TWI631754B - The 3d network structure binder and the anode materials included it for lithium ion batteries - Google Patents

Abstract

The present invention provides an adhesive and a negative electrode material comprising the same, wherein the adhesive comprises a conjugate. The conjugate comprises: a chitin group; a polymer group having at least one functional group selected from the group consisting of a hydroxyl group (-OH), a carboxyl group (-COOH), and an amine group (-NH _{2 )} a group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ).

The adhesive of the present invention uses a three-dimensional network structure composed of a conjugate for a lithium battery negative electrode material, overcoming the disadvantages of the conventional negative electrode material.

Description

Lithium battery adhesive with three-dimensional structure and lithium battery anode material containing same

The invention relates to an adhesive for a negative electrode material; in particular to an adhesive for a negative electrode material of a lithium battery.

With the rapid development of the electronics industry in recent years, the convenience of electronic equipment has also increased, and portable electronic products have received much attention. Lithium batteries are one of the most widely available portable power supplies in the world today. Compared with nickel-metal hydride batteries, lithium-ion batteries have high power, high energy density, and good cycle life. They have been used in electronic devices such as mobile phones, cameras, and notebook computers for many years.

The lithium battery is composed of a positive electrode, a negative electrode, a separator and an electrolyte, wherein the positive electrode material and the negative electrode material directly affect the lithium battery. Therefore, the development of electrode materials and the development of electrode-related processes are extremely important for their development. The commonly used negative electrode material is a carbon-based material, that is, a graphite material, and examples thereof include artificial graphite (Natural Graphite; NG), natural graphite (AG), hard carbon (HC), and soft carbon (Soft Carbon; SC) or mesocarbon microbeads (MCMB) and the like. The carbon-based material is capable of intercalating and embedding lithium ions due to a layered structure. Further, since the carbon-based material is stable in nature, the carbon-based material is used as a negative electrode material for the lithium battery. A key breakthrough in commercial applications. However, graphite materials have a capacitance of up to 372 mAh/g, and because of the high cost of preparation of mesocarbon microbeads, there is a demand for other materials to replace carbon materials as anode materials for lithium batteries.

Under the premise of pursuing high capacity and low cost, bismuth materials have begun to attract attention. The ruthenium material has the following advantages as a lithium ion anode material:

(1) The material capacity of the crucible is about 3579 mAh/g. In addition to metallic lithium, this capacitor has an unparalleled capacity advantage of other high-capacity materials.

(2) The microstructure of the tantalum material is transformed into amorphous after the first lithium intercalation, and it maintains this amorphous state during the subsequent cycle, so it can be considered to be relatively stable in structure.

(3) In the process of electrochemical intercalation and deintercalation, the material is not easily agglomerated.

(4) The discharge platform is slightly higher than the carbon-based material.

(5) Rich in content, low in price, and will not cause environmental pollution. Due to the above advantages, bismuth materials have become one of the best anode materials for new generation high capacity lithium batteries.

However, the bismuth material still has the following technical difficulties to be overcome:

(1) When lithium is embedded and embedded, the volume of the electrode material changes greatly, which leads to loosening and pulverization of the electrode material, resulting in poor cycle life. This is a great obstacle to the commercial development of tantalum materials.

(2) The conductivity of the crucible material is low, and it is necessary to use an appropriate promoter to enhance the conductivity of the electrode.

In order to overcome the above-mentioned defects in the material, the solution strategy is to improve the material structure. However, the process of improving the structure of the material is cumbersome, energy-consuming and high in preparation cost. Therefore, the development of a three-dimensional network structure adhesive, the use of its network structure and coating characteristics for the volume expansion of the ruthenium-based anode material The problem is overcome and only needs to be operated in the electrode plate preparation process, which is a feasible method for industrial production processes.

[references]

Sharma, RA and Seefurth, RN Thermodynamic Properties of the Lithium-Silicon System. J. Electrochem. Soc. 1976 , 123, 1763-1768

Boukamp, BA; Lesh, GC; Huggins, RA All-Solid Lithium Electrodes with Mixed-Conductor Matrix. J. Electrochem. Soc. 1981 , 128, 725-729

Wen, CJ and Huggins, RA Chemical Diffusion in Intermediate Phases in the Lithium-Silicon System. J. Solid State Chem. 1981 , 37, 271-278

Obrovac, MN and Christensen, L. Structural Changes in Silicon Anodes during Lithium Insertion/Extraction. Electrochem. Solid State Lett. 2004 , 7, A93-A96

Tang, H.; Weng, Q.; Tang, Z. Chitosan Oligosaccharides: A Novel and Efficient Water Soluble Binder for Lithium Zinc Titanate Anode in Lithium-ion Batteries. Electrochim. Acta. 2015 , 151, 27-34.

