard carbon anode material, its preparation method and sodium ion battery, which has the following advantages:

[0024] First, good uniformity. Dispersants are a class of surfactants that can convert bitumen from hydrophobic to hydrophilic, allowing it to mix uniformly with glucose, promoting the uniformity of soft and hard carbon precursor crosslinking. Spray drying not only provides a constantly updated oxidation atmosphere, but also provides a high-speed, high-temperature oxygen-containing air column that is conducive to the unfolding of bitumen and glucose molecular chains, making them less obstructive to each other and more uniform in crosslinking.

[0025] Second, excellent electrochemical performance. The acidic environment provided by the inorganic acid can protonate the hydroxyl groups of the glucose molecules, increasing their electrophilicity. In addition, under the action of the acid, the molecular chains of bitumen and glucose tend to unfold, exposing functional groups. Therefore, after using inorganic acid, the oxidation crosslinking of soft and hard carbon in the air atmosphere is strengthened, the graphitization process is inhibited, and the carbon chain structure is more stable; at the same time, the inorganic acid can also act as a pore-forming agent and a dopant, increasing the active sites for sodium ion storage. The graphitization inhibitor reacts with the hydroxyl groups on the bitumen molecules to form a -C-O-C structure, increasing the steric hindrance during graphitization and inhibiting the polymerization of adjacent fragments, thereby inhibiting the graphitization process and increasing the disorder of bitumen-based carbon materials, promoting hard carbonization. The graphitization inhibitor, in combination with the spray drying method, can fully disperse the inhibitor uniformly inside the particles, fully inhibit the graphitization of each particle, and greatly reduce the amount of inhibitor used, to less than 1% or even lower, reducing the impact of impurities on the final product. For some preferred graphitization inhibitors, the content can be further reduced to eliminate the need for subsequent ash removal, thereby simplifying the overall process.

[0026] Third, simple process. Spray drying can simultaneously achieve oxidation crosslinking, granulation, and drying, among other processes. This process does not require the complex operations of traditional processes such as mixing, granulation, drying, and re-heating for oxidation crosslinking, greatly simplifying the production process. The temperature control range of spray drying is wide, which is conducive to controlling the crosslinking at the appropriate temperature, avoiding the phenomenon of insufficient crosslinking at too low a temperature or excessive carbonization at too high a temperature.

[0027] Fourth, low cost. Because the process is simple, the energy consumption in the whole process is reduced; the addition of inhibitors and inorganic acid is complementary, synergistic effect, which can greatly improve the hard carbon efficiency, improve the utilization of raw materials, and reduce the production cost. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The first cycle charge-discharge curve of the material obtained in Example 1 at a current density of 20 mA / g;

[0029] Figure 2 The XRD pattern of the material obtained in Example 1;

[0030] Figure 3 The first cycle charge-discharge curve of the material obtained in Comparative Example 1 at a current density of 20 mA / g;

[0031] Figure 4 The XRD pattern of the material obtained in Comparative Example 1;

[0032] Figure 5 The first cycle charge-discharge curve of the material obtained in Example 2 at a current density of 20 mA / g;

[0033] Figure 6 The XRD pattern of the material obtained in Example 2;

[0034] Figure 7 The first cycle charge-discharge curve of the material obtained in Comparative Example 2 at a current density of 20 mA / g;

[0035] Figure 8 The XRD pattern of the material obtained in Comparative Example 2;

[0036] Figure 9 The first cycle charge-discharge curve of the material obtained in Example 3 at a current density of 20 mA / g;

[0037] Figure 10 The XRD pattern of the material obtained in Example 3;

[0038] Figure 11 The first cycle charge-discharge curve of the material obtained in Comparative Example 3 at a current density of 20 mA / g;

[0039] Figure 12 The XRD pattern of the material obtained in Comparative Example 3;

[0040] Figure 13 The first cycle charge-discharge curve of the material obtained in Example 4 at a current density of 20 mA / g;

[0041] Figure 14 The XRD pattern of the material obtained in Example 4;

