KR102228769B1 - Anode material with graphene-agnw-silicon of secondary battery and the method thereof - Google Patents

Abstract

The present invention relates to an anode of a secondary battery including a composition material graphene- silver nanowire-silicon and a method for preparing the same. The method for preparing the anode of the secondary battery including a composition material graphene- silver nanowire-silicon includes: obtaining silicone particles surface-modified with an alkoxysilane-based surface modifier by modifying the silicon particles using the alkoxysilane-based surface modifier; obtaining graphene-silver nanowire-silicon composite material powders by ultrasonic-dispersing the silicone particles surface-modified with the alkoxysilane-based surface modifier, the graphene oxide, silver nanowire, and lithium titanate in a solvent, and freeze-drying and pulverizing the result; and calcinating the graphene-silver nanowire-silicon composite material powders, cooling the result, and mixing the result with a fluorine-based polymer, thereby preparing for the anode of the secondary battery including the composition material graphene-silver nanowire-silicon.

Description

Graphene-silver nanowire-silicon-containing composite material secondary battery anode material and its manufacturing method {ANODE MATERIAL WITH GRAPHENE-AGNW-SILICON OF SECONDARY BATTERY AND THE METHOD THEREOF}

The present invention relates to a graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material and a method for manufacturing the same, and more particularly, silicon particles surface-modified with an alkoxysilane-based surface modifier, graphene oxide, silver nanowire, and lithium The present invention relates to a graphene-silver nanowire-silicon composite material containing titanate-containing graphene-silver nanowire-silicon composite material secondary battery negative electrode material, and a method of manufacturing the same.

In 1991, Sony Corporation of Japan commercialized a 3 V-class lithium secondary battery (LIB), which has an operating voltage three times higher than that of Ni-MH batteries. With the advent of lithium secondary batteries with improved energy density, it is possible to reduce the size and weight of batteries, and lithium secondary batteries have led the mobile device market such as mobile phones and notebook PCs. Currently, lithium secondary battery applications are not only power sources for portable devices, but also in the existing markets such as electric bicycles and power tools, and in recent years, they are used in transportation applications such as HEV, PHEV, EV, and a key field for green growth. Is expanding to.

The future market for large-sized secondary batteries such as electric vehicles is demanding high capacity and high output technologies for lithium secondary batteries. A lithium secondary battery consists of a positive electrode, a negative electrode, a separator, and an organic electrolyte, and uses transition metal oxide as a positive electrode material and carbon as a negative electrode material.

Early lithium secondary batteries used lithium metal as a negative electrode material, but as charging and discharging are repeated, dissolution or dendrite occurs due to ionization of lithium metal, resulting in an internal short circuit of the battery, resulting in a safety problem of the battery. Commercialization failed. After about 20 years of research and development from the 1970s, it was commercialized while solving the battery safety problem by replacing lithium metal with a carbon material. Since commercialization, lithium secondary batteries have dramatically improved battery performance due to the optimization and design of the internal space of the battery, but they have reached their limits at present. Since they can no longer rely on existing methods, battery makers are focusing on developing negative and positive electrode materials for higher capacity and higher output technologies.

The carbon-based negative electrode material has a potential close to the electrode potential of lithium metal, and the change in crystal structure is small during the process of insertion and desorption of lithium ions, enabling continuous and repetitive redox reactions at the electrode, making lithium secondary batteries have high capacity. And it provided a basis for showing an excellent life.

Meanwhile, since the discovery of carbon nanotubes (CNTs) in 1991, both single-walled and multi-walled carbon nanotubes (singlewall CNTs; SWCNTs, multiwall CNTs; MWCNTs) are widely used as anode materials for secondary batteries. The study was conducted. In particular, CNTs have excellent electrical and mechanical properties and thermal stability, as well as adsorption and transport properties, so when used with other cathode materials, much better results are shown.

The highest theoretical storage capacity figure was recorded at 1,116 mAhg-1 when SWCNT was used in the LiC2 structure. This is inferred because lithium ions are inserted in a stable place in the surface of pseudo graphitic layers and inside the central tube of the CNT. However, more research is needed to experimentally confirm this theoretical figure. In order to develop CNT as a negative electrode material for secondary batteries, various synthetic approaches, acid treatments, or surface treatment studies such as ball milling have been actively conducted.

The Di Leo research group developed a lithium secondary battery with a high storage capacity of over 1,050 mAhg-1 using SWCNTs manufactured by a laser vaporization procedure. However, the need to increase coulombic efficiency due to structure defects and high voltage hysteresis of CNTs remains a task. In order to solve this problem, studies focusing on the morphological features of CNTs such as wall thickness, tube diameter, and porosity of CNTs are being actively conducted.

Oktaviano's research group introduced a study that produced chemically perforated CNTs using cobalt oxide. 14 Secondary batteries made using MWCNTs with 4 nm pores recorded high storage capacity, improved cycle stability, and coulomb efficiency.

Meanwhile, in order to improve the storage capacity and long-term stability of the lithium secondary battery, nanostructures such as Si, Ge, Sn, Sn-Sb or metal oxides such as MxOy (M = Fe, Mn, Mo, Cu, Cr, Ni) A lot of research has been conducted to hybridize By manufacturing such a hybrid system, it is possible to obtain the effect of not only improving the electrical conductivity of CNTs, but also reducing the volume change during the charging and discharging process.

For example, the Fan research group was able to obtain a high charging capacity of 800 mAhg-1 by uniformly coating Fe3O4 on CNTs oriented in one direction through magnetron sputtering. In addition, the Mahanthy research group reported that a MoS2/MWCNTs hybrid was prepared that maintained a high storage capacity of 1,030 mAhg-1 after 60 charge/discharge cycles.

In the case of graphene, since it was first introduced in 1987, it has received a lot of attention due to its excellent properties and various applications such as chemical, physical, bio, and engineering. In particular, graphene is evaluated as a very suitable material as a negative electrode material for lithium secondary batteries due to its excellent electrical properties, charge mobility, and specific surface area. However, a theoretical study reported that when graphene exists as a single layer, the amount of lithium that can be charged is less than that of graphite itself (372 mAhg-1).

However, when several graphene sheets are present together, it has been reported that it can have a capacity of 780 or 1,116 mAhg-1, which significantly exceeds the storage capacity of graphite. The first low value is when the adsorption of lithium ions occurs on both sides of graphene (Li2C6 stoichiometry), and the latter is the calculated value when lithium is chemically bonded to the benzene ring of graphene (covalent bond). (LiC2 stoichiometry).

Interestingly, there are a lot of research activities using graphene as a negative electrode material for lithium secondary batteries. The Pan research group manufactured amorphous graphene sheets by various methods to manufacture secondary batteries with a storage capacity of 790 to 1,050 mAhg-1. However, graphene having an amorphous structure has a problem in that its electrical properties are much inferior.

