CN113851638A

CN113851638A - SnO (stannic oxide)2-xPreparation method and application thereof, and composite electrode

Info

Publication number: CN113851638A
Application number: CN202110997319.6A
Authority: CN
Inventors: 胡彦杰; 江浩; 李春忠; 王一涛; 季兵; 万欣怡; 董涵泳
Original assignee: East China University of Science and Technology
Current assignee: East China University of Science and Technology
Priority date: 2021-08-27
Filing date: 2021-08-27
Publication date: 2021-12-28
Anticipated expiration: 2041-08-27
Also published as: CN113851638B

Abstract

The invention discloses SnO_2‑xA preparation method and application thereof, and a composite electrode. The SnO_2‑xThe preparation method comprises the following steps: performing flame spray pyrolysis on the mixed solution to obtain the composite material; wherein the mixed solution comprises a tin source, a surfactant, an organic solvent and water. SnO of the present invention_2‑xThe preparation method has short reaction time, and the obtained SnO_2‑xThe oxygen vacancy concentration is higher and is in a certain rangeInternal controllable, made of SnO_2‑xThe prepared electrode has excellent electrical properties and SnO_2‑xThe composite electrode prepared by the additive has excellent electrical properties.

Description

SnO (stannic oxide)2-xPreparation method and application thereof, and composite electrode

Technical Field

The invention relates to SnO_2-xA preparation method and application thereof, and a composite electrode.

Background

The negative electrode of the lithium ion battery material is mainly made of graphite material, and the most successful reason is the stable lithium storage mechanism and performance, but the low reversible capacity of the graphite material becomes a main factor for limiting the development of the lithium ion battery due to the requirement on the energy density of the lithium ion battery. SnO₂The material becomes one of the candidates of the next generation of negative electrode material due to its ultra-high reversible lithium storage reaction. But has poor cycle performance due to its low electrical conductivity and near 300% volume expansion by the conversion and alloying reaction mechanisms. Recently, materials rich in oxygen vacancies have brought a huge improvement in electrical properties due to their effects on intrinsic conductivity, SnO_2-xA new material that becomes a high-capacity negative electrode material having excellent stability is one of strong competitors to further improve the energy density of lithium ion batteries. On the other hand, nanocrystallization has the ability to buffer large stress strain, thereby reducing the influence of volume expansion and shortening the transmission path of lithium ions and electrons, and has become a research hotspot in recent years.

Patent document CN106268750A discloses a visible light response type photoreduction active SnO_2-xMethod for preparing nanoparticles, SnO obtained by the preparation thereof_2-xThe nano particles have low oxygen vacancy concentration, the prepared electrode cannot achieve good effect, the reaction time needs 20-27 hours, and the reaction time is too long, so that the nano particles are not beneficial to industrial production。

In the prior art, most of the research has focused on SnO_2-xPrepared into cathode materials without containing SnO_2-xThe composite electrode of (3) was studied.

The above studies indicate that SnO with higher oxygen vacancy concentration can be rapidly prepared_2-xNanoparticles have a profound impact on the development of lithium ion batteries.

Disclosure of Invention

The technical problem to be solved by the invention is SnO in the prior art_2-xThe preparation method has the defects of low oxygen vacancy concentration and low reaction rate, and provides SnO_2-xA preparation method and application thereof, and a composite electrode. SnO of the present invention_2-xThe preparation method has short reaction time, and the obtained SnO_2-xThe oxygen vacancy concentration is higher and controllable within a certain range, and is made of SnO_2-xThe prepared electrode has excellent electrical properties and SnO_2-xThe composite electrode prepared by the additive has excellent electrical properties.

The invention solves the technical problems through the following technical scheme.

The invention provides SnO_2-xSaid SnO _2-x3d of medium Sn element_3/2The bonding energy of the orbitals is 486.3-486.8 eV, and the bonding energy of Sn is 3d_5/2The binding energy of the orbitals is 494.7-495.2 eV.

