CN106784658A - A kind of Morphological control method of lithium ion battery metal oxide/carbon negative pole material - Google Patents

Abstract

The invention discloses a method for controlling the morphology of a metal oxide/carbon ( _MOx /C) composite material for a negative electrode of a lithium ion battery. Add metal ions and monodentate ligands in different proportions to the solvent, stir for a period of time, add multidentate ligands, place in a reaction kettle and heat for a period of time to obtain metal-organic framework (MOF) precursor materials with different morphologies. MO _x /C composites with different morphologies were obtained after the precursor was calcined under an inert gas atmosphere for a period of time. The composite material has a high specific surface area and a rich pore structure, and has excellent rate performance and cycle stability as an anode material for lithium-ion batteries. The morphology control method is simple to operate, easy to realize large-scale application, and can be extended to other fields that focus on material morphology control.

Description

A method for controlling the morphology of metal oxide/carbon anode materials for lithium-ion batteries

technical field

The invention belongs to the technical field of high-energy battery materials, and in particular relates to a method for regulating the morphology of _MOx /C composite negative electrode materials for lithium ion batteries.

Background technique

Lithium-ion batteries have been widely used in portable electronic devices due to their high energy density and long cycle life, and have good application prospects in the fields of energy storage and power batteries. However, in order to further increase the energy density of lithium-ion batteries, we need to develop new high-capacity anode materials to replace the existing commercial graphite anode (its theoretical capacity is only 372mAh·g ^-1 ). Metal oxide anode materials based on conversion mechanism have the advantages of high specific capacity and low price, which are expected to meet the requirements of next-generation lithium-ion battery anode materials.

At present, metal oxides as anode materials for lithium-ion batteries mainly have problems such as slow kinetic process, large crystal volume change during charge and discharge, and poor cycle performance. In order to improve the electrochemical performance of metal oxides, researchers have proposed many beneficial means, such as nanomaterials, carbon coating, graphene/carbon nanotube loading, and material mesoporization, etc. (see (a) Jiang, H. ; Hu, Y.; Guo, S.; Yan, C.; Lee, P.S.; Li, C. Kim, H.-S.; Ahn, H.; Wang, G. Journal of Power Sources 2011, 196(6), 3346-3349.(c) Xia, Y.; Xiao, Z.; Dou, X.; Huang, H.; Lu, X.; Yan, R.; Gan, Y.; Zhu, W.; .(d) Zhao, G.; Huang, X.; Wang, X.; Connor, P.; Li, J.; Zhang, S.; Irvine, J.T.S. Journal of Materials Chemistry A 2015,3(1),297 -303.). It is well known that the morphology and structure of materials have an important impact on their electrochemical performance. How to effectively design high-performance electrode materials with controllable morphology is still the research focus of researchers.

Metal-organic frameworks (MOFs) have good application prospects in the fields of gas storage, separation, catalysis, chemical sensing, and drug transfer due to their large specific surface area, abundant pores, and easy synthesis (see (a) James, SLChemical Society Reviews 2003,32(5),276-288;(b)Chaemchuen,S.;Kabir,NA;Zhou,K.;Verpoort,F.Chemical Society Reviews2013,42(24),9304-9332;(c) Li, J.-R.; Kuppler, RJ; Zhou, H.-C. Chemical Society Reviews 2009, 38(5), 1477-1504; (d) Liu, J.; Chen, L.; Cui, H. ; Zhang, J.; Zhang, L.; Su, C.-Y. Chemical Society Reviews 2014, 43(16), 6011-6061.). Recently, more and more literatures have reported the use of MOF materials as precursors to synthesize various metal oxide anode materials, such as noodle-like α-Fe ₂ O ₃ , porous ZnO/ZnFe ₂ O ₄ /C 8 hehedral, anatase porous TiO ₂ , mesoporous Co ₃ O ₄ nanoparticles, etc. (see (a) Xu, X.; Cao, R.; Jeong, S.; Cho, J. Nano letters 2012,12(9 ), 4988-4991.(b). Feng, Z.; Xianluo, H.; Zhen, L.; Long, Q.; Chenchen, H.; Rui, Z.; Yan, J.; Yunhui, H. Advanced Materials 2014, 26(38), 6622–6628.(c) Wang, Z.; Li, X.; Xu, H.; Yang, Y.; Cui, Y.; Pan, H.; Wang, Z.; Chen, B.; Qian, G. Journal of Materials Chemistry A 2014, 2(31), 12571-12575. (d) Li, C.; Chen, T.; Xu, W.; Lou, X.; Pan, L .; Chen, Q.; Hu, B. Journal of Materials Chemistry A 2015, 3(10), 5585-5591. (e) Zheng, F.; Xia, G.; Yang, Y.; Chen, Q. Nanoscale 2015, 7(21), 9637-9645.). However, the reports in these literatures are limited to a simple calcination process for known MOF precursor materials. As far as we know, there is no report on controlling the morphology of MOF precursors by controlling the MOF assembly process, and then obtaining metal oxides and carbon materials with different morphologies.