Similarly, Lian's research team developed a secondary battery with a storage capacity of 1,200 mAhg-1 using high-quality graphite (specific surface area ~ 490 m2 g-1) composed of 3 to 4 graphene layers as a negative electrode material. .

Recently, Wang's research group reported a study on developing a doped hierarchically porous graphene electrode and applying it to a secondary battery. This secondary battery showed high lithium storage characteristics during 3,000 repetitive charging and discharging at a current density of 5 Ag-1.

This excellent property is interpreted to be due to the acceleration of the electrochemical reaction and mass transport of lithium due to the porous structure, high conductivity network, and hetero-atom doping.

Among graphenes, nanoribbons made from MWCNTs are particularly highly anticipated in lithium secondary batteries. In particular, the Fahlman research group synthesized both reduced and oxide graphene nanoribbons, of which graphene oxide nanoribbons recorded a stable storage capacity of 800 mAhg-1.

Currently, research on lithium secondary batteries is focused on using various hybrid materials of graphene and metal (metal oxide) or semiconductor materials as suitable anode materials. For example, it is well known that SnO2 has excellent cathode properties, but shows rapid volume changes during repeated charging and discharging.

This problem can be solved by making graphene/SnO2 particle hybrids. In fact, graphene penetrates between SnO2 nanoparticles to increase the electrical conductivity of SnO2, and as a result, a hybrid system of 2~3 nm SnO2 nanoparticles and nitrogen-doped graphene becomes 1,220 mAhg- after 100 charging and discharging. Recorded a high storage capacity of 1. As a new attempt, a secondary battery with excellent stability was developed by planting Fe3O4 nanorods in graphene, showing a storage capacity of 867 mAhg-1 and a capacity reduction of only 5% even after repeated charge/discharge cycles.

On the other hand, the conductive additive is used in a small amount in the electrode, but plays a very important role in improving the performance of the lithium secondary battery. Various sp2 carbon materials such as carbon black (CB), conducting graphite, ethylene black and carbon nanotubes (CNT) have been used as conductive materials.

Kang's research group proved for the first time that graphene, which has excellent electrical conductivity, is an effective conductive material for lithium secondary batteries. In addition, it was revealed that the electrochemical performance of LiFePO4 can be improved through a different contact method compared to the conventional conductive material. Compared to commercial carbon-based conductive materials having a point-to-point conduction mode, graphene has a 2D structure, so it is possible to form a flexible conductive network through the plane-to-point mode. You can connect.

The Lestriez research group showed that the use of graphene significantly improves the electrochemical performance, regardless of the cycling conditions, unlike the conventional Si electrode that used acetylene black as a conductive material. As the amount of the conductive material increases, the electrode electrical resistance decreases until the percolation threshold of the conductive path formed by the conductive material is reached.

Kim's research group showed that the percolation limit of graphene with aspect ratios exceeding 104 in the LTO electrode was 1.8 wt%. According to the concept of distance between particles, the predicted percolation limit was 0.54 wt% for graphene, which was smaller than that for CB particles.

The Oh and Song research groups studied the effect of graphene as a conductive material for negative active materials. As a result of the study, it was found that graphene contributes to the reduction of charge transfer resistance. In addition, graphene provides more active sites into which lithium ions such as edges and defects can be inserted, and even a very small amount ultimately increases the reversible capacity of the electrode. In addition, when graphene is added to the electrode, a larger faradaic pseudocapacitive effect occurs during charging and discharging, thereby improving capacity and high rate performance.

The biggest advantage of using graphene as a conductive material is that the volumetric energy density is improved by using a small amount compared to the existing conductive material. When graphene is exfoliated from bulk graphite, electrons are released and move more easily, resulting in higher electrical conductivity and surface utilization than other types of conductive materials.

In addition, a more efficient hierarchical conduction network can be formed by mixing graphene and other carbon components. When different nanocarbon building blocks are used together to form a hierarchical nanostructure, each element can be well dispersed and a multifunctional conductive network can be formed.

Zhang's research group has succeeded in forming short- and long-distance electron paths in LiFePO4 anodes using hierarchical CNT-CB. With hierarchical CNT-CB, LiFePO4/C anode shows excellent lithium storage performance and improved electrochemical dynamics.

Kang's research group found that lithium secondary batteries made by mixing two types of conductive materials have better performance at low rate and high rate discharge capacity than lithium secondary batteries using single-component conductive materials.

Kim's group showed that when CB nanoparticles were added to CN, the gaps between CNTs were effectively filled, thereby enhancing the solid conduction network. Different geometric shapes, aspect ratios, and dispersion characteristics showed synergistic effects to improve electrical conductivity. Therefore, with a mixed conductive material of 0.2% CNT and 0.2% CB, the percolation limit was low. This result suggests that the percolation limit of the conductive material in the electrode may be lowered, and therefore more efforts should be made to optimize the composition of graphene as a conductive material of a lithium secondary battery. The conductivity of chemically synthesized graphene is lower than that of CB and CNT. This is a task to be solved in the use of graphene in electrochemical applications. Therefore, the conductivity of graphene needs to be further optimized for application of a conductive material.

Another problem with graphene is that it interferes with the diffusion of lithium ions. Kang's research group studied the performance of graphene as a conductive material for commercial 10 Ah batteries. Compared to batteries using commercial conductive materials (7 wt% CB and 3 wt% conductive graphite), 10 Ah batteries using only 1 wt% graphene and 1 wt% CB have low internal resistance under slow charge/discharge rates. And showed high energy density.

However, this cell showed large polarization at high C-rate (> 3C), suggesting that graphene delays lithium ion transport. However, few studies have focused on the optimization of graphene conductive materials. The reason is that different evaluation systems show different results, and coin cells show higher high-speed performance as the graphene content increases, whereas commercial cells show the opposite results.

Kang's research group found that the electrode thickness had a significant effect on the high rate performance of LiFePO4 electrodes using graphene conductive materials. The thicker the electrode, the longer the lithium ion diffusion path, thus exhibiting high polarization and low performance at a high rate. This phenomenon does not appear with thin electrodes used in coin cells. Therefore, much more effort must be made for the practical application of the graphene conductive material, and the electrode structure (eg, hole formation), as well as the sheet size, defects and conductivity, needs to be optimized.

Dispersing graphene evenly on the electrode is another great challenge in this application. Although many methods for dispersing graphene in a liquid have been developed, there are two major problems during the electrode manufacturing process.

First, since the slurry has a large viscosity, graphene cannot be dispersed well with simple stirring and sonication cannot be applied. The second is that the battery industry strictly controls the composition of electrodes in consideration of safety and cycle stability. A variety of dispersing agents may be helpful in dispersing graphene, but only some of them may be used.

It has been reported that graphene can be dispersed using many organic solvents such as NMP for the preparation of slurries. The concentration of the graphene dispersion is too low compared to the actual application, and aggregation occurs when the concentration is too high. A method to solve this is to prepare a hybrid conductive material of graphene and CNT. CNTs act as spacers to prevent agglomeration, so that the obtained dispersion can build a hierarchical conductive network on the electrode.

