KR20140031953A - Three-dimensional porous silicon-based composite negative electrode material of lithium ion cell and preparation method thereof - Google Patents

Abstract

The present invention relates to a lithium ion battery porous silica-based composite negative electrode material and a method of manufacturing the same. The present invention has a 3D network structure so that the electrode active material is uniformly distributed on the inside and the surface of the negative electrode material, and has a high temperature resistance and good conductivity, such as copper foil, copper sand, copper foam or nickel foam It is provided. In addition, the immersion method combines a slurry of silicon or a mixture of silicon and metal M with copper foil, copper sand, copper foam or nickel foam and forms a 3D porous silica-based composite anode material by heat treatment (alloying or annealing). do. According to the present invention, the 3D porous structure, the formation of the silica metal alloy, and the good bonding strength between the negative electrode material and the 3D porous current collector material are relatively high in discharge capacity, initial charge and discharge efficiency, and good cycle. Performance.

Description

Lithium-ion battery 3D porous silica-based composite anode material and manufacturing method therefor {THREE-DIMENSIONAL POROUS SILICON-BASED COMPOSITE NEGATIVE ELECTRODE MATERIAL OF LITHIUM ION CELL AND PREPARATION METHOD THEREOF}

The present invention belongs to the technical field of lithium ion battery electrode material, and specifically relates to a lithium ion battery porous silica-based composite anode material and a method of manufacturing the same.

In the research field of lithium ion batteries, the focus of research is on anode materials. Preferred cathode materials should have good charge-discharge reversibility and cycle life, ② the initial non-reversible capacity should be relatively small, ③ good compatibility with electrolyte solvents, ④ high specific capacity, ⑤ safe and contaminated ⑥ There must be several conditions, such as ⑥ abundant resources and low price. Current anode materials are difficult to satisfy the above requirements at the same time, and carbon-based materials (graphite, non-graphitizable carbon and digraphitizable carbon, etc.) are used as anode materials commercialized in current lithium ion batteries. The volume expansion coefficient is about 9% or less, indicating relatively high coulombic efficiency and good cycle stability. However, due to the relatively low theoretical lithium storage capacity (LiC6,372mAh / g) of the graphite electrode itself, it is difficult to expect further progress. Therefore, it is urgently required to research and develop a new anode material having high specific capacity, high charging and discharging efficiency, high cycle performance, high magnification charging and discharging performance, high stability, and low cost, which is already drawing attention in the field of lithium ion battery research. As a problem to be received, it has a very important significance for the development of lithium ion batteries.

In the study of new non-carbon anode materials, we found metals and other alloy materials that can be alloyed with Li such as Si, Al, Mg and Sn. Their irreversible lithium storage capacity is significantly higher than that of graphite anodes, and silicon is the most It has high theoretical lithium storage capacity (Li22Si5, 4200mAh / g), low lithium insertion potential (lower than 0.5V vs Li / Li +), low electrolyte reaction activity, rich storage capacity and low price in nature. Silicon, silicon oxide, silicon metallization and silicon / carbon composites are the most studied silica-based materials, but silicon is a kind of semiconductor material with limited conductivity and incompatible with conventional electrolytes. Silica-based materials are all very remarkable in volume expansion, similar to those of ordinary alloy materials during advanced lithium insertion and release processes. Phase exists (volume expansion> 300%) The mechanical stress generated from this results in the electrode material gradually becoming powdered during the cycle, the structure of the material is destroyed, and the electrical contact between the active materials is lost and the cycle performance is reduced. In addition, silica-based materials have a relatively high initial irreversible capacity, possibly due to the decomposition of electrolytes and the presence of miscellaneous materials such as oxides, etc. Due to these reasons, the commercialization of silica materials is limited. Complementing the cycle warmth of silica materials and reducing their initial irreversible capacity to realize commercialization and commercialization has become an important and difficult point of research on these materials.

Until now, the following methods have been tried to improve the performance of silica anode materials: Binder suitable for silica anode materials by suppressing the volume change and improving conductivity through the design and composition of silica anode materials And the development of electrolyte additives to explore new current collectors and electrode structures. Among them, the improvement of the electrochemical performance of the silica-based material itself is still a key factor in commercializing the silica cathode. The main policy to promote silica-based materials has been realized through nano-, thin-film, composite, and porous systems in order to adapt the volume effect of silicon by designing the composition and microstructure of the material, and to maintain the electrical conductivity system of the electrode. .

 (1) Reducing the particle size (for example, nanosize) of the active material is one way of improving alloy stability. Nanomaterials have features such as large specific surface area, short ion diffusivity, strong interlocking and high plasticity, which can alleviate the volume effect of alloying materials to some extent and improve electrochemical performance. However, ultrafine powders, especially nanomaterials, produce more oxide impurities, form more surface films, and produce more electrolyte precipitation and osmosis, all of which lead to an increase in initial irreversible capacity and significantly reduce initial cycle efficiency. In addition, the nanomaterials undergo vigorous agglomeration during the cycle, so that the material after the agglomeration does not exhibit the characteristics of the nanoparticles mentioned above, thereby suppressing the improvement of the cycle performance.

 (2) Thinning of the material is also one of the effective methods for improving the cycle warmth of the material. The reason is that the thin film material has a relatively large specific surface area and thickness ratio, and when the material is thinned, the volume expansion effect due to the alloy can be effectively alleviated, thereby reducing the capacity reduction and improving cycle stability. In addition, the thinning of the material allows lithium ions to diffuse rapidly, so that the reversibility of the material and the cycle stability of the large current are good.

