Preparation method of spindle-shaped mnco3 graphene lithium ion battery negative material

Abstract

The application discloses a preparation method of a spindle-shaped MnCO3 graphene lithium ion battery negative electrode material. The method comprises the following steps: adding GO dispersion liquid drops into a PDDA modified MnO2 nanorod precursor dispersion liquid, stirring at room temperature to obtain a MnO2 / GO composite material, adding thiourea after being dispersed in deionized water, and carrying out hydrothermal reaction at 90-180 DEG C for 3-24 hours in a high-pressure reaction kettle to obtain the spindle-shaped MnCO3 graphene lithium ion battery negative electrode material. The reversible specific capacity of the composite material obtained by the application reaches 1885 mAh g ‑1 after 230 cycles at a current density of 0.2 Ag ‑1 .

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of energy storage materials, and specifically relates to a preparation method of a spindle-shaped manganese carbonate graphene lithium ion battery negative electrode material. BACKGROUND

[0002] With the popularity and development of household appliances, electronic products and aerospace facilities, it is essential to design and use innovative energy storage systems with excellent cycle stability and high power / energy density. Graphite, as a common commercialized lithium ion battery negative electrode material, has the advantages of stable chemical properties, low charge-discharge potential platform, and insignificant volume expansion. However, the theoretical specific capacity of graphite is relatively low, only 372 mAh g -1 . As a representative transition metal carbonate (TMC), manganese carbonate negative electrode material has great application potential in the field of energy storage due to its high capacity (>1000 mA h g -1 ), suitable working voltage, good stability and low cost. However, the low electrical conductivity and slow reaction kinetics make it difficult to fully utilize its capacity, resulting in poor rate performance. At the same time, the volume change during lithium storage leads to electrode material pulverization and collapse, which causes serious capacity decay.

[0003] In the traditional "bottom-up" synthesis method, manganese carbonate material is mainly obtained by adding a precipitating agent to a water-soluble manganese salt, such as the patent CN105304981B, which proposes adding manganese acetate, nickel acetate and urea to deionized water and alcohol solvent to prepare manganese carbonate composite material by hydrothermal reaction. However, this method easily causes disordered accumulation of MnCO3 crystals, increasing the difficulty of microstructure regulation and synthesis. Designing and synthesizing manganese carbonate-based materials with unique fine micro-nano structure is an effective measure to improve the electrochemical performance of negative electrode materials. Therefore, the present application uses manganese dioxide and thiourea as raw materials to realize the regulation of the fine structure of manganese carbonate by an innovative thiourea reduction auxiliary method, and prepares manganese carbonate graphene composite material with multiple structural advantages to solve the problems encountered by manganese carbonate negative electrode material in the application of lithium ion battery negative electrode. SUMMARY

[0004] The present application aims to provide a preparation method of a novel spindle-shaped MnCO3 graphene lithium ion battery negative material with micro / nano structure, which can overcome the problem of the difficulty in forming fine order and stable structure of manganese carbonate in the current traditional preparation method, and affect the electrochemical performance. Unlike the previous invention which uses water-soluble manganese salt and precipitant as raw materials, the present application uses one-dimensional structure MnO2 solid and thiourea as reaction precursor and double reducing agent respectively, and finally obtains spindle-shaped MnCO3 graphene lithium ion battery negative material assembled by nanorods through high-temperature hydrothermal reaction. The reversible specific capacity of the composite material obtained by the present application reaches 1885mAh g-1 after 230 cycles at a current density of 0.2A g-1. -1 -1 .

[0005] The technical scheme of the present application is:

[0006] A preparation method of a spindle-shaped MnCO3 graphene lithium ion battery negative material, which comprises the following steps:

[0007] (1) MnSO4·H2O, (NH4)2S2O8, (NH3)2SO4 are added to deionized water and stirred until uniformly dispersed; a surfactant sodium dodecyl sulfate (SDS) is added thereto, and stirred at room temperature for 0.1-1h; then poured into a high-pressure reaction kettle, and reacted at 90-180℃ for 6-20h, after which the precipitate is washed by centrifugation with deionized water and dried to obtain MnO2 nanorods;

