CN115196641B - Preparation process of porous SiOx negative electrode material with high lithium storage performance - Google Patents

Preparation process of porous SiOx negative electrode material with high lithium storage performance Download PDF

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CN115196641B
CN115196641B CN202211106280.5A CN202211106280A CN115196641B CN 115196641 B CN115196641 B CN 115196641B CN 202211106280 A CN202211106280 A CN 202211106280A CN 115196641 B CN115196641 B CN 115196641B
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lithium
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CN115196641A (en
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何磊
阮劲进
武志强
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Fuyang Longneng Technology Co ltd
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Longneng Technology Nantong Co ltd
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Abstract

The invention discloses a preparation process of a porous SiOx anode material with high lithium storage performance, which comprises the following steps: s1, preparing Si-SiO with core-shell structure X The composite core material has Si particle as the inner core and SiO as the outer layer X A coating layer; s2, preparing porous Si-SiO by etching the surface of the composite core material X A composite core material; s3, utilizing porous Si-SiO X The composite core material reacts with organic lithium to prepare lithium-loaded porous Si-SiO X A composite core material; s4, carrying lithium on porous Si-SiO X Carbon coating is carried out on the composite core material to obtain lithium-loaded porous C-Si-SiO X A composite core material; s5, adopting modified carbon nano tube to carry lithium to the porous C-Si-SiO X And coating the composite core material to obtain the porous SiOx anode material with high lithium storage performance. The porous SiOx anode material with high lithium storage performance prepared by the invention has excellent electrochemical performance and cycle stability, and has wide application prospect.

Description

Preparation process of porous SiOx negative electrode material with high lithium storage performance
Technical Field
The invention relates to the field of battery materials, in particular to a preparation process of a porous SiOx anode material with high lithium storage performance.
Background
Silicon oxide (SiOx) is one of the most abundant materials on earth, has a high theoretical specific capacity, is low in cost and easy to synthesize, and is considered as a more promising alternative than silicon-based negative electrode materials. Silicon oxide shows less volume change during cycling than elemental silicon and Li generated in situ during the first lithiation process 2 O and lithium silicate can buffer certain volume changes, and have been the main direction of research and development of various large and new energy material enterprises in recent years. For example, a preparation method of SiOx composite anode material disclosed in patent CN105977463A, and a preparation method of SiOx-Si@C@CNTs composite material disclosed in patent CN112467102AA preparation method and the like.
The lithium intercalation mechanism of SiOx is: siOx is limited to lithium ion reactions to Si, li 2 O and lithium silicate, si reacts with lithium ion to form reversible LixSi, irreversible Si buffer volume expansion and tissue Si agglomeration, but Li 2 The production of O and lithium silicate consumes a portion of the lithium ions, resulting in enhanced irreversible capacity and reduced coulombic efficiency of SiOx. An increase in oxygen content in SiOx decreases discharge specific capacity and coulombic efficiency, but can enhance the volume expansion buffer effect, thereby enhancing the cycle stability ([ 1)]Cai Shaoyan Synthesis of SiO_x and SiOC-based negative electrode materials and study of lithium storage Property [ D ]]University of Zhejiang industry). Therefore, silicon oxide has some disadvantages, such as: the inherently low conductivity of the insulator limits electrochemical activity; the problem of volume change is still not negligible, so that the application of the material is limited, and reasonable improvement is needed to prepare the anode material with excellent comprehensive performance.
Disclosure of Invention
The invention aims to solve the technical problem of providing a preparation process of a porous SiOx anode material with high lithium storage performance aiming at the defects in the prior art.
In order to solve the technical problems, the invention adopts the following technical scheme: a preparation process of a porous SiOx anode material with high lithium storage performance comprises the following steps:
s1, preparing Si-SiO with core-shell structure X Composite core material of SiO X The inner core of the composite core material is Si particles, and the outer layer is SiO X A coating layer, wherein x=1 to 2;
s2, by preparing the Si-SiO X Etching the surface of the composite core material to prepare porous Si-SiO X A composite core material;
s3, utilizing porous Si-SiO X The composite core material reacts with organic lithium to prepare lithium-loaded porous Si-SiO X A composite core material;
s4, carrying lithium on porous Si-SiO X Carbon coating is carried out on the composite core material to obtain lithium-loaded porous C-Si-SiO X A composite core material;
s5, adopting the modified carbon nano tube to carry more lithiumPore C-Si-SiO X And coating the composite core material to obtain the porous SiOx anode material with high lithium storage performance.
Preferably, the step S1 specifically includes: using acetone as a ball milling medium, ball milling silicon powder with the particle size of 1-10 mu m for 3-8 hours at the rotating speed of 280-450rpm, heating the ball milling product at 130-260 ℃ in air atmosphere for 2-8 hours, and cooling to obtain the Si-SiO X And (5) a composite core material.
Preferably, the step S2 specifically includes: by Si-SiO X Adding the composite core material into 0.2-3mol/L alkali solution, stirring, performing ultrasonic treatment for 3-15min, reacting at 30-55deg.C for 4-16h, centrifuging, filtering, washing solid product, and vacuum drying at 50-90deg.C to obtain porous Si-SiO X And (5) a composite core material.
Preferably, the alkaline solution is sodium hydroxide solution.
Preferably, the step S3 specifically includes:
s3-1, namely the porous Si-SiO obtained in the step S2 X Adding the composite core material into ethanol, and performing ultrasonic treatment for 5-45min;
s3-2, adding an organic lithium solution and an alkane solvent solution into the product obtained in the step S3-1, performing ultrasonic dispersion for 0.5-2h, and stirring at 35-55 ℃ for reaction for 8-24h;
s3-3, centrifuging after the reaction is finished, filtering, washing a solid product with ethanol, vacuum drying at 60-95 ℃, and grinding to obtain the lithium-loaded porous Si-SiO X And (5) a composite core material.
Preferably, the organic lithium solution is diethyl ether solution of phenyl lithium with concentration of 0.5-2mol/L, and the alkane solvent solution is cyclohexane solution.
Preferably, the step S4 specifically includes:
s4-1, carrying lithium porous Si-SiO obtained in the step S3 X Mixing the composite core material and glucose, stirring uniformly, adding into a ball mill, and ball milling for 3-15min at a rotating speed of 100-300 rpm;
s4-2, adding the mixture obtained in the step S4-1 into a tube furnace, heating to 480-750 ℃ at a heating rate of 3-15 ℃/min, sintering for 1.5-5h under nitrogen atmosphere, and cooling to obtain the lithium-loaded porous C-Si-SiO X And (5) a composite core material.