The invention also provides SnO_2-xThe preparation method comprises the following steps:

performing flame spray pyrolysis on the mixed solution to obtain the composite material;

wherein the mixed solution comprises a tin source, a surfactant, an organic solvent and water.

In the flame spray pyrolysis, after the mixed solution is atomized and undergoes a series of reactions such as combustion, explosion, hydrolysis, sintering and the like, a vacuum pump brings product particles to a glass fiber filter membrane of a collector along with airflow, and the product particles are deposited to obtain SnO_2-xAnd (3) nanoparticles.

In the present invention, preferably, the flame spray pyrolysis includes atomizing the mixed solution to obtain liquid droplets.

Wherein, the size of the liquid drop is preferably 5 to 20 micrometers.

Wherein, preferably, the liquid drops are obtained by subjecting the mixed solution to gas shearing.

Preferably, the gas is O₂。

Preferably, the shearing pressure generated by the gas is 0.1-0.3 MPa.

Preferably, the feeding speed of the mixed solution during the atomization is 2-10 mL/min, for example, 5 mL/min.

Preferably, the mixed solution is fed by a syringe pump or a continuous syringe pump during atomization, for example, a peristaltic syringe pump can be used.

In the present invention, the flame for flame spray pyrolysis is generally obtained by burning an oxygen-containing gas.

Wherein, preferably, the oxygen-containing gas is H₂And O₂The mixed gas of (3); more preferably, in the oxygen-containing gas, H₂The flow rate of (2) is 0.08-2 m³H, e.g. 0.15m³/h，O₂The flow rate of (2) is 0.5 to 1.2m³H, e.g. 1m³/h。

In the invention, preferably, in the flame spray pyrolysis, the temperature of a combustion flame region is 800-1500 ℃.

In the present invention, the tin source may be an organic and/or inorganic substance capable of providing tin element, which is conventional in the art, preferably one or more of tin tetrachloride, stannous octoate, tetrabutyltin and tin dichloride, and more preferably tin tetrachloride.

In the present invention, preferably, the surfactant is one or more of polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone and tween.

In the present invention, the molar ratio of the tin source to the surfactant is preferably 3:10 to 10:3, for example, 2:3 or 1: 1.

In the present invention, the organic solvent may be an organic solvent conventional in the art, and preferably one or more of ethanol, toluene, xylene, and propionic acid.

In the present invention, the volume ratio of the organic solvent to the water is preferably 1:1 to 9:1, for example, 1.4 or 1.6.

In the present invention, preferably, the mixed solution is obtained by mixing and stirring the tin source, the surfactant, the organic solvent and the water, and the stirring time is preferably 3 to 6 hours, for example, 5 hours.

In the present invention, preferably, in the mixed solution, a ratio of a total mole number of the tin source and the surfactant to a volume of the organic solvent is 0.1 to 1mol/L, for example, 0.43mol/L, 0.67mol/L, or 0.83 mol/L.

The invention also provides SnO_2-xConsisting of SnO as previously described_2-xThe preparation method.

In the present invention, preferably, the SnO_2-xThe particle size of (A) is 5 to 20 nm.

In the present invention, preferably, the SnO_2-xThe specific surface area of (A) is 100 to 130m²/g。

In the present invention, preferably, the SnO_2-xIs in rutile phase.

In the present invention, preferably, the SnO_2-xThe electron paramagnetic resonance spectrum (EPR) has an intensity of 2000 or more, preferably 2014.8 to 3464.8. The SnO can be judged by electron paramagnetic resonance spectrum (EPR) intensity_2-xThe concentration of oxygen vacancies. As will be appreciated by those skilled in the art, the higher the EPR peak intensity, the SnO_2-xThe higher the oxygen vacancy concentration of (a). Those skilled in the art also know that when judging the oxygen vacancy intensity from the EPR map, it is generally necessary to make a judgment based on the test results of the same inspection machine.