In addition, another material that is currently emerging as a next-generation anode material for lithium-ion batteries is silicon. Silicon has a theoretical energy density of about 10 times or more than graphite, but its electrical conductivity is very low, and when charging and discharging are repeated, the volume expands by about 4 times. There is even a problem that the battery performance is rapidly reduced due to the breakage of the particles or the peeling of the electrode, which is an obstacle to commercialization. This is the reason why studies on the complexization of silicon and various materials are actively conducted at home and abroad to overcome this.

As such, it is the biggest problem to solve the phenomenon that the battery life is shortened due to the low electrical conductivity of silicon, the side reaction of the electrolyte, and the increase in the thickness of the negative electrode due to the change in the silicon volume. Accordingly, the development of a silicon-carbon-based composite material was suggested as a solution, and in particular, the development of a silicon-graphene composite material having high electrical conductivity and excellent mechanical strength is actively progressing.

In accordance with the above circumstances, the present invention is to propose a new technology for a negative electrode material for a composite secondary battery including graphene and silicon, which has a very high electrical conductivity and sufficient stability.

Next, the prior art existing in the field to which the technology of the present invention belongs will be briefly described, and then the technical matters that the present invention intends to achieve differently compared to the prior art will be described.

First, Korean Patent Publication No. 10-2014-0036496 (published on 26 March 2014) discloses a silicon-graphene composite material that can be used as a negative electrode material for a secondary battery. The method of manufacturing the silicon-graphene-based composite includes a first step of forming a porous material by mixing silicon chloride and glycol, which is a dihydric alcohol; A second step of heat-treating the porous material in an inert gas atmosphere to form a silicon oxide represented by the general formula SiOx in which the oxygen content (x) is in the range of 0<x<2; A third step of forming a composite powder of Si-SiOx by mixing and solid-phase reaction of the silicon oxide and the metal silicon formed in the second step; And a fourth step of heat-treating in an inert gas atmosphere after mixing the Si-SiOx composite powder and graphene powder formed in the third step; Has been.

In addition, Korean Patent Application Publication No. 10-2017-0120254 (published on October 31, 2017) includes the steps of preparing a buffer solution containing dopamine hydrochloride; Forming a first solution by mixing silicon nanoparticles with the buffer solution, and forming silicon nanoparticles coated with polydopamine; Forming a sandwich-type graphene composite structure by alternately filtering a second solution containing a graphene oxide sheet and a first solution containing silicon nanoparticles coated with the polydopamine; And thermally treating the sandwich-type graphene composite structure to form carbon-coated silicon nanoparticles, and inducing a chemical bond between the carbon-coated silicon nanoparticles and the graphene oxide sheet. A method of manufacturing a pin composite structure is described.

In addition, Korean Patent Publication No. 10-1634723 (published on 30.06.2016) discloses that a colloidal solution in which a water-soluble carbon precursor and graphene oxide are mixed in a silicon sludge solution composed of silicon particles and silicon carbide particles is subjected to ultrasonic treatment. A secondary battery anode material using a silicon-carbon-graphene composite that simultaneously sprays a colloidal solution and then performs drying and heat treatment processes to selectively separate silicon particles and simultaneously manufacture a silicon-carbon-graphene composite in a single process. Description of the related art is described.

The prior art documents include technology related to a secondary battery anode material including silicon and graphene, but development of a silicon-graphene composite anode material having higher electrical conductivity and excellent mechanical strength and stability is still required. There is a situation.

Unexamined Patent Publication No. 10-2014-0036496 (2014.03.26. Publication date) Unexamined Patent Publication No. 10-2017-0120254 (published on October 31, 2017) Registered Patent Publication No. 10-1634723 (2016.06.30. Publication date)

The present invention was created to solve the above problems, in a silicon-graphene composite negative electrode material comprising silicon and graphene, graphene oxide, silver nanowire, lithium titer on silicon particles as an alkoxysilane-based surface modifier. By mixing nate and fluorine-based polymer (binder), the surface-modified silicon forms a network by chemically or physically bonding with graphene oxide, silver nanowire, lithium titanate, and fluorine-based polymer polymer to form a network. An object thereof is to provide a silicon-graphene composite negative electrode material having high electrical conductivity and stability compared to graphene-containing negative electrode materials for secondary batteries.

The method for manufacturing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to an embodiment of the present invention includes surface-modified silicon particles with an alkoxysilane-based surface modifier, and surface-modified with an alkoxysilane-based surface modifier. Obtaining a; Step of obtaining a graphene-silver nanowire-silicon composite powder by ultrasonically dispersing silicon particles, graphene oxide, silver nanowires and lithium titanate surface-modified with the alkoxysilane-based surface modifier in a solvent, freeze-drying, and pulverizing ; And calcining the graphene-silver nanowire-silicon composite material powder, cooling it, and mixing it with a fluorine-based polymer polymer to prepare a graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material. It is characterized.

In addition, in the method of manufacturing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to an embodiment of the present invention, the alkoxysilane-based surface modifier is characterized in that it is a material represented by the following formula (A).

[Formula A]

Si(OR)4-nXn

R means a C1 to C3 alkyl group, X may be a C1 to C6 alkylene group including an amine group, an epoxy group, a carbonyl group, a carboxyl group or a thiol group at the terminal, and n may be 1 or 2.