 (3) Compounding can achieve the complementary purpose by using the synergistic effect between each component of the composite material. The main effect is to reduce the volumetric effect of the active phase of silicon and to produce multiphase composite cathode materials by introducing active or inert buffer substrates with good conductivity and low volumetric effect. Improve your sincerity. Depending on the type of dispersing matrix introduced, there are generally two types of silicon-non-metal complexes and silicon-metal complexes.

In recent years, Si-metal composite materials have received much attention from battery researchers. Examples of metal elements capable of forming a compound with silicon include Li, Fe, Ti, Mn, Cu, Co, Ni, Al, Zn, Sn, and Mg.

Metal elements capable of forming intact compounds with silicon are alloyed or partially alloyed with silicon to take advantage of the advantages of good electrical conductivity, elongation and high mechanical strength of the metal. The addition of metal is a charge transfer reaction of Si and lithium. In addition to improving the electrical conductivity of the silicon electrode, the volume change during charge / discharge of the silicon can be suppressed or alleviated.

That is, the purpose of compounding with metal is to improve the electrical conductivity of silicon on one side and to disperse and relax on the other side. The silicon metal composite materials reported to date are Si-Ni-C, Si-Mn, Al-Si-Mn, FeSi-C, Si-Co-Co3O4, Si-Zn-C, Si-Al-Mn, Si- Al-Sn, Si-Mn-C, Si-Cu-C, Si-Sn-C, Ti-Si, Ti-Si-Al, and the like. Depending on whether the metal has lithium intercalation activity, the silicon-metal complex is divided into two classes: silicon / inert lithium intercalation metal complex and silicon / active lithium intercalation complex. From the studies to date, the circulating warmth of the silicon / inert lithium compound metal composite is relatively good and the capacity of the silicon / active lithium compound metal composite is relatively high.

Since the active lithium insertion metal material (M = Sn, Mg, Al, etc.) has its own lithium insertion performance, the volume expansion of the material is floating by utilizing the lithium insertion effect at different potentials of Si and M which are active centers. It can be generated under one potential to relieve internal stress due to volume effects, thereby enhancing the structural warmth of the material and improving its circulation performance. Among them, when tin forms Li4.4Sn alloy, the electrochemical specific capacity per theoretical unit mass is 994 mAh / g, and the electrochemical specific capacity per unit volume is 7200 mAh / cm3. The theoretical specific capacity of Al is 2235 mAh / g, and the theoretical specific capacity of Mg is 2205 mAh / g, which has a higher specific capacity than carbon-based materials, which is very important for miniaturization and development of electric appliances. After searching for the prior art, Kim H et al. Published a paper published in Journal of The Electrochemical Society (1999), 146 Volume 12, page 4401-4405, “The insertion mechanism of lithium into Mg2Si anode material for Li-ion batteries”. (Lithium insertion mechanism of lithium ion battery Mg2Si cathode material) was found, among which Mg2Si nanoalloy was manufactured by vapor deposition and the initial lithium insertion capacity reached 1370mAh / g, but the cycle performance of electrode material was very bad and the capacity after 10 cycles It is said to reach 200mAh / g or less.

Since the inert lithium insert metal material itself does not have a lithium insertion capability, the cycle performance of the material can be improved, but the inert substrate is limited in mitigating the volume change of the active material. In addition, since a certain volume (capacity) of material does not contribute to capacity during the battery assembly process, the volume energy density (mass energy density) of the assembled battery is limited, so that the application of these materials is limited in future high energy density cells. have.

From this, it can be seen that the research results on the silica-based composite material are far from their industrialization. Therefore, finding substrates with greater mitigation effects and higher electrical conductivity and designing and constructing composites with superior performance has become a major direction in the development of silica-based composites.

 (4) Design the porous structure to leave the expansion space in advance. The porous material has the following advantages due to its unique structure: (1) The porous structure has a relatively high specific surface area and large pores allow the liquid electrolyte to be transported. (2) The porous structure ensures sufficient contact between the electrolyte and the active material. It reduces the diffusivity of the ions, ③ The porous structure improves the electrochemical reaction rate by increasing the conductivity of lithium ions, ④ The porous structure provides the active site for reaction, improving the electrochemical reaction speed, ⑤Binder and conductive agent There is no need to add ⑥ to effectively absorb or mitigate the volume expansion effect of Si to improve the cycle performance of the material.

As can be seen from the above, the effect of promoting the cycle performance of the alloying material using nanomaterials is not ideal and the single active addition or inert addition partially inhibits the volume expansion of the silica-based material, but the dispersion and aggregation problems of silicon Cannot be completely solved. In addition, in consideration of large-scale production and manufacturing costs, manufacturing a negative electrode material combining a complex and a porous phase is a major policy in the development of a silica-based negative electrode material.

An object of the present invention is to solve the problem that the charge and discharge specific capacity, initial charge and discharge efficiency and cycle performance of a battery manufactured using a conventional silica-based negative electrode is not ideal and can not be applied to the industrialization of lithium ion batteries In addition, the present invention provides a 3D porous silica-based composite material having low unit cost and applicable to industrialization of a lithium ion battery, and a method of manufacturing the same. The lithium ion battery 3D reticulated porous silica metal composite anode material manufactured by integrating the active / active composite, the active / inactive composite and the porosity method of the present invention improves the conductivity of the silica anode material and alleviates its volume expansion problem. Improved electrochemical performance (specific capacity, magnification performance, especially cycle performance).