In the present invention, preferably, the SnO _2-x3d of medium Sn element_3/2The bonding energy of the orbitals is 486.3-486.8 eV, and the bonding energy of Sn is 3d_5/2The binding energy of the orbitals is 494.7-495.2 eV. As known to those skilled in the art, the SnO_2-xThe bonding energy of the 3d orbital in the medium Sn element can be obtained by X-ray photoelectron spectroscopy (XPS) test, and the SnO can be prepared_2-xX-ray photoelectrons ofEnergy Spectroscopy (XPS) and SnO₂Comparing the XPS spectra, and judging the deviation amount of the peak position, wherein the more the deviation amount is, the SnO_2-xThe higher the oxygen vacancy concentration in (a). It is also known to those skilled in the art that when judging the oxygen vacancy concentration from the XPS spectrum, it is generally necessary to make a judgment based on the test results of the same detection machine.

The invention also provides SnO_2-xA method of making an electrode comprising the steps of:

coating the first mixed slurry on the surface of a substrate material and then heating;

wherein the first mixed slurry comprises SnO as described above_2-xConductive agent, binder and solvent;

the SnO_2-xSaid SnO_2-xThe total amount of the conductive agent and the binder is 70% by mass or more and not 100%.

In the present invention, the substrate material may be an electrode substrate material conventional in the art, and is preferably a copper foil or an aluminum foil.

In the present invention, preferably, the SnO_2-xSaid SnO_2-xThe total amount of the conductive agent and the binder is 70 to 80 mass%, and more preferably 70 mass%.

In the present invention, the kind of the conductive agent may be conventional in the art, and preferably one or more of ketjen black, conductive carbon black and acetylene black.

In the present invention, preferably, the conductive agent is in the SnO_2-xThe total amount of the conductive agent and the binder is 30% by mass or less and is not 0, more preferably 20% by mass or less, and still more preferably 20% by mass.

In the present invention, the binder may be of a type conventional in the art, and is preferably polyvinylidene fluoride (PVDF) and/or carboxymethyl cellulose.

In the present invention, the binder is in the SnO_2-xThe total amount of the conductive agent and the binder is 20% by mass or less and is not 0, more preferably 10% by mass or less, and still more preferably 10% by mass or less。

In the present invention, the kind of the solvent may be conventional in the art, and preferably N-methylpyrrolidone (NMP).

In the present invention, preferably, the SnO_2-xThe mass ratio of the solvent to the solvent is 1: 1-7: 12, for example 7: 9.

In the present invention, preferably, the SnO_2-x: the conductive agent: the mass ratio of the binder is 7:2: 1.

In the present invention, the operation and parameters of the heating may be conventional in the art, and the heating is generally continued until the first mixed slurry is dried.

Wherein, the heating temperature is preferably 130-150 ℃, for example 120 ℃.

Wherein, the heating time is preferably 10 to 15 hours, for example, 12 hours.

Wherein, preferably, the heating is performed under vacuum condition.

The invention also provides SnO_2-xElectrodes made of SnO as described previously_2-xThe preparation method of the electrode.

The invention also provides a preparation method of the composite electrode, which comprises the following steps:

coating the second mixed slurry on the surface of the substrate material and then heating;

wherein the second mixed slurry comprises SnO as described above_2-xGraphite, a conductive agent, a binder and a solvent;

the SnO_2-xSaid SnO_2-xAnd the total amount of the graphite, the conductive agent, and the binder is 32% by mass or less and is not 0.

In the present invention, preferably, the SnO_2-xSaid SnO_2-x16 to 32 percent of the total amount of the graphite, the conductive agent and the binder.

In the present invention, the graphite may be commercially available graphite.

In the present invention, preferably, the graphite occupies the SnO_2-xThe total amount of the graphite, the conductive agent and the binder is 64% by mass or more and is not 100%, and more preferably 48% to 64%.

In the present invention, preferably, the conductive agent is in the SnO_2-xThe total amount of the graphite, the conductive agent, and the binder is 20% by mass or less and is not 0, more preferably 10% by mass or less, for example 10%.

In the present invention, the binder may be of a kind conventional in the art, and preferably polyvinylidene fluoride and/or carboxymethyl cellulose.