In addition, in the method for manufacturing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to an embodiment of the present invention, the alkoxysilane-based surface modifier is 3-aminopropyltriethoxysilane, 3-aminopropyltri Methoxysilane, (3-glycidyloxypropyl) triethoxysilane, (3-glycidyloxypropyl) trimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, diethoxy(3-glycidyloxypropyl)methoxysilane, (3-mercaptopropyl)trimethoxysilane and (3-mer) It is characterized in that it contains at least one or more of captopropyl) triethoxysilane.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder may include 35 to 45 wt%, 5 to 15 wt% of silver nanowire, 20 to 30 wt% of silicon particles surface-modified with an alkoxysilane-based surface modifier, and 15 to 25 wt% of lithium titanate were ultrasonically dispersed in a solvent, and then freeze-dried and pulverized. It is characterized in that to obtain a graphene-silver nanowire-silicon composite material powder.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes the alkoxysilane-based surface Silicon particles, graphene oxide, silver nanowire, lithium titanate, and conductive carbon black surface-modified with a modifier are ultrasonically dispersed in a solvent, freeze-dried, and pulverized to obtain graphene-silver nanowire-silicon composite powder. It is done.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder may include 35 to 45 wt%, 5 to 15 wt% of silver nanowires, 20 to 30 wt% of silicon particles surface-modified with an alkoxysilane-based surface modifier, 15 to 25 wt% of lithium titanate, and 5 to 10 wt% of conductive carbon black are ultrasonicated in a solvent After dispersing, it is characterized in that the graphene-silver nanowire-silicon composite material powder is obtained by pulverizing after freeze-drying.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes the alkoxysilane-based surface Silicon particles, graphene oxide, silver nanowire, lithium titanate and tin acetate surface-modified with a modifier are ultrasonically dispersed in a solvent, freeze-dried, and pulverized to obtain graphene-silver nanowire-silicon composite powder. It is done.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder may include 35 to 45 wt%, 5 to 15 wt% of silver nanowires, 20 to 30 wt% of silicon particles surface-modified with an alkoxysilane-based surface modifier, 15 to 25 wt% of lithium titanate, and 5 to 10 wt% of tin acetate in a solvent After ultrasonic dispersion, freeze-drying and pulverization to obtain graphene-silver nanowire-silicon composite powder.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes the alkoxysilane-based surface Silicon particles, graphene oxide, silver nanowire, lithium titanate, and cobalt acetate surface-modified with a modifier are ultrasonically dispersed in a solvent, freeze-dried, and pulverized to obtain graphene-silver nanowire-silicon composite powder. It is done.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder may include 35 to 45 wt%, 5 to 15 wt% of silver nanowire, 20 to 30 wt% of silicon particles surface-modified with an alkoxysilane-based surface modifier, 15 to 25 wt% of lithium titanate, and 5 to 10 wt% of cobalt acetate are ultrasonicated in a solvent After dispersing, it is characterized in that the graphene-silver nanowire-silicon composite material powder is obtained by pulverizing after freeze-drying.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes the alkoxysilane-based surface Silicon particles, graphene oxide, silver nanowires, lithium titanate, tin acetate, and cobalt acetate surface-modified with a modifier are ultrasonically dispersed in a solvent, freeze-dried, and pulverized to obtain graphene-silver nanowire-silicon composite powder. Characterized in that to obtain.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder may include 35 to 45 wt%, silver nanowire 5 to 15 wt%, silicone particles surface-modified with alkoxysilane-based surface modifier 20 to 30 wt%, lithium titanate 15 to 25 wt%, tin acetate 5 to 10 wt% and cobalt acetate 5 to 10 wt% is ultrasonically dispersed in a solvent, and then freeze-dried and pulverized to obtain graphene-silver nanowire-silicon composite powder.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes the alkoxysilane-based surface Silicon particles, graphene oxide, silver nanowire, lithium titanate, conductive carbon black, tin acetate, and cobalt acetate surface modified with a modifier are ultrasonically dispersed in a solvent, freeze-dried, and pulverized to form graphene-silver nanowire-silicon. It is characterized in that to obtain a composite powder.

In addition, in the method for manufacturing a negative electrode material for a graphene-silver nanowire-silicon-containing composite material secondary battery according to an embodiment of the present invention, the step of obtaining the graphene-silver nanowire-silicon composite material powder may include 35 to 45 wt%, silver nanowire 5 to 15 wt%, silicon particles surface-modified with alkoxysilane-based surface modifier 20 to 30 wt%, lithium titanate 15 to 25 wt%, conductive carbon black 5 to 10 wt%, tin acetate 5 to 10 wt% and 5 to 10 wt% of cobalt acetate are ultrasonically dispersed in a solvent, and then freeze-dried and pulverized to obtain a graphene-silver nanowire-silicon composite powder.

In addition, in the method for manufacturing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to an embodiment of the present invention, the fluorine-based polymer polymer is a polyvinylidene fluoride (PVDF) polymer, a polyvinylidene fluoride. Polyvinylidene Fluoride-Hexafluoropropylene Copolymer, Polyvinylidene Fluoride-Chlorotrifluoroethylene (CTFE) Copolymer and Polyvinylidene Fluoride-Hexafluoropropylene Copolymer -Tetrafluoroethylene, TFE) is characterized in that one selected from the copolymer.

In addition, in the method for manufacturing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to an embodiment of the present invention, the step of preparing the negative electrode material for a composite material secondary battery containing the graphene-silver nanowire-silicon material includes, calcination It is characterized in that a graphene-silver nanowire-silicon composite material secondary battery negative electrode material is prepared by mixing 85 to 95 wt% of the treated graphene-silver nanowire-silicon composite powder and 5 to 15 wt% of a fluorine-based polymer polymer. .

In addition, in the method for manufacturing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to an embodiment of the present invention, the step of preparing the negative electrode material for a composite material secondary battery containing the graphene-silver nanowire-silicon, the The graphene-silver nanowire-silicon composite material powder is calcined at 700 to 900°C for 6 to 12 hours to prepare a graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material.

In addition, in the method for manufacturing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to an embodiment of the present invention, the silver nanowire has a diameter of 5 to 50 nm, a length of 50 to 200 μm, and an aspect ratio of 1000 It is characterized in that to 40000.

In addition, the graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material according to another embodiment of the present invention is characterized in that it is manufactured by any one of the above manufacturing methods.

In addition, the graphene-silver nanowire-silicon-containing composite secondary battery negative electrode according to another embodiment of the present invention includes the graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material using an electrospray method to collect current. It is characterized in that it is manufactured by applying it on the whole.

The graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material according to the present invention is, in a silicon-graphene composite negative electrode material including silicon and graphene, graphene oxide on silicon particles as an alkoxysilane-based surface modifier, By mixing silver nanowire, lithium titanate and fluorine-based polymer polymer, the surface-modified silicon forms a dense network by chemically or physically bonding with graphene oxide, silver nanowire, lithium titanate, and fluorine-based polymer polymer. Compared to the silicon and graphene-containing negative electrode materials of secondary batteries, it has a high charge-discharge capacity and has high stability, such as a reduction in volume expansion rate.

In addition, the graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material according to the present invention is used to mix silicon, graphene, and silver nanowires in a silicon-graphene composite negative electrode material including silicon and graphene. In this regard, by including conductive carbon black in addition to graphene oxide and silver nanowires, there is an effect of having high electrical conductivity and stability while lowering the manufacturing cost of the negative electrode agent.

In addition, the graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material according to the present invention is, in the silicon-graphene composite negative electrode material including silicon and graphene, by additionally including a tin metal salt and/or a cobalt metal salt. , There is an effect of manufacturing a high-capacity negative electrode material.

1 is a flow chart showing a method of manufacturing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, a preferred implementation of a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to the present invention so that those of ordinary skill in the art can easily implement the present invention. Let's explain the example in detail.

In each drawing of the present invention, the size or dimensions of the structures are shown to be enlarged or reduced than in actuality for the sake of clarity of the present invention, and the known configurations have been omitted so as to reveal a characteristic configuration, so the drawings are not limited thereto. .

In describing the principle of the preferred embodiment of the present invention in detail, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

The present invention relates to a graphene-silver nanowire-silicon-containing composite secondary battery anode material having a network structure of silicon particles, graphene oxide, silver nanowire, lithium titanate, and fluorine-based polymer polymer.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a flow chart showing a method of manufacturing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to an embodiment of the present invention.