An object of the present invention is to provide a negative electrode material for a lithium battery, an adhesive added to the foregoing negative electrode material, and a modified negative electrode material to overcome the pulverization of the negative electrode material, the irreversible capacity of the first charge and discharge, and the poor cycle life. problem.

To achieve the foregoing objective, the present invention provides a negative electrode material for a lithium battery, comprising: a 5 to 50 weight percent conjugate comprising: a chitin group; a polymer group having at least one selected from the group consisting of a group of functional groups: a hydroxyl group (-OH), a carboxyl group (-COOH), and an amine group (-NH ₂ ); a group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ); The chitin group forms a covalent bond with the polymer group; wherein the polymer group forms a covalent bond with the aldehyde group and/or the amine group; wherein the chitin group and the aldehyde are The group and/or the amine group form a carbon-nitrogen double bond or a peptide bond; and a 50 to 90 weight percent ruthenium substrate; wherein the aforementioned weight percentage is based on the total weight of the foregoing negative electrode material.

Preferably, the foregoing negative electrode material further contains 1 to 40% by weight of a co-ducing agent.

Preferably, the aforementioned polymer group is a polysaccharide, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, carboxymethyl cellulose, methyl cellulose, polyallylamine, sodium alginate or a combination thereof.

Preferably, the aforementioned group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) is a decane, an aldehyde or a combination thereof.

Preferably, the aforementioned group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) is glutaraldehyde (GA) or (3-aminopropyl)triethoxydecane (APTES) or combination.

Preferably, the ruthenium substrate is a nano-scale ruthenium substrate, a micro-scale ruthenium substrate, a ruthenium-metal composite ruthenium substrate, a ruthenium-carbon composite ruthenium substrate, a ruthenium-metal oxide composite ruthenium substrate or a combination thereof .

Preferably, the auxiliary agent is graphite, vapor grown carbon fiber (VGCF), carbon nanotube (CNT), acetylene black (AB), carbon black (CB) or a combination thereof.

The present invention further provides a negative electrode material adhesive formulation for a lithium battery, comprising: a conjugate comprising a chitin group; a polymer group having at least one functional group selected from the group consisting of: a hydroxyl group (-OH), a carboxyl group (-COOH), and an amine group (-NH ₂ ); a group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ); wherein the aforementioned chitin group is The aforementioned polymer group forms a covalent bond; wherein the polymer group forms a covalent bond with the aforementioned aldehyde group and/or amine group; wherein the aforementioned chitin group and the aforementioned aldehyde group and/or amine group The group forms a carbon-nitrogen double bond or a peptide bond.

Preferably, the aforementioned polymer group is a polysaccharide, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, carboxymethyl cellulose, methyl cellulose, polyallylamine, sodium alginate or a combination thereof.

Preferably, the aforementioned group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) is a decane, an aldehyde or a combination thereof.

Preferably, the aforementioned group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) is glutaraldehyde (GA) or (3-aminopropyl)triethoxydecane (APTES) or combination.

The present invention further provides a modified lithium battery negative electrode comprising: a ruthenium substrate; and a conjugate modified to the ruthenium substrate; wherein the conjugate comprises: a chitin group; a polymer base a group having at least one functional group selected from the group consisting of a hydroxyl group (-OH), a carboxyl group (-COOH), and an amine group (-NH ₂ ); an aldehyde group (-CHO) and/or an amine group ( a group of -NH ₂ ); wherein the aforementioned chitin group forms a covalent bond with the aforementioned polymer group; wherein the polymer group forms a covalent bond with the aforementioned group having an aldehyde group and/or an amine group; The aforementioned chitin group forms a carbon-nitrogen double bond or a peptide bond with the aforementioned group having an aldehyde group and/or an amine group; wherein the aforementioned group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) Forming a covalent bond with the aforementioned ruthenium substrate.