In the present invention, the binder is in the SnO_2-xThe total amount of the graphite, the conductive agent, and the binder is 20% by mass or less and is not 0, more preferably 10% by mass or less, and still more preferably 10% by mass.

In the present invention, preferably, the SnO_2-x: the graphite: the conductive agent: the mass ratio of the binder is 16:64:10:10, or 32:48:10: 10.

Wherein, the heating time is preferably 10 to 15 hours, for example, 12 hours.

Wherein, preferably, the heating is performed under vacuum condition.

The invention also provides a composite electrode, which is prepared by the preparation method of the composite electrode.

The invention also provides SnO as mentioned above_2-xUse of an electrode or a composite electrode as hereinbefore described in a lithium ion battery.

The invention also provides a lithium ion battery which comprises the SnO_2-xAn electrode or a composite electrode as previously described.

On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.

The reagents and starting materials used in the present invention are commercially available.

The positive progress effects of the invention are as follows:

SnO of the present invention_2-xThe preparation method has short reaction time, and the obtained SnO_2-xThe oxygen vacancy concentration is higher and controllable within a certain range, and is made of SnO_2-xThe prepared electrode has excellent rate performance and SnO_2-xThe composite electrode prepared by the additive has excellent rate capability, reversible capacity and cycle performance.

Drawings

FIG. 1 is SnO of example 1_2-xTransmission electron micrograph (c).

FIG. 2 shows SnO of examples 1 to 3_2-xXRD profile of (a).

FIG. 3 shows SnO of examples 1 to 3_2-xEPR curve of (1).

FIG. 4 shows SnO of examples 1 to 3_2-xXPS curve of (2).

FIG. 5 is a graph of rate capability of the electrodes of example 3-1, example 3-2, and comparative example 1.

FIG. 6 is a graph of rate capability of the electrodes of examples 1-3 and comparative example 2.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.

In the following examples and comparative examples, polyethylene glycol was obtained from Shanghai Linfeng Chemicals, Inc., and Ketjen Black and PVDF were obtained from Synfei Kejing materials, Inc.

Example 1

(1) Preparing a mixed solution: weighing 0.02mol of stannic chloride, dissolving in a mixed solvent of 35mL of ethanol and 25mL of deionized water, adding 0.006mol of polyethylene glycol, mixing, and stirring for 5 hours to obtain a mixed solution for later use;

(2) feeding the mixed solution into a spray combustion reactor at a feeding rate of 5mL/min by using a peristaltic injection pump, forming fine liquid drops with the size of about 13 microns by using an atomizing burner, and feeding the liquid drops into the spray combustion reactor with a shearing gas of O₂The resulting shear pressure was 0.1 MPa. Atomized droplets in H₂/O₂Mixed gas (H) of (2)₂At a flow rate of 0.15m³/h，O₂Has a flow rate of 1m³H) in flame at about 1200 deg.C, making a series of reactions of combustion, explosion, hydrolysis and sintering, then using vacuum pump to drive air flow to drive granules, and making deposition on glass fibre filter membrane of collector to obtain SnO_2-x，SnO_2-xHas an average particle diameter of 13nm and a specific surface area of 104.8m²/g；

(3)SnO_2-xPreparing an electrode: SnO_2-xGrinding with Ketjen black, adding into slurry containing PVDF and NMP, SnO_2-x: ketjen black: the mass ratio of PVDF is 7:2:1, NMP and SnO_2-xThe mass ratio of (1) to (2) is 7:9, and a first mixed slurry is prepared. Pouring the first mixed slurry on a copper foil, and drying the copper foil in a vacuum oven at 120 ℃ for 12h to obtain SnO_2-xAnd an electrode.

SnO of example 1_2-xTransmission electron microscopy was performed with a ThermoFisher Talos F200X model, and the results are shown in FIG. 1.

