CN112838207A

CN112838207A - Carbon-coated MnO-Co particles and preparation method and application thereof

Info

Publication number: CN112838207A
Application number: CN202110016799.3A
Authority: CN
Inventors: 林晓明; 林佳; 许旋; 罗一帆
Original assignee: South China Normal University
Current assignee: South China Normal University
Priority date: 2021-01-07
Filing date: 2021-01-07
Publication date: 2021-05-25
Anticipated expiration: 2041-01-07
Also published as: CN112838207B

Abstract

The invention discloses a carbon-coated MnO-Co particle and a preparation method and application thereof. The carbon-coated MnO-Co particles comprise a plurality of MnO nano particles and a plurality of Co nano particles which are stacked and encapsulated in a carbon layer, nitrogen-doped carbon nano tubes growing on the carbon layer and oxygen vacancies distributed in the MnO nano particles, and the preparation method comprises the following steps: 1) carrying out coprecipitation reaction of manganese salt and potassium cobalt cyanide to prepare Mn-Co-MOF; 2) pretreating Mn-Co-MOF by ammonia water to obtain Mn-Co-MOF-N; 3) and calcining the Mn-Co-MOF-N in a protective atmosphere. The carbon-coated MnO-Co particles have high density and good conductivity, and when used as the negative electrode material of the lithium ion battery, the carbon-coated MnO-Co particles have the advantages of excellent rate capability, excellent high-temperature cycle performance, small volume expansion effect, small capacity attenuation and the like, and the preparation process is simple and is suitable for large-area application.

Description

Carbon-coated MnO-Co particles and preparation method and application thereof

Technical Field

The invention relates to the technical field of electrode materials, in particular to carbon-coated MnO-Co particles capable of being used as a lithium ion battery cathode material.

Background

Lithium Ion Batteries (LIBs) have high energy density and long cycle life, and have become mainstream Energy Storage Systems (ESSs) for storing energy in electronics, automobiles and power grids, wherein the electrode material technology is the core technology. Lithium titanate and graphite are negative electrode materials that have been commercially used in large areas at present, but in view of their limitations in electrochemical properties, many researchers have been working on developing more excellent negative electrode materials for lithium ion batteries.

The Transition Metal Oxides (TMOs) have the advantages of environmental friendliness, abundant natural sources, high theoretical capacity and the like, and are potential negative electrode materials capable of replacing lithium titanate and graphite. However, the transition metal oxide has the defects of poor conductivity, obvious volume expansion effect, fast capacity fading, poor cycle stability and the like, so that the practical application is greatly limited. Research shows that the conductivity of the obtained negative electrode material is enhanced and the volume expansion effect is reduced by combining the transition metal oxide with one-dimensional high-conductivity carbon materials (such as carbon nanotubes and carbon fibers) or depositing the transition metal oxide on a carbon substrate (such as graphene and carbon cloth), but the conductive slurry prepared from the negative electrode material is easy to phase separate during coating, drying and long-period circulation, and finally the utilization rate of the material is low, the conductivity is poor, the electrochemical resistance is large, and the practical application cannot be carried out.

Therefore, it is required to develop a negative electrode material having a small capacity degradation, an excellent rate capability, and a good high-temperature cycle performance.

Disclosure of Invention

It is an object of the present invention to provide carbon-coated MnO-Co particles.

The second object of the present invention is to provide a method for producing the above carbon-coated MnO-Co particles.

The invention also aims to provide application of the carbon-coated MnO-Co particles.

The technical scheme adopted by the invention is as follows:

a carbon-coated MnO-Co particle comprising a composition including a plurality of MnO nanoparticles and a plurality of Co nanoparticles stacked and encapsulated within a carbon layer, a nitrogen-doped carbon nanotube grown on the carbon layer, and oxygen vacancies distributed in the MnO nanoparticles.

Preferably, the carbon-coated MnO-Co particles have a particle size of 0.8 μm to 2 μm.

The preparation method of the carbon-coated MnO-Co particle comprises the following steps:

1) carrying out coprecipitation reaction of manganese salt and potassium cobalt cyanide to obtain Mn-Co-MOF;

2) pretreating Mn-Co-MOF by ammonia water to obtain Mn-Co-MOF-N;

3) and calcining the Mn-Co-MOF-N in a protective atmosphere to obtain the carbon-coated MnO-Co particles.