In order to achieve the above object, the present invention provides a method for producing a lithium ion battery 3D porous silica-based composite anode material comprising the following steps:

Step (1): Washing the 3D porous current collector material, the material of the 3D porous current collector material is an inert lithium insert metal, the inert lithium insert metal is a metal that can not form a compound or alloy between lithium and metal, economical In consideration of the unit price, the inert lithium insertion metal is preferably a kind selected from copper foil, copper tetrag, copper foam, and nickel foam.

Step (2): a silicon or a mixture of silicon and metal M and a binder are added to a solvent to stir sufficiently to prepare a slurry, and the solvent is an aqueous solvent or an oil solvent, and the 3D porous current collector material is immersed in the slurry. After sufficient immersion, lightly scrape off the unnecessary slurry on the surface to form a slurry-immersed 3D porous current collector material, and then the slurry-immersed 3D porous current collector material under 80-90 ° C. for 0.5 to 1 hour. Vacuum drying and roll-in under 2-6 MPa pressure to obtain a 3D porous silica-based composite electrode precursor, wherein the metal M is an active lithium intercalation metal.

Step (3): The 3D porous silica-based composite electrode precursor obtained in step (2) is heat-treated in a vacuum or inert atmosphere to obtain a 3D porous silica-based composite anode material.

The washing step in step (1) of the technical scheme is as follows: 3D porous current collector material such as grithin film net, copper yarn net, copper foam or nickel foam in the order of acetone, 10% dilute hydrochloric acid, distilled water and ethanol anhydride. Follow ultrasonic cleaning. The reagents used are all analytical reagents and the solution is prepared with secondary distilled water. The purpose of cleaning is to remove miscellaneous substances such as grease and surface oxides from the surface.

In the step (1), the average bore diameter of the 3D porous current collector material is 100 to 200 m, and the thickness is 400 to 1000 m.

During step (2), the mixture of silicon silicon and metal M is in powder form and the particle size is micron, submicron or nanometer. The metal M is an active lithium intercalation metal, and the active lithium intercalation metal refers to a metal capable of forming an intermetallic compound or alloy with lithium. For example, magnesium, calcium, aluminium, germanium, tin, lead, arsenic, and stenium , Bismuth, platinum, silver, gold, zinc, cadmium, indium, and the like. The mixture of silicon and metal M is a mixture formed by mixing any one or two or more of silicon and an active lithium-inserted metal. The purity of the lithium intercalated metal is at least 99.5%.

In consideration of environmental protection and economic cost, preferably one or more combinations of tin, magnesium and aluminum may be used, and the purity of the silicon, tin, magnesium and aluminium is at least 99.5%.

The aqueous solvent in step (2) is water or an ethanol aqueous solution and the oily solvent is normal methylpyrrolidone, dimethylformamide or dimethyl sulfoxide.

The proportion of silicon and metal M in the silicon and metal M mixture directly affects the capacity and cycle stability of the composite. The mass ratio of silicon and metal M in the mixture of silicon and metal M in order to exhibit a good cooperative effect between the components, that is, to exhibit high capacity characteristics of silicon and good electrical conductivity of metals such as tin, magnesium and aluminium 1: 1 to 9: 1, and when using two or more metals, the ratio of the sum of the masses of the silicon and the two or more metals is 1: 1 to 9: 1. The binder is one of carboxymethyl cellulose, polyamide imide and polyacrylic acid.

The mass ratio of the said silicon or the mixture of silicone and metal M, and a binder is 36: 1-45: 1. The amount of the solvent should be 30% to 40% of the solids content of the slurry so that the current collector such as copper foil net, copper yarn net, copper foam or nickel foam should be sufficiently immersed in the slurry. The solids content of the slurry refers to the percentage by which the mass of the solid material in the slurry accounts for the total mass of the slurry.

In step (3) of the technical scheme, the heat treatment is carried out as follows: The 3D porous silica-based composite electrode precursor obtained in step (2) is heated to 200 ° C. to 850 ° C. and subjected to the conditions of 200 ° C. to 850 ° C. The alloying process is carried out by maintaining the temperature for 2 to 6 hours, and then cooled to 100 to 200 ° C., followed by annealing by maintaining the temperature for 1 to 3 hours. Cool to

The term "raise to 200 ° C to 850 ° C" refers to raising the temperature from room temperature to 200 ° C to 850 ° C. The heat treatment is performed in a vacuum or inert atmosphere to prevent oxidation. The term “heat treatment in a vacuum or inert atmosphere” refers to maintaining a vacuum or inert atmosphere at both the elevated temperature, the two-stage insulation, and the cooling in the furnace during the heat treatment process. However, in order to save energy, in particular, when the vacuum condition is formed by the vacuum device, the operation of the vacuum device also consumes energy, so after cooling below 85 ° C., the operation of the vacuum device may be stopped.

In the present invention, the alloy treatment is said to produce a corresponding alloy through interdiffusion or partial interdiffusion by keeping the substrate, the melting point of Si and metal M, and the eutectic point temperature of the associated alloy for a certain time. The formation of the bar alloy is advantageous for improving the electrochemical performance (specific capacity and cycle performance) of the 3D porous silica-based composite electrode material. The annealing treatment functions to promote uniformity of alloy components, finer grains of crystal grains, stress cancellation, enhancement of bonding strength between materials and current collectors, and improved plasticity to facilitate processing. The heat treatment improves the microstructure of the 3D porous silica-based composite electrode precursor so that the silicon or Si-M fine granules are uniformly and warmly distributed in the 3D mesh structure of copper foil, copper sag, copper foam or nickel foam. It improves the bond between the ground and the substrate, and also improves the mechanical performance of the material, thereby improving the cycle stability of the silica-based anode material by suppressing the volume change during the charging and discharging process of the active material.