Example 2

(1) Preparing a mixed solution: weighing 0.02mol of stannic chloride, dissolving the stannic chloride in a mixed solvent of 30mL of ethanol and 30mL of deionized water, adding 0.02mol of polyethylene glycol, mixing, and stirring for 5 hours to obtain a mixed solution for later use;

(2) feeding the mixed solution into a spray combustion reactor at a feeding rate of 5mL/min by using a peristaltic injection pump, forming fine liquid drops with the size of 13 microns by using an atomizing burner, and feeding the liquid drops into the spray combustion reactor with a shearing gas of O₂The resulting shear pressure was 0.1 MPa. Atomized droplets in H₂/O₂Mixed gas (H) of (2)₂At a flow rate of 0.15m³/h，O₂Has a flow rate of 1m³H) in flame at about 1200 deg.C, making a series of reactions of combustion, explosion, hydrolysis and sintering, then using vacuum pump to drive air flow to drive granules, and making deposition on glass fibre filter membrane of collector to obtain SnO_2-x，SnO_2-xHas an average particle diameter of 18nm and a specific surface area of 120.3m²/g；

Example 3

(1) Preparing a mixed solution: weighing 0.02mol of stannic chloride, dissolving in a mixed solvent of 40mL of ethanol and 25mL of deionized water, adding 0.03mol of polyethylene glycol, mixing, and stirring for 5 hours to obtain a mixed solution for later use;

(2) feeding the mixed solution into a spray combustion reactor at a feeding rate of 5mL/min by using a peristaltic injection pump, forming fine liquid drops with the size of 13 microns by using an atomizing burner, and feeding the liquid drops into the spray combustion reactor with a shearing gas of O₂The resulting shear pressure was 0.1 MPa. Atomized droplets in H₂/O₂Mixed gas (H) of (2)₂At a flow rate of 0.15m³/h，O₂Has a flow rate of 1m³H) in flame at about 1200 deg.C, making a series of reactions of combustion, explosion, hydrolysis and sintering, then using vacuum pump to drive air flow to drive granules, and making deposition on glass fibre filter membrane of collector to obtain SnO_2-x，SnO_2-xHas an average particle diameter of 10nm and a specific surface area of 123.3m²/g。

SnO prepared according to examples 1 to 3_2-xAn X-ray diffraction test (XRD) was carried out using an X-ray polycrystal diffractometer (polycrystal/D8 advanced DaVinci, Bruker AXS Co., Ltd. in Germany) and the results are shown in FIG. 2. SnO examples 1 to 3_2-xAll are rutile phase.

SnO prepared according to examples 1 to 3_2-xAn electron paramagnetic resonance spectroscopy (EPR) was performed using an electron paramagnetic resonance spectrometer (bruker a300) and the results are shown in fig. 3. The EPR intensities of examples 1 to 3 were 2014.8, 2591.1 and 3464.8, respectively.

SnO prepared according to examples 1 to 3_2-xAn X-ray photoelectron spectroscopy (XPS) test was performed using a Thermo ESCALAB 250Xi (semer feishal) test apparatus, and the results are shown in fig. 4. 3d of Sn element in examples 1 to 3_3/2Binding energy of track and 3d_5/2The binding energy results for the tracks are shown in table 1.

TABLE 13 d of Sn element in examples 1 to 3_3/2Binding energy of track and 3d_5/2Binding energy of rail

	3d_3/2Binding energy of track (eV)	3d_5/2Binding energy of track (eV)
			Example 1	486.8	495.2
Example 2	486.6	495
			Example 3	486.3	494.7

The shift of the Sn 3d peak in XPS indicates SnO_2-xFormation of mesooxygen vacancies. As is clear from Table 1, the peak shifts (3 d) of example 2 and example 1 relative to example 3 are shown_3/2Orbital binding energy) were 0.2eV and 0.5eV, respectively.

Combining the EPR and XPS results, example 3 has a greater concentration of oxygen vacancies than example 2 than example 1.

Example 3-1

(1) Preparing a composite electrode: SnO prepared in step (2) of example 3_2-xGrinding with Ketjen black, adding into slurry containing graphite, PVDF and NMP, SnO_2-x: graphite: ketjen black: the mass ratio of PVDF is 16:64:10:10, NMP and SnO_2-xThe mass ratio of (1) to (2) is 7:9, and a second mixed slurry is prepared. And pouring the second mixed slurry on the copper foil, and drying for 12h in a vacuum oven at 120 ℃ to obtain the composite electrode.