Preferably, the step S5 specifically includes:
s5-1, preparing N, na composite doped modified carbon nanotubes;
s5-2, adding the modified carbon nano tube obtained in the step S5-1 into an ethanol water solution, adding a cobalt nitrate solution, stirring, and performing ultrasonic dispersion for 15-60min to obtain a mixture A;
s5-3, carrying lithium porous C-Si-SiO prepared in the step S4 X Adding the composite core material into ethanol, and performing ultrasonic dispersion for 15-60min to obtain a mixture B;
s5-4, uniformly mixing the mixture A and the mixture B, and ball-milling to obtain slurry;
s5-5, drying the slurry obtained in the step S5-4 at the temperature of 90-120 ℃ to obtain powder;
s5-6, adding the powder obtained in the step S5-5 into a tube furnace, heating to 400-750 ℃ at a heating rate of 2-15 ℃/min, sintering for 4-10 hours under the protection of nitrogen, and cooling to obtain the porous SiOx anode material with high lithium storage performance.
Preferably, the step S5-1 specifically includes:
s5-1-1, preparing a hydroxylated carbon nano tube;
s5-1-2, carrying out N, na doping modification on the hydroxylated carbon nano tube:
s5-1-2-1, adding the hydroxylated carbon nanotubes obtained in the step S5-1-1 into deionized water at 55-80 ℃, and carrying out ultrasonic treatment for 3-20min to obtain a dispersion;
s5-1-2-2, adding pentasodium diethylenetriamine pentaacetate into deionized water at 55-80 ℃ and stirring for 2-8min;
s5-1-2-3, adding the dispersion liquid obtained in the step S5-1-2-1 into the product obtained in the step S5-1-2-2, adding dicyclohexylcarbodiimide, stirring at 40-80 ℃ for reaction for 1-5h, filtering after the reaction, sequentially cleaning the solid product with deionized water and ethanol, and drying at 55-85 ℃ for 8-24h to obtain the N, na composite doped modified carbon nanotube.
Preferably, the step S5-1-1 specifically comprises the following steps: adding the carbon nano tube into 30-65% nitric acid solution, stirring at 50-85 ℃ for reaction for 2-8 hours, cooling, adding the reaction product into deionized water, centrifuging the obtained mixture, filtering, washing the solid product to be neutral by using deionized water, vacuum drying at 70-95 ℃ for 4-12 hours, and grinding to obtain the hydroxylated carbon nano tube.
The beneficial effects of the invention are as follows:
the method firstly uses silicon powder as a raw material to prepare the silicon powder with the inner core of Si particles and the outer layer of SiO by a ball milling method X SiO of coating layer X The composite core material is etched to obtain porous Si-SiO X Composite core material, then in porous Si-SiO X Lithium ions are loaded in the composite core material, and carbon coating is carried out to obtain lithium-loaded porous C-Si-SiO X A composite core material; finally, the modified carbon nano tube is used for carrying lithium to the porous C-Si-SiO X The composite core material is coated to obtain the porous SiOx anode material with high lithium storage performance, which has excellent electrochemical performance and cycle stability and wide application prospect;
in the present invention, siO X The composite core material is a core-shell structure with SiOx layers coating inner core Si particles, the oxidation degree from the inner side to the outer layer is gradually enhanced, the X value is larger and larger, the X value of the inner layer is small, the silicon content is high, and the composite core material can be SiO X The composite core material provides higher lithium storage capacity, the X value of the outer layer becomes larger, the oxygen content is high, the buffering effect of volume expansion is better, the buffering of volume change is facilitated, and the core-shell structure can facilitate the improvement of the circulation stability.
In the invention, by the method of preparing SiO X The composite core material is etched by strong alkali, so that the porous structure can be obtained and can be SiO at the same time X The surface of the composite core material is introduced with a large amount of hydroxyl groups, and the abundant hydroxyl groups have at least the following two functions: 1. through the adsorption characteristic of the porous structure and the coordination action of hydroxyl on lithium ions, the SiO-containing porous lithium-ion-activated polymer can react with organic lithium X A large amount of lithium ions are introduced into the composite core material, so that the conductivity can be improved, and the composite core material can be used as a lithium supplementing agent to compensate SiO X Part of lithium ions consumed in the reaction with lithium reduces irreversible capacity in an initial cycle and improves coulomb efficiency; 2. the hydroxyl can react with Li in the lithium ion battery material to form an SEI film with excellent performance, and the SEI film can effectively inhibit the electrolyte solvent pairThe electrode material is damaged, so that the cycle performance and the service life of the electrode are greatly improved.
In the invention, after lithium ions are loaded, glucose is used as a carbon source to load lithium porous Si-SiO by a sintering method X Coating the carbon layer on the composite core material to obtain C-Si-SiO X The composite core material can further improve the conductivity of the material and can be used as a protective layer to enable Si-SiO to be formed X The lithium on the composite core material is more stably loaded, so that the loss of the lithium in the subsequent process is reduced; while the carbon layer coating is to maintain Si-SiO X The structural stability of the composite core material and the buffering of the volume change of the composite core material also have promotion effects.
In the invention, the modified carbon nano tube is adopted for C-Si-SiO by the sintering method X The composite core material is coated, a three-dimensional space conductive network can be formed, and the material particles are connected together through the carbon nano tube, so that the connection strength and the conductivity between the particles are improved, the conductivity and the stability are obviously improved, and the cycle performance of the battery is improved; the tubular column structure of the carbon nano tube enables electrons and ions to be rapidly transported on the tube wall, and can effectively improve the multiplying power performance; on the other hand, the modified carbon nano tube has excellent mechanical property and can improve C-Si-SiO X The structural stability of the composite core material buffers the volume expansion of the composite core material, and reduces Si-SiO X Is pulverized into powder.
Detailed Description
The present invention is described in further detail below with reference to examples to enable those skilled in the art to practice the same by referring to the description.
It will be understood that terms, such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.
The test methods used in the following examples are conventional methods unless otherwise specified. The material reagents and the like used in the following examples are commercially available unless otherwise specified. The following examples were conducted under conventional conditions or conditions recommended by the manufacturer, without specifying the specific conditions. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
The invention provides a preparation process of a porous SiOx anode material with high lithium storage performance, which comprises the following steps:
s1, preparing Si-SiO with core-shell structure X Composite core material of SiO X The inner core of the composite core material is Si particles, and the outer layer is SiO X A coating layer, wherein x=1 to 2; the method comprises the following specific steps:
ball milling silicon powder with particle size of 1-10 μm with acetone as ball milling medium at 280-450rpm for 3-8 hr, heating ball milling product at 130-260 deg.c in air atmosphere for 2-8 hr, and cooling to obtain Si-SiO X And (5) a composite core material.