As shown in FIG. 1, the method for manufacturing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon according to the present invention includes surface-modifying silicon particles with an alkoxysilane-based surface modifier, and using an alkoxysilane-based surface modifier. Obtaining surface-modified silicon particles (S101); Step of obtaining a graphene-silver nanowire-silicon composite powder by ultrasonically dispersing silicon particles, graphene oxide, silver nanowires and lithium titanate surface-modified with the alkoxysilane-based surface modifier in a solvent, freeze-drying, and pulverizing (S102); And calcining the graphene-silver nanowire-silicon composite material powder, cooling it, and mixing it with a fluorine-based polymer polymer (binder) to prepare a graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material (S103 ); includes.

The graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material manufacturing method according to the present invention uses silicon particles as an alkoxysilane-based surface modifier as described above, so that it is difficult to combine silicon materials with graphene and silver nanoparticles. Chemical bonding including hydrogen bonding of two-dimensional materials such as wires is possible, and then crosslinking reactions with crosslinkable polymers can be effectively performed.

At this time, the alkoxy silane-based surface modifier refers to a surface modifier including two or three alkoxy groups (-OR) in Si atoms, and specifically represented by the following formula (A).

[Formula A]

Si(OR)4-nXn

R means a C1 to C3 alkyl group, X may be a C1 to C6 alkylene group including an amine group, an epoxy group, a carbonyl group, a carboxyl group or a thiol group at the terminal, and n may be 1 or 2.

More specifically, the alkoxy silane-based surface modifier, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, (3-glycidyloxypropyl)triethoxysilane, (3-glycy) Dyloxypropyl)trimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, diethoxy(3 -Glycidyloxypropyl)methoxysilane, (3-mercaptopropyl)trimethoxysilane, and (3-mercaptopropyl)triethoxysilane may contain at least one or more.

In addition, in order to significantly improve the tensile strength of the graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material according to the present invention, an amine group may be introduced on the surface of silicon. Selected from methoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and N-(2-aminoethyl)-3-aminopropyltriethoxysilane One or two or more compounds to be used may be used as a surface modifier.

On the other hand, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes 35 to 45 wt% of graphene oxide, 5 to 15 wt% of silver nanowire, and 20 to 30 silicon particles surface-modified with an alkoxy silane-based surface modifier. wt% and 15 to 25 wt% of lithium titanate were ultrasonically dispersed in a solvent, freeze-dried, and pulverized to obtain graphene-silver nanowire-silicon composite powder. By freeze drying as described above, the microstructure and properties of the materials contained in the graphene-silver nanowire-silicon composite powder are prevented from being destroyed or deformed.

In addition, as another embodiment, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes silicon particles surface-modified with the alkoxysilane-based surface modifier, graphene oxide, silver nanowire, lithium titanate, and The conductive carbon black may be ultrasonically dispersed in a solvent, freeze-dried, and then pulverized to obtain graphene-silver nanowire-silicon composite powder.

In this case, the preferred mixing composition ratio is 35 to 45 wt% of graphene oxide, 5 to 15 wt% of silver nanowire, 20 to 30 wt% of silicon particles surface-modified with an alkoxysilane-based surface modifier, 15 to 25 wt% of lithium titanate, and 5 to 10 wt% of conductive carbon black is ultrasonically dispersed in a solvent.

In addition, as another embodiment, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes silicon particles surface-modified with the alkoxysilane-based surface modifier, graphene oxide, silver nanowire, lithium titanate, and After the tin acetate is ultrasonically dispersed in a solvent, freeze-dried and pulverized to obtain a graphene-silver nanowire-silicon composite powder.

In this case, the preferred mixing composition ratio is 35 to 45 wt% of graphene oxide, 5 to 15 wt% of silver nanowire, 20 to 30 wt% of silicon particles surface-modified with an alkoxysilane-based surface modifier, 15 to 25 wt% of lithium titanate, and And 5 to 10 wt% of tin acetate are ultrasonically dispersed in a solvent.

In addition, as another embodiment, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes silicon particles surface-modified with the alkoxysilane-based surface modifier, graphene oxide, silver nanowire, lithium titanate, and After the cobalt acetate is ultrasonically dispersed in a solvent, freeze-dried and pulverized to obtain graphene-silver nanowire-silicon composite powder.

In this case, the preferred mixing composition ratio is 35 to 45 wt% of graphene oxide, 5 to 15 wt% of silver nanowire, 20 to 30 wt% of silicon particles surface-modified with an alkoxysilane-based surface modifier, 15 to 25 wt% of lithium titanate, and 5 to 10 wt% of cobalt acetate is ultrasonically dispersed in a solvent.

In addition, as another embodiment, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes silicon particles surface-modified with the alkoxysilane-based surface modifier, graphene oxide, silver nanowire, lithium titanate, The tin acetate and cobalt acetate are ultrasonically dispersed in a solvent, and then freeze-dried and pulverized to obtain a graphene-silver nanowire-silicon composite powder.

In this case, the preferred mixing composition ratio is 35 to 45 wt% of graphene oxide, 5 to 15 wt% of silver nanowire, 20 to 30 wt% of silicon particles surface-modified with an alkoxysilane-based surface modifier, 15 to 25 wt% of lithium titanate, 5 to 10 wt% of tin acetate and 5 to 10 wt% of cobalt acetate are ultrasonically dispersed in a solvent.

In addition, as another embodiment, the step of obtaining the graphene-silver nanowire-silicon composite material powder includes silicon particles surface-modified with the alkoxysilane-based surface modifier, graphene oxide, silver nanowire, lithium titanate, Conductive carbon black, tin acetate, and cobalt acetate are ultrasonically dispersed in a solvent, and then freeze-dried and pulverized to obtain graphene-silver nanowire-silicon composite powder.

In this case, the preferred mixing composition ratio is 35 to 45 wt% of graphene oxide, 5 to 15 wt% of silver nanowire, 20 to 30 wt% of silicon particles surface-modified with an alkoxysilane-based surface modifier, 15 to 25 wt% of lithium titanate, 5 to 10 wt% of conductive carbon black, 5 to 10 wt% of tin acetate, and 5 to 10 wt% of cobalt acetate are ultrasonically dispersed in a solvent.

In addition, the solvent used in the step of obtaining the graphene-silver nanowire-silicon composite material powder includes both inorganic and organic solvents, and more preferably, an organic solvent is used.

The organic solvent used in the step of obtaining the graphene-silver nanowire-silicon composite powder is ethanol, methanol, ethylene glycol or isopropanol, n-butanol, diethyl ether, toluene, tetrahydrofuran, chloroform, dichloromethane, Benzene and at least one of N, N-dimethylformamide.

In addition, in the step of preparing the graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material, the fluorine-based polymer polymer mixed as a binder with the graphene-silver nanowire-silicon composite material powder is polyvinylidene fluoride. Fluoride, PVDF) polymer, polyvinylidene Fluoride-Hexafluoropropylene copolymer, polyvinylidene fluoride-chlorotrifluoroethylene (CTFE) copolymer and polyvinylidene It includes one selected from fluoride-tetrafluoroethylene (Polyvinylidene Fluoride-Tetrafluoroethylene, TFE) copolymers.