In the present invention, the term "vacuum" means at least 1 x 10 ^-2 Pa.

In the present invention, "room temperature" refers to a temperature range of 18-25 ℃.

In the present invention, "purity" refers to mass percentage.

If the temperature increase during the heat treatment is too fast, shrinkage may occur too quickly, such as cracking may occur, so the temperature increase rate during the temperature increase process is preferably 3-15 ° C / min.

In another aspect of the present invention provides a lithium ion battery 3D porous silica-based composite anode material, characterized in that the manufacturing method.

The present invention has the following advantages:

 (1) In the present invention, since it is no longer necessary to add a conductive agent alone, process operation can be simplified and the process cost can be further reduced.

 (2) The active lithium insertion metal M itself has good electrical conductivity and lithium insertion performance. The present invention utilizes the lithium insertion effect at dislocations in which Si and metal M are dissimilar, so that volume expansion of the material occurs at dislocations with different dislocations. In this way, the internal stress due to the volume effect is alleviated to enhance the structural warmth of the material, thereby improving its cycle performance.

 (3) The lithium ion battery 3D porous silica-based composite anode material of the present invention is a porous composite electrode, and the active material of the electrode is a partial alloy mainly composed of Si and Si-M, and the content of high capacity silicon, which is the main active material, of the electrode active material. Adjust the storage capacity of lithium through

 (4) The inert lithium-inserted metal current collector material of the present invention, for example, copper foil net, copper yarn net, copper foam or nickel foam has a 3D network structure so that the electrode active materials are uniformly dispersed in or on the surface thereof and at a constant high temperature. Good resistance and good electrical conductivity. The 3D porous current collector material not only acts as a supporter and current collector of the electrode, but also uses the physicochemical affinity of the electrode during the heat treatment process to cause mutual diffusion or partial diffusion with the negative electrode material. For example, Si-Cu or Si-Ni alloys are formed to enhance the overall structural warmth and performance of the composite battery. On the other hand, since the current collector material itself has a 3D network structure, the contact area between the material and the electrolyte is greatly improved, thereby reducing polarization and improving the charge / discharge cycle performance of the metal electrode by reducing the volume change during the charge / discharge process. It also improves the high-magnification charge / discharge electrical performance of metal electrodes.

 (5) In the present invention, the 3D porous structure, the formation of the silica metal alloy, and the good bonding force between the negative electrode material and the 3D porous current collector material paper make the battery made of the porous silica-based composite negative electrode material relatively high discharge specific capacity and initial discharge efficiency. And favorable cycle performance. The present invention is expected to have great prospects in the field of lithium ion battery negative electrode because of its simple operation, low cost, and easy production on a large scale.

1 is a flow chart of a method according to the invention.
2 is a shape view of the copper foam of Example 1. FIG.
3 is a 3D porous silica-based composite negative electrode material prepared in Example 1. FIG.
Figure 4 is a cycle graph of the 3D porous silica-based composite anode material prepared in Example 1.

DETAILED DESCRIPTION Hereinafter, the present invention will be described in detail with reference to Examples and drawings, which are merely illustrative for clarifying the present invention, and are not intended to limit the scope of the present invention. It should be defined according to the description.

Example 1

Ultrasonic cleaning of copper foil, copper yarn net, copper foam or nickel foam with an average pore diameter of 700 μm and a thickness of 700 μm in the order of acetone, 10% dilute hydrochloric acid, distilled water and ethanol anhydrous Remove it. Si powder (purity 99.5%, D ₅₀ = 1.5 μm) and carboxymethyl cellulose (CMC) were added to water at a mass ratio of 36: 1 to sufficiently stir to prepare a slurry (solid content 35%). Copper foil netting, copper yarn netting, copper foaming or nickel foam current collectors are immersed in the copper foil netting, copper yarn netting, copper foaming or nickel foaming current collector by immersing the sludge on the surface. Then, the slurry-impregnated copper foil net, copper yarn net, copper foam or nickel foam current collector was vacuum dried at 80 ° C. for 1 hour, and then rolled-in at 4 MPa pressure to obtain a thickness of 3D porous silica. type to obtain a composite electrode precursor obtained to a heat treatment conducted under the 3D porous silica-based composite electrode precursor put in a vacuum box (vacuum degree is 2 × 10 ^-3 Pa) or an inert atmosphere and heat treatment Figure 820 ℃, the heating rate is 12 ℃ / min, the warming time proceeds to the alloying treatment proceeds to 4 hours, then continue to lower the temperature to 200 ℃ and insulated for 2 hours to proceed annealing. The heating is stopped and cooled to room temperature in the furnace to obtain a 3D porous silica-based composite anode material whose main electroactive material is Si.To prevent oxidation, a vacuum or inert atmosphere must be maintained during the heat treatment process.

The 3D porous silica-based composite negative electrode plate obtained from the copper foam substrate and the metal lithium were formed with a half cell to test the electrochemical performance under the condition of current density of 0.6 mA / cm ² and charge and discharge voltage of 0-2.0V. The discharge capacity of the anode plate reaches 2200mAh / g, the initial efficiency is 86%, and still maintains 93% capacity after 50 cycles.