Preferably, the aforementioned polymer group is a polysaccharide, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, carboxymethyl cellulose, methyl cellulose, polyallylamine, sodium alginate or a combination thereof.

Preferably, the aforementioned group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) is a decane, an aldehyde or a combination thereof.

Preferably, the aforementioned group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) is glutaraldehyde (GA) or (3-aminopropyl)triethoxydecane (APTES) or combination.

The invention further provides a preparation method of the foregoing adhesive formulation, which comprises the steps of: (a) adding a polymer to a carrier to prepare a step (a) solution; (b) adding a chitin to the step (a) preparing a solution of step (b) in solution; (c) adding a compound having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) to the solution of step (b), a step (c) of the solution; wherein the preparation is carried out in an acidic environment.

Preferably, the aforementioned acidic solution is hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, phosphoric acid, citric acid or a combination thereof.

Preferably, the aforementioned preparation method is carried out at normal temperature.

In summary, the present invention provides an adhesive and a method of preparing the same. The present invention successfully modifies the surface structure of the negative electrode material by adding an adhesive to the negative electrode material, thereby reducing the first irreversible capacitance and prolonging the cycle life. Applying the foregoing adhesive to the negative electrode material can help break through the technical bottleneck encountered by the ruthenium substrate in the development of the lithium battery, and improve the industrial application value of the ruthenium substrate.

The first figure shows the electrochemical performance of the button type battery produced by using the adhesives of Examples 1 to 3 and Comparative Examples 1 to 2 of the present invention at different current densities.

The second graph shows the charge and discharge cycle life at a current density of 50 m A/g for a button type battery obtained by using the adhesives of Examples 1 to 3 and Comparative Examples 1 to 2 of the present invention.

The third graph shows the charge and discharge cycle life at a current density of 500 m A/g using a button type battery obtained by using the adhesives of Examples 1 to 3 and Comparative Examples 1 to 2 of the present invention.

An object of the present invention is to provide a dramatic volume change of a tantalum substrate as a negative electrode material for a lithium ion battery during lithium insertion and embedding. This characteristic causes loosening and pulverization of the negative electrode material, which in turn causes problems such as excessive irreversible capacity and poor cycle life performance of the first charge and discharge.

In order to solve the above problems, the present invention is to develop a suitable adhesive for the ruthenium-based negative electrode material to modify the surface of the negative electrode material. Furthermore, an adhesive composed of specific raw materials was developed to successfully solve the problems faced by this material.

Accordingly, the present invention provides a lithium battery anode material comprising: 5 to 50% by weight of a conjugate, and 50 to 90% by weight of a ruthenium substrate. The raw material of the negative electrode material is calculated by weight based on the total weight of the negative electrode material. This conjugate is the adhesive of the present invention.

The main feature of the present invention is a conjugate in the negative electrode material, which is composed of a chitin group, a polymer group, and an aldehyde group (-CHO) and/or an amine group ( a group of -NH ₂ ).

In a preferred embodiment, the aforementioned chitin group is obtained from Polyethylene and International Corporation. The aforementioned chitin group is yellow to brown in appearance, odorless, and has a particle size of >40 mesh (Mesh). Furthermore, the deacetylation ratio of the aforementioned chitin group is 70 to 90%, and the water content measured by the Loss on drying method is about 10%, measured by Residue on ignition. Ash content is about <1%. The composition of the aforementioned chitin group has an arsenic content of about <0.5 ppm and a heavy metal content of about <10 ppm.

It is desirable for the aforementioned polymer group to have at least one polar functional group selected from the group consisting of a hydroxyl group (-OH), a carboxyl group (-COOH), and an amine group (-NH ₂ ). These groups can be matched and combined with each other according to experimental needs. Specifically, the polymer may, for example, be a polysaccharide, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, carboxymethyl cellulose, methyl cellulose, polyallylamine, sodium alginate or a combination thereof. For sodium alginate.

The group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) may be selected from decane, aldehyde or a combination thereof. The group having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) may specifically be, for example, glutaraldehyde (GA) or (3-aminopropyl)triethoxydecane (APTES). ) or a combination thereof.

The essential components of the above conjugate are bonded to each other. Forming a covalent bond between the chitin group and the polymer group; forming a covalent bond between the polymer group and the aldehyde group and/or the amine group; and the chitin group and the foregoing The formation of carbon-nitrogen double bonds or peptide bonds between aldehyde groups and/or amine groups plays a very important role in the bonding of stable ruthenium-based electrodes.