Preferably, the preparation method of the carbon-coated MnO-Co particles comprises the following steps:

1) dispersing manganese salt and potassium cobalt cyanide in water, and carrying out coprecipitation reaction to obtain Mn-Co-MOF;

2) dispersing Mn-Co-MOF in a mixed solution consisting of ammonia water, ethanol and water, and standing to obtain Mn-Co-MOF-N;

3) and (2) putting the Mn-Co-MOF-N in a protective atmosphere, heating to 650-750 ℃ at the speed of 1-3 ℃/min, and calcining at constant temperature to obtain the carbon-coated MnO-Co particles.

Further preferably, the preparation method of the carbon-coated MnO-Co particles comprises the following steps:

1) slowly adding a manganese salt solution into a potassium cobalt cyanide solution, stirring, carrying out a coprecipitation reaction, and then aging to obtain Mn-Co-MOF;

Preferably, the molar ratio of the manganese salt to the potassium cobalt cyanide in the step 1) is 1.2: 1-1.6: 1.

Preferably, the manganese salt in step 1) is at least one of manganese chloride, manganese sulfate and manganese nitrate.

Preferably, the standing time in the step 2) is 10-15 h.

Preferably, the protective atmosphere in step 3) is an argon atmosphere or a nitrogen atmosphere.

Preferably, the calcining time in the step 3) is 1-3 h.

The invention has the beneficial effects that: the carbon-coated MnO-Co particles have high density and good conductivity, and when used as the negative electrode material of the lithium ion battery, the carbon-coated MnO-Co particles have the advantages of excellent rate capability, excellent high-temperature cycle performance, small volume expansion effect, small capacity attenuation and the like, and the preparation process is simple and is suitable for large-area application.

Drawings

FIG. 1 is an SEM photograph of Mn-Co-MOF-N in example 1.

FIG. 2 is an XRD pattern of Mn-Co-MOF-N in example 1.

FIG. 3 shows O in example 1_VSEM pictures of MnO/Co NCPs.

FIG. 4 shows O in example 1_VTEM images of MnO/Co NCPs.

FIG. 5 shows O in example 1_VHRTEM image of MnO/Co NCPs.

FIG. 6 shows O in example 1_VSAED spectrum of MnO/Co NCPs.

FIG. 7 shows O in example 1_VEDS elemental map of Co, Mn, O, C and N associated with MnO/Co NCPs.

FIG. 8 shows O in example 1_VXRD patterns of MnO/Co NCPs.

FIG. 9 shows O in example 1_VRaman spectra of MnO/Co NCPs.

FIG. 10 shows O in example 1_VXPS survey of MnO/Co NCPs.

FIG. 11 shows O in example 1_V Mn 2p high resolution XPS spectra of MnO/Co NCPs.

FIG. 12 shows O in example 1_V Co 2p high resolution XPS spectra of MnO/Co NCPs.

FIG. 13 shows O in example 1_VHigh resolution XPS spectrum of N1s of MnO/Co NCPs.

FIG. 14 shows O in example 1_VHigh resolution XPS spectrum of O1s for MnO/Co NCPs.

FIG. 15 shows O in example 1_VHigh resolution XPS spectrum of C1s for MnO/Co NCPs.

FIG. 16 shows O in example 1_VEPR spectra of MnO/Co NCPs.

FIG. 17 shows O in example 1_VNitrogen adsorption-desorption curves and pore size profiles for MnO/Co NCPs.

FIG. 18 shows O in example 1_VCV curves of MnO/Co NCPs three cycles before sweep at 0.1 mV/s.

FIG. 19 is a charge/discharge curve at a current density of 1A/g for OV-MnO/Co NCPs in example 1.

FIG. 20 shows O in example 1_VCyclic stability test patterns of MnO/Co NCPs electrodes at a current density of 1A/g.

FIG. 21 shows O in example 1_VSEM image of section of MnO/Co NCPs pole piece.

FIG. 22 shows O in example 1_V-MnO/Co NCPs electrode rate capability test chart under different current density (0.1-10A/g).

FIG. 23 shows O in example 1_V-MnO/Co NCPs electrode cycling stability test pattern at a current density of 1A/g in a temperature environment of 50 ℃.

Detailed Description

The invention will be further explained and illustrated with reference to specific examples.