S2, by reacting Si-SiO X Etching the surface of the composite core material to prepare porous Si-SiO X A composite core material; the method comprises the following specific steps:
by Si-SiO X Adding the composite core material into 0.2-3mol/L alkali solution, stirring, performing ultrasonic treatment for 3-15min, reacting at 30-55deg.C for 4-16h, centrifuging, filtering, washing solid product, and vacuum drying at 50-90deg.C to obtain porous Si-SiO X And (5) a composite core material.
In a preferred embodiment, the alkaline solution is sodium hydroxide solution.
S3, utilizing porous Si-SiO X The composite core material reacts with organic lithium to prepare lithium-loaded porous Si-SiO X A composite core material; the method comprises the following specific steps:
s3-1, porous Si-SiO obtained in the step S2 X Adding the composite core material into ethanol, and performing ultrasonic treatment for 5-45min;
s3-2, adding an organic lithium solution and an alkane solvent solution into the product obtained in the step S3-1, performing ultrasonic dispersion for 0.5-2h, and stirring at 35-55 ℃ for reaction for 8-24h;
s3-3, centrifuging after the reaction is finished, filtering, washing with ethanol, vacuum drying a solid product at 60-95 ℃, and grinding to obtain the lithium-loaded porous Si-SiO X And (5) a composite core material.
In a preferred embodiment, the organolithium solution is an ether solution of phenyllithium at a concentration of 0.5-2mol/L and the alkane solvent solution is a cyclohexane solution.
S4, carrying lithium on porous Si-SiO X Carbon coating is carried out on the composite core material to obtain lithium-loaded porous C-Si-SiO X A composite core material; the method comprises the following specific steps:
s4-1, carrying lithium porous Si-SiO obtained in the step S3 X Mixing the composite core material and glucose, stirring uniformly, adding into a ball mill, and ball milling for 3-15min at a rotating speed of 100-300 rpm;
s4-2, adding the mixture obtained in the step S4-1 into a tube furnace, heating to 480-750 ℃ at a heating rate of 3-15 ℃/min, sintering for 1.5-5h under nitrogen atmosphere, and cooling to obtain the lithium-loaded porous C-Si-SiO X And (5) a composite core material.
S5, adopting modified carbon nano tube to carry lithium to the porous C-Si-SiO X Coating the composite core material to obtain a porous SiOx anode material with high lithium storage performance; the specific steps are as follows.
S5-1, preparing N, na composite doped modified carbon nanotubes:
s5-1-1, preparing hydroxylated carbon nano tubes:
adding the carbon nano tube into 30-65% nitric acid solution, stirring at 50-85 ℃ for reaction for 2-8 hours, cooling, adding the reaction product into deionized water, centrifuging the obtained mixture, filtering, washing the solid product with deionized water to be neutral, vacuum drying at 70-95 ℃ for 4-12 hours, and grinding to obtain the hydroxylated carbon nano tube;
s5-1-2, carrying out N, na doping modification on the hydroxylated carbon nano tube:
s5-1-2-1, adding the hydroxylated carbon nanotubes obtained in the step S5-1-1 into deionized water at 55-80 ℃, and carrying out ultrasonic treatment for 3-20min to obtain a dispersion;
s5-1-2-2, adding pentasodium diethylenetriamine pentaacetate into deionized water at 55-80 ℃ and stirring for 2-8min;
s5-1-2-3, adding the dispersion liquid obtained in the step S5-1-2-1 into the product obtained in the step S5-1-2-2, adding dicyclohexylcarbodiimide, stirring at 40-80 ℃ for reaction for 1-5h, filtering after the reaction, sequentially cleaning the solid product with deionized water and ethanol, and drying at 55-85 ℃ for 8-24h to obtain the N, na composite doped modified carbon nanotube.
S5-2, adding the modified carbon nano tube obtained in the step S5-1 into an ethanol aqueous solution, adding a cobalt nitrate solution, stirring, and performing ultrasonic dispersion for 15-60min to obtain a mixture A;
s5-3, carrying lithium porous C-Si-SiO prepared in the step S4 X Adding the composite core material into ethanol, and performing ultrasonic dispersion for 15-60min to obtain a mixture B;
s5-4, uniformly mixing the mixture A and the mixture B, and ball-milling to obtain slurry;
s5-5, drying the slurry obtained in the step S5-4 at the temperature of 90-120 ℃ to obtain powder;
s5-6, adding the powder obtained in the step S5-5 into a tube furnace, heating to 400-750 ℃ at a heating rate of 2-15 ℃/min, sintering for 4-10 hours under the protection of nitrogen, and cooling to obtain the porous SiOx anode material with high lithium storage performance.
The following describes the main principle of the preparation process of the porous SiOx anode material with high lithium storage performance according to the present invention, so as to facilitate understanding of the present invention.
First, the general scheme of the invention is as follows: firstly, silicon powder is used as a raw material to prepare Si particles serving as an inner core and SiO serving as an outer layer through a ball milling method X SiO of coating layer X The composite core material is etched to obtain porous Si-SiO X Composite core material, then in porous Si-SiO X Lithium ions are loaded in the composite core material, and carbon coating is carried out to obtain lithium-loaded porous C-Si-SiO X A composite core material; finally, the modified carbon nano tube is used for carrying lithium to the porous C-Si-SiO X Coating the composite core material to obtain a final product: porous SiOx negative electrode material with high lithium storage performance.
(1) In the invention, the surface of the Si particles is oxidized into SiOx in the ball milling process to form a core-shell structure of SiOx layer coated with the inner core Si particles, the oxidation degree from the inner side to the outer layer is gradually enhanced, the value of X is larger and larger, the value of X in the inner layer is small, the silicon content is high, and the Si particles can be SiO X The composite core material provides higher lithium storage capacity, the X value of the outer layer becomes larger, the oxygen content is high, the buffering effect of volume expansion is better, the buffering of volume change is facilitated, and the core-shell structure can facilitate the improvement of the circulation stability.
(2) In the invention, by the method of preparing SiO X The composite core material is etched by strong alkali, so that the porous structure can be obtained and can be SiO at the same time X The surface of the composite core material is introduced with a large amount of hydroxyl groups, and the abundant hydroxyl groups have at least the following two functions: 1. through the adsorption characteristic of the porous structure and the coordination action of hydroxyl on lithium ions, the SiO-containing porous lithium-ion-activated polymer can react with organic lithium X A large amount of lithium ions are introduced into the composite core material, so that the conductivity can be improved, and the composite core material can be used as a lithium supplementing agent to compensate SiO X Part of lithium ions consumed in the reaction with lithium reduces irreversible capacity in an initial cycle and improves coulomb efficiency; 2. the hydroxyl can react with Li in the lithium ion battery material to form an SEI film with excellent performance, and the SEI film can effectively inhibit damage of electrolyte solvent to the electrode material, so that the cycle performance and the service life of the electrode are greatly improved.