The conjugate composed of the above components is calculated by weight based on the total weight of the composition of the negative electrode material, and is contained in an amount of 5 to 50% by weight (% by weight), preferably 5 to 30% by weight (% by weight), more preferably It is 5 to 20 weight percent (wt%).

The polymer group for the conjugate of the negative electrode material and the aldehyde group (-CHO) and/or the amine group (-NH ₂ ) group have a plurality of selectable group types according to the above description, so that various kinds of different groups can be derived. combination. Specifically, for example, a negative electrode material as shown in Table 1 can be prepared.

For the aforementioned ruthenium substrate, a single component material or a composite component material may be selected. Specific examples of the single component material include, for example, a nano-scale ruthenium substrate, a micro-scale ruthenium substrate, or a combination thereof. Specific examples of the composite component material include a ruthenium-metal composite ruthenium substrate, a ruthenium-carbon composite ruthenium substrate, a ruthenium-metal oxide composite ruthenium substrate, or a combination thereof.

The foregoing ruthenium substrate is calculated by weight based on the total weight of the composition of the negative electrode material, and is contained in an amount of 50 to 90% by weight (wt%), preferably 60 to 80% by weight (wt%), more preferably 70 to 75% by weight. (wt%).

In addition to the aforementioned conjugate and the aforementioned ruthenium substrate, the negative electrode material may further contain a further auxiliary agent.

Specific examples of the above-mentioned auxiliary agent include graphite, vapor grown carbon fiber (VGCF), carbon nanotube (CNT), acetylene black (AB), carbon black (CB) or its combination. Without affecting the use of the conjugate of the present invention, they can be combined and combined according to experimental requirements.

The above-mentioned auxiliary agent is calculated by weight based on the total weight of the constituent negative electrode material, and is contained in an amount of 1 to 40% by weight (wt%), preferably 5 to 30% by weight (% by weight), more preferably 10 to 20% by weight. (wt%).

The present invention further provides an adhesive for a lithium battery anode material comprising a conjugate. The aforementioned conjugates are as described in the preceding paragraphs and will not be repeated here.

For the adhesive of the present invention, the preparation method comprises the steps of: adding a polymer to the carrier to prepare a solution of the step (a); adding a chitin to the solution of the step (a) to prepare a step ( b) a solution; adding a compound having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) to the solution of the step (b) to prepare a solution of the step (c); for the chitin in the step, The use of polymers, compounds having aldehyde groups (-CHO) and/or amine groups (-NH2), and carriers are as described in the above paragraphs and will not be repeated here.

For the aforementioned carrier, N-methylpyrrolidone (NMP), water or a combination thereof may be used. The choice of carrier is adjusted according to the composition of the adhesive, so before the effect of the adhesive is not damaged It can be selected according to the needs of each experiment without special limitation. The adhesive according to the present invention is preferably water as the carrier of the present invention.

In a preferred embodiment, the adhesive preparation method is carried out in an acidic environment. After verifying the experimental results of the subsequent examples, it was found that the adhesive prepared in an acidic environment can improve the battery performance of the adhesive. The acidic environment can adjust the acidic environment to an appropriate pH value by adding the following acidic solution, such as hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, phosphoric acid, citric acid, etc.; preferably citric acid, acetic acid, more preferably acetic acid. . Under the limitation of the acidic environment, although the characteristics of the negative electrode material can be more effectively improved, the adhesive prepared in the acidic environment still has the excellent effects claimed by the present invention.

In the preparation method of the adhesive of the present invention, the conditions of temperature and air pressure are set to normal temperature and normal pressure, that is, no special adjustment of temperature and pressure is required, so as to create a specific adhesive or negative electrode material preparation environment. The preparation of the present invention can be carried out in the environment in which the person skilled in the art can practice the invention. In a possible implementation, the aforementioned normal temperature and pressure (NTP) is conventionally defined as 25 ° C, 1 atm. This is also an advantage that the adhesive of the present invention can be widely applied to the preparation of a negative electrode material.

In a possible embodiment, in the above preparation method, each component is added, that is, stirred, so that the added components can be sufficiently mixed. The stirring time and/or the stirring rate are not particularly limited, and the purpose of uniform mixing can be achieved.