The present invention designs a space-confined assembly method. By restricting the assembly of MOF materials in one or several directions, the effective regulation of MOF morphology is successfully realized, and the metal oxidation with controllable morphology is obtained after heat treatment. material/carbon composites.

Contents of the invention

The object of the present invention is to provide a method for controlling the morphology of the MO _x /C negative electrode material by adjusting the morphology of the MOF precursor. The method has simple process, convenient operation, low production cost and is suitable for large-scale production. The MO _x /C material prepared by this method has excellent electrochemical performance as the negative electrode material of lithium ion battery.

A method for controlling the morphology of metal oxide/carbon negative electrode materials for lithium-ion batteries. By controlling the feeding sequence, the metal ion source and a certain proportion of monodentate ligands are first dissolved in a solvent, and then the multidentate ligands are added after sufficient stirring. After reacting at a certain temperature for a period of time, the MOF precursor is obtained; the morphology of the product is also adjusted by adjusting the ratio of the monodentate ligand and the metal ion, and the precursor is sintered in an inert or reducing atmosphere to obtain MO _x /C Composite.

The metal ion source is: manganese, iron, cobalt, nickel, copper, zinc acetate; manganese, iron, cobalt, nickel, copper, zinc hydrochloride; manganese, iron, cobalt, nickel, copper, Nitrate of zinc; one or more of sulfates of manganese, iron, cobalt, nickel, copper, and zinc.

The monodentate ligand is: one or more of benzoate, phenylacetate, acetate, F ^- , NH ₃ , CN ^- . The bidentate ligands are: terephthalate, phthalate, trimesate, oxalic acid, ethylenediamine, oxalate, bipyridine, ethylenediaminetetraacetate, salicylaldehyde one or more of.

The molar ratio of the monodentate ligand to the metal ion ≤ the maximum coordination number of the metal center ion to the ligand -2.

The method for controlling the morphology of metal oxide/carbon negative electrode materials for lithium ion batteries uses manganese as a metal ion source, benzoic acid as a monodentate ligand, and terephthalic acid as a multidentate ligand, and controls Mn: benzoic acid The molar ratio is 1:(1~4) to control the morphology.

Described solvent is: one or more in dimethylformamide, water, ethylene glycol, ethanol, propanol, hexanediol, chloroform.

The certain reaction temperature is: 50-200°C, and the reaction time is: 3-48h.

_Described inert gas is: pure Ar gas, N Gas or the mixed gas of H and Ar, described reducing gas is the mixed gas of _CO and _{CO ;} H in the mixed gas of Ar and _Ar Volume fraction The volume fraction of CO in the mixed gas of CO and _CO2 is 5-20%.

The sintering temperature: 500-1000°C, sintering time: 1-10h; heating rate: 1-15°C/min.

A metal oxide/carbon negative electrode material for a lithium ion battery is prepared by the above method.