(3) In the invention, after lithium ions are loaded, glucose is used as a carbon source to load lithium porous Si-SiO by a sintering method X Coating the carbon layer on the composite core material to obtain C-Si-SiO X The composite core material can further improve the conductivity of the material and can be used as a protective layer to enable Si-SiO to be formed X The lithium on the composite core material is more stably loaded, so that the loss of the lithium in the subsequent process is reduced; while the carbon layer coating is to maintain Si-SiO X The structural stability of the composite core material and the buffering of the volume change of the composite core material also have promotion effects.
(4) In the invention, the modified carbon nano tube is adopted for C-Si-SiO by the sintering method X The composite core material is coated, a three-dimensional space conductive network can be formed, and the material particles are connected together through the carbon nano tube, so that the connection strength and the conductivity between the particles are improved, the conductivity and the stability are obviously improved, and the cycle performance of the battery is improved; the tubular column structure of the carbon nano tube enables electrons and ions to be rapidly transported on the tube wall, and can effectively improve the multiplying power performance;
on the other hand, the modified carbon nano tube has excellent mechanical property and can improve C-Si-SiO X The structural stability of the composite core material buffers the volume expansion of the composite core material, and reduces Si-SiO X Is pulverized to prevent the agglomeration and growth of nano particles;
in the present invention, in the modification ofThe cobalt nitrate is introduced while the sexual carbon nano tube is coated, and in the sintering process, the cobalt nitrate is decomposed and oxidized, so that Co can be uniformly deposited on the surface of the modified carbon nano tube 3 O 4 Co having excellent electrochemical activity 3 O 4 Can increase the surface activity and electron density and improve the conductivity of the material.
(5) Further, the modified carbon nanotube in the invention is N, na composite doped modified carbon nanotube, and specifically:
the invention firstly carries out hydroxylation on a carbon nano tube to obtain a modified carbon nano tube with the surface rich in hydroxyl groups, and then adopts diethyl triamine pentaacetic acid sodium to carry out N, na doping modification on the hydroxylated carbon nano tube with the surface, wherein the chemical structural formula of diethyl triamine pentaacetic acid sodium is as shown in the following formula I:
it can be seen that sodium diethylenetriamine pentaacetate has a rich carboxyl function, on which sodium ions are complexed, and which contains the element N.
According to the invention, the sodium diethylenetriamine pentaacetate is uniformly and firmly grafted to the surface of the hydroxylated carbon nano tube through the condensation reaction of the carboxyl functional group on the sodium diethylenetriamine pentaacetate and the hydroxyl functional group on the hydroxylated carbon nano tube, and simultaneously, the doping of N and the uniform loading of sodium ions are realized.
Carbon nanotubes are susceptible to agglomeration due to the high surface energy of their nanostructures, and cannot be sufficiently dispersed in the system to exert their efficacy. In the invention, the doping of N can also promote the hydrophilicity of the carbon nano tube and improve the dispersibility of the carbon nano tube; and the introduction of sodium ions can enhance the surface contact between the carbon nano tube and the battery active material, and can improve the dispersibility of the carbon nano tube in a material system.
Meanwhile, the doping nitrogen can also increase the electron concentration and improve the conductivity of the carbon nano tube. The doping of sodium ions can increase the surface active reaction sites of the carbon nanotubes, can construct a stable conductive network in the battery active material, and can further improve the conductivity of the carbon nanotubes.
The foregoing is a general inventive concept and the following detailed examples and comparative examples are provided on the basis thereof to further illustrate the invention.
Example 1
A preparation process of a porous SiOx anode material with high lithium storage performance comprises the following steps:
s1, preparing Si-SiO with core-shell structure X Composite core material of SiO X The inner core of the composite core material is Si particles, and the outer layer is SiO X A coating layer, wherein x=1 to 2; the method comprises the following specific steps:
using acetone as ball milling medium, ball milling silica powder (commercially available, jiangsu Longjing novel materials Co., ltd.) with particle size of 1-10 μm at ball material ratio of 8:1 at rotational speed of 350rpm for 5h, heating ball milling product at 220deg.C in air atmosphere for 3h, and cooling to obtain Si-SiO X And (5) a composite core material.
S2, by reacting Si-SiO X Etching the surface of the composite core material to prepare porous Si-SiO X A composite core material; the method comprises the following specific steps:
5gSi-SiO X Adding the composite core material into 500mL sodium hydroxide solution with concentration of 1mol/L, stirring, performing ultrasonic treatment for 10min, reacting at 45 ℃ for 8h, centrifuging, filtering, washing solid products, and vacuum drying at 60 ℃ to obtain porous Si-SiO X And (5) a composite core material.
S3, utilizing porous Si-SiO X The composite core material reacts with organic lithium to prepare lithium-loaded porous Si-SiO X A composite core material; the method comprises the following specific steps:
s3-1, 4g of porous Si-SiO X Adding the composite core material into 100mL of ethanol, and performing ultrasonic treatment for 25min;
s3-2, adding 80mL of diethyl ether solution of phenyl lithium with the concentration of 1mol/L and 40mL of cyclohexane solution into the product obtained in the step S3-1, performing ultrasonic dispersion for 1h, and stirring at the temperature of 40 ℃ for reaction for 12h;
s3-3, centrifuging after the reaction is finished, filtering, cleaning a solid product by ethanol, then vacuum drying at 80 ℃, and grinding to obtain the lithium-loaded porous Si-SiO X And (5) a composite core material.
S4, carrying lithium on porous Si-SiO X Carbon coating is carried out on the composite core material to obtain lithium-loaded porous C-Si-SiO X A composite core material; the method comprises the following specific steps:
s4-1, porous Si-SiO carrying lithium X Composite core material and glucose are mixed (lithium-loaded porous Si-SiO) X The mass ratio of the composite core material to the glucose is 3:2), stirring uniformly, adding into a ball mill, and ball milling for 5min at a rotating speed of 160 rpm;
s4-2, adding the mixture obtained in the step S4-1 into a tube furnace, heating to 650 ℃ at a heating rate of 10 ℃/min, sintering for 4 hours under nitrogen atmosphere, and cooling to obtain the lithium-loaded porous C-Si-SiO X And (5) a composite core material.
S5, adopting modified carbon nano tube to carry lithium to the porous C-Si-SiO X Coating the composite core material to obtain a porous SiOx anode material with high lithium storage performance; the specific steps are as follows.