[0042] Figure 15 First cycle charge-discharge curves of the material obtained in Comparative Example 4 at a current density of 20 mA / g;

[0043] Figure 16 XRD pattern of the material obtained in Comparative Example 4;

[0044] Figure 17 First cycle charge-discharge curves of the material obtained in Example 5 at a current density of 20 mA / g;

[0045] Figure 18 XRD pattern of the material obtained in Example 5;

[0046] Figure 19 First cycle charge-discharge curves of the material obtained in Comparative Example 5 at a current density of 20 mA / g;

[0047] Figure 20 XRD pattern of the material obtained in Comparative Example 5; DETAILED DESCRIPTION

[0048] In order to make the person skilled in the art better understand the technical solutions of the present application, the product of the present application will be further described in detail below in combination with examples.

[0049] The application discloses a preparation method of a sodium ion battery hard carbon negative material.

[0050] S1, preparation of a precursor suspension: add pitch and glucose into an aqueous solution containing a dispersant and stir until they are uniformly dispersed, then add inorganic acid and graphitization inhibitor to form a precursor suspension;

[0051] S2, preparation of crosslinked precursor particles: use spray drying granulation on the precursor suspension in step S1, adjust the temperature interval of the outlet, adjust the air speed, and make the mixed particles continuously rotate in high-speed and high-temperature air, so as to realize solid-phase oxidation of pitch and glucose by using oxygen in the air, and obtain crosslinked precursor particles;

[0052] S3, high-temperature carbonization: high-temperature carbonize the crosslinked precursor particles obtained in step S2 in a protective atmosphere to obtain a solid-phase-oxidized sodium ion battery negative hard carbon material;

[0053] In step S1, the mass ratio of pitch to glucose ranges from 1:9 to 9:1; the mass proportion of the dispersant in the precursor suspension is 1-10%; the mass proportion of the inorganic acid in the precursor suspension is 0.1-10%; and the mass proportion of the graphitization inhibitor in the precursor suspension is 0.1-10%.

[0054] Further, in step S2, the spray drying conditions are: outlet temperature 90-150℃, mixed particle rotation time 0.5-2h.

[0055] Further, in step S3, the high-temperature carbonization conditions are: carbonization temperature 1000-1400℃, carbonization time 1-3h.

[0056] Further, in step S3, the protective atmosphere is one or two or more of argon, hydrogen, carbon monoxide, nitrogen, and the gas flow rate of the protective atmosphere is in the range of 50-150sccm.

[0057] Further, the dispersant is one or two or more of polyvinyl alcohol, F127 polyether ester, and dextran.

[0058] Further, the inorganic acid is one or two or more of phosphoric acid solution, nitric acid solution, and boric acid particles.

[0059] Further, the graphitization inhibitor is a substance containing one or more combinations of elements Nb, W, Mn, S, Cr, V, Mg, Ce, B, Al, Si, and Ti.

[0060] Another aspect of the present application is to protect a sodium ion battery hard carbon anode material prepared by the above preparation method.

[0061] Example 1

[0062] The preparation method of the hard carbon anode material of the present embodiment includes the following steps:

[0063] S1, preparation of a precursor suspension: 1g of polyvinyl alcohol was weighed into 50mL of water and stirred until completely dissolved to prepare a polyvinyl alcohol aqueous solution. 1g of pitch and 9g of glucose were added to the polyvinyl alcohol aqueous solution and stirred until evenly dispersed; 0.5mL of phosphoric acid solution and 0.01g of manganese chloride were added to the above mixture and stirred thoroughly to form a precursor suspension.

[0064] S2, preparation of crosslinked precursor particles: the precursor suspension in S1 was granulated using a spray drying method, the outlet temperature was adjusted to 90℃, the gas velocity was adjusted, and the mixed particles were continuously rotated in high-speed, high-temperature air for 1h to achieve solid-phase oxidation of pitch and glucose using oxygen in the air to obtain crosslinked precursor particles.