Morphology and structure have an important impact on the electrochemical performance of materials, and the morphology-controlled synthesis is still the research focus of researchers. The present invention designs a space-confined assembly method to regulate the morphology of the MOF precursor, and then calcines in an inert gas to finally obtain a MO _x /C composite material with a corresponding morphology. The present invention takes benzoic acid as a monodentate ligand and terephthalic acid as a multidentate ligand as an example for the reaction principle shown in FIG. 1 . The metal ion Mn ²⁺ is a six-coordination center ion with an octahedral field. When Mn ²⁺ and terephthalic acid form MOF, terephthalic acid can interact with Mn ² from the six vertices of the Mn ²⁺ octahedral field. ⁺ undergoes coordination growth. If we add monodentate benzoic acid in advance, the carboxyl group of benzoic acid can coordinate with Mn ²⁺ . When the molar ratio of Mn:benzoic acid = 1:1, benzoic acid occupies a vertex (such as x) of the Mn ²⁺ octahedral field, and terephthalic acid can be obtained from (-x, y, -y, z and -z ) direction to coordinate growth with Mn ²⁺ . When the molar ratio of Mn:benzoic acid=1:2, due to the steric effect, benzoic acid occupies the opposite vertices (such as x and -x) of the Mn ²⁺ octahedral field, and terephthalic acid can only be obtained from (y, -y , z and -z) directions to coordinate growth with Mn ²⁺ . When the molar ratio of Mn:benzoic acid is 1:4, benzoic acid preferentially occupies the xy plane, and terephthalic acid can only coordinate with Mn ²⁺ to grow from the Z axis. That is to say, the growth of Mn-MOF can be affected by benzoic acid as a regulator, and the purpose of controlling the morphology of Mn-MOF can be achieved. After calcination of Mn-MOF with different morphologies, we can obtain MnO/C composites with different morphologies. Materials synthesized using MOF as a precursor have the advantages of large specific surface area, abundant pores, and appropriate pore size ratio, which can increase the intercalation sites of lithium ions and increase the reversible capacity. At the same time, its porous structure can inhibit the charging and discharging process of metal oxide materials. The volume expansion in the electrode is conducive to the improvement of the cycle stability of the electrode. The principle of the present invention is not only applicable to Mn-MOF, but also applicable to MOF materials of other metals, and the morphology is not limited to the types mentioned later in the present invention.

In a word, the present invention regulates the morphology of the product by controlling the order of addition and the ratio of monodentate ligands and metal ions. Because the monodentate ligand first occupies the coordination site on the metal ion, and the addition ratio is controlled according to the need to determine how many sites are occupied, and then the multidentate ligand is added to occupy the remaining coordination sites. On the basis of understanding the principle of action, the method of the present invention can be applied to the reactions of other metal ions, monodentate ligands and multidentate ligands.

Advantages and positive effects of the present invention

The present invention has following salient features:

1): The present invention proposes a space-confined assembly method, through controlling the morphology of MOF precursors, to achieve the purpose of controlling the morphology of MO _x /C, and to provide researchers with new ideas for controlling the morphology of materials.

2): The morphology control method proposed by the present invention has simple flow, convenient operation and is suitable for large-scale production. At the same time, this method can prepare a large number of porous MO _x /C composites with high specific surface area.

3): Since metal ions are uniformly dispersed in organic ligands in MOF, metal oxides can be uniformly embedded in the conductive network of carbon after high-temperature calcination, which is beneficial to improve the electronic conductivity of the material. At the same time, the abundant pores of the material can better inhibit the volume expansion of the material during the process of lithium intercalation and deintercalation. Therefore, MO _x /C composites prepared by this method can obtain excellent electrochemical performance.

Positive effect of the present invention:

The space-confined assembly method proposed by the invention can provide researchers with new ideas for designing and controlling the shape and structure of materials. At the same time, it provides a reference for studying the influence of morphology and structure on the electrochemical performance of materials, and this method can also be extended to some fields that pay more attention to the morphology of materials. Considering that there are many types of MOFs and metal oxides, this space-confined assembly method has good application prospects.

Description of drawings

Figure 1 is a schematic diagram of the principle of regulating the morphology of the Mn-MOF precursor by taking benzoic acid as a monodentate ligand and terephthalic acid as a multidentate ligand as an example in the present invention;

Figure 2(a), (b), (c) and (d) are the SEM images of the Mn-MOF precursors prepared in Example 1, Example 2, Example 3 and Example 4, respectively;

Fig. 3 is the XRD pattern that embodiment 1, example 2, example 3 and example 4 prepare MnO/C material;

Figure 4 is a TEM image of the MnO/C material prepared in Example 4.

detailed description

The present invention will be further described below by way of examples, rather than limiting the present invention.