[0008] wherein the molar ratio of the three solutes MnSO4·H2O, (NH4)2S2O8, (NH3)2SO4 is 1:0.2-2:1-5; the mass of MnSO4·H2O added to every 10-100mL deionized water is 0.5-3.0g, and the mass ratio of the surfactant SDS to MnSO4·H2O is 0.01-0.5:1;

[0009] (2) surface modification: the MnO2 nanorod precursor obtained in the previous step is ultrasonically dispersed in deionized water, a modifier polydiallyldimethylammonium chloride (PDDA) is added, and stirred for 0.1-1h, after which the PDDA-modified MnO2 nanorod precursor (PDDA-MnO2) is obtained by centrifugation and washing with deionized water; and the dispersion liquid A is obtained by stirring the dispersion in deionized water again;

[0010] wherein the mass ratio is MnO2 precursor: polydiallyldimethylammonium chloride = 1:0.001-0.5; and in the dispersion liquid A, 50-400mg of the PDDA-modified MnO2 nanorod precursor (PDDA-MnO2) is added to every 50-300mL deionized water;

[0011] ​(4) Preparation of graphene oxide dispersion: after drying, the graphene oxide is ultrasonically dispersed in deionized water to obtain a GO dispersion, denoted as dispersion B;

[0012] The mass concentration of the GO dispersion is 0.1-2 mg / mL -1 ;

[0013] (5) MnO2 and GO composite: the dispersion B is added dropwise into the dispersion A, stirred at room temperature for 10-90 min to obtain a turbid solution; the precipitate is centrifuged, washed with deionized water and dried to obtain a MnO2 / GO composite material;

[0014] The mass ratio of PDDA-MnO2: GO is 10: 0.1-2;

[0015] (6) Hydrothermal reaction: the MnO2 / GO composite material obtained in (5) is dispersed in deionized water, thiourea is added, stirred for 5-50 min, the mixed solution is transferred to a high-pressure reaction kettle, and hydrothermal reaction is carried out at 90-180℃ for 3-24 hours; the obtained product is soaked and washed with deionized water, and then freeze-dried to obtain a spindled MnCO3 graphene lithium ion battery negative electrode material;

[0016] The mass ratio of thiourea: MnO2 and GO composite material is 1: 0.1-0.5; in the mixed solution, 200-1000 mg of thiourea is added per 5-50 mL of deionized water.

[0017] The graphene oxide in step (4) is prepared by the improved Hummers method.

[0018] The mass of the modified MnO2 precursor is the theoretical value, i.e. the mass of the unmodified MnO2 precursor; the molar mass of the graphene-coated spindled MnCO3 after hydrothermal reaction is the theoretical value, i.e. according to the molar mass of the manganese dioxide precursor before the reaction;

[0019] The application of the spindled MnCO3 graphene lithium ion battery negative electrode material prepared by the method is used as a negative electrode sheet of a lithium ion battery;

[0020] The method comprises the following steps: mixing the electrode material obtained in (6) with conductive carbon and a binder at a mass ratio of 8:1:1 to obtain a mixed material, adding 600-1000 μL of deionized water to 50-250 mg of the mixed material, and stirring at room temperature for 6-24 h; after stirring, the obtained suspension is uniformly coated on a copper foil, and the unit area coating amount is about 0.5-2 mg / cm -2 , and vacuum drying at 80-120℃ for 10-20 h to obtain a negative electrode sheet of a lithium ion battery;

[0021] The binder is sodium carboxymethyl cellulose, and the conductive carbon is Super P.

[0022] The positive electrode of the lithium ion battery is a metal lithium sheet, the separator is a glass fiber membrane, and the electrolyte is a solution of LiPF6 in a mixed dimethyl carbonate (DMC), methyl ethyl carbonate (EMC) and ethylene carbonate (EC) in a volume ratio of 1:1:1. - 1 LiPF6 in a mixed dimethyl carbonate (DMC), methyl ethyl carbonate (EMC) and ethylene carbonate (EC) in a volume ratio of 1:1:1.

[0023] The substantial features of the present application are:

[0024] In previous papers, the traditional method for preparing manganese carbonate-based materials often causes disordered stacking of the crystal structure, making it difficult to fine-tune the microstructure of manganese carbonate materials, which reduces the high capacity of manganese carbonate negative materials and also reduces the rate performance.