[0065] S3, high-temperature carbonization: the above crosslinked precursor particles were carbonized at a high temperature of 1000℃ for 1h under a nitrogen atmosphere with a flow rate of 50sccm to obtain 1LQ-9G-0.5P-0.01Mn-90-1000.

[0066] For comparison, the glucose of Example 1 was replaced by pitch or the pitch was replaced by glucose, and then the material of Comparative Example 1 of Example 1 was prepared according to the method of Example 1. The sample of pure glucose is marked as G-1000, and the sample of pure pitch is marked as LQ-1000.

[0067] The material of Example 1 and its comparative example were respectively subjected to electrical performance test and XRD test, and the results are shown in Figures 1-4

[0068] From Figure 1 and Figure 3 It can be seen that when the current density is 20 mA / g, the capacity of the material LQ-1000 obtained from pure pitch under this treatment condition is 147.26 mA h / g and 56.92%, the capacity of the material G-1000 obtained from pure glucose is 175.59 mAh / g and 56.19%, and the capacity of the treated material is 276.07 mA h / g and 72.44%, indicating that the performance is improved; a platform capacity appears after treatment, indicating that the material is hard carbon.

[0069] From the XRD patterns of Figure 2 and Figure 4 It can be seen that the material appears (002) and (100) peaks after treatment, and no graphite sharp peak appears, indicating that oxidation and crosslinking occur in the precursor during the pretreatment process, thereby inhibiting graphitization.

[0070] Example 2

[0071] This embodiment relates to a pitch-glucose solid-phase sodium ion battery negative electrode hard carbon material, and a preparation method thereof is as follows:

[0072] S1, preparation of precursor suspension: 1 g of F127 polyether ester was weighed in 60 mL of water, and stirred until completely dissolved to prepare an F127 polyether ester aqueous solution. 2 g of pitch and 8 g of glucose were added to the F127 polyether ester aqueous solution and stirred until uniformly dispersed; 3 mL of phosphoric acid solution and 0.05 g of manganese chloride were added to the above mixture, and stirred thoroughly to form a precursor suspension.

[0073] S2, preparation of crosslinked precursor particles: the precursor suspension in S1 was granulated by spray drying, the outlet temperature was adjusted to 100°C, and the gas speed was adjusted so that the mixed particles continuously rotated in high-speed, high-temperature air for 2 h, and the solid-phase oxidation of pitch and glucose was realized by using oxygen in the air to obtain crosslinked precursor particles.

[0074] S3, high-temperature carbonization: the above crosslinked precursor particles were carbonized at a high temperature of 1100°C for 2 h under a nitrogen atmosphere with a flow rate of 60 sccm to obtain 2LQ-8G-3P-0.05Mn-100-1100.

[0075] ​For comparison, the glucose of Example 2 was replaced by pitch or the pitch was replaced by glucose, and then the material of Comparative Example 2 of Example 2 was prepared according to the method of Example 2. The sample of pure glucose is marked as G-1100, and the sample of pure pitch is marked as LQ-1100.

[0076] The material of Example 2 and its comparative example were respectively subjected to electrical performance test and XRD test, and the results are shown in Figures 5-8

[0077] As can be seen from Figure 5 and Figure 7 , when the current density is 20 mA / g, the capacity of the material LQ-1100 obtained under the treatment condition is 142.65 mA h / g and 63.91% for the first efficiency, and the capacity of the material G-1100 obtained by pure glucose is 188.55 mAh / g and 64.35%, and the capacity of the treated material is 279.61 mA h / g and 71.40%, indicating that the performance is improved; the platform capacity appears after the treatment, indicating that the material is hard carbon.

[0078] As can be seen from the XRD patterns of Figure 6 and Figure 8 , the material appears (002) and (100) peaks after treatment, and no graphite sharp peak appears, indicating that the precursor produces oxidative crosslinking during the pretreatment process, thereby inhibiting graphitization.