Examples 3 to 2

(1) Preparing a composite electrode: SnO prepared in step (2) of example 3_2-xGrinding with Ketjen black, adding into slurry containing graphite, PVDF and NMP, SnO_2-x: graphite: ketjen black: the mass ratio of PVDF is 32:48:10:10, NMP and SnO_2-xThe mass ratio of (1) to (2) is 7:9, and a second mixed slurry is prepared.And pouring the second mixed slurry on the copper foil, and drying for 12h in a vacuum oven at 120 ℃ to obtain the composite electrode.

Comparative example 1

After mixing graphite with ketjen black, adding to a slurry containing PVDF and NMP, graphite: ketjen black: and preparing a third mixed slurry, wherein the mass ratio of PVDF is 8:1:1, and the mass ratio of NMP to graphite is 7: 9. And pouring the third mixed slurry on a copper foil, and drying for 12h in a vacuum oven at 120 ℃ to obtain the graphite electrode.

The electrodes of example 3-1, example 3-2 and comparative example 1 were subjected to a rate capability test as shown in fig. 5 and table 2.

TABLE 2 specific capacities (mAh. g) of examples 3-1, 3-2 and comparative example 1 at different current densities^-1)

Current density	0.1Ag^-1	0.2Ag^-1	0.5Ag^-1	1Ag^-1	2Ag^-1	5Ag^-1	10Ag^-1
								Example 3-1	441.9	444.6	416.5	358.1	280.8	179.7	133.6
Examples 3 to 2	777.6	712.8	662.7	593.9	503.7	398.2	338.9
								Comparative example 1	387.3	314	154.6	51.6	29	11.6	51

When SnO prepared in step (2) of example 3 is reacted_2-xExample 3-1 and example 3-2 were at 0.1A g for the preparation of composite electrodes with graphite as an additive^-1After circulating for 100 circles under the current density of (1), 589.4mAh g is kept^-1851.9mAh g^-1The specific capacity of (A).

In a laboratory assembled button full cell, the electrodes of example 3-1 and example 3-2 still had 279mAh g, respectively, after 100 cycles of stable cycling^-1And 387mAh · g^-1The reversible specific capacity of (a). Wherein, the full cell assembly process is as follows: using commercial ternary material NCM811 as anodeThe material is mixed with Ketjen black and PVDF according to the mass ratio of 8:1:1, a proper amount of NMP (N-methyl pyrrolidone) is added to prepare slurry, the slurry is poured on an aluminum foil, a vacuum oven is used for drying for 12 hours at 120 ℃ to obtain an electrode, and the prepared composite negative electrode is used as a counter electrode to assemble a button cell. The test instrument was model LAND-2001A.

Comparative example 2

(1) Preparing a mixed solution: weighing 0.02mol of stannic chloride, dissolving in 60mL of ethanol, mixing, and stirring for 5h to obtain a mixed solution for later use;

(2) feeding the mixed solution into a spray combustion reactor at a feeding rate of 5mL/min by using a peristaltic injection pump, forming fine liquid drops with the size of 13 microns by using an atomizing burner, and feeding the liquid drops into the spray combustion reactor with a shearing gas of O₂The resulting shear pressure was 0.1 MPa. Atomized droplets in H₂/O₂Mixed gas (H) of (2)₂At a flow rate of 0.15m³/h，O₂Has a flow rate of 1m³H) in flame at about 1200 deg.C, making a series of reactions of combustion, explosion, hydrolysis and sintering, then using vacuum pump to drive air flow to drive granules, and making deposition on glass fibre filter membrane of collector to obtain SnO₂，SnO₂Has an average particle diameter of 60 nm;

(3)SnO₂preparing an electrode: SnO₂Grinding with Ketjen black, adding into slurry containing PVDF and NMP, SnO₂: ketjen black: the mass ratio of PVDF is 7:2:1, NMP and SnO₂The mass ratio of (1) to (2) is 7:9, and a first mixed slurry is prepared. Pouring the first mixed slurry on a copper foil, and drying the copper foil in a vacuum oven at 120 ℃ for 12h to obtain SnO₂And an electrode.