In a preferred embodiment, all of the components constituting the negative electrode material are added, and after the negative electrode material is sufficiently stirred, the negative electrode material is defoamed.

After the preparation of the negative electrode material is completed, the process of the negative electrode tab is performed. The process can be roughly divided into the following steps:

(1) Preparation of copper foil: The copper foil was wiped clean and cut to an appropriate size, and the copper foil was laid flat on the coater platform.

(2) Coating: The negative electrode material was uniformly coated on the copper foil at a fixed speed using a doctor blade of adjustable pitch.

(3) Preheating: The copper foil of the coated negative electrode material was placed on a hot plate and prebaked to remove the carrier in the negative electrode material.

(4) Rolling: The negative electrode material is rolled by a rolling mill to adjust the thickness of the negative electrode material. After the rolling is completed, the negative electrode plate is completed.

(5) Cutting: The negative electrode plate is cut by a cutting machine and cut into a circular negative pole piece of a fixed diameter.

(6) Heating: The negative electrode tab was placed in a vacuum oven to remove residual carrier.

(7) To be assembled: The heated negative pole piece is moved into a glove box of a specific gas environment. Button cell assembly is to be carried out.

The negative pole piece process is not the technical focus of the present invention, so the experimental conditions in the above steps can be adjusted according to actual conditions and conventional processes in the field.

After the addition of the adhesive of the present invention, the preparation of the negative electrode material, and the preparation of the negative electrode tab, the modified lithium battery negative electrode of the present invention is completed. The modified lithium battery negative electrode comprises: a ruthenium substrate and a conjugate that modifies the substrate. For the bonding between the components and the components contained in the conjugate, reference may be made to the above description for the negative electrode material, and the description thereof will not be repeated. The modified lithium battery anode material of the present invention is characterized in that an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) is contained in the conjugate, except that a bond is formed between the components contained in the conjugate. The group also forms a covalent bond with the aforementioned ruthenium substrate. Accordingly, by adding the adhesive of the present invention, the coating property of the adhesive can be exerted, and a plurality of bonds are formed between the negative electrodes, thereby forming an intricate, stable, and elastic three-dimensional network structure. The three-dimensional network structure becomes a coating layer on the surface of the negative electrode, and the composition of the solid electrolyte interphase (SEI) on the surface of the negative electrode can be changed.

The benefit of the present invention is that the surface of the negative electrode is modified to overcome the looseness of the negative electrode material caused by the drastic volume change of the ruthenium substrate as the negative electrode material of the lithium battery when the lithium is embedded and embedded. With the problem of chalking. By adding an adhesive to improve the anode material, the first charge and discharge reversible capacity is reduced, and the cycle life performance of the lithium battery is significantly improved.

The following examples are intended to illustrate the advantages of the invention, and are not intended to limit the scope of the invention.

Process 1: Preparation of the adhesive of the present invention.

In the present process, Example 1 of the conjugate adhesive of the present invention will be prepared. Sodium alginate was first added to deionized water and a pre-formulated aqueous solution of chitin (2 wt%) was added and mixed until homogeneous. Next, the solvent-free liquid glutaraldehyde (GA) was further added, and the mixture was stirred again until uniform, and the adhesive example 1 of the present invention was completed.

In the present process, Example 2 of the conjugate adhesive of the present invention will be prepared. Sodium alginate was first added to deionized water and mixed with a pre-formulated aqueous solution of chitin (2 wt%) until homogeneous. Next, liquid (3-aminopropyl)triethoxydecane (APTES) was further added, stirred again, and mixed until uniform to complete the adhesive example 2 of the present invention.

Adhesive Example 3 having the conjugate of the present invention will be prepared in this process. Sodium alginate was first added to deionized water and mixed with a pre-formulated aqueous solution of chitin (2 wt%) until homogeneous. Next, liquid (3-aminopropyl)triethoxydecane (APTES) was further added, stirred, and mixed until homogeneous. Further, an acidic solution of an aqueous acetic acid solution was added to adjust the above mixture, and the mixture was stirred and mixed until uniform, and the adhesive example 3 of the present invention was completed.

Comparative Example 1 in which an adhesive is to be produced in this process. First, sodium alginate was added to deionized water, stirred, and mixed until uniform, and Comparative Example 1 was completed.