Example 1:

a carbon-coated MnO-Co particle is prepared by the following steps:

1) dispersing 4.5mmol of tetrahydrate manganese chloride in 40mL of deionized water to prepare a manganese chloride solution, dispersing 3mmol of potassium cobalt cyanide in 40mL of deionized water to prepare a potassium cobalt cyanide solution, slowly adding the manganese chloride solution into the potassium cobalt cyanide solution, stirring for 30min, aging at room temperature for 24h, centrifuging, washing the centrifuged solid with deionized water for 3 times, and vacuum-drying at 70 ℃ for 24h to obtain Mn-Co-MOF;

2) dispersing Mn-Co-MOF in a mixed solution consisting of 4mL of ammonia water, 28mL of ethanol and 28mL of deionized water, standing for 12h, centrifuging, washing the centrifuged solid with deionized water for 3 times, and vacuum-drying at 70 ℃ for 24h to obtain Mn-Co-MOF-N;

3) putting Mn-Co-MOF-N in nitrogen atmosphere, heating to 700 ℃ at the speed of 1 ℃/min, and calcining at constant temperature for 2h to obtain carbon-coated MnO-Co particles (marked as O)_V-MnO/Co NCPs)。

And (3) performance testing:

1) the SEM picture of Mn-Co-MOF-N is shown in figure 1, and the XRD picture is shown in figure 2.

As can be seen from fig. 1 and 2: the Mn-Co-MOF-N is in a uniform micron polyhedron shape, the particle size is 0.8-2 mu m, and the purity is high.

2)O_VSEM of-MnO/Co NCPs is shown in FIG. 3, TEM is shown in FIG. 4, HRTEM is shown in FIG. 5, SAED is shown in FIG. 6, and EDS elemental map is shown in FIG. 7 (all scales in the figure represent 1 μm).

As can be seen from fig. 3: o is_VThe MnO/Co NCPs maintain the morphology of the Mn-Co-MOF-N micro-polyhedron, the particle size is 0.8-2 mu m, the micro-polyhedron is formed by stacking a plurality of nano-particles with relatively rough surfaces, and one-dimensional self-derived carbon nano-tubes grow on the outer surface of the micro-polyhedron randomly.

As can be seen from fig. 4: MnO nano-particles and Co nano-particles are encapsulated in the carbon layer of the polyhedron, and a multi-layer micro/nano structure is integrally formed.

As can be seen from fig. 5: some Co nanoparticles were dispersed on top of about 4nm thick CNT, 0.20nm lattice fringes correspondedIn the (111) crystal plane of Co; o is_VThe (200) lattice spacing of MnO in MnO/Co NCPs is enlarged from 0.22nm to 0.25nm, which is attributable to the introduction of oxygen vacancies.

As can be seen from fig. 6: main diffraction ring and O in corresponding annular Selected Area Electron Diffraction (SAED) spectrogram_VThe (111) crystal plane of Co in MnO/Co NCPs and the (300), (113) and (112) crystal planes of MnO are well matched.

As can be seen from fig. 7: o is_VHomogeneous distribution of Co, Mn, O, C and N elements in-MnO/Co NCPs, proving that O is present_VSuccessful construction of MnO/Co NCPs.

3)O_VThe XRD pattern of-MnO/Co NCPs is shown in FIG. 8, and the Raman spectrum is shown in FIG. 9.

As can be seen from fig. 8: typical diffraction peaks at 34.9 °, 40.6 °, 58.7 ° and 70.2 ° with

The (111), (200), (220) and (311) crystal planes of the cubic MnO phase of the space group (JCPDS No. 77-2363) are matched, and the crystal diffraction peaks at 44.2 deg., 51.5 deg. and 75.9 deg. correspond to the (111), (200) and (220) crystal planes of cubic metallic Co (JCPDS No. 89-4307).

As can be seen from fig. 9: 1345cm^-1And 1587cm^-1Two sp at which the characteristic peaks are respectively designated as disordered carbons³(D band) and sp of graphitic carbon²(G band); o is_VI of MnO/Co NCPs_D/I_GA strength of 1.46, indicating that the presence of high disorder and defects of carbon in the material is effective in improving electron conductivity and mitigating exfoliation of MnO and inevitable volume expansion; at 648cm^-1The vibration peak at (a) is correlated with the Mn — O vibration mode.

4)O_VThe XPS survey of-MnO/Co NCPs is shown in FIG. 10, the Mn 2p high resolution XPS spectrum is shown in FIG. 11, the Co 2p high resolution XPS spectrum is shown in FIG. 12, the N1s high resolution XPS spectrum is shown in FIG. 13, the O1s high resolution XPS spectrum is shown in FIG. 14, the C1s high resolution XPS spectrum is shown in FIG. 15, and the EPR spectrum is shown in FIG. 16.