S5-1, preparing N, na composite doped modified carbon nanotubes:
s5-1-1, preparing hydroxylated carbon nano tubes:
adding 1g of carbon nano tube (commercial multiwall carbon nano tube with the length of 0.5-2 microns and the diameter of 30-50nm, which is purchased from Jiangsu Xianfeng nano material technology Co., ltd.) into 50mL of nitric acid solution with the concentration of 45%, stirring and reacting for 4 hours at 80 ℃, cooling, adding the reaction product into deionized water, centrifuging the obtained mixture, filtering, washing the solid product with deionized water to be neutral, vacuum drying for 10 hours at 85 ℃, and grinding to obtain hydroxylated carbon nano tube;
s5-1-2, carrying out N, na doping modification on the hydroxylated carbon nano tube:
s5-1-2-1, adding the hydroxylated carbon nanotubes obtained in the step S5-1-1 into deionized water at 65 ℃, and carrying out ultrasonic treatment for 15min to obtain a dispersion;
s5-1-2-2, adding pentasodium diethylenetriamine pentaacetate into deionized water at 60 ℃, and stirring for 3min;
s5-1-2-3, adding the dispersion liquid obtained in the step S5-1-2-1 into the product obtained in the step S5-1-2-2, adding Dicyclohexylcarbodiimide (DCC), stirring at 70 ℃ for reaction for 4 hours, filtering after the reaction, sequentially cleaning the solid product with deionized water and ethanol, and drying at 75 ℃ for 14 hours to obtain the N, na composite doped modified carbon nanotube. Wherein, according to the hydroxylated carbon nano tube: the mass ratio of the diethylene triamine penta sodium acetate to the additive raw material is 10:1.5.
S5-2, adding the modified carbon nano tube obtained in the step S5-1 into an ethanol aqueous solution, adding a cobalt nitrate solution with the concentration of 1mol/L, stirring, and performing ultrasonic dispersion for 45min to obtain a mixture A, wherein the modified carbon nano tube is prepared by the following steps: the mass ratio of the cobalt nitrate is 10:0.8;
s5-3, carrying lithium porous C-Si-SiO prepared in the step S4 X Adding the composite core material into ethanol, and performing ultrasonic dispersion for 45min to obtain a mixture B;
s5-4, uniformly mixing the mixture A and the mixture B, and ball-milling to obtain slurry; wherein, the lithium-loaded porous C-Si-SiO X Composite core material: the mass ratio of the modified carbon nano tube is 100:2.5;
s5-5, drying the slurry obtained in the step S5-4 at 110 ℃ to obtain powder;
s5-6, adding the powder obtained in the step S5-5 into a tube furnace, heating to 600 ℃ at a heating rate of 5 ℃/min, sintering for 8 hours under the protection of nitrogen, and cooling to obtain the porous SiOx anode material with high lithium storage performance.
Example 2
A preparation process of a porous SiOx anode material with high lithium storage performance comprises the following steps:
s1, preparing Si-SiO with core-shell structure X Composite core material of SiO X The inner core of the composite core material is Si particles, and the outer layer is SiO X A coating layer, wherein x=1 to 2; the method comprises the following specific steps:
using acetone as ball milling medium, ball milling silica powder (commercially available, jiangsu Longjing novel materials Co., ltd.) with particle size of 1-10 μm at ball material ratio of 8:1 at rotational speed of 350rpm for 5h, heating ball milling product at 220deg.C in air atmosphere for 3h, and cooling to obtain Si-SiO X And (5) a composite core material.
S2, by reacting Si-SiO X Etching the surface of the composite core material to prepare porous Si-SiO X A composite core material; the method comprises the following specific steps:
5gSi-SiO X Adding the composite core material into 500mL sodium hydroxide solution with concentration of 1mol/L, stirring, performing ultrasonic treatment for 10min, reacting at 45 ℃ for 8h, centrifuging, filtering, washing solid products, and vacuum drying at 60 ℃ to obtain porous Si-SiO X And (5) a composite core material.
S3, utilizing porous Si-SiO X The composite core material reacts with organic lithium to prepare lithium-loaded porous Si-SiO X A composite core material; the method comprises the following specific steps:
s3-1, 4g of porous Si-SiO X Adding the composite core material into 100mL of ethanol, and performing ultrasonic treatment for 25min;
s3-2, adding 80mL of diethyl ether solution of phenyl lithium with the concentration of 1mol/L and 40mL of cyclohexane solution into the product obtained in the step S3-1, performing ultrasonic dispersion for 1h, and stirring at the temperature of 40 ℃ for reaction for 12h;
s3-3, centrifuging after the reaction is finished, filtering, cleaning a solid product by ethanol, then vacuum drying at 80 ℃, and grinding to obtain the lithium-loaded porous Si-SiO X And (5) a composite core material.
S4, carrying lithium on porous Si-SiO X Carbon coating is carried out on the composite core material to obtain lithium-loaded porous C-Si-SiO X A composite core material; the method comprises the following specific steps:
s4-1, porous Si-SiO carrying lithium X Composite core material and glucose are mixed (lithium-loaded porous Si-SiO) X The mass ratio of the composite core material to the glucose is 1:1), and after being stirred uniformly, the mixture is added into a ball mill, and ball milling is carried out for 5min at the rotating speed of 160 rpm;
s4-2, adding the mixture obtained in the step S4-1 into a tube furnace, heating to 650 ℃ at a heating rate of 10 ℃/min, sintering for 4 hours under nitrogen atmosphere, and cooling to obtain the lithium-loaded porous C-Si-SiO X And (5) a composite core material.
S5, adopting modified carbon nano tube to carry lithium to the porous C-Si-SiO X Coating the composite core material to obtain a porous SiOx anode material with high lithium storage performance; the specific steps are as follows.