[0025] The present application first uses one-dimensional MnO2 nanorods as a precursor and a sacrificial template, and uses graphene oxide as a two-dimensional conductive substrate precursor, and through surface modification, first electrostatically combines manganese dioxide with graphene oxide, and then uses thiourea as a double reducing agent to finally design and synthesize a spindle-shaped manganese carbonate graphene composite material with nanorod homodirectional self-assembly under hydrothermal conditions.

[0026] The present application has the following beneficial effects:

[0027] (1) The present application first uses manganese dioxide as a precursor to obtain manganese carbonate material by one-step hydrothermal method through the reduction effect of a specific reducing agent, and theoretically, the fine tuning of the morphology of manganese carbonate can be realized by preparing a precursor with different morphologies.

[0028] (2) The application utilizes a polydiallyldimethylammonium chloride (PDDA) solution to modify the surface of a manganese dioxide precursor, so that the manganese dioxide nanoparticles can be uniformly dispersed in a solvent;

[0029] (3) The modified manganese dioxide is uniformly attached to the surface of a graphene oxide sheet layer with a negative surface through electrostatic adsorption, and the operation process is simple and the experimental conditions are mild;

[0030] (4) By adding thiourea as a double reducing agent, the manganese dioxide precursor and the graphene oxide are both reduced, and finally a manganese carbonate graphene (MnCO3@rGO) composite material is obtained; the nitrogen and sulfur elements generated by the decomposition of the reducing agent thiourea under high-temperature hydrothermal conditions can be doped into the manganese carbonate and graphene carbon skeleton, further improving the electrochemical performance of the composite material;

[0031] (5) The spindle-shaped MnCO3@rGO composite material prepared in the experiment has a reversible specific capacity of 1885 mAh g-1 after 230 cycles at a current density of 0.2 A g-1 -1 -1 ;

[0032] (6) The reversible specific capacity of the material reaches 886 mAh g-1 -1 and 545 mAh g-1 -1 at a current density of 1 A g-1 -1 and 5 A g-1 -1， respectively, and the reversible specific capacity can still reach 594 mAh g-1 -1 after 1100 cycles at a current density of 2 A g-1 -1 . This provides a theoretical basis for the commercial application of the material in the field of energy storage materials;

[0033] (7) The application can also realize fine control of the nanostructure of manganese carbonate in the composite material by preparing manganese dioxide precursors with different morphologies and structures. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a scanning electron microscope image of the manganese dioxide nanorod precursor in Example 1;

[0035] Figure 2 is an X-ray diffraction pattern of the manganese dioxide precursor in Example 1;

[0036] Figure 3 is an X-ray diffraction pattern of the nanorod self-assembled manganese carbonate graphene composite material (MnCO3@rGO) in Example 1;

[0037] Figure 4 ​Scanning electron microscope image of the nanorod oriented assembly of the spindle-like MnC03@rGO composite material in Example 1 ;

[0038] Figure 5 Cycling performance plot for the nanorod oriented assembly of the spindle-like MnC03@rGO composite material in Example 1 ;

[0039] Figure 6 Scanning electron microscope image of the dried manganese dioxide nanosheet layer in Example 2;

[0040] Figure 7 Scanning electron microscope image of the m-MnC03@rGO composite material in Example 2;

[0041] Figure 8 Cycling performance plot for the m-MnC03@rGO composite material in Example 2;

[0042] Figure 9 Scanning electron microscope image of the spindle-like manganese carbonate material (pure-MnC03) in Example 3;

[0043] Figure 10 Cycling performance of the pure spindle-like manganese carbonate material (pure-MnC03) in Example 3;

[0044] Figure 11 Cycling performance of the spindle-like MnC03graphene composite material (MnC03@rGO-150) in Example 4;

[0045] Figure 12 Cycling performance of the spindle-like MnC03graphene composite material (MnC03@rGO-400) in Example 5. DETAILED DESCRIPTION

[0046] Example 1

[0047] Into 40 mL of deionized water, 1.365 g (0.008 mol) of MnS04-H20, 1.825 g (0.008 mol) of (NH4)2S20s, 2.6428 g (0.02 mol) of (NH4)2S04were added, stirred at room temperature for 0.5 h to form a clear transparent solution. 0.125 sodium dodecyl sulfate (SDS) was added to the above clear solution, stirred at room temperature for 0.5 h to obtain a uniform transparent solution; the above solution was transferred to a 100 mL hydrothermal kettle, reacted at 120 °C for 12 h, and after cooling to room temperature, centrifugation was performed to obtain a brown-black solid powder, and washing was performed with distilled water and anhydrous ethanol. The washed product was dried in a 50 °C blast drying oven overnight to obtain a Mn02nanorod precursor.