Example 2

Ultrasonic cleaning of copper foil, copper yarn net, copper foam or nickel foam with average pore diameter of 100μm and thickness of 1000μm in the order of acetone, 10% dilute hydrochloric acid, distilled water and ethanol anhydrous Remove it. Si powder (purity 99.9%, D ₅₀ = 100 nm) and polyamide imide (PAI) were added to normal methylpyrrolidone in a mass ratio of 45: 1 to stir sufficiently to prepare a slurry (solid content 30%). After immersing the copper foil net, copper yarn net, copper foam or nickel foam current collector sufficiently in the slurry, lightly scrape off unnecessary sludge on the surface, so that the slurry is immersed copper foil net, copper yarn net, copper foam or nickel foam Then, the slurry-impregnated copper foil net, copper yarn net, copper foam or nickel foam current collector system was vacuum dried at 90 ° C. for 0.5 hours, and then rolled in at 6 MPa pressure to obtain a desired thickness. A 3D porous silica-based composite electrode precursor is obtained, and the obtained 3D porous silica-based electrode electrode precursor is placed in a box and subjected to heat treatment under vacuum (vacuum degree of 2 × 10 ^-3 Pa) or inert atmosphere. The heat treatment temperature is 850 ° C., the temperature increase rate is 15 ° C./min, and the heat retention time is 2 hours to proceed with the alloying treatment. After the binding, the electric heating is stopped and cooled to room temperature in the furnace to obtain a 3D porous silica-based composite anode material, whose main electrode active material is Si. In order to prevent oxidation, a vacuum or inert atmosphere must be maintained during the heat treatment process. .

3D porous silica-based composite negative electrode plate obtained from a nickel foam substrate and a lithium metal half cell were formed to test the electrochemical performance under the condition of current density of 0.6 mA / cm ² and charge and discharge voltage of 0-2.0V. The discharge capacity of the negative plate reaches 2500mAh / g, the initial efficiency is 90%, and still maintains 95% capacity after 50 cycles.

Example 3

Ultrasonic cleaning of copper foil, copper yarn net, copper foam or nickel foam with average pore diameter of 100μm and thickness of 400μm in the order of acetone, 10% dilute hydrochloric acid, distilled water and ethanol anhydrous Remove it. Si-Sn mixed powder (Si purity 99.9%, D ₅₀ = 1.5μm; Sn purity 99.6%, D ₅₀ = 100nm; Si: Sn = 1: 1) and polyacrylic acid [poly (acrylic acid)] Was added to an aqueous ethanol solution at a mass ratio of 36: 1 to stir sufficiently to prepare a slurry (solid content of 32%). Lightly scrape off unnecessary sludge from the surface to form a slurry-immersed copper foil net, copper yarn net, copper foam or nickel-foam collector system, followed by slurry-impregnated copper foil net, copper yarn net, copper foam or The nickel-foam collector system was vacuum-dried at 80 ° C. for 1 hour, and then rolled-in at 2 MPa pressure to obtain a 3D porous silica-based composite electrode precursor having a desired thickness. Ball (degree of vacuum is 1 × 10 ^-3 Pa), or proceeds to a heat treatment in an inert atmosphere and the heat treatment temperature is 200 ℃ and the rate of temperature rise is 3 ℃ / min, maintaining time proceeds the alloying proceeds to 6 hours. Subsequently the temperature The temperature is lowered to 100 ° C., followed by annealing for 3 hours, after the binding is stopped, the electric heating is stopped and cooled to room temperature in a furnace to obtain a 3D porous silica-based composite anode material. The main electrode active materials are Si and Si. -Sn partial alloy In order to prevent oxidation, vacuum or inert atmosphere should be maintained during heat treatment.

The 3D porous silica-based composite negative electrode plate obtained from the copper foil substrate and the metal lithium were used to test the electrochemical performance under the condition of current density of 0.6 mA / cm ² and charge and discharge voltage of 0-2.0V. The discharge capacity of the anode plate reaches 1200mAh / g, the initial efficiency is 89%, and still maintains 97% capacity after 50 cycles.

Example 4

Ultrasonic cleaning of copper foil, copper yarn net, copper foam or nickel foam with an average pore diameter of 700 μm and a thickness of 700 μm in the order of acetone, 10% dilute hydrochloric acid, distilled water and ethanol anhydrous Remove it. Si-Sn mixed powder (Si purity: 99.7%, D ₅₀ = 1.8μm; Sn purity 99.9%, D ₅₀ = 500nm; Si: Sn = 5: 1) and carboxymethyl cellulose (CMC) were 40: Into the slurry at a mass ratio of 1, the mixture was sufficiently stirred to prepare a slurry (solid content: 34%), and the copper foil net, copper yarn net, copper foam, or nickel foam current collector was immersed in the slurry, and then sufficiently immersed in the surface. Lightly scrape off the sludge to form a slurry-immersed copper foil netting, copper yarn netting, copper foam or nickel-foam current collector system, followed by slurry dipped copper foil netting, copper yarn netting, copper-foam netting or nickel-foam collector The system was vacuum dried for 1 hour at 85 ° C., and then rolled in at 4 MPa pressure to obtain a 3D porous silica-based composite electrode precursor having a desired thickness. × 10 ^{- 3} Pa) or heat treatment under inert atmosphere, heat treatment temperature is 230 ℃, heating rate is 5 ℃ / min, heat retention time is 4 hours, and alloying treatment is continued. After thermal insulation, the heating is stopped and the electric heating is stopped and cooled to room temperature in the furnace to obtain a 3D porous silica-based composite anode material. The main electroactive materials are Si and Si-Sn partial alloys. To prevent this, the vacuum or inert atmosphere should be maintained during the heat treatment.