[0079] Example 3

[0080] This example relates to a pitch-glucose solid-phase sodium ion battery negative electrode hard carbon material, and the preparation method thereof is as follows:

[0081] S1, preparation of precursor suspension: 1 g of F127 dextran was weighed in 70 mL of water, and stirred until completely dissolved to prepare a dextran aqueous solution. 3 g of pitch and 7 g of glucose were added to the dextran aqueous solution and stirred until uniformly dispersed; 1 mL of phosphoric acid solution, 1 mL of nitric acid solution, and 0.1 g of manganese chloride were added to the above mixture, and stirred thoroughly to form a precursor suspension.

[0082] S2, preparation of crosslinked precursor particles: the precursor suspension in S1 was granulated by spray drying method, the outlet temperature was adjusted to 110°C, and the gas speed was adjusted so that the mixed particles continuously rotated in high-speed and high-temperature air for 1 h, and the solid-phase oxidation of pitch and glucose was realized by using oxygen in the air to obtain crosslinked precursor particles.

[0083] S3, high-temperature carbonization: the above crosslinked precursor particles were carbonized at a high temperature of 1200°C for 1 h under a nitrogen atmosphere with a flow rate of 70 sccm to obtain 3LQ-7G-1P1N-0.1Mn-110-1200.

[0084] ​For comparison, the glucose in Example 3 was replaced by pitch or the pitch was replaced by glucose, and then the material was prepared according to the method of Example 3 to obtain Comparative Example 3 of Example 3. The sample of pure glucose is marked as G-1200, and the sample of pure pitch is marked as LQ-1200.

[0085] The material obtained in Example 3 and its comparative example were respectively subjected to electrical performance test and XRD test, and the results are shown in Figures 9-12

[0086] From Figure 9 and Figure 11 it can be seen that when the current density is 20 mA / g, the capacity of the material LQ-1200 obtained under the treatment condition is 139.51 mA h / g and 67.24% for the first efficiency, and the capacity of the material G-1200 obtained by pure glucose is 250.53 mA h / g and 65.86%, and the capacity of the treated material is 283.85 mA h / g and 71.37%, indicating that the performance is improved; the platform capacity appears after treatment, indicating that the material is hard carbon.

[0087] From the XRD patterns of Figure 10 and Figure 12 it can be seen that the material appears (002) and (100) peaks after treatment, and no graphite sharp peak appears, indicating that the precursor produces oxidative crosslinking in the pretreatment process, thereby inhibiting graphitization.

[0088] Example 4

[0089] This embodiment relates to a pitch-glucose solid-phase sodium ion battery negative electrode hard carbon material, and a preparation method thereof is as follows:

[0090] S1, preparation of precursor suspension: 1 g of polyvinyl alcohol, 1 g of F127 polyether ester and 1 g of dextran were weighed in 80 mL of water, and stirred until completely dissolved to prepare an aqueous dispersant solution. 4 g of pitch and 6 g of glucose were added to the aqueous dispersant solution and stirred until uniformly dispersed; 0.5 g of boric acid particles and 0.01 g of magnesium chloride were added to the above mixture and stirred thoroughly to form a precursor suspension.

[0091] S2, preparation of crosslinked precursor particles: the precursor suspension in S1 was granulated by spray drying, the outlet temperature was adjusted to 120°C, and the gas velocity was adjusted so that the mixed particles continuously rotated in high-speed, high-temperature air for 2 h, and the solid-phase oxidation of pitch and glucose was realized by using oxygen in the air to obtain crosslinked precursor particles.

[0092] S3, high-temperature carbonization: the above crosslinked precursor particles were carbonized at a flow rate of 80 sccm of argon gas at a high temperature of 1300°C for 2 h to obtain 4LQ-6G-0.5B-0.01Mg-120-1300. ​

[0093] For comparison, the glucose of Example 4 was replaced by pitch or the pitch was replaced by glucose, and then the material of Example 4 was prepared according to the method of Example 4 to obtain Comparative Example 4 of Example 4. The sample of pure glucose is marked as G-1300, and the sample of pure pitch is marked as LQ-1300.