Comparative Example 2 in which an adhesive is to be produced in this process. First, sodium alginate was added to deionized water, and a pre-formulated aqueous solution of chitin (2 wt%) was added thereto to be homogeneous, and Comparative Example 2 was completed.

The preparation of each of the above examples and comparative examples was carried out under a normal temperature and pressure in a gas atmosphere, and the operating instrument was a stirrer.

Table 1 is prepared for the components of Examples 1 to 3 and the comparative examples and the experimental conditions.

Process 2: Preparation of a negative electrode tab using the adhesive of the present invention.

First, an appropriate amount of DI water is weighed, and then the yttrium-metal composite negative electrode material is made up to 70 weight percent (wt%), graphite (trade name KS-6, manufactured by Timcal Corporation) at 15 weight percent (wt %), Process A prepared adhesive was added to deionized water in an order of 12 weight percent (wt%), with carbon black (trade name super P, manufactured by Timcal) at 3 weight percent (wt%). After the above mixture was stirred until uniform, defoaming was carried out to obtain a negative electrode plate coating slurry (i.e., the negative electrode material of the present invention).

The copper foil was wiped clean and cut to an appropriate size, and then laid flat on the coater platform, and the negative electrode slurry was uniformly coated on the copper foil at a fixed speed using an adjustable pitch doctor blade. The copper foil coated with the negative electrode slurry is placed on a hot plate for prebaking to remove the carrier, and then negatively held by the roller compactor The thickness of the pole material is adjusted, and the electrode after rolling is cut into a circular pole piece having a diameter of 13 mm by a cutter, and then the cut pole piece is placed in a vacuum oven to remove residual carrier, and then placed after completion. The argon-filled glove box (moisture and oxygen less than 1 ppm) is assembled into a button-type battery.

Process 3: Battery assembly of a negative electrode tab using the adhesive of the present invention.

The battery upper cover, the lower cover, the spring piece and the stainless steel piece are washed and dried with alcohol, and after being completely dried, they are sent into a glove box for assembly of the lithium battery. First, the negative electrode tab is placed at the center of the lower cover, and the electrolyte is dropped (the electrolyte is dissolved in a mixture of ethyl carbonate and ethyl methyl carbonate in a volume ratio of 1:2). A solution of lithium hexafluorophosphate (Lithium hexafluorophosphate), which is prepared by adding 2 wt% of vinylene carbonate and fluorocarbonate. Next, the separator is immersed in the electrolyte to be wetted, and then covered on the negative electrode tab. Place the lithium metal or positive electrode tab on the separator in sequence, and confirm that it is at the center position and does not exceed the separator. Then place the stainless steel sheet on the lithium metal (if the positive electrode plate is used, the stainless steel sheet is not required) Place the spring piece in the center of the stainless steel piece. Finally, the upper cover is closed, and a button type battery is used for sealing the button type battery.

Process 4: Electrochemical testing of button cells.

The micro-current battery automatic charge and discharge test host (produced by Jiayou Technology Co., Ltd.) was used as an electrochemical test instrument for testing.

The electrochemical results measured by the button-type battery assembled from the negative electrode sheets prepared in the above respective examples of the present invention and the comparative examples are shown in Table 2.

The results of Table 2 are discussed below, wherein the button type battery using Example 1 as an adhesive is simply referred to as Example 1 in the following discussion of results, and so on. As shown in Table 2, Comparative Example 1 uses only a single component adhesive, and its first charge capacity (ie, the first reversible capacity) is 720 mAh/g (mAh/g), and the first coulombic efficiency is 78.6%. In Comparative Example 2, the two-component adhesive was used, and the first reversible capacity and the first coulombic efficiency were 720 mAh/g and 77.9%, respectively, which were similar to those of Comparative Example 1.

In the first embodiment, the adhesive of the present invention was used, and the first coulombic efficiency was 78.7%, which was not significantly different from that of Comparative Example 1 and Comparative Example 2, but the first reversible capacity was increased to 737 mAh/g. The first reversible capacity of Example 2 was 766 mAh/g, which was about 50 mAh/g higher than that of Comparative Example 1 and Comparative Example 2. Moreover, the first Coulomb efficiency has even reached 80.8%. Example 3 is an improvement of the experimental conditions of Example 2 to obtain an adhesive of the present invention, the first reversible capacity and the coulombic efficiency are 765 mAh/g and 81.4%, respectively, similar to Example 2, but in the charge The capacity retention rate after discharging 100 times was 70%, and the storage rate was only 59% after 100 times of charge and discharge compared with the sample 2.