The electrodes of examples 1 to 3 and comparative example 2 were subjected to 1Ag^-1Cycling performance at current density was tested as shown in fig. 6 and table 3.

TABLE 3 specific capacities (mAh. g) at different numbers of cycles for examples 1 to 3 and comparative example 1^-1)

Number of cycles	100	200
			Example 1	612.4	419.2
Example 2	703.4	602
			Example 3	738.6	742.6
Comparative example 2	480.5	313.9

As mentioned above, the only preferred SnO of the present invention with adjustable vacancy concentration_2-xThe scope of the present invention is not limited thereto, and any person skilled in the art to which the present invention pertains, who may make equivalent substitutions or changes according to the preparation scheme of the present invention, should be covered by the scope of the present invention.

Claims

1. SnO (stannic oxide)_2-xCharacterized in that said SnO_2-x3d of medium Sn element_3/2The bonding energy of the orbitals is 486.3-486.8 eV, and the bonding energy of Sn is 3d_5/2The binding energy of the orbitals is 494.7-495.2 eV.

2. SnO (stannic oxide)_2-xThe preparation method is characterized by comprising the following steps:

3. The SnO of claim 2_2-xCharacterized in that said SnO_2-xThe preparation method of (a) satisfies one or more of the following conditions:

(1) the flame spray pyrolysis comprises atomizing the mixed solution to obtain liquid drops;

preferably, the size of the liquid drop is 5-20 microns;

preferably, the liquid drops are obtained by subjecting the mixed solution to gas shearing; the gas is preferably O₂(ii) a The shearing pressure generated by the gas is preferably 0.1-0.3 MPa;

preferably, the feeding speed of the mixed solution during the atomization is 2-10 mL/min, for example, 5 mL/min;

preferably, during the atomization, the mixed solution is fed by using a syringe pump or a continuous syringe pump;

(2) the flame of the flame spray pyrolysis is obtained by combusting an oxygen-containing gas;

preferably, the oxygen-containing gas is H₂And O₂The mixed gas of (3); more preferably, in the oxygen-containing gas, H₂The flow rate of (2) is 0.08-2 m³/h，O₂The flow rate of (2) is 0.5 to 1.2m³/h；

(3) In the flame spray pyrolysis, the temperature of a combustion flame area is 800-1500 ℃;

(4) the tin source is one or more of stannic chloride, stannous octoate, tetrabutyltin and stannic chloride;

(5) the surfactant is one or more of polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone and tween;

(6) the molar ratio of the tin source to the surfactant is 3: 10-10: 3, for example 2:3 or 1: 1;

(7) the organic solvent is one or more of ethanol, toluene, xylene and propionic acid;

(8) the volume ratio of the organic solvent to the water is 1: 1-9: 1, such as 1.4 or 1.6;

(7) the mixed solution is obtained by mixing and stirring the tin source, the surfactant, the organic solvent and the water; the stirring time is preferably 3-6 h, for example 5 h;

(8) in the mixed solution, the ratio of the total mole number of the tin source and the surfactant to the volume of the organic solvent is 0.1-1 mol/L, for example, 0.43mol/L, 0.67mol/L or 0.83 mol/L.

4. SnO (stannic oxide)_2-xCharacterized in that it consists of the SnO according to claim 2 or 3_2-xThe preparation method of (1);

preferably, the SnO_2-xThe particle size of (A) is 5-20 nm;

preferably, the SnO_2-xThe specific surface area of (A) is 100 to 130m²/g；

Preferably, the SnO_2-xIs in a rutile phase;

preferably, the SnO_2-xThe intensity of electron paramagnetic resonance spectrum is above 2000, preferably 2014.8-3464.8;

preferably, the SnO_2-x3d of medium Sn element_3/2The bonding energy of the orbitals is 486.3-486.8 eV, and the bonding energy of Sn is 3d_5/2The binding energy of the orbitals is 494.7-495.2 eV.