The 3D porous silica-based composite negative electrode plate obtained from a copper yarn net substrate and a metal lithium were used to test the electrochemical performance under conditions of a current density of 0.6 mA / cm ² and a charge / discharge voltage of 0-2.0 V. The discharge capacity of the anode plate reaches 1500mAh / g, the initial efficiency is 86%, and still maintains 95% capacity after 50 cycles.

Example 5

Ultrasonic cleaning of copper foil, copper yarn net, copper foam, or nickel foam with an average pore diameter of 400 μm and a thickness of acetone, 10% dilute hydrochloric acid, distilled water and ethanol, followed by ultrasonic cleaning Remove it. Si-Mg mixed powder (Si purity: 99.6%, D ₅₀ = 1.5μm; Mg purity 99.5%, D ₅₀ = 3μm; Si: Mg = 6: 1) and polyamide imide (PAI) 38: 1 The mixture was added to dimethylformamide at a mass ratio of 1 to a sufficient stirring to prepare a slurry (solid content of 36%). Lightly scrape away the unnecessary sludge to form a slurry-immersed copper foil net, copper yarn net, copper foam or nickel-foam collector system, followed by slurry-impregnated copper foil net, copper yarn net, copper-foam net or nickel-foam house The whole system was vacuum dried for 1 hour at 80 ° C., and then rolled in under 2 MPa pressure to obtain a 3D porous silica-based composite electrode precursor having a desired thickness.The 3D porous silica-based electrode electrode precursor obtained was put into a box and vacuumed. Degrees 1 × 10 ^-3 Pa), or proceeds to a heat treatment in an inert atmosphere and the heat treatment temperature is a temperature raising rate is 550 ℃ 9 ℃ / min, maintaining time proceeds the alloying proceeds to 5 hours. Subsequently the temperature of 150 ℃ After heat insulation, the annealing is performed after stopping the heat, and the electric heating is stopped and cooled to room temperature in the furnace to obtain a 3D porous silica-based composite anode material. The main electrode active materials are Si and Si-Mg parts. Alloys should be kept in a vacuum or inert atmosphere during heat treatment to prevent oxidation.

The 3D porous silica-based composite negative electrode plate obtained from the copper foil substrate and the metal lithium were used to test the electrochemical performance under the condition of current density of 0.6 mA / cm ² and charge and discharge voltage of 0-2.0V. The discharge capacity of the negative electrode plate reaches 1800mAh / g, the initial efficiency is 88%, and still maintains the capacity of 96% after 50 cycles.

Example 6

Ultrasonic cleaning of copper foil, copper yarn net, copper foam or nickel foam with average pore diameter of 200μm and thickness of 1000μm in the order of acetone, 10% dilute hydrochloric acid, distilled water and ethanol anhydrous Remove it. Si-Mg mixed powder (Si purity 99.9%, D ₅₀ = 1.8μm; Mg purity 99.9%, D ₅₀ = 5μm; Si: Mg = 9: 1) and polyacrylic acid [poly (acrylic acid)] To a mass ratio of 42: 1 and stirred sufficiently to prepare a slurry (solid content of 38%), after which copper foil net, copper yarn net, copper foam or nickel foam current collector was immersed sufficiently. Lightly scrape away unnecessary sludge from the surface to form a slurry-immersed copper foil netting, copper yarn netting, copper foam or nickel-foam collector system, followed by a slurry-immersed copper foil netting, copper yarn netting, copper froth or nickel The foam current collector was vacuum dried at 90 ° C. for 0.5 hour, and then rolled in at 6 MPa pressure to obtain a 3D porous silica-based composite electrode precursor having a desired thickness. Vacuum degree 2 × 10 ^-3 Pa) or an inert atmosphere, and the heat treatment temperature is 620 ° C., the heating rate is 10 ° C./min, and the heat retention time is 3 hours. After heat insulation, the annealing is performed after stopping the heat, and the electric heating is stopped and cooled to room temperature in the furnace to obtain a 3D porous silica-based composite anode material. The main electrode active materials are Si and Si-Mg parts. Alloys should be kept in a vacuum or inert atmosphere during heat treatment to prevent oxidation.

The 3D porous silica-based composite negative electrode plate obtained from the copper foil substrate and the metal lithium were used to test the electrochemical performance under the condition of current density of 0.6 mA / cm ² and charge and discharge voltage of 0-2.0V. The discharge capacity of the anode plate reaches 2000mAh / g, the initial efficiency is 86%, and still maintains 94% capacity after 50 cycles.

Example 7

Ultrasonic cleaning of copper foil, copper yarn net, copper foam or nickel foam with average pore diameter of 100μm and thickness of 400μm in order of acetone, 10% dilute hydrochloric acid, distilled water and ethanol anhydrous Remove it. Si-Al mixed powder (Si purity 99.5%, D ₅₀ = 1.5 μm; Al purity 99.5%, D ₅₀ = 100 nm; Si: Al = 8: 1) and carboxymethyl cellulose (CMC) were 39: Into the slurry at a mass ratio of 1, the mixture was sufficiently stirred to prepare a slurry (solid content of 35%), and the copper foil net, copper yarn net, copper foam or nickel foam current collector was immersed in the slurry, and then sufficiently immersed in the surface. Lightly scrape off the sludge to form a slurry-immersed copper foil netting, copper yarn netting, copper foam or nickel-foam current collector system, followed by slurry dipped copper foil netting, copper yarn netting, copper-foam netting or nickel-foam collector The system was vacuum dried for 1 hour at 80 ° C., and then rolled in at 2 MPa pressure to obtain a 3D porous silica-based composite electrode precursor having a desired thickness. × 10 ^-3 P a) or heat treatment under inert atmosphere, heat treatment temperature is 550 ℃, heating rate is 6 ℃ / min, heat retention time is 4 hours, and alloying treatment is continued. After the insulation is bound, the electrical heating is stopped and cooled to room temperature in the furnace to obtain a 3D porous silica-based composite anode material whose main electroactive materials are Si and Si-Al partial alloys. In order to maintain the vacuum or inert atmosphere during the heat treatment process.