[0048] The 200 mg of the above obtained manganese dioxide nanorod precursor and 200 μL of polydimethyl diallyl ammonium chloride solution (PDDA Mw = 10000-20000, 30 wt%) were ultrasonically dispersed in 200 mL of deionized water and stirred for 1 h. The precipitate was centrifuged and washed with deionized water to obtain PDDA modified MnO2 nanorods (PDDA-MnO2). The obtained PDDA-MnO2 full product (i.e. without considering the loss of manganese dioxide, the theoretical value is 200 mg) was again dispersed in 200 mL of deionized water to obtain dispersion A; 40 mL of graphene oxide (GO-prepared based on the improved Hummers method, literature number: Journal of Alloys and Compounds 862 (2021) 158472 dispersion (0.75 mg mL -1 ) was prepared as dispersion B, and dispersion B was added dropwise to dispersion A and continued to stir for 1 hour. Then, the obtained GO attached with MnO2 nanorods (MnO2 / GO) was collected by centrifugation. 200 mg of MnO2 / GO was dispersed in 15 mL of thiourea solution (70 mg mL -1 ), and stirred for 30 min. The above mixed solution was transferred to a reaction kettle, and kept sealed at 180°C for 24 h. After cooling, the product was soaked in deionized water for 24 hours to remove impurities, and then freeze-dried at -30°C for 24 h, finally obtaining a nanorod homodirectionally assembled spindle-shaped MnCO3 and rGO composite material (labeled as MnCO3@rGO).

[0049] The obtained MnCO3@rGO composite material was uniformly mixed with conductive carbon (Super P) and binder (sodium carboxymethyl cellulose) at a mass ratio of 8:1:1 (total amount of 125 mg) to obtain a MnCO3@rGO mixed material, and 800 μL of deionized water was added, and stirred at room temperature for 12 h; after stirring, the obtained MnCO3@rGO mixed material suspension was uniformly coated on a copper foil (the coating amount on each square centimeter of copper foil was about 1 mg), and vacuum dried at 100°C for 12 h; the obtained electrode sheet was cut into a circular sheet with a diameter of 12 mm by a manual slicer to obtain a negative electrode sheet. In this embodiment, the battery adopts a standard half-cell configuration, the battery shell is a CR2025 type stainless steel button cell, lithium sheet is used as the counter electrode, Celgard 2500 is used as the separator, and the electrolyte is a mixed solution of 1M LiPF6 in ethylene carbonate (EC), dimethyl carbonate (DMC) and methyl ethyl carbonate (EMC) (volume ratio 1:1:1). The voltage range of this test is 0.01-3 V, the test current is 0.2 A g -1 , and the test uses a LAND CT2001A type battery test system.

[0050] Figure 1The scanning electron microscope image of the manganese dioxide precursor in Example 1. The MnO2 is a nanorod structure without particle agglomeration, and the length of the nanorod is about 400 nm.

[0051] Figure 2 The XRD test curve of the manganese dioxide precursor in Example 1.

[0052] Figure 3 The XRD test curve of the MnCO3@rGO composite material in Example 1, which is a composite of spindle-shaped MnCO3 assembled by nanorods and rGO lamellas.

[0053] Figure 4 The scanning electron microscope image of the MnCO3@rGO composite material in Example 1. The MnCO3 is a spindle-shaped structure of nanorods homodromous self-assembly, which is uniformly attached to the graphene lamella.

[0054] Figure 5 The cycle performance diagram of the MnCO3@rGO composite material. The discharge and charge specific capacity of the composite material in the first cycle are 1817 and 1058 mA h g -1 , respectively, and the reversible specific capacity after 230 cycles reaches 1885 mA h g -1 , and the coulombic efficiency is close to 100%.