As can be seen from fig. 10: the prepared sample has the coexistence of Mn, Co, O, C and N elements.

As can be seen from fig. 11: the high resolution Mn 2p energy level spectrum can be split into two characteristic sub-peaks of 640.8eV and 652.7eV, which correspond to O_VMn in MnO/Co NCPs²⁺Related Mn 2p_3/2And Mn 2p_1/2。

As can be seen from fig. 12: characteristic peaks at 778.4eV and 793.8eV in the high-resolution Co 2p level spectrum can be assigned to Co 2p_3/2And Co 2p_1/2Prove that metallic Co⁰Is present.

As can be seen from fig. 13: the high-resolution N1s energy level spectrum can be split into three sub-peaks of graphite nitrogen (401.1eV), pyrrole nitrogen (399.6eV) and pyridine nitrogen (398.4eV), wherein the graphite nitrogen with more electrons can effectively optimize the electronic structure, and the inner part sp of the carbon lattice²Carbon is substituted to improve conductivity.

As can be seen from fig. 14: the high resolution O1s level spectrum can be divided into four peaks corresponding to C ═ O (533.8eV), C — O (532.1eV), Mn — O (529.9eV), and vacancy oxygen (531.0eV), further indicating successful introduction of oxygen vacancies.

As can be seen from fig. 15: the three sub-peaks in the high resolution C1s energy level spectrum can be assigned to graphitic carbon, O-C ═ O, and C-N bond correlations.

As can be seen from fig. 16: o is_VThe appearance of characteristic signals at g 2.003 from oxygen vacancy formation in MnO/Co NCPs systematically confirms O_VAbundant oxygen vacancies in MnO/Co NCPs.

5)O_VThe nitrogen adsorption-desorption curves and the pore size distribution profiles of the-MnO/Co NCPs are shown in FIG. 17.

As can be seen from fig. 17: o due to high porosity of MOF precursors and gas evolution during carbonization_VN at 77K of MnO/Co NCPs₂The adsorption/desorption isotherm exhibits typical type III adsorption/desorption characteristics; o is_VThe Brunauer-Emmett-Teller (BET) surface areas of the-MnO/Co NCPs reach 120.8m²The pore diameter is mainly distributed in the range of 1nm to 180 nm; o is_VThe multilevel micro-mesoporous structure of MnO/Co NCPs provides a shorter diffusion path for charge transfer, more contact area between an electrode and electrolyte, relieves the volume expansion effect, and accelerates the lithium ionDiffusion dynamics of the cell in the process of lithium intercalation/deintercalation, and Li is reduced⁺Diffusion resistance, which in turn contributes to excellent rate performance.

6) By assembling a CR2032 button cell, O was studied in full_VLithium storage Properties of MnO/Co NCPs O at a scan rate of 0.1mV/s between 0.01V and 3.0V_VThe cyclic voltammograms of the initial three cycles of the-MnO/Co NCPs are shown in FIG. 18, the galvanostatic charge/discharge (GCD) curves at different cycles of activation at 0.05A/g current density followed by 1A/g current density are shown in FIG. 19, O_VThe cyclic stability test chart of the-MnO/Co NCPs electrode at a current density of 1A/g is shown in FIG. 20, O_VSEM images of the cross section of the-MnO/Co NCPs pole pieces are shown in FIG. 21.

As can be seen from fig. 18: at O_VIn the first anodic scan of MnO/Co NCPs, the peak at 0.62V corresponds to irreversible decomposition of the electrolysis and formation of the solid electrolyte interface film (SEI), but disappears in the subsequent cycles; reduction peaks below 0.28V were assigned to Mn²⁺Reduction to Mn⁰And Li₂Formation of O, Mn in subsequent cycles due to increased reaction rate and structural reconstruction of the active material after the first cycle²⁺The reduction peak of (a) shifts to about 0.46V; oxidation peak at 1.30V with Mn during oxidation⁰To Mn²⁺The conversion reaction of (1) is related; from the second cycle on, the CV curves overlap each other, indicating O_VReversibility of MnO/Co NCPs transitions; meanwhile, a representative redox peak of Co species was observed at 2.05V during the cathodic scan, indicating that part of the Co was gradually activated and involved in the entire electrochemical reaction during this cycle, providing advantageous additional capacity.