S5-1, preparing N, na composite doped modified carbon nanotubes:
s5-1-1, preparing hydroxylated carbon nano tubes:
adding 1g of carbon nano tube (commercial multiwall carbon nano tube with the length of 0.5-2 microns and the diameter of 30-50nm, which is purchased from Jiangsu Xianfeng nano material technology Co., ltd.) into 50mL of nitric acid solution with the concentration of 45%, stirring and reacting for 4 hours at 80 ℃, cooling, adding the reaction product into deionized water, centrifuging the obtained mixture, filtering, washing the solid product with deionized water to be neutral, vacuum drying for 10 hours at 85 ℃, and grinding to obtain hydroxylated carbon nano tube;
s5-1-2, carrying out N, na doping modification on the hydroxylated carbon nano tube:
s5-1-2-1, adding the hydroxylated carbon nanotubes obtained in the step S5-1-1 into deionized water at 65 ℃, and carrying out ultrasonic treatment for 15min to obtain a dispersion;
s5-1-2-2, adding pentasodium diethylenetriamine pentaacetate into deionized water at 60 ℃, and stirring for 3min;
s5-1-2-3, adding the dispersion liquid obtained in the step S5-1-2-1 into the product obtained in the step S5-1-2-2, adding Dicyclohexylcarbodiimide (DCC), stirring at 70 ℃ for reaction for 4 hours, filtering after the reaction, sequentially cleaning the solid product with deionized water and ethanol, and drying at 75 ℃ for 14 hours to obtain the N, na composite doped modified carbon nanotube. Wherein, according to the hydroxylated carbon nano tube: the mass ratio of the diethylene triamine penta sodium acetate to the raw materials is 10:2.
S5-2, adding the modified carbon nano tube obtained in the step S5-1 into an ethanol aqueous solution, adding a cobalt nitrate solution with the concentration of 1mol/L, stirring, and performing ultrasonic dispersion for 45min to obtain a mixture A, wherein the modified carbon nano tube is prepared by the following steps: the mass ratio of the cobalt nitrate is 10:0.8;
s5-3, carrying lithium porous C-Si-SiO prepared in the step S4 X Adding the composite core material into ethanol, and performing ultrasonic dispersion for 45min to obtain a mixture B;
s5-4, uniformly mixing the mixture A and the mixture B, and ball-milling to obtain slurry; wherein, the lithium-loaded porous C-Si-SiO X Composite core material: the mass ratio of the modified carbon nano tube is 100:3;
s5-5, drying the slurry obtained in the step S5-4 at 110 ℃ to obtain powder;
s5-6, adding the powder obtained in the step S5-5 into a tube furnace, heating to 600 ℃ at a heating rate of 5 ℃/min, sintering for 8 hours under the protection of nitrogen, and cooling to obtain the porous SiOx anode material with high lithium storage performance.
Example 3
A preparation process of a porous SiOx anode material with high lithium storage performance comprises the following steps:
s1, preparing Si-SiO with core-shell structure X Composite core material of SiO X The inner core of the composite core material is Si particles, and the outer layer is SiO X A coating layer, wherein x=1 to 2; the method comprises the following specific steps:
using acetone as ball milling medium, ball milling silica powder (commercially available, jiangsu Longjing novel materials Co., ltd.) with particle size of 1-10 μm at ball material ratio of 8:1 at rotational speed of 350rpm for 5h, heating ball milling product at 220deg.C in air atmosphere for 3h, and cooling to obtain Si-SiO X And (5) a composite core material.
S2, by reacting Si-SiO X Etching the surface of the composite core material to prepare porous Si-SiO X A composite core material; the method comprises the following specific steps:
5gSi-SiO X Adding the composite core material into 500mL sodium hydroxide solution with concentration of 1mol/L, stirring, performing ultrasonic treatment for 10min, reacting at 45 ℃ for 8h, centrifuging, filtering, washing solid products, and vacuum drying at 60 ℃ to obtain porous Si-SiO X And (5) a composite core material.
S3, utilizing porous Si-SiO X The composite core material reacts with organic lithium to prepare lithium-loaded porous Si-SiO X A composite core material; the method comprises the following specific steps:
s3-1, 4g of porous Si-SiO X Adding the composite core material into 100mL of ethanol, and performing ultrasonic treatment for 25min;
s3-2, adding 80mL of diethyl ether solution of phenyl lithium with the concentration of 1mol/L and 40mL of cyclohexane solution into the product obtained in the step S3-1, performing ultrasonic dispersion for 1h, and stirring at the temperature of 40 ℃ for reaction for 12h;
s3-3, centrifuging after the reaction is finished, filtering, cleaning a solid product by ethanol, then vacuum drying at 80 ℃, and grinding to obtain the lithium-loaded porous Si-SiO X And (5) a composite core material.
S4, carrying lithium on porous Si-SiO X Carbon coating is carried out on the composite core material to obtain lithium-loaded porous C-Si-SiO X A composite core material; the method comprises the following specific steps:
s4-1, porous Si-SiO carrying lithium X Composite core material and glucose are mixed (lithium-loaded porous Si-SiO) X The mass ratio of the composite core material to the glucose is 1:1), and after being stirred uniformly, the mixture is added into a ball mill, and ball milling is carried out for 5min at the rotating speed of 160 rpm;
s4-2, adding the mixture obtained in the step S4-1 into a tube furnace, heating to 650 ℃ at a heating rate of 10 ℃/min, sintering for 4 hours under nitrogen atmosphere, and cooling to obtain the lithium-loaded porous C-Si-SiO X And (5) a composite core material.
S5, adopting modified carbon nano tube to carry lithium to the porous C-Si-SiO X Coating the composite core material to obtain a porous SiOx anode material with high lithium storage performance; the specific steps are as follows.
S5-1, preparing N, na composite doped modified carbon nanotubes:
s5-1-1, preparing hydroxylated carbon nano tubes:
adding 1g of carbon nano tube (commercial multiwall carbon nano tube with the length of 0.5-2 microns and the diameter of 30-50nm, which is purchased from Jiangsu Xianfeng nano material technology Co., ltd.) into 50mL of nitric acid solution with the concentration of 45%, stirring and reacting for 4 hours at 80 ℃, cooling, adding the reaction product into deionized water, centrifuging the obtained mixture, filtering, washing the solid product with deionized water to be neutral, vacuum drying for 10 hours at 85 ℃, and grinding to obtain hydroxylated carbon nano tube;
s5-1-2, carrying out N, na doping modification on the hydroxylated carbon nano tube:
s5-1-2-1, adding the hydroxylated carbon nanotubes obtained in the step S5-1-1 into deionized water at 65 ℃, and carrying out ultrasonic treatment for 15min to obtain a dispersion;
s5-1-2-2, adding pentasodium diethylenetriamine pentaacetate into deionized water at 60 ℃, and stirring for 3min;
s5-1-2-3, adding the dispersion liquid obtained in the step S5-1-2-1 into the product obtained in the step S5-1-2-2, adding Dicyclohexylcarbodiimide (DCC), stirring at 70 ℃ for reaction for 4 hours, filtering after the reaction, sequentially cleaning the solid product with deionized water and ethanol, and drying at 75 ℃ for 14 hours to obtain the N, na composite doped modified carbon nanotube. Wherein, according to the hydroxylated carbon nano tube: the mass ratio of the diethylene triamine penta sodium acetate to the raw materials is 10:2.