[0055] Example 2

[0056] The steps are the same as in Example 1, except that the manganese dioxide nanorod precursor in dispersion A is changed to a manganese dioxide nanosheet precursor.

[0057] The preparation process of the manganese dioxide nanosheet is as follows: 1.6 g of potassium permanganate and 1.42 g of ammonium oxalate are dissolved in 70 mL of deionized water and transferred to a 100 mL hydrothermal reactor for reaction at 90°C for 24 hours. The obtained precipitate is washed with deionized water and dried at 60°C overnight to obtain manganese dioxide nanosheets. According to the same steps in Example 1, after PDDA modification, centrifugation and redispersion, dispersion A is obtained. Dispersion B is added dropwise to dispersion A, and other conditions remain unchanged to obtain a manganese dioxide nanosheet composite GO material, which is used as a precursor to go through the same steps as in Example 1, and finally a micron-sized manganese carbonate graphene composite material (denoted as m-MnCO3@rGO) is obtained.

[0058] Figure 6 The scanning electron microscope image of the dried manganese dioxide nanosheet layer, which presents an irregular structure, mainly due to the accumulation of the manganese dioxide nanosheet layer after drying. In the inset in the figure, the dispersion of the manganese dioxide nanosheet layer is shown, and the laser pen irradiation exhibits obvious Tyndall effect of colloids, indicating the high dispersibility of the nanosheet layer in deionized water. Figure 7Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers. Figure 8 Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers. -1 Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers. -1 Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers. Figure 7 Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers.

[0059] Example 3

[0060] The procedure is the same as in Example 1, except that the dispersion liquid A is not added with the dispersion liquid B, and other conditions remain unchanged. After the same procedure as in Example 1, a pure spindle-shaped manganese carbonate material (pure-MnC03) is obtained. Figure 9 Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers. Figure 10 Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers. -1 Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers. -1 Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers.

[0061] Example 4

[0062] The procedure is the same as in Example 1, except that the mass of the manganese dioxide nanorods added in the dispersion liquid A is changed to 150 mg, other conditions remain unchanged, and the manganese dioxide nanorods are first mixed with the dispersion liquid B as a precursor. After the same procedure as in Example 1, a spindle-shaped manganese carbonate graphene composite material (MnC03@rGO-150) is obtained. Figure 11 Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers. -1 Figure 6 is a scanning electron microscope image of the m-MnC03@rGO composite material, in which micron-sized manganese carbonate particles are uniformly attached to the graphene sheet layers. -1The coulombic efficiency is close to 100%. As the main body of the electrode material, the manganese carbonate in MnCO3@rGO-400 has excessive content, which is not conducive to the performance of manganese carbonate in MnCO3@rGO-400 to fully play, so its performance decreases, but is superior to example 3.

[0063] Example 5

[0064] Only the added mass of manganese dioxide nanorods in dispersion A is changed to 400 mg, other conditions remain unchanged, and it is first mixed with dispersion B as a precursor, and after the same steps as in example 1, the spindle-shaped manganese carbonate graphene composite material (MnCO3@rGO-400) is obtained. Figure 12 The cycle performance chart of the MnCO3@rGO-400 composite material. The discharge and charge specific capacities in the first cycle of the composite material are 1466 and 650 mA h g -1 , respectively, and the reversible specific capacity after 230 cycles reaches 774 mA h g -1 , and the coulombic efficiency is close to 100%. Excessive manganese carbonate content is not conducive to the performance of manganese carbonate in MnCO3@rGO-400 to fully play, so its performance decreases, but is superior to example 3.

[0065] From the above examples, it can be seen that the product of the application is a spindle-shaped manganese carbonate graphene composite material (MnCO3@rGO) obtained by using one-dimensional nanorod-shaped MnO2 as a precursor and a sacrificial template, compounding with graphene oxide through surface modification, and self-assembling in the same direction after reduction by a specific reducing agent thiourea. Among them, the fine control of the structure of manganese carbonate in the product can be realized by adjusting the morphology of the manganese dioxide precursor, which illustrates the universal applicability of the method. In addition, by adjusting the ratio of manganese dioxide nanorods to graphene oxide, the electrochemical performance of the composite material can be further improved.