As can be seen from fig. 19: the lithium insertion/removal behavior of the GCD curve at low current density is identical to the CV result, revealing lower voltage hysteresis and accelerated kinetics after initial cycling; o is_VMnO/Co NCPs showed initial discharge/charge capacity of 1637.7/2124.2mAh/g, corresponding to an Initial Coulombic Efficiency (ICE) of 77.1%; irreversible capacity loss results from the formation of SEI films and decomposition of the electrolyte, which is unavoidable for the conversion reaction type mechanism TMO anode materialFree; o is_VThe coulombic efficiency of the MnO/Co NCPs electrodes rapidly recovers to 100% in subsequent cycles, due to the gradual stabilization of the SEI; thanks to the multilayer micro/nano structure, appropriate specific surface area and abundant Ov, sufficient contact between the electrolyte and the active substance is ensured, side reaction is reduced, and O is facilitated_VExcellent electrochemical performance of MnO/Co NCPs; with the proceeding of lithium intercalation/deintercalation, O_VMnO/Co NCPs show a discharge plateau at about 0.75V and a charge plateau at about 2.05V, which can be attributed to the transition between Co and CoO. It is thus understood that after a long-term activation process, the metal Co in the electrode participates in the lithium storage process and contributes to the increase of O_V-discharge capacity of MnO/Co NCPs materials.

As can be seen from fig. 20: o is_VThe MnO/Co NCPs can maintain a specific capacity of 1349.2mAh/g and 1713.5mAh/cm after being cycled for 1000 times under a current density of 1A/g³The volume to capacity ratio of; compared with the sixth cycle, the capacity retention rate is 96.3%, and the cycle stability and the reversibility are shown; from the whole circulation process, the capacity which circulates for 1000 times can undergo a short-time attenuation (circulation of 6 th to 70 th), continuous increase (circulation of 70 th to 580 th) and stable long circulation process; the decline in capacity stems from SEI formation and structural reconstruction of the electrode, and the increase in capacity can be attributed to improved conductivity, mitigated volume expansion effects, and gradual activation of Co and MnO components; the introduction of Ov significantly enhances the reversible capacity and cycling stability of the electrode cycling due to enhanced electron conductivity and diffusion kinetics; furthermore, O_VThe carbonaceous micro-polyhedron assembled by MnO/Co NCPs multilayer carbon nanotubes and the nano-particles with the internal structure form a 3D diffusion path and provide enough active reaction sites, the volume change in the long-cycle process is relieved by proper porosity and micro/nano structure, and the corresponding specific volume capacity is calculated by the following method:

O_Vvolumetric specific capacity (C) of the electrodes of MnO/Co NCPs_v) Can be represented by formula C_v＝C_gX rho is calculated, wherein C_gIs the mass specific capacity, and ρ is the pole piece density. P is again defined by p ═ m_arealCalculated as/TT is the thickness of the active material of the pole piece measured by SEM sectional view, m_arealIs the loading of the pole piece.

As can be seen from fig. 21: o is_VThe thickness T of the-MnO/Co NCPs electrode was 21.2 μm and its specific mass capacity C was at 1A/g current density_gAnd area density m of pole piece_areal1349.2mAh/g and 2.7mg/cm respectively². Thus, calculate O_VVolumetric specific capacity C corresponding to the electrodes of MnO/Co NCPs_vIs 1713.5mAh/cm³。

7)O_VFIG. 22 shows the multiplying power performance test chart of-MnO/Co NCPs electrode under different current densities (0.1-10A/g), O_VThe cyclic stability test chart of the-MnO/Co NCPs electrode at a current density of 1A/g in a temperature environment of 50 ℃ is shown in FIG. 23.

As can be seen from fig. 22: o is_VMnO/Co NCPs show specific discharge capacities of 1469.1mAh/g, 1398.8mAh/g, 1302.3mAh/g, 1201.4mAh/g, 1100.7mAh/g and 882.5mAh/g at current densities of 0.1A/g, 0.2A/g, 0.5A/g, 1A/g, 2A/g and 5A/g, respectively, and have excellent rate capability; even if the current density reaches 10A/g, O_VMnO/Co NCPs can still maintain considerable specific discharge capacity of 670.2 mAh/g; when the current density is recovered to 0.1A/g, the capacity can be recovered to the initial value; the introduction of oxygen vacancy is expected to effectively promote ion diffusion, and simultaneously, the N-doped carbon layer and the metal Co have positive effects on improving the conductivity, so that O is further improved_VRate capability of MnO/Co NCPs.