S5-2, adding the modified carbon nano tube obtained in the step S5-1 into an ethanol aqueous solution, adding a cobalt nitrate solution with the concentration of 1mol/L, stirring, and performing ultrasonic dispersion for 45min to obtain a mixture A, wherein the modified carbon nano tube is prepared by the following steps: the mass ratio of the cobalt nitrate is 10:0.8;
s5-3, carrying lithium porous C-Si-SiO prepared in the step S4 X Adding the composite core material into ethanol, and performing ultrasonic dispersion for 45min to obtain a mixture B;
s5-4, uniformly mixing the mixture A and the mixture B, and ball-milling to obtain slurry; wherein, the lithium-loaded porous C-Si-SiO X Composite core material: the mass ratio of the modified carbon nano tube is 100:4;
s5-5, drying the slurry obtained in the step S5-4 at 110 ℃ to obtain powder;
s5-6, adding the powder obtained in the step S5-5 into a tube furnace, heating to 600 ℃ at a heating rate of 5 ℃/min, sintering for 8 hours under the protection of nitrogen, and cooling to obtain the porous SiOx anode material with high lithium storage performance.
Comparative example 1
This example is essentially the same as example 2, with the following main differences listed.
A preparation process of a porous SiOx anode material comprises the following steps:
s1, preparing Si-SiO with core-shell structure X Composite core material of SiO X The inner core of the composite core material is Si particles, and the outer layer is SiO X A coating layer, wherein x=1 to 2; the specific procedure was the same as in example 2.
S2, by reacting Si-SiO X Etching the surface of the composite core material to prepare porous Si-SiO X A composite core material; the procedure is the same as in example 2.
S3, for porous Si-SiO X Carbon coating is carried out on the composite core material to obtain porous C-Si-SiO X Composite core material:
s4-1, porous Si-SiO X Composite core material and glucose mixture (porous Si-SiO) X The mass ratio of the composite core material to the glucose is 11), adding the mixture into a ball mill after uniformly stirring, and ball-milling for 5min at a rotating speed of 160 rpm;
s4-2, adding the mixture obtained in the step S4-1 into a tube furnace, heating to 650 ℃ at a heating rate of 10 ℃/min, sintering for 4 hours under nitrogen atmosphere, and cooling to obtain porous C-Si-SiO X And (5) a composite core material.
S5, adopting modified carbon nano tube to make porous C-Si-SiO X Coating the composite core material to obtain a porous SiOx anode material; the specific procedure was the same as in example 2.
Comparative example 2
This example is essentially the same as example 2, with the following main differences listed.
A preparation process of a porous SiOx anode material comprises the following steps:
s1, preparing a lithium-loaded SiOx/C core material by utilizing the reaction of commercial SiOx/C and organic lithium; the method comprises the following specific steps:
s1-1, adding 4g of porous SiOx/C core material (4-15 μm, new carbon material of Ontario Co., ltd.) into 100mL of ethanol, and performing ultrasonic treatment for 25min;
s1-2, adding 80mL of diethyl ether solution of phenyl lithium with the concentration of 1mol/L and 40mL of cyclohexane solution into the product obtained in the step S1-1, performing ultrasonic dispersion for 1h, and stirring at the temperature of 40 ℃ for reaction for 12h;
s1-3, centrifuging after the reaction is finished, filtering, washing a solid product with ethanol, then vacuum drying at 80 ℃, and grinding to obtain the lithium-carrying SiOx/C core material.
S2, carrying out carbon coating on the lithium-loaded SiOx/C core material to obtain the lithium-loaded porous C-Si-SiO X A composite core material; the specific procedure was the same as in example 2.
S3, adopting modified carbon nano tube to carry lithium to the porous C-Si-SiO X Coating the composite core to obtain a porous SiOx anode material; the specific procedure was the same as in example 2.
Comparative example 3
This example is essentially the same as example 2, with the following main differences: step S5 is not included in this example, i.e., the lithium-loaded porous C-Si-SiO prepared in this example using step S4 of example 2 X Composite core material as porous SiOx negative electrode material。
Comparative example 4
This example is essentially the same as example 2, with the following main differences:
a preparation process of a porous SiOx anode material with high lithium storage performance comprises the following steps:
s1, preparing Si-SiO with core-shell structure X Composite core material of SiO X The inner core of the composite core material is Si particles, and the outer layer is SiO X A coating layer, wherein x=1 to 2; the specific procedure was the same as in example 2.
S2, by reacting Si-SiO X Etching the surface of the composite core material to prepare porous Si-SiO X A composite core material; the specific procedure was the same as in example 2.
S3, utilizing porous Si-SiO X The composite core material reacts with organic lithium to prepare lithium-loaded porous Si-SiO X A composite core material; the specific procedure was the same as in example 2.
S4, carrying lithium on porous Si-SiO X Carbon coating is carried out on the composite core material to obtain lithium-loaded porous C-Si-SiO X A composite core material; the specific procedure was the same as in example 2.
S5, adopting the carbon nano tube to carry lithium to the porous C-Si-SiO X Coating the composite core material to obtain a porous SiOx anode material with high lithium storage performance; the specific steps are as follows.
S5-1, adding a carbon nano tube (commercial multi-wall carbon nano tube with the length of 0.5-2 microns and the diameter of 30-50nm and purchased from Jiangsu first-class nano material science and technology Co., ltd.) into an aqueous solution of ethanol, adding a cobalt nitrate solution with the concentration of 1mol/L, stirring, and performing ultrasonic dispersion for 45min to obtain a mixture A, wherein the carbon nano tube: the mass ratio of the cobalt nitrate is 10:0.8;
s5-2, carrying lithium porous C-Si-SiO prepared in the step S4 X Adding the composite core material into ethanol, and performing ultrasonic dispersion for 45min to obtain a mixture B;
s5-3, uniformly mixing the mixture A and the mixture B, and ball-milling to obtain slurry; wherein, the lithium-loaded porous C-Si-SiO X Composite core material: the mass ratio of the carbon nano tubes is 100:3;
s5-4, drying the slurry obtained in the step S5-3 at 110 ℃ to obtain powder;
s5-5, adding the powder obtained in the step S5-4 into a tube furnace, heating to 600 ℃ at a heating rate of 5 ℃/min, sintering for 8 hours under the protection of nitrogen, and cooling to obtain the porous SiOx anode material.