[0094] The material obtained in Example 4 and its comparative example were respectively subjected to electrical performance test and XRD test, and the results are shown in Figures 13-16

[0095] From Figure 13 and Figure 15 it can be seen that when the current density is 20 mA / g, the capacity of the material LQ-1300 obtained from pure pitch under the treatment condition is 139.03 mA h / g and 63.94%, the capacity of the material G-1300 obtained from pure glucose is 251.41 mA h / g and 67.24%, and the capacity of the treated material is 290.66 mA h / g and 72.17%, indicating that the performance is improved; the platform capacity appears after the treatment, indicating that the material is hard carbon.

[0096] From the XRD patterns of Figure 14 and Figure 16 it can be seen that the material appears (002) and (100) peaks after treatment, and no graphite sharp peak appears, indicating that the precursor produces oxidative crosslinking during the pretreatment process, thereby inhibiting graphitization.

[0097] Example 5

[0098] This embodiment relates to a pitch-glucose solid-phase oxidation sodium-ion battery negative electrode hard carbon material, and a preparation method thereof is as follows:

[0099] S1, preparation of a precursor suspension: 1 g of F127 polyether ester and 2 g of dextran were weighed into 100 mL of water, and stirred until completely dissolved to prepare an aqueous dispersant solution. 5 g of pitch and 5 g of glucose were added to the aqueous dispersant solution and stirred until uniformly dispersed; 1 mL of phosphoric acid solution, 1 mL of nitric acid solution, 1 g of boric acid particles and 0.05 g of magnesium chloride were added to the above mixture, and stirred thoroughly to form a precursor suspension.

[0100] S2, preparation of crosslinked precursor particles: the precursor suspension in S1 was granulated by spray drying, the outlet temperature was adjusted to 130°C, and the gas speed was adjusted so that the mixed particles continuously rotated in high-speed, high-temperature air for 2 h, and the solid-phase oxidation of pitch and glucose was realized by using oxygen in the air to obtain crosslinked precursor particles.

[0101] ​S3, high-temperature carbonization: the cross-linked precursor particles obtained in the above step S2 were carbonized at a high temperature of 1400℃ for 2h under an argon atmosphere with a flow rate of 90sccm to obtain 5LQ-5G-1P1N1B-0.05Mg-130-1400.

[0102] For the purpose of comparison, the glucose in Example 5 was replaced by pitch or the pitch was replaced by glucose, and then the material was prepared according to the method of Example 5 to obtain Comparative Example 5 of Example 5. The sample of pure glucose is marked as G-1400, and the sample of pure pitch is marked as LQ-1400.

[0103] The material obtained in Example 5 and its comparative example were respectively subjected to electrical performance test and XRD test, and the results are shown in Figures 17-20

[0104] From Figure 17 and Figure 19 it can be seen that when the current density is 20 mA / g, the capacity of the material LQ-1400 obtained from pure pitch under this treatment condition is 125.01 mA h / g and 62.44%, the capacity of the material G-1400 obtained from pure glucose is 246.09 mA h / g and 66.17%, and the capacity of the treated material is 290.23 mA h / g and 71.79%, indicating that the performance is improved; the platform capacity appears after treatment, indicating that the material is hard carbon.

[0105] From the XRD patterns of Figure 18 and Figure 20 it can be seen that the material appears (002) and (100) peaks after treatment, and no graphite sharp peak appears, indicating that oxidation and cross-linking occur in the precursor during the pretreatment process, thereby inhibiting graphitization.