It can be seen from the above results that the adhesive having a three-dimensional network structure can not only improve the bonding property and stability between the ruthenium-based anode material and the adhesive, but also have a coating property on the surface of the ruthenium-based anode material, thereby changing the solid electrolyte membrane ( The composition of solid electrolyte interphase (SEI) achieves the result of improving reversible capacity and battery performance.

The results of the electrical test of the button type battery assembled by the negative electrode tabs prepared in the above respective embodiments of the present invention and the comparative examples are as shown in the first, second and third figures.

The results of the first and second figures are discussed below, wherein the button type battery using the embodiment 1 as the adhesive is simply referred to as the embodiment 1 in the following discussion of the results, and so on. According to the first figure, Comparative Example 2 exhibited the best capacitance performance at a high current density, and secondly, Example 3. According to the second figure, the results of the electrochemical tests performed at the low current densities of the above respective examples and comparative examples were not much different. According to the third figure, it is a cycle life test comparison at 500 mAh/g. It can be found that after 100 charge and discharge in Example 3, the capacity retention rate is still 70%, and Comparative Example 1 and Comparative Example 2 The capacity retention rate is only about 55%.

In summary, it can be seen that the three-dimensional network structure adhesive disclosed in the present invention not only can modify the surface of the ruthenium base electrode, but also can modify the composition of the solid electrolyte membrane on the surface of the electrode material by surface modification, and can also strengthen the overall structure of the electrode. Improve the problem of excessive irreversible capacity and poor cycle life for the first charge and discharge.

Claims (24)