In addition, the preferred mixing composition ratio in the step of preparing the graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material is calcined graphene-silver nanowire-silicon composite powder 85 to 95 wt% and a fluorine-based polymer polymer It is preferred to mix 5 to 15 wt%.

In addition, in the step of preparing the negative electrode material for the graphene-silver nanowire-silicon-containing composite material secondary battery, the graphene-silver nanowire-silicon composite material powder is calcined at 700 to 900°C for 6 to 12 hours. It is preferable to perform the calcining treatment at 750 to 850° C. for 8 to 10 hours.

Graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material according to an embodiment of the present invention includes all of the negative electrode material manufactured by the above-described manufacturing method.

Hereinafter, the result of evaluating the characteristics of the negative electrode material of the graphene-silver nanowire-silicon-containing composite secondary battery according to the present invention will be described through examples.

<Example 1>

To 94 g of silicone, 5 g of 3-aminopropyltriethoxysilane and 1 g of hydrogen chloride are mixed with an alkoxy silane-based surface modifier, and stirred for 4 hours using a bead mill to prepare silicone modified with an alkoxy silane-based surface modifier.

After ultrasonically dispersing 25 g of silicon particles surface-modified with the alkoxysilane-based surface modifier, 40 g of graphene oxide, 10 g of silver nanowire and 20 g of lithium titanate in ethanol, freeze at -30°C and vacuum at 0.5 mmHg After drying, it is pulverized to prepare a graphene-silver nanowire-silicon composite powder.

The graphene-silver nanowire-silicon composite powder thus prepared was calcined at 800°C, cooled to room temperature, and then mixed with 5 g of PVDF (Polyvinylidene Fluoride) as a binder, and stirred for 2 hours to make graphene-silver nanoparticles. Wire-Silicone-containing composite material secondary battery negative electrode material is manufactured.

<Example 2>

To 94 g of silicone, 5 g of 3-aminopropyltriethoxysilane and 1 g of hydrogen chloride are mixed with an alkoxy silane-based surface modifier, and stirred for 4 hours using a bead mill to prepare silicone modified with an alkoxy silane-based surface modifier.

25 g of silicon particles surface-modified with the alkoxysilane-based surface modifier, 30 g of graphene oxide, 10 g of silver nanowire, 10 g of conductive carbon black and 20 g of lithium titanate were ultrasonically dispersed in ethanol, and then frozen at -30°C. Then, vacuum-dried at 0.5 mmHg and pulverized to prepare a graphene-silver nanowire-silicon composite powder.

The graphene-silver nanowire-silicon composite powder thus prepared was calcined at 800°C, cooled to room temperature, and then mixed with 5 g of PVDF (Polyvinylidene Fluoride) as a binder, and stirred for 2 hours to make graphene-silver nanoparticles. Wire-Silicone-containing composite material secondary battery negative electrode material is manufactured.

<Example 3>

To 94 g of silicone, 5 g of 3-aminopropyltriethoxysilane and 1 g of hydrogen chloride are mixed with an alkoxy silane-based surface modifier, and stirred for 4 hours using a bead mill to prepare silicone modified with an alkoxy silane-based surface modifier.

25 g of silicon particles surface-modified with the alkoxysilane-based surface modifier, 30 g of graphene oxide, 10 g of silver nanowire, 20 g of lithium titanate and 10 g of tin acetate were ultrasonically dispersed in ethanol, and then frozen at -30°C. Then, vacuum-dried at 0.5 mmHg and pulverized to prepare a graphene-silver nanowire-silicon composite powder.

The graphene-silver nanowire-silicon composite powder thus prepared was calcined at 800°C, cooled to room temperature, and then mixed with 5 g of PVDF (Polyvinylidene Fluoride) as a binder, and stirred for 2 hours to make graphene-silver nanoparticles. Wire-Silicone-containing composite material secondary battery negative electrode material is manufactured.

<Example 4>

To 94 g of silicone, 5 g of 3-aminopropyltriethoxysilane and 1 g of hydrogen chloride are mixed with an alkoxy silane-based surface modifier, and stirred for 4 hours using a bead mill to prepare silicone modified with an alkoxy silane-based surface modifier.

25 g of silicon particles surface-modified with the alkoxysilane-based surface modifier, 30 g of graphene oxide, 10 g of silver nanowire, 20 g of lithium titanate and 10 g of cobalt acetate were ultrasonically dispersed in ethanol, and then frozen at -30°C. Then, vacuum-dried at 0.5 mmHg and pulverized to prepare a graphene-silver nanowire-silicon composite powder.

The graphene-silver nanowire-silicon composite powder thus prepared was calcined at 800°C, cooled to room temperature, and then mixed with 5 g of PVDF (Polyvinylidene Fluoride) as a binder, and stirred for 2 hours to make graphene-silver nanoparticles. Wire-Silicone-containing composite material secondary battery negative electrode material is manufactured.

<Example 5>

To 94 g of silicone, 5 g of 3-aminopropyltriethoxysilane and 1 g of hydrogen chloride are mixed with an alkoxy silane-based surface modifier, and stirred for 4 hours using a bead mill to prepare silicone modified with an alkoxy silane-based surface modifier.

After ultrasonic dispersion of 25 g of silicon particles surface-modified with the alkoxysilane-based surface modifier, 30 g of graphene oxide, 10 g of silver nanowire, 10 g of lithium titanate, 10 g of tin acetate and 10 g of cobalt acetate in ethanol ,-After freezing at -30 ℃ vacuum drying at 0.5 mmHg, and then pulverized to prepare a graphene-silver nanowire-silicon composite material powder.

The graphene-silver nanowire-silicon composite powder thus prepared was calcined at 800°C, cooled to room temperature, and then mixed with 5 g of PVDF (Polyvinylidene Fluoride) as a binder, and stirred for 2 hours to make graphene-silver nanoparticles. Wire-Silicone-containing composite material secondary battery negative electrode material is manufactured.

<Example 6>

To 94 g of silicone, 5 g of 3-aminopropyltriethoxysilane and 1 g of hydrogen chloride are mixed with an alkoxy silane-based surface modifier, and stirred for 4 hours using a bead mill to prepare silicone modified with an alkoxy silane-based surface modifier.

20 g of silicon particles surface-modified with the alkoxysilane-based surface modifier, 30 g of graphene oxide, 10 g of silver nanowire, 10 g of conductive carbon black, 10 g of lithium titanate, 8 g of tin acetate and 7 g of cobalt acetate After ultrasonic dispersion in ethanol, frozen at -30°C, vacuum-dried at 0.5 mmHg, and pulverized to prepare a graphene-silver nanowire-silicon composite powder.