Example 1: Weigh 1.354g of manganese acetate and 2.75g of terephthalic acid, dissolve them in 50ml of dimethylformamide (in DMF), transfer them into a 100ml hydrothermal reactor, and heat and stir at 180°C for 10h. The reacted product was centrifuged, washed twice with absolute ethanol and deionized water, dried in an oven, and ground to obtain a white MOF precursor, which was designated as MOF-Mn(PTA)B ₀ . The above white precursor was placed in a tube furnace filled with Ar gas flow, calcined at 600°C for 2h, and then naturally cooled to room temperature to obtain MnO-B ₀ /C material. Figure 1a records the SEM image of the precursor MOF-Mn(PTA)B _0. It can be seen that MOF-Mn(PTA)B ₀ has a parallelepiped shape with a size of about 5 μm. Figure 2 records the XRD pattern of MnO-B ₀ /C. It can be seen from the figure that the material phase is mainly MnO, and contains a small amount of Mn ₃ O ₄ impurity phase. Table 1 records the BET specific surface area test results. It can be seen that the specific surface area of this material is as high as 216m ² ·g ^-1 , and the pore size is 10-20nm.

The active material, acetylene black and polyvinylidene fluoride (PVDF) were weighed in a mass ratio of 8:1:1, mixed evenly, and then dropped into a few drops of N-methylpyrrolidone (NMP) to grind it into a slurry, and coated on Put it on the copper foil, dry it in a vacuum drying oven at 100°C for 12 hours, and then cut it into disc-shaped electrode pieces with a punching machine. The electrode pole piece is used as the positive electrode, the lithium sheet is used as the counter electrode, the mixed solvent of 1 mol/L LiPF ₆ (EC:DEC=1:1 volume ratio) is used as the electrolyte, and the polypropylene microporous membrane is used as the separator. A CR2016 button cell was assembled in an atmosphere glove box. Table 2 records that the battery has a reversible capacity of 310mAh·g ^-1 at a current density of 0.3Ag ^-1 and a capacity of 532mAh·g ^-1 after 50 cycles.

Example 2

Weigh 1.354g of manganese acetate and 0.674g of benzoic acid and dissolve them in 50ml of DMF. After stirring overnight, add 2.018g of terephthalic acid, transfer to a 100ml hydrothermal reactor, and heat and stir at 180°C for 10h. The reacted product was centrifuged, washed twice with absolute ethanol and deionized water, dried in an oven, and ground to obtain a white MOF precursor, which was designated as MOF-Mn(PTA)B ₁ . The above white precursor was placed in a tube furnace, calcined at 600° C. for 2 h in an argon atmosphere, and then cooled naturally to room temperature to obtain MnO—B ₁ /C. The SEM of the precursor MOF-Mn(PTA)B ₁ is shown in Figure 1b. It can be seen that MOF-Mn(PTA)B ₁ is in the shape of a micron sheet with a length of 3 μm and a width of 0.8 μm. Figure 2 records the XRD pattern of MnO-B ₁ /C. It can be seen from the figure that the material phase is mainly MnO, and contains a small amount of Mn ₃ O ₄ impurity phase. See Example 1 for battery assembly and electrochemical performance testing. Table 1 records the BET specific surface area test results of the MnO-B ₁ /C material. It can be seen that the specific surface area of the material is as high as 220m ² ·g ^-1 , and the pore size is 10-20nm. After preparing the pole piece and assembling the battery according to Example 1, the test was carried out. Table 2 records that the first reversible capacity of the battery is 740mAh·g ^-1 at a current density of 0.3Ag ^-1 , and the capacity after 50 cycles is 631mAh·g ^-1 .