The 3D porous silica-based composite negative electrode plate obtained from a copper yarn net substrate and a metal lithium were used to test the electrochemical performance under conditions of a current density of 0.6 mA / cm ² and a charge / discharge voltage of 0-2.0 V. The discharge capacity of the negative electrode plate reaches 1900mAh / g, the initial efficiency is 90%, and still maintains the capacity of 96% after 50 cycles.

Example 8

Ultrasonic cleaning of copper foil, copper yarn net, copper foam or nickel foam with an average pore diameter of 200 μm and thickness of 1000 μm in the order of acetone, 10% dilute hydrochloric acid, distilled water and ethanol anhydrous Remove it. Si-Al mixed powder (Si purity: 99.9%, D ₅₀ = 1.8μm; Al purity 99.9%, D ₅₀ = 500nm; Si: Al = 4: 1) and polyamide imide (PAI) 43: 1 The mixture was added to dimethyl sulfoxide at a mass ratio of and stirred sufficiently to prepare a slurry (solid content of 40%). Lightly scrape away the unnecessary sludge to form a slurry-immersed copper foil net, copper yarn net, copper foam or nickel-foam collector system, followed by slurry-impregnated copper foil net, copper yarn net, copper-foam net or nickel-foam house The whole system was vacuum dried at 90 ° C. for 0.5 hour, and then rolled in under 6 MPa pressure to obtain a 3D porous silica-based composite electrode precursor having a desired thickness.The 3D porous silica-based electrode electrode precursor obtained was put into a box and vacuumed (vacuum). A 1 × 10 ^-3 Pa), or proceeds to a heat treatment in an inert atmosphere and the heat treatment temperature is 650 ℃ and the rate of temperature rise is 8 ℃ / min, maintaining time proceeds the alloying proceeds to 2 hours. Subsequently the temperature 200 ℃ After heat insulation, the annealing is performed after stopping the heat, and the electric heating is stopped and cooled to room temperature in the furnace to obtain a 3D porous silica-based composite anode material. The main electrode active materials are Si and Si-Al parts. Alloys should be kept in a vacuum or inert atmosphere during heat treatment to prevent oxidation.

The 3D porous silica-based composite negative electrode plate obtained from a copper foam substrate and a metal lithium were used to test the electrochemical performance under conditions of a current density of 0.6 mA / cm ² and a charge / discharge voltage of 0-2.0 V. The discharge capacity of the negative plate reaches 1600mAh / g, the initial efficiency is 89%, and still maintains 95% capacity after 50 cycles.

Example 9

Ultrasonic cleaning of copper foil, copper yarn net, copper foam or nickel foam with an average pore diameter of 800 μm and a thickness of 800 μm in the order of acetone, 10% dilute hydrochloric acid, distilled water and ethanol anhydrous Remove it. Si-Sn-Mg mixed powder (Si purity 99.9%, D ₅₀ = 100 nm; Sn purity 99.8%, D ₅₀ = 100 nm; Mg purity 99.6%, D ₅₀ = 500 nm; and Si: (Sn + Mg) = 7: 1) and carboxymethyl cellulose (CMC) are added to water at a mass ratio of 40: 1 and sufficiently stirred to prepare a slurry (solid content of 33%). After immersing the foam or nickel foam current collector sufficiently, lightly scrape off the unnecessary sludge on the surface to form a slurry-immersed copper foil net, copper yarn net, copper foam or nickel foam current collector system. The copper foil net, copper yarn net, copper foam or nickel foam current collector system was vacuum dried at 80 ° C. for 1 hour and rolled in at a pressure of 4.5 MPa to obtain a 3D porous silica-based composite electrode precursor having a desired thickness. Box 3D porous silica based electrode precursor Heat treatment is carried out in a furnace (vacuum degree of 1 × 10 ^-3 Pa) or in an inert atmosphere, the heat treatment temperature is 230 ° C., the heating rate is 5 ° C./min, and the warming time is 5 hours. The temperature is lowered to 100 ° C., followed by warming for 3 hours, followed by annealing, after stopping the electrical heating and cooling to room temperature in a furnace to obtain a 3D porous silica-based composite anode material. 、 Si-Sn and Si-Mg partial alloy In order to prevent oxidation, vacuum or inert atmosphere should be maintained during heat treatment.

The 3D porous silica-based composite negative electrode plate obtained from the nickel-foamed substrate and a metal lithium were used to test the electrochemical performance under conditions of a current density of 0.6 mA / cm ² and a charge / discharge voltage of 0-2.0 V. The discharge capacity of the negative electrode plate reaches 1900mAh / g with an initial efficiency of 91% and still maintains a capacity of 97% after 50 cycles.