The negative electrode materials prepared in examples 1 to 4 and comparative example 1 were assembled into button cells by the following steps: pulping, coating and drying a negative electrode material to obtain a negative electrode plate, and assembling a battery by taking a metal lithium plate as a counter electrode and performing electrochemical test, wherein the specific test method comprises the following steps: the electrolyte mixed by three components of LiPF6 with the concentration of 1mol/L and DMC:EMC=1:1:1 (v/v) is used as a separator, and the 2025 button cell is assembled by using a polypropylene microporous membrane as a separator. The method adopts a LAND battery test system of the Wuhan Jinno electronics limited company to test at normal temperature, and the test conditions are as follows: the first charge and discharge i=0.1c, cycle i=0.1c, voltage range 0.01 to 1.5V, test results are shown in table 1 below.
TABLE 1
From the test results of examples 1 to 3, it can be seen that the porous SiOx anode material with high lithium storage performance prepared by the method has excellent electrochemical performance and cycle stability.
Although embodiments of the present invention have been disclosed above, it is not limited to the use of the description and embodiments, it is well suited to various fields of use for the invention, and further modifications may be readily apparent to those skilled in the art, and accordingly, the invention is not limited to the particular details without departing from the general concepts defined in the claims and the equivalents thereof.

Claims (5)

1. The preparation process of the porous SiOx anode material with high lithium storage performance is characterized by comprising the following steps of:
s1, preparing Si-SiO with core-shell structure X Composite core material of SiO X The inner core of the composite core material is Si particles, and the outer layer is SiO X The coating layer is formed by a coating layer,wherein x=1 to 2;
s2, by preparing the Si-SiO X Etching the surface of the composite core material to prepare porous Si-SiO X A composite core material;
s3, utilizing porous Si-SiO X The composite core material reacts with organic lithium to prepare lithium-loaded porous Si-SiO X A composite core material;
s4, carrying lithium on porous Si-SiO X Carbon coating is carried out on the composite core material to obtain lithium-loaded porous C-Si-SiO X A composite core material;
s5, adopting modified carbon nano tube to carry lithium to the porous C-Si-SiO X Coating the composite core material to obtain a porous SiOx anode material with high lithium storage performance;
the step S1 specifically comprises the following steps: using acetone as a ball milling medium, ball milling silicon powder with the particle size of 1-10 mu m for 3-8 hours at the rotating speed of 280-450rpm, heating the ball milling product at 130-260 ℃ in air atmosphere for 2-8 hours, and cooling to obtain the Si-SiO X A composite core material;
the step S2 specifically comprises the following steps: by Si-SiO X Adding the composite core material into 0.2-3mol/L alkali solution, stirring, performing ultrasonic treatment for 3-15min, reacting at 30-55deg.C for 4-16h, centrifuging, filtering, washing solid product, and vacuum drying at 50-90deg.C to obtain porous Si-SiO X A composite core material;
the step S3 specifically comprises the following steps:
s3-1, namely the porous Si-SiO obtained in the step S2 X Adding the composite core material into ethanol, and performing ultrasonic treatment for 5-45min;
s3-2, adding an organic lithium solution and an alkane solvent solution into the product obtained in the step S3-1, performing ultrasonic dispersion for 0.5-2h, and stirring at 35-55 ℃ for reaction for 8-24h;
s3-3, centrifuging after the reaction is finished, filtering, washing a solid product with ethanol, vacuum drying at 60-95 ℃, and grinding to obtain the lithium-loaded porous Si-SiO X A composite core material;
the step S4 specifically includes:
s4-1, carrying lithium porous Si-SiO obtained in the step S3 X Mixing the composite core material and glucose, stirring uniformly, adding into a ball mill, and ball milling for 3-15min at a rotating speed of 100-300 rpm;
s4-2, adding the mixture obtained in the step S4-1 into a tube furnace, heating to 480-750 ℃ at a heating rate of 3-15 ℃/min, sintering for 1.5-5h under nitrogen atmosphere, and cooling to obtain the lithium-loaded porous C-Si-SiO X A composite core material;
the step S5 specifically comprises the following steps:
s5-1, preparing N, na composite doped modified carbon nanotubes;
s5-2, adding the modified carbon nano tube obtained in the step S5-1 into an ethanol water solution, adding a cobalt nitrate solution, stirring, and performing ultrasonic dispersion for 15-60min to obtain a mixture A;
s5-3, carrying lithium porous C-Si-SiO prepared in the step S4 X Adding the composite core material into ethanol, and performing ultrasonic dispersion for 15-60min to obtain a mixture B;
s5-4, uniformly mixing the mixture A and the mixture B, and ball-milling to obtain slurry;
s5-5, drying the slurry obtained in the step S5-4 at the temperature of 90-120 ℃ to obtain powder;
s5-6, adding the powder obtained in the step S5-5 into a tube furnace, heating to 400-750 ℃ at a heating rate of 2-15 ℃/min, sintering for 4-10 hours under the protection of nitrogen, and cooling to obtain the porous SiOx anode material with high lithium storage performance.
2. The process for preparing a porous SiOx negative electrode material with high lithium storage performance according to claim 1, wherein the alkaline solution is sodium hydroxide solution.
3. The preparation process of the porous SiOx anode material with high lithium storage performance according to claim 1, wherein the organic lithium solution is an diethyl ether solution of phenyl lithium with the concentration of 0.5-2mol/L, and the alkane solvent solution is a cyclohexane solution.
4. The process for preparing the porous SiOx negative electrode material with high lithium storage property according to claim 1, wherein the step S5-1 specifically comprises:
s5-1-1, preparing a hydroxylated carbon nano tube;
s5-1-2, carrying out N, na doping modification on the hydroxylated carbon nano tube:
s5-1-2-1, adding the hydroxylated carbon nanotubes obtained in the step S5-1-1 into deionized water at 55-80 ℃, and carrying out ultrasonic treatment for 3-20min to obtain a dispersion;
s5-1-2-2, adding pentasodium diethylenetriamine pentaacetate into deionized water at 55-80 ℃ and stirring for 2-8min;
s5-1-2-3, adding the dispersion liquid obtained in the step S5-1-2-1 into the product obtained in the step S5-1-2-2, adding dicyclohexylcarbodiimide, stirring at 40-80 ℃ for reaction for 1-5h, filtering after the reaction, sequentially cleaning the solid product with deionized water and ethanol, and drying at 55-85 ℃ for 8-24h to obtain the N, na composite doped modified carbon nanotube.
5. The process for preparing the porous SiOx negative electrode material with high lithium storage performance according to claim 4, wherein the step S5-1-1 specifically comprises: adding the carbon nano tube into 30-65% nitric acid solution, stirring at 50-85 ℃ for reaction for 2-8 hours, cooling, adding the reaction product into deionized water, centrifuging the obtained mixture, filtering, washing the solid product to be neutral by using deionized water, vacuum drying at 70-95 ℃ for 4-12 hours, and grinding to obtain the hydroxylated carbon nano tube.
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