Example 3

Weigh 1.354g of manganese acetate and 1.348g of benzoic acid and dissolve in 50ml of DMF. After stirring overnight, add 1.834g of terephthalic acid, transfer to a 100ml hydrothermal reactor, and heat and stir at 180°C for 10h. The reacted product was centrifuged, washed twice with absolute ethanol and deionized water, dried and ground to obtain a white MOF precursor, which was designated as MOF-Mn(PTA)B ₂ . The obtained white precursor was placed in a tube furnace filled with Ar gas, calcined at 600°C for 2h, and then naturally cooled to room temperature to obtain a MnO/C material which was designated as MnO-B ₂ /C. Figure 1c records the SEM image of the precursor MOF-Mn(PTA)B _2. It can be seen that MOF-Mn(PTA)B ₂ is in the shape of a micron sheet, with a length of about 3 μm and a width of about 0.9 μm, but the thickness should be obvious smaller than MOF-Mn(PTA)B ₁ . Figure 2 records the XRD pattern of MnO-B ₂ /C, it can be seen that the material phase is mainly MnO, and contains a small amount of Mn ₃ O ₄ heterophase. See Example 1 for battery assembly and electrochemical performance testing. Table 1 records the BET specific surface area test results. It can be seen that the specific surface area of this material is as high as 219m ² ·g ^-1 , and the pore size is 10-20nm. After preparing the pole piece and assembling the battery according to Example 1, the test was carried out. Table 2 records that the first reversible capacity of the battery at a current density of 0.3Ag ^-1 is 775mAh·g ^-1 , and the capacity after 50 cycles is 869mAh·g ^-1 .

Example 4

Weigh 1.354g of manganese acetate and 2.696g of benzoic acid and dissolve in 50ml of DMF. After stirring overnight, add 0.917g of terephthalic acid, transfer to a 100ml hydrothermal reactor, and heat and stir at 180°C for 10h. The reacted product was centrifuged, washed twice with absolute ethanol and deionized water, dried and ground to obtain a white MOF precursor, which was designated as MOF-Mn(PTA)B ₄ . The white precursor obtained above was placed in a tube furnace filled with Ar gas, calcined at 600°C for 2h, and then cooled naturally to room temperature to obtain MnO/C, which was denoted as MnO-B ₄ /C. Figure 1c records the SEM image of the precursor MOF-Mn(PTA)B _4. It can be seen that MOF-Mn(PTA)B ₄ is in the shape of microrods with a length of 4 μm and a width of 0.3 μm. Figure 2 records the XRD pattern of MnO-B ₄ /C, it can be seen that the material phase is mainly MnO, and contains a small amount of Mn ₃ O ₄ heterophase. Figure 2 shows its TEM image. It can be seen that the calcined MnO-B ₄ /C maintains the morphology of the MOF-Mn(PTA)B ₄ precursor, and is still a microrod with a length of 3-4 μm and a width of 0.2-0.3 μm. See Example 1 for battery assembly and electrochemical performance testing. Table 1 records the BET specific surface area test results. It can be seen that the specific surface area of this material is as high as 309m ² ·g ^-1 , and the pore size is 10-20nm. After preparing the pole piece and assembling the battery according to Example 1, the test was carried out. Table 2 records that the first reversible capacity of the battery is 1165mAh·g ^-1 at a current density of 0.3Ag ^-1 , and the capacity after 50 cycles is 1120mAh·g ^-1 .

Example 5

Weigh 1.354g of manganese acetate and 0.93g of NaF and dissolve it in 50ml of DMF. After stirring overnight, add 0.917g of terephthalic acid, transfer to a 100ml hydrothermal reactor, and heat and stir at 190°C for 10h. The reacted product was centrifuged, washed twice with absolute ethanol and deionized water, dried and ground to obtain a white MOF precursor. The white precursor obtained above was placed in a tube furnace, calcined at 700 °C for 5 h in an Ar gas atmosphere, and then naturally cooled to room temperature to obtain MnO/C, which was denoted as MnO-F/C. Table 1 records the BET specific surface area test results. It can be seen that the specific surface area of this material is as high as 280m ² ·g ^-1 , and the pore size is 10-20nm. See Example 1 for battery assembly and electrochemical performance testing. Table 2 records that the first reversible capacity of the battery at a current density of 0.3Ag ^-1 is 1052mAh·g ^-1 , and the capacity after 50 cycles is 1021mAh·g ^-1 .