[0106] Example 6

[0107] This example relates to a pitch-glucose solid-phase oxidized sodium ion battery negative electrode hard carbon material, and a preparation method thereof is as follows:

[0108] S1, preparation of a precursor suspension: pitch and glucose were added to an aqueous solution containing a dispersant and stirred until uniformly dispersed, and then inorganic acid and graphitization inhibitor were added to form a precursor suspension;

[0109] S2, preparation of cross-linked precursor particles: the precursor suspension in step S1 was granulated by spray drying, the outlet temperature was adjusted to a temperature interval, the air speed was adjusted, and the mixed particles were continuously rotated in high-speed and high-temperature air. The solid-phase oxidation of pitch and glucose was realized by using oxygen in the air to obtain cross-linked precursor particles;

[0110] S3, high-temperature carbonization: the cross-linked precursor particles obtained in step S2 were carbonized at a high temperature under a protective atmosphere to obtain a solid-phase oxidized sodium ion battery negative electrode hard carbon material;​

[0111] In step S1, the mass ratio of pitch to glucose ranges from 1:9; the mass proportion of dispersant in the precursor suspension is 5%; the mass proportion of inorganic acid in the precursor suspension is 0.1-5%; and the mass proportion of graphitization inhibitor in the precursor suspension is 10%. The dispersant is polyvinyl alcohol. The inorganic acid is phosphoric acid solution. The graphitization inhibitor contains Nb, W, Mn, S, and Cr elements.

[0112] In step S2, the spray drying conditions are as follows: the outlet temperature is 150°C, and the mixed particles rotate for 1h.

[0113] In step S3, the high-temperature carbonization conditions are as follows: the carbonization temperature is 1400°C, the carbonization time is 2h, the protective atmosphere is argon, hydrogen, or nitrogen, and the gas flow rate of the protective atmosphere ranges from 50sccm.

[0114] Example 7

[0115] This example relates to a pitch-glucose solid-phase oxidized sodium-ion battery negative electrode hard carbon material, and a preparation method thereof is as follows:

[0116] S1, preparation of a precursor suspension: pitch and glucose are added to an aqueous solution containing a dispersant and stirred until uniformly dispersed, and then inorganic acid and graphitization inhibitor are added to form a precursor suspension;

[0117] S2, preparation of crosslinked precursor particles: the precursor suspension obtained in step S1 is spray dried to form particles, the outlet temperature is adjusted to a temperature interval, the gas velocity is adjusted, the mixed particles are continuously rotated in high-temperature air, and solid-phase oxidation of pitch and glucose is achieved by using oxygen in the air to obtain crosslinked precursor particles;

[0118] S3, high-temperature carbonization: the crosslinked precursor particles obtained in step S2 are subjected to high-temperature carbonization in a protective atmosphere to obtain a solid-phase oxidized sodium-ion battery negative electrode hard carbon material;

[0119] In step S1, the mass ratio of pitch to glucose ranges from 4:1; the mass proportion of dispersant in the precursor suspension is 1%; the mass proportion of inorganic acid in the precursor suspension is 10%; and the mass proportion of graphitization inhibitor in the precursor suspension is 5%. The dispersant is F127 polyether ester and dextran. The inorganic acid is phosphoric acid solution and boric acid particles. The graphitization inhibitor contains Cr, V, Mg, Ce, B, Al, Si, and Ti elements.

[0120] In step S2, the spray drying conditions are as follows: the outlet temperature is 120°C, and the mixed particles rotate for 0.5h.

[0121] In step S3, the high-temperature carbonization conditions are: carbonization temperature 1200℃, carbonization time 1h; the protective atmosphere is argon, nitrogen, and the gas flow range of the protective atmosphere is 150sccm.

[0122] Embodiment 8

[0123] This embodiment relates to a pitch-glucose solid-phase oxidized sodium ion battery negative electrode hard carbon material, and a preparation method thereof is:

[0124] S1, preparation of a precursor suspension: pitch and glucose are added to an aqueous solution containing a dispersant and stirred until uniformly dispersed, then inorganic acid and graphitization inhibitor are added to form a precursor suspension;

[0125] S2, preparation of crosslinked precursor particles: the precursor suspension in step S1 is spray-dried and granulated, the outlet temperature is adjusted to a temperature interval, the gas velocity is adjusted, the mixed particles are continuously rotated in high-speed and high-temperature air, and the solid-phase oxidation of pitch and glucose is realized by using oxygen in the air to obtain crosslinked precursor particles;