Example 10

Ultrasonic cleaning of copper foil, copper yarn net, copper foam or nickel foam with an average pore diameter of 500 μm in thickness in order of acetone, 10% dilute hydrochloric acid, distilled water and ethanol anhydrous Remove it. Si-Al-Mg mixed powder (Si purity 99.8%, D ₅₀ = 1.5μm; Al purity 99.8%, D ₅₀ = 500nm; Mg purity 99.7%, D ₅₀ = 1.0μm; Si: (Al + Mg ) = 9: 1) and polyamide imide (PAI) were added to normal methylpyrrolidone in a mass ratio of 45: 1 to stir sufficiently to prepare a slurry (solid content 39%). The copper yarn net, copper foam or nickel foam current collector is immersed sufficiently and then scraped off unnecessary sludge on the surface to form a copper foil net, copper yarn net, copper foam or nickel foam current collector system in which the slurry is immersed. Subsequently, the slurry-impregnated copper foil net, copper yarn net, copper foam or nickel foam current collector system was vacuum dried at 90 ° C. for 0.5 hours, and then rolled in at 2.5 MPa pressure to obtain a 3D porous silica-based composite electrode having a desired thickness. A precursor is obtained. Putting the precursor in a box proceeding to a heat treatment under vacuum (degree of vacuum is 2 × 10 ^-3 Pa) or an inert atmosphere and the heat treatment temperature is 600 ℃ and the temperature raising rate is 6 ℃ / min, maintaining time is the alloying proceeds to 4 hours Then, the temperature is lowered to 200 ° C., and the annealing is performed by keeping warm for 2 hours After the heat is bound, electrical heating is stopped and cooled to room temperature in the furnace to obtain a 3D porous silica-based composite anode material. The active materials are Si, Si-Al and Si-Mg partial alloys, which must be maintained in a vacuum or inert atmosphere during heat treatment to prevent oxidation.

The 3D porous silica-based composite negative electrode plate obtained from the copper foil substrate and the metal lithium were used to test the electrochemical performance under the condition of current density of 0.6 mA / cm ² and charge and discharge voltage of 0-2.0V. The discharge capacity of the anode plate reaches 2100mAh / g, the initial efficiency is 90%, and still maintains the capacity of 96% after 50 cycles.

What has been described above is a relatively preferred embodiment of the present invention, not the present invention. Substantial technical solutions of the present invention and all technical solutions obtained through simple modifications, changes, and equivalent structures for the above embodiments are all within the scope of the present invention.

Claims (10)

Method for producing a lithium ion battery 3D porous silica-based composite negative electrode material comprising the following steps:
Step (1): washing the 3D porous current collector material, wherein the material of the 3D porous current collector material is an inert lithium insert metal;
Step (2): a silicon or a mixture of silicon and metal M and a binder are added to a solvent to stir sufficiently to prepare a slurry, and the solvent is an aqueous solvent or an oil solvent, and the 3D porous current collector material is immersed in the slurry. The slurry is immersed to form a 3D porous current collector material, and then the slurry-immersed 3D porous current collector material is vacuum-dried for 0.5 to 1 hour under the conditions of 80 to 90 ° C and roll-in under 2 to 6 MPa pressure. ) To obtain a 3D porous silica-based composite electrode precursor, wherein the metal M is an active lithium insertion metal.
And step (3): the 3D porous silica-based composite electrode precursor obtained in step (2) is heat-treated in a vacuum or inert atmosphere to obtain a 3D porous silica-based composite anode material. According to claim 1, wherein the average pore diameter of the 3D porous current collector material in the step (1) is 100-200μm and the thickness is 400μm ~ 1000μm method for producing a lithium ion battery 3D porous silica-based composite negative electrode material . The method of claim 1, wherein the lithium insertion metal in the step (2) is magnesium, calcium, aluminium, germanium, tin, lead, acetonitrile, styrene, bismuth, platinum, silver, gold, zinc, cadmium, indium Method for producing a lithium ion battery 3D porous silica-based composite negative electrode material, characterized in that one or two or more selected from the group consisting of. The lithium ion battery 3D porous silica system of claim 1, wherein the mixture of silicon, silicon, and metal M in step (2) is present in powder form and has a particle size of micron, submicron, or nanometer. Method for producing a composite negative electrode material. The method of claim 1, wherein the mass ratio of silicon and metal M in the mixture of silicon and metal M in the step (2) is 1: 1 to 9: 1 manufacturing of a lithium ion battery 3D porous silica-based composite negative electrode material Way. The method of manufacturing a lithium ion battery 3D porous silica-based composite anode material according to claim 5, wherein the binder in step (2) is one of carboxymethyl cellulose, polyamide imide, and polyacrylic acid. . 7. The method of manufacturing a lithium ion battery 3D porous silica-based composite anode material according to claim 6, wherein the solid content of the slurry in the step (2) is 30-40%. The method according to claim 7, wherein, during the step (3), the heat treatment is performed to increase the temperature of the 3D porous silica-based composite electrode precursor obtained in the step (2) to 200 ° C to 850 ° C and 2 to 6 hours at 200 ° C to 850 ° C. The alloying treatment is carried out by maintaining the temperature, and subsequently cooled to 100 ° C. to 200 ° C., and then annealed by maintaining the temperature for 1 to 3 hours. After the insulation is bound, the electric heating is stopped and cooled in the furnace to room temperature Method for producing a lithium ion battery 3D porous silica-based composite negative electrode material comprising a.
The method of manufacturing a lithium ion battery 3D porous silica-based composite negative electrode material according to claim 8, wherein the temperature increase rate during the temperature increase process in step (3) is 3-15 ° C / min. A lithium ion battery 3D porous silica-based composite anode material obtained according to any one of claims 1 to 9.

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