5. SnO (stannic oxide)_2-xThe preparation method of the electrode is characterized by comprising the following steps:

wherein the first mixed slurry comprises the SnO of claim 4_2-xConductive agent, binder and solvent;

the SnO_2-xSaid SnO_2-xThe total amount of the conductive agent and the binder is 70% by mass or more, and notIs 100%;

preferably, the SnO_2-xThe preparation method of the electrode meets one or more of the following conditions:

(1) the substrate material is copper foil or aluminum foil;

(2) the SnO_2-xSaid SnO_2-xThe mass percentage of the total amount of the conductive agent and the binder is 70-80%, preferably 70%;

(3) the conductive agent is one or more of Ketjen black, conductive carbon black and acetylene black;

(4) the conductive agent is in the SnO_2-xThe total amount of the conductive agent and the binder is 30% by mass or less and is not 0, preferably 20% by mass or less, and more preferably 20% by mass or less;

(5) the binder is polyvinylidene fluoride and/or carboxymethyl cellulose;

(6) the binder is in the SnO_2-xThe total amount of the conductive agent and the binder is 20% by mass or less and is not 0, preferably 10% by mass or less, more preferably 10%;

(7) the solvent is N-methyl pyrrolidone;

(8) the SnO_2-xThe mass ratio of the solvent to the solvent is 1: 1-7: 12, for example, 7: 9;

(9) the SnO_2-x: the conductive agent: the mass ratio of the binder is 7:2: 1;

(10) the heating temperature is 130-150 ℃, for example 120 ℃;

(11) the heating time is 10-15 h, for example 12 h;

(12) the heating is performed under vacuum.

6. SnO (stannic oxide)_2-xAn electrode comprising the SnO of claim 5_2-xThe preparation method of the electrode.

7. The preparation method of the composite electrode is characterized by comprising the following steps of:

wherein the second mixed slurry comprises the SnO of claim 4_2-xGraphite, a conductive agent, a binder and a solvent;

the SnO_2-xSaid SnO_2-xThe total amount of the graphite, the conductive agent, and the binder is 32% by mass or less and is not 0;

preferably, the preparation method of the composite electrode meets one or more of the following conditions:

(1) the substrate material is copper foil or aluminum foil;

(2) the SnO_2-xSaid SnO_2-x16 to 32 mass percent of the total amount of the graphite, the conductive agent and the binder;

(3) the graphite occupies the SnO_2-xThe total amount of the graphite, the conductive agent and the binder is 64% by mass or more and is not 100%, preferably 48% to 64%;

(4) the conductive agent is one or more of Ketjen black, conductive carbon black and acetylene black;

(5) the conductive agent is in the SnO_2-xThe total amount of the graphite, the conductive agent, and the binder is 20% by mass or less and is not 0, preferably 10% by mass or less, for example 10%;

(6) the binder is polyvinylidene fluoride and/or carboxymethyl cellulose;

(7) the binder is in the SnO_2-xThe total amount of the graphite, the conductive agent and the binder is 20% by mass or less and is not 0, preferably 10% by mass or less, more preferably 10% by mass;

(8) the solvent is N-methyl pyrrolidone;

(9) the SnO_2-xThe mass ratio of the solvent to the solvent is 1: 1-7: 12, for example, 7: 9;

(10) the SnO_2-x: the graphite: the conductive agent: the mass ratio of the binder is 16:64:10:10, or 32:48:10: 10;

(11) the heating temperature is 130-150 ℃, for example 120 ℃;

(12) the heating time is 10-15 h, for example 12 h;

(13) the heating is performed under vacuum.

8. A composite electrode produced by the method for producing a composite electrode according to claim 7.

9. The SnO of claim 6_2-xUse of an electrode or a composite electrode according to claim 8 in a lithium ion battery.

10. A lithium ion battery comprising the SnO according to claim 6_2-xAn electrode or a composite electrode as claimed in claim 8.