[0066] The details of the application are known technologies.

Claims

1. A method for preparing a spindle-shaped MnCO3 graphene lithium-ion battery negative electrode material, characterized in that the method comprises the following steps: (1) Add MnSO4·H2O, (NH4)2S2O8, and (NH3)2SO4 to deionized water and stir until uniformly dispersed. Add surfactant sodium dodecyl sulfate (SDS) and stir at room temperature for 0.1-1 h. Pour the mixture into a high-pressure reactor and react at 90-180°C for 6-20 h. Wash the precipitate with deionized water by centrifugation and dry it to obtain MnO2 nanorods. in, The molar ratio of the three solutes MnSO4·H2O, (NH4)2S2O8, and (NH3)2SO4 is 1:0.2~2:1~5; the mass of MnSO4·H2O added per 10~100mL of deionized water is 0.5~3.0g, and the mass ratio of surfactant SDS to MnSO4·H2O is 0.01~0.5:1; (2) Surface modification: The MnO2 nanorod precursor obtained in the previous step was ultrasonically dispersed in deionized water, and the modifier polydimethylammonium chloride (PDDA) was added and stirred for 0.1-1 h. After centrifugation and washing with deionized water, the MnO2 nanorod precursor modified with PDDA was obtained. The MnO2 nanorod precursor modified with PDDA was dispersed in deionized water again and stirred to obtain dispersion A. The mass ratio of MnO2 precursor to polydimethylammonium chloride is 1:0.001~0.

5. In dispersion A, 50~400 mg of PDDA-modified MnO2 nanorod precursor is added to every 50~300 mL of deionized water. (3) Preparation of graphene oxide dispersion: The dried graphene oxide was ultrasonically dispersed in deionized water to obtain a GO dispersion, which was designated as dispersion B. The mass concentration of GO dispersion is 0.1~2 mg mL -1 ; (4) Composite preparation of MnO2 and GO: Dispersion B was added dropwise to dispersion A and stirred at room temperature for 10–90 min to obtain a turbid solution. The precipitate was centrifuged, washed with deionized water, and dried to obtain a MnO2 / GO composite material. Among them, the mass ratio of MnO2 nanorod precursor: GO = 10:0.1~2; (5) Hydrothermal reaction: The MnO2 / GO composite material obtained in (4) was dispersed in deionized water, thiourea was added, and stirred for 5-50 min. The mixed solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 90-180 °C for 3-24 hours. The obtained product was soaked and washed with deionized water and freeze-dried to obtain a spindle-shaped MnCO3 graphene lithium-ion battery negative electrode material. The mass ratio of thiourea: MnO2 to GO composite material is 1:0.1~0.5; 200~1000 mg of thiourea is added to every 5~50 mL of deionized water in the mixed solution.

2. The method for preparing the spindle-shaped MnCO3 graphene lithium ion battery negative electrode material according to claim 1, characterized in that The graphene oxide in step (3) is graphene oxide prepared by the improved Hummers method.

3. The application of the spindle-shaped MnCO3 graphene lithium ion battery negative electrode material prepared by the method according to claim 1, characterized in that it is used as a negative electrode sheet of a lithium ion battery.

4. The method according to claim 3, further comprising the steps of: The spindle-shaped MnCO3 graphene lithium-ion battery negative electrode material is mixed with conductive carbon and a binder at a mass ratio of 8:1:1 to obtain a mixed material. Deionized water is then added, and 50-250 mg of the mixed material is added to every 600-1000 μL of deionized water. The mixture is stirred at room temperature for 6-24 hours. After stirring, the resulting suspension is coated on copper foil and vacuum-dried at 80-120°C for 10-20 hours to obtain a negative electrode sheet for a lithium-ion battery. The coating amount per unit area is 0.5-2 mg cm -2 ; The binder is sodium carboxymethyl cellulose and the conductive carbon is Super P.

5. The use according to claim 3, wherein the positive electrode of the lithium-ion battery is a metal lithium sheet, the separator is a glass fiber membrane, and the electrolyte is 1.0 mol L -1 Solution of LiPF6 in a mixture of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and ethylene carbonate (EC) in a volume ratio of 1:1:1.

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