The graphene-silver nanowire-silicon composite powder thus prepared was calcined at 800°C, cooled to room temperature, and then mixed with 5 g of PVDF (Polyvinylidene Fluoride) as a binder, and stirred for 2 hours to make graphene-silver nanoparticles. Wire-Silicone-containing composite material secondary battery negative electrode material is manufactured.

Table 1 below is a table showing the composition ratio of the negative electrode material of the graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material according to Examples 1 to 6.

unit
(wt%) silicon
(Reform O) Oxidation
Graphene Silver nano
wire conductivity
Carbon black lithium
Titanate Remark
Acetate cobalt
Acetate PVDF Example 1 25 40 10 - 20 - - 5 Example 2 25 30 10 10 20 - - 5 Example 3 25 30 10 - 20 10 - 5 Example 4 25 30 10 - 20 - 10 5 Example 5 25 30 10 - 10 10 10 5 Example 6 20 30 10 10 10 8 7 5

<Comparative Example 1>

45 g of silicon particles and 50 g of graphene oxide were ultrasonically dispersed in ethanol, frozen at -30°C, vacuum-dried at 0.5 mmHg, and pulverized to prepare graphene-silicon powder.

The graphene-silicon powder thus prepared was calcined at 800°C, cooled to room temperature, mixed with 5 g of SBR (Styrene-Butadiene Rubber) as a binder, and stirred for 2 hours to form a graphene-silicon composite negative electrode material. To manufacture.

<Comparative Example 2>

45 g of silicon particles, 30 g of graphene oxide, and 20 g of carbon nanotubes were ultrasonically dispersed in ethanol, frozen at -30°C, vacuum-dried at 0.5 mmHg, and pulverized to prepare graphene-silicon powder.

The graphene-silicon powder thus prepared was calcined at 800°C, cooled to room temperature, mixed with 5 g of SBR (Styrene-Butadiene Rubber) as a binder, and stirred for 2 hours to form a graphene-silicon composite negative electrode material. To manufacture.

<Comparative Example 3>

45 g of silicon particles, 30 g of graphene oxide, and 20 g of carbon nanotubes were ultrasonically dispersed in ethanol, frozen at -30°C, vacuum-dried at 0.5 mmHg, and pulverized to prepare graphene-silicon powder.

The graphene-silicon powder thus prepared was calcined at 800°C, cooled to room temperature, mixed with 5 g of PVDF (Polyvinylidene Fluoride) as a binder, and stirred for 2 hours to prepare a graphene-silicon composite negative electrode material. do.

Table 2 below is a table showing the composition ratio of graphene-silicon anode materials according to Comparative Examples 1 to 3.

unit
(wt%) silicon
(Modification X) Oxidation
Graphene carbon
Nanotube conductivity
Carbon black lithium
Titanate Remark
Acetate cobalt
Acetate SBR Comparative Example 1 45 50 - - - - - 5 Comparative Example 2 45 30 20 - - - - 5 Comparative Example 3 45 30 20 - - - - PVDF 5

<Experimental Example>

The negative electrode materials prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were coated on a copper current collector at a level of 60 μm by electrospraying to prepare a negative electrode thin film. The negative electrode on which the final thin film was formed was compressed through a heating roll press, and the electrode density was controlled to be 1.6 g/cc. Lithium secondary batteries each employing the negative electrodes thus prepared were fabricated to evaluate the characteristics of the lithium secondary batteries. Table 3 below is a table showing the characteristics of a lithium secondary battery employing the negative electrode materials of Examples 1 to 6 and Comparative Examples 1 to 3.

unit
(wt%) Charging capacity
(mAh/g) Discharge capacity
(mAh/g) Capacity retention rate
(%) Volume expansion rate
(%) Capacity per electrode volume (mAh/cc) Example 1 645 587 91.00775194 47 876 Example 2 654 610 93.27217125 45 878 Example 3 661 620 93.79727685 46 886 Example 4 669 629 94.02092676 39 897 Example 5 691 651 94.21128799 37 1009 Example 6 721 681 94.45214979 34 1379 Comparative Example 1 535 439 82.05607477 98 761 Comparative Example 2 546 452 82.78388278 88 785 Comparative Example 3 601 536 89.18469218 85 804

As shown in Table 3, as shown in Examples 1 to 6, when graphene and silicon are mixed, when silicon particles and silver nanowires surface-modified with an alkoxysilane-based surface modifier are mixed, silicon and carbon nanowires that are not surface-modified It can be seen that when the tubes are mixed, they exhibit a higher charge-discharge capacity and have a higher electrode volume per volume.

In addition, when graphene and silicon are mixed, when silicon particles and silver nanowires surface-modified with an alkoxysilane-based surface modifier are used, it has been shown that the characteristics of significantly lowering the volume expansion rate can be maintained for a long time compared to when using unmodified silicon.

In addition, it was found that the charge-discharge capacity characteristics can be further improved when conductive carbon black, tin acetate, and cobalt acetate are mixed in an appropriate composition as in Examples 2 to 6 in addition to silicon and graphene.

As described above, the present invention has been described with reference to the embodiments shown in the accompanying drawings, but this is only exemplary, and various modifications and other equivalent embodiments are possible from those of ordinary skill in the art. You will understand. Therefore, the technical protection scope of the present invention should be determined by the following claims.

S101: obtaining surface-modified silicon particles
S102: obtaining a graphene-silver nanowire-silicon composite material powder
S103: preparing a negative electrode material for a composite material secondary battery containing graphene-silver nanowire-silicon

Claims (20)