As can be seen from fig. 23: after 750 cycles, O_VMnO/Co NCPs reach 1384.9mAh/g (the capacity retention rate is 86.3 percent relative to the initial capacity), which shows that the NCPs have a practical application prospect in power batteries.

Example 2:

a carbon-coated MnO-Co particle is prepared by the following steps:

1) dispersing 4.2mmol of tetrahydrate manganese chloride in 40mL of deionized water to prepare a manganese chloride solution, dispersing 3mmol of potassium cobalt cyanide in 40mL of deionized water to prepare a potassium cobalt cyanide solution, slowly adding the manganese chloride solution into the potassium cobalt cyanide solution, stirring for 30min, aging at room temperature for 24h, centrifuging, washing the centrifuged solid with deionized water for 3 times, and vacuum-drying at 70 ℃ for 24h to obtain Mn-Co-MOF;

2) dispersing Mn-Co-MOF in a mixed solution consisting of 4mL of ammonia water, 28mL of ethanol and 28mL of deionized water, standing for 14h, centrifuging, washing the centrifuged solid with deionized water for 3 times, and vacuum-drying at 70 ℃ for 24h to obtain Mn-Co-MOF-N;

3) and (3) putting the Mn-Co-MOF in a nitrogen atmosphere, heating to 700 ℃ at the speed of 2 ℃/min, and calcining at constant temperature for 1h to obtain the carbon-coated MnO-Co particles.

Tests show that the morphology and performance of the carbon-coated MnO-Co particles prepared in this example are very similar to those of the carbon-coated MnO-Co particles prepared in example 1.

Example 3:

a carbon-coated MnO-Co particle is prepared by the following steps:

1) dispersing 4.8mmol of tetrahydrate manganese chloride in 40mL of deionized water to prepare a manganese chloride solution, dispersing 3mmol of potassium cobalt cyanide in 40mL of deionized water to prepare a potassium cobalt cyanide solution, slowly adding the manganese chloride solution into the potassium cobalt cyanide solution, stirring for 30min, aging at room temperature for 24h, centrifuging, washing the centrifuged solid with deionized water for 3 times, and vacuum-drying at 70 ℃ for 24h to obtain Mn-Co-MOF;

2) dispersing Mn-Co-MOF in a mixed solution consisting of 4mL of ammonia water, 28mL of ethanol and 28mL of deionized water, standing for 10h, centrifuging, washing the centrifuged solid with deionized water for 3 times, and vacuum-drying at 70 ℃ for 24h to obtain Mn-Co-MOF-N;

3) and (3) putting the Mn-Co-MOF in a nitrogen atmosphere, heating to 750 ℃ at the speed of 2 ℃/min, and calcining at constant temperature for 2h to obtain the carbon-coated MnO-Co particles.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A carbon-coated MnO-Co particle comprising a composition including a plurality of MnO nanoparticles and a plurality of Co nanoparticles stacked and encapsulated within a carbon layer, a nitrogen-doped carbon nanotube grown on the carbon layer, and oxygen vacancies distributed in the MnO nanoparticles.

2. The carbon-coated MnO-Co particle of claim 1, wherein: the particle size of the carbon-coated MnO-Co particles is 0.8-2 μm.

3. The method of making carbon-coated MnO-Co particles of claim 1 or 2, comprising the steps of:

2) pretreating Mn-Co-MOF by ammonia water to obtain Mn-Co-MOF-N;

4. The method of making carbon-coated MnO-Co particles of claim 3, comprising the steps of:

5. The method of making carbon-coated MnO-Co particles of claim 3 or 4, wherein: the molar ratio of the manganese salt to the potassium cobalt cyanide in the step 1) is 1.2: 1-1.6: 1.

6. The method of making carbon-coated MnO-Co particles of claim 5, wherein: the manganese salt in the step 1) is at least one of manganese chloride, manganese sulfate and manganese nitrate.

7. The method of making carbon-coated MnO-Co particles of claim 3 or 4, wherein: and 3) the protective atmosphere is argon atmosphere or nitrogen atmosphere.

8. The method of making carbon-coated MnO-Co particles of claim 3 or 4, wherein: the calcining time in the step 3) is 1-3 h.

9. A lithium ion battery negative electrode material is characterized in that: comprising the carbon-coated MnO-Co particles of claim 1 or 2.

10. A lithium ion battery, characterized by: comprising the carbon-coated MnO-Co particles of claim 1 or 2.