[0126] S3, high-temperature carbonization: the crosslinked precursor particles obtained in step S2 are high-temperature carbonized under a protective atmosphere to obtain a solid-phase oxidized sodium ion battery negative electrode hard carbon material;

[0127] In step S1, the mass ratio of pitch to glucose is in the range of 9:1; the mass fraction of the dispersant in the precursor suspension is 10%; the mass fraction of the inorganic acid in the precursor suspension is 5%; and the mass fraction of the graphitization inhibitor in the precursor suspension is 0.1%. The dispersant is polyvinyl alcohol, F127 polyether ester, and dextran. The inorganic acid is a phosphoric acid solution and a nitric acid solution. The graphitization inhibitor contains Nb, W, Mn, S, Cr, V, Mg, Ce, B, Al, Si, Ti elements.

[0128] In step S2, the spray-drying conditions are: outlet temperature 90℃, and the mixed particles are rotated for 2h.

[0129] In step S3, the high-temperature carbonization conditions are: carbonization temperature 1000℃, carbonization time 3h; the protective atmosphere is argon, hydrogen, carbon monoxide, and nitrogen, and the gas flow range of the protective atmosphere is 100sccm.

[0130] The above embodiments are only specific embodiments of the present application, which are described in more detail and in more detail, but should not be construed as limiting the scope of the present application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, and these obvious alternative forms all belong to the protection scope of the present application.

Claims

1. A method for preparing a sodium-ion battery hard carbon anode material, characterized by The method comprises the following steps: S1, preparation of a precursor suspension: adding pitch and glucose into an aqueous solution containing a dispersant and stirring until they are uniformly dispersed, then adding an inorganic acid and a graphitization inhibitor to form a precursor suspension; S2, preparation of crosslinked precursor particles: using spray drying to granulate the precursor suspension prepared in step S1 to obtain crosslinked precursor particles; S3, high-temperature carbonization: carbonizing the crosslinked precursor particles obtained in step S2 under a protective atmosphere to obtain a solid-phase oxidized sodium-ion battery negative electrode hard carbon material; In step S1, the mass ratio of pitch to glucose ranges from 1:9 to 9:1; the mass fraction of the dispersant in the precursor suspension is 1-10%; the mass fraction of the inorganic acid in the precursor suspension is 0.1-10%; and the mass fraction of the graphitization inhibitor in the precursor suspension is 0.1-10%.

2. The method of claim 1, wherein the method further comprises: In step S2, the spray drying conditions are as follows: the outlet temperature is 90-150℃, and the rotating time of the mixed particles is 0.5-2h.

3. The method for preparing the hard carbon anode material for sodium-ion batteries according to claim 1, characterized in that: In step S3, the high-temperature carbonization conditions are as follows: the carbonization temperature is 1000-1400℃, and the carbonization time is 1-3h.

4. The method for preparing the hard carbon anode material for sodium-ion batteries according to claim 1, characterized in that: In step S3, the protective atmosphere is one or more of argon, hydrogen, carbon monoxide, and nitrogen, and the gas flow rate of the protective atmosphere ranges from 50 to 150sccm.

5. The method for preparing the hard carbon anode material for sodium-ion batteries according to claim 1, characterized in that: The dispersant is one or more of polyvinyl alcohol, F127 polyether ester, and dextran.

6. The method for preparing the hard carbon anode material for sodium-ion batteries according to claim 1, characterized in that: The inorganic acid is one or more of a phosphoric acid solution, a nitric acid solution, and boron acid particles.

7. The method for preparing the hard carbon anode material for sodium-ion batteries according to claim 1, characterized in that: The graphitization inhibitor is a substance containing one or more of the elements Nb, W, Mn, S, Cr, V, Mg, Ce, B, Al, Si, and Ti.

8. A sodium-ion battery hard carbon anode material, characterized in that: The method is prepared by any one of claims 1-7.

9. A sodium-ion battery, characterized in that: The hard carbon negative electrode material of claim 8 is used as a negative electrode.

Images