Surface-modifying the silicone particles with an alkoxy silane-based surface modifier to obtain silicone particles surface-modified with an alkoxy silane-based surface modifier;
Step of obtaining a graphene-silver nanowire-silicon composite powder by ultrasonically dispersing silicon particles, graphene oxide, silver nanowires and lithium titanate surface-modified with the alkoxysilane-based surface modifier in a solvent, freeze-drying, and pulverizing ; And
The graphene-silver nanowire-silicon composite material powder is calcined, cooled, and mixed with a fluorine-based polymer polymer to prepare a graphene-silver nanowire-silicon-containing composite secondary battery negative electrode material; Graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material manufacturing method.
The method of claim 1,
The alkoxy silane-based surface modifier,
Graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material manufacturing method, characterized in that the material represented by the following formula (A).
[Formula A]
Si(OR)4-nXn
R means a C1 to C3 alkyl group, X may be a C1 to C6 alkylene group including an amine group, an epoxy group, a carbonyl group, a carboxyl group or a thiol group at the terminal, and n may be 1 or 2.
The method of claim 1,
The alkoxy silane-based surface modifier,
3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, (3-glycidyloxypropyl) triethoxysilane, (3-glycidyloxypropyl) trimethoxysilane, N-(2 -Aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, diethoxy(3-glycidyloxypropyl)methoxysilane, (3 -Mercaptopropyl) trimethoxysilane and (3-mercaptopropyl) triethoxysilane, characterized in that it comprises at least one or more of graphene-silver nanowire-silicon-containing composite material secondary battery anode material manufacturing method.
The method of claim 1,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
After ultrasonically dispersing 35 to 45 wt% of graphene oxide, 5 to 15 wt% of silver nanowire, 20 to 30 wt% of silicon particles surface-modified with an alkoxysilane-based surface modifier, and 15 to 25 wt% of lithium titanate in a solvent, Graphene-silver nanowire-silicon composite material secondary battery anode material manufacturing method, characterized in that the pulverization after freeze-drying to obtain a powder.
The method of claim 1,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
The silicon particles, graphene oxide, silver nanowire, lithium titanate, and conductive carbon black surface-modified with the alkoxysilane-based surface modifier are ultrasonically dispersed in a solvent, freeze-dried, and pulverized to form a graphene-silver nanowire-silicon composite powder. Graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material manufacturing method, characterized in that to obtain a.
The method of claim 5,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
Graphene oxide 35 to 45 wt%, silver nanowire 5 to 15 wt%, silicon particles surface-modified with an alkoxysilane-based surface modifier 20 to 30 wt%, lithium titanate 15 to 25 wt%, and conductive carbon black 5 to 10 wt % Is ultrasonically dispersed in a solvent, freeze-dried, and then pulverized to obtain graphene-silver nanowire-silicon composite powder.
The method of claim 1,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
The silicon particles, graphene oxide, silver nanowire, lithium titanate, and tin acetate surface-modified with the alkoxysilane-based surface modifier are ultrasonically dispersed in a solvent, freeze-dried, and pulverized to form a graphene-silver nanowire-silicon composite powder. Graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material manufacturing method, characterized in that to obtain a.
The method of claim 7,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
Graphene oxide 35 to 45 wt%, silver nanowire 5 to 15 wt%, silicon particles surface-modified with an alkoxysilane-based surface modifier 20 to 30 wt%, lithium titanate 15 to 25 wt%, and tin acetate 5 to 10 Graphene-silver nanowire-silicon composite material secondary battery anode material manufacturing method, characterized in that by ultrasonically dispersing wt% in a solvent, followed by lyophilization and pulverization to obtain a graphene-silver nanowire-silicon composite powder.
The method of claim 1,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
The silicon particles, graphene oxide, silver nanowire, lithium titanate, and cobalt acetate surface-modified with the alkoxysilane-based surface modifier are ultrasonically dispersed in a solvent, freeze-dried, and pulverized to form a graphene-silver nanowire-silicon composite powder. Graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material manufacturing method, characterized in that to obtain a.
The method of claim 9,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
Graphene oxide 35 to 45 wt%, silver nanowire 5 to 15 wt%, silicon particles surface-modified with an alkoxysilane-based surface modifier 20 to 30 wt%, lithium titanate 15 to 25 wt%, and cobalt acetate 5 to 10 wt % Is ultrasonically dispersed in a solvent, freeze-dried, and then pulverized to obtain graphene-silver nanowire-silicon composite powder.
The method of claim 1,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
Silicon particles, graphene oxide, silver nanowire, lithium titanate, tin acetate, and cobalt acetate surface-modified with the alkoxysilane-based surface modifier are ultrasonically dispersed in a solvent, freeze-dried, and pulverized to graphene-silver nanowire- Graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material manufacturing method, characterized in that to obtain a silicon composite material powder.
The method of claim 11,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
Graphene oxide 35 to 45 wt%, silver nanowire 5 to 15 wt%, silicon particles surface-modified with an alkoxysilane-based surface modifier 20 to 30 wt%, lithium titanate 15 to 25 wt%, tin acetate 5 to 10 wt % And 5 to 10 wt% of cobalt acetate are ultrasonically dispersed in a solvent, freeze-dried and pulverized to obtain graphene-silver nanowire-silicon composite powder. Method for manufacturing a secondary battery negative electrode material.
The method of claim 1,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
Silicon particles, graphene oxide, silver nanowire, lithium titanate, conductive carbon black, tin acetate, and cobalt acetate surface-modified with the alkoxysilane-based surface modifier are ultrasonically dispersed in a solvent, freeze-dried, and pulverized to graphene. Graphene-silver nanowire-silicon-containing composite material secondary battery anode material manufacturing method, characterized in that to obtain a silver nanowire-silicon composite material powder.
The method of claim 13,
The step of obtaining the graphene-silver nanowire-silicon composite material powder,
Graphene oxide 35 to 45 wt%, silver nanowire 5 to 15 wt%, silicon particles surface-modified with an alkoxysilane-based surface modifier 20 to 30 wt%, lithium titanate 15 to 25 wt%, conductive carbon black 5 to 10 wt %, 5 to 10 wt% of tin acetate and 5 to 10 wt% of cobalt acetate are ultrasonically dispersed in a solvent, freeze-dried and pulverized to obtain graphene-silver nanowire-silicon composite powder. Fin-silver nanowire-silicon-containing composite material secondary battery anode material manufacturing method.
The method of claim 1
The fluorine-based polymer polymer,
Polyvinylidene Fluoride (PVDF) Polymer, Polyvinylidene Fluoride-Hexafluoropropylene Copolymer, Polyvinylidene Fluoride-Chlorotrifluoroethylene (CTFE) ) Copolymer and polyvinylidene fluoride-tetrafluoroethylene (Polyvinylidene Fluoride-Tetrafluoroethylene, TFE), characterized in that one selected from the copolymer, graphene-silver nanowire-silicon-containing composite material secondary battery anode material manufacturing method.
The method of claim 1,
The step of preparing a negative electrode material for a composite material secondary battery containing the graphene-silver nanowire-silicon,
It is characterized in that a graphene-silver nanowire-silicon composite material secondary battery negative electrode material is prepared by mixing 85 to 95 wt% of the calcined graphene-silver nanowire-silicon composite powder and 5 to 15 wt% of a fluorine-based polymer polymer. Graphene-silver nanowire-silicon-containing composite material secondary battery anode material manufacturing method.
The method of claim 1,
The step of preparing a negative electrode material for a composite material secondary battery containing the graphene-silver nanowire-silicon,
The graphene-silver nanowire-silicon composite material powder is calcined at 700 to 900 ℃ for 6 to 12 hours, characterized in that the graphene-silver nanowire-silicon-containing composite material secondary battery anode material manufacturing method.
The method of claim 1,
The silver nanowire,
Graphene-silver nanowire-silicon-containing composite material secondary battery anode material manufacturing method, characterized in that the diameter is 5 to 50 nm, the length is 50 to 200 μm, the aspect ratio is 1000 to 40000.
Graphene-silver nanowire-silicon-containing composite material secondary battery negative electrode material prepared by the manufacturing method of any one of claims 1 to 18.
Graphene-silver nanowire-silicon-containing composite material prepared according to claim 19. A composite material containing graphene-silver nanowire-silicon, characterized in that it is produced by coating a secondary battery negative electrode material on a current collector using an electrospray method. Secondary battery negative electrode.

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