Example 6

Weigh 2.28g of cobalt nitrate and 2.696g of benzoic acid and dissolve it in 50ml of DMF. After stirring overnight, add 0.917g of terephthalic acid, transfer to a 100ml hydrothermal reaction kettle, and heat and stir at 180°C for 10h. The reacted product was centrifuged, washed twice with absolute ethanol and deionized water, dried and ground to obtain a white MOF precursor. The white precursor obtained above was placed in a tube furnace, calcined at 800° C. for 2 h under N ₂ gas atmosphere, and then naturally cooled to room temperature to obtain a CoO _x /C material. Table 1 records the BET specific surface area test results. It can be seen that the specific surface area of this material is as high as 260m ² ·g ^-1 , and the pore size is 10-20nm. See Example 1 for battery assembly and electrochemical performance testing. Table 2 records that the first reversible capacity of the battery is 1010mAh·g ^-1 at a current density of 0.3Ag ^-1 , and the capacity after 50 cycles is 921mAh·g ^-1 .

Example 7

Weigh 1.354g of manganese acetate and 2.696g of benzoic acid and dissolve them in 50ml of DMF. After stirring overnight, add 0.917g of terephthalic acid, transfer to a 100ml hydrothermal reactor, and heat and stir at 160°C for 24h. The reacted product was centrifuged, washed twice with absolute ethanol and deionized water, dried and ground to obtain a white MOF precursor. The white precursor obtained above was placed in a tube furnace, calcined at 650 °C in an Ar/H ₂ mixed atmosphere (H ₂ volume fraction 8%) for 3 h, and then naturally cooled to room temperature to obtain a MnO/C material. Table 1 records the BET specific surface area test results. It can be seen that the specific surface area of this material is as high as 301m ² ·g ^-1 , and the pore size is 10-20nm. See Example 1 for battery assembly and electrochemical performance testing. Table 2 records that the first reversible capacity of the battery is 1105mAh·g ^-1 at a current density of 0.3Ag ^-1 , and the capacity after 50 cycles is 1012mAh·g ^-1 .

Example 8

Weigh 1.354g of manganese acetate and 2.696g of benzoic acid and dissolve them in 50ml of ethanol. After stirring overnight, add 0.917g of terephthalic acid, transfer to a 100ml hydrothermal reactor, and heat and stir at 150°C for 18h. The reacted product was centrifuged, washed twice with absolute ethanol and deionized water, dried and ground to obtain a white MOF precursor. The white precursor obtained above was placed in a tube furnace, calcined at 800 °C in an Ar/H ₂ mixed atmosphere (H ₂ volume fraction 5%) for 2 h, and then naturally cooled to room temperature to obtain a MnO/C material. Table 1 records the BET specific surface area test results. It can be seen that the specific surface area of this material is as high as 202m ² ·g ^-1 , and the pore size is 10-20nm. See Example 1 for battery assembly and electrochemical performance testing. Table 2 records that the first reversible capacity of the battery is 1042mAh·g ^-1 at a current density of 0.3Ag ^-1 , and the capacity after 50 cycles is 958mAh·g ^-1 .

Example 9

Weigh 1.4g of ferrous acetate and 0.391g of NaCN and dissolve in 50ml of ethylene glycol, stir overnight, add 1.50g of ethylenediamine, transfer to a 100ml hydrothermal reaction kettle, heat and stir at 180°C for 18h. The reacted product was centrifuged, washed twice with absolute ethanol and deionized water, dried and ground to obtain a white MOF precursor. The white precursor obtained above was placed in a tube furnace, calcined at 600 °C in an Ar/H ₂ mixed atmosphere (H ₂ volume fraction 5%) for 2 h, and then naturally cooled to room temperature to obtain a FeO/C material. Table 1 records its BET specific surface area test results, it can be seen that the specific surface area of this material is up to 198m ² ·g ^-1 , and the pore size is 10-20nm. See Example 1 for battery assembly and electrochemical performance testing. Table 2 records that the first reversible capacity of the battery is 623mAh·g ^-1 at a current density of 0.3Ag ^-1 , and the capacity after 50 cycles is 651mAh·g ^-1 .

Example 10

Weigh 1.83g of zinc acetate and 1.60g of benzoic acid and dissolve in 50ml of DMF, stir overnight, add 3.12g of ethylenediamine, transfer to a 100ml hydrothermal reactor, heat and stir at 180°C for 18h. The reacted product was centrifuged, washed twice with absolute ethanol and deionized water, dried and ground to obtain a white MOF precursor. The white precursor obtained above was placed in a tube furnace, calcined at 600°C in an Ar/H ₂ mixed atmosphere (H ₂ volume fraction 5%) for 2 h, and then naturally cooled to room temperature to obtain a ZnO/C material. Table 1 records its BET specific surface area test results, it can be seen that the specific surface area of the material is up to 212m ² ·g ^-1 , and the pore size is 10-20nm. See Example 1 for battery assembly and electrochemical performance testing. Table 2 records that the initial reversible capacity of the battery is 517mAh·g ^-1 at a current density of 0.3Ag ^-1 , and the capacity after 50 cycles is 501mAh·g ^-1 .

Table 1 records the BET specific surface area and pore size distribution of MO _x /C materials prepared in Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, Example 9 and Example 10 respectively data.

Table 2 respectively records the first reversible capacity and 50 times of MO _x /C materials prepared in Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, Example 8, Example 9 and Example 10 Reversible capacity after cycling.

Table 1

Table 2

Claims (10)

1. A method for controlling the morphology of metal oxide/carbon negative electrode materials for lithium ion batteries, characterized in that, Dissolve the metal ion source and a certain proportion of monodentate ligands in the solvent by controlling the feeding sequence, and then add the multidentate ligands after stirring sufficiently, and obtain the MOF precursor after reacting at a certain temperature for a period of time; also by adjusting the monodentate ligands The ratio of the precursor and the metal ion is used to control the morphology of the product, and the precursor is sintered in an inert or reducing atmosphere to obtain the MO _x /C composite material. 2. The method for controlling the morphology of metal oxide/carbon negative electrode materials for lithium ion batteries according to claim 1, wherein the metal ion source is: manganese, iron, cobalt, nickel, copper, zinc Acetates; hydrochlorides of manganese, iron, cobalt, nickel, copper, zinc; nitrates of manganese, iron, cobalt, nickel, copper, zinc; sulfates of manganese, iron, cobalt, nickel, copper, zinc one or more of. 3. The method for regulating the morphology of metal oxide/carbon negative electrode materials for lithium ion batteries according to claim 1, wherein the monodentate ligands are: benzoate, phenylacetate, acetate, One or more of F ^- , NH ₃ , CN ^- ; the bidentate ligands are: terephthalate, phthalate, trimesate, oxalic acid, ethylenediamine , one or more of oxalate, bipyridine, ethylenediaminetetraacetate, salicylaldehyde. 4. The method for regulating the morphology of the metal oxide/carbon negative electrode material for lithium ion batteries according to claim 1, wherein the molar ratio of the monodentate ligand to the metal ion ≤ the maximum value of the metal center ion to the ligand Coordination number -2. 5. the morphology control method of metal oxide/carbon negative electrode material for lithium ion battery according to claim 1, is characterized in that, with manganese as metal ion source, benzoic acid is monodentate ligand, and terephthalic acid is Multi-dentate ligands, control the molar ratio of Mn:benzoic acid to 1:(1~4) to control the morphology. 6. the morphology control method of metal oxide/carbon negative electrode material for lithium ion battery according to claim 1, is characterized in that, described solvent is: dimethyl formamide, water, ethylene glycol, ethanol, One or more of propanol, hexanediol, and chloroform. 7. The morphology control method of metal oxide/carbon negative electrode material for lithium ion battery according to claim 1, characterized in that, the certain reaction temperature is: 50～200°C, and the reaction time is: 3-48h . 8. the morphology regulation and control method of metal oxide/carbon negative electrode material for lithium ion battery according to claim ₁ , is characterized in that, described inert gas is: pure Ar gas, N Gas or H _The mixture of Ar and Ar Mixed gas, the reducing gas is a mixed gas of CO and CO2 _; the volume fraction of _H2 in the mixed gas of _H2 and Ar is 3-20%; the volume fraction of CO in the mixed gas of CO and _CO2 is 5% ~20%. 9. The method for regulating the morphology of metal oxide/carbon negative electrode materials for lithium ion batteries according to claim 1, characterized in that, the sintering temperature: 500～1000°C, the sintering time: 1～10h; heating rate For: 1 ~ 15 ℃ / min. 10. A metal oxide/carbon negative electrode material for lithium ion batteries, characterized in that it is prepared by the method according to any one of claims 1-9.