A negative electrode material for a lithium battery, comprising: a 5 to 50 weight percent conjugate comprising: a chitin group; a polymer group having at least one functional group selected from the group consisting of hydroxyl groups (-OH), carboxyl (-COOH), and amino (-NH _2); an aldehyde (-CHO) group; wherein the chitin group to the polymer radical forming a covalent bond; wherein The aforementioned polymer group forms a covalent bond with the aforementioned aldehyde group-containing group; wherein the aforementioned chitin group forms a carbon-nitrogen double bond or a peptide bond with the aforementioned aldehyde group; and a 50 to 90 weight percent a base material; wherein the aforementioned weight percentage is based on the total weight of the foregoing negative electrode material. A negative electrode material for a lithium battery, comprising: a 5 to 50 weight percent conjugate comprising: a chitin group; a polymer group having at least one functional group selected from the group consisting of hydroxyl groups (-OH), a carboxyl group (-COOH), and an amine group (-NH ₂ ); an alkyl group having an amine group (-NH ₂ ); wherein the aforementioned chitin group forms a covalent bond with the aforementioned polymer group Wherein the aforementioned polymer group forms a covalent bond with the aforementioned alkyl group having an amine group; wherein the aforementioned chitin group forms a carbon-nitrogen double bond or a peptide bond with the aforementioned alkyl group having an amine group; 90% by weight of the ruthenium substrate; wherein the aforementioned weight percentage is based on the total weight of the foregoing anode material. The negative electrode material of claim 1 or 2, which comprises 5 to 30% by weight of the conjugate, 50 to 90% by weight of the ruthenium substrate, and 1 to 40% by weight of a co-catalyst. The negative electrode material according to claim 1 or 2, wherein the polymer group is a polysaccharide, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, carboxymethyl cellulose, methyl cellulose, polyallylamine, seaweed Sodium or a combination thereof. The negative electrode material of claim 1, wherein the aforementioned aldehyde group (-CHO) group is an aldehyde. The negative electrode material of claim 5, wherein the aldehyde group (-CHO)-containing group is glutaraldehyde (GA). The negative electrode material of claim 2, wherein the aforementioned alkyl group having an amine group (-NH ₂ ) is (3-aminopropyl)triethoxydecane (APTES). The anode material of claim 1, wherein the ruthenium substrate is a nano-scale ruthenium substrate, a micro-scale ruthenium substrate, a ruthenium-metal composite ruthenium substrate, a ruthenium-carbon composite ruthenium substrate, and a ruthenium-metal oxide. Composite tantalum substrates or combinations thereof. The anode material of claim 3, wherein the auxiliary agent is graphite, vapor-grown carbon fiber (VGCF), carbon nanotube (CNT), acetylene black (AB), carbon black (CB) ) or a combination thereof. An adhesive formulation for a negative electrode material for a lithium battery, comprising: a conjugate comprising a chitin group; a polymer group having at least one functional group selected from the group consisting of hydroxyl groups (- OH), a carboxyl group (-COOH), and an amine group (-NH ₂ ); a group having an aldehyde group (-CHO); wherein the aforementioned chitin group forms a covalent bond with the aforementioned polymer group; wherein the aforementioned polymerization The group forms a covalent bond with the aforementioned aldehyde group; wherein the aforementioned chitin group forms a carbon-nitrogen double bond or a peptide bond with the aforementioned aldehyde group. An adhesive formulation for a negative electrode material for a lithium battery, comprising: a conjugate comprising a chitin group; a polymer group having at least one functional group selected from the group consisting of hydroxyl groups (- OH), a carboxyl group (-COOH), and an amine group (-NH ₂ ); an alkyl group having an amine group (-NH ₂ ); wherein the aforementioned chitin group forms a covalent bond with the aforementioned polymer group; The aforementioned polymer group forms a covalent bond with the aforementioned alkyl group having an amine group; wherein the aforementioned chitin group forms a carbon-nitrogen double bond or a peptide bond with the aforementioned alkyl group having an amine group. The adhesive of claim 10, wherein the polymer group is a polysaccharide, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, carboxymethyl cellulose, methyl cellulose, polyallylamine, seaweed Sodium or a combination thereof. The adhesive of claim 10, wherein the aforementioned aldehyde group (-CHO) group is an aldehyde. The adhesive of claim 13, wherein the aforementioned aldehyde group (-CHO) group is glutaraldehyde (GA). The adhesive according to claim 11, wherein the aforementioned oxime group having an amine group (-NH ₂ ) is (3-aminopropyl)triethoxydecane (APTES). A modified lithium battery negative electrode comprising: a ruthenium substrate; and a conjugate modified to the ruthenium substrate; wherein the conjugate comprises: a chitin group; a polymer group having At least one functional group selected from the group consisting of a hydroxyl group (-OH), a carboxyl group (-COOH), and an amine group (-NH ₂ ); an aldehyde group (-CHO) group; wherein the aforementioned chitin group Forming a covalent bond with the aforementioned polymer group; wherein the aforementioned polymer group forms a covalent bond with the aforementioned aldehyde group; wherein the aforementioned chitin group forms a carbon-nitrogen double bond with the aforementioned aldehyde group Or a peptide bond; wherein the aforementioned group having an aldehyde group (-CHO) forms a covalent bond with the aforementioned ruthenium substrate. A modified lithium battery negative electrode comprising: a ruthenium substrate; and a conjugate modified to the ruthenium substrate; wherein the conjugate comprises: a chitin group; a polymer group having At least one functional group selected from the group consisting of a hydroxyl group (-OH), a carboxyl group (-COOH), and an amine group (-NH ₂ ); an alkyl group having an amine group (-NH ₂ ); wherein the aforementioned chitin The group forms a covalent bond with the aforementioned polymer group; wherein the polymer group forms a covalent bond with the aforementioned alkyl group having an amine group; wherein the chitin group forms a group with the aforementioned alkyl group having an amine group a carbon-nitrogen double bond or a peptide bond; wherein the aforementioned alkyl group having an amine group (-NH ₂ ) forms a covalent bond with the aforementioned ruthenium substrate. The lithium battery negative electrode according to claim 16 or 17, wherein the polymer group is a polysaccharide, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, carboxymethyl cellulose, methyl cellulose, polyallylamine, Sodium alginate or a combination thereof. The lithium battery negative electrode according to Item 16, wherein the aldehyde group (-CHO) group is an aldehyde. The lithium battery negative electrode according to claim 19, wherein the aldehyde group (-CHO)-containing group is glutaraldehyde (GA). The lithium battery negative electrode according to claim 17, wherein the aforementioned oxime group having an amine group (-NH ₂ ) is (3-aminopropyl)triethoxydecane (APTES). A method for preparing an adhesive formulation according to claim 10 or 11, which comprises the steps of: adding a polymer to a carrier to prepare a solution of the step (a); and adding a chitin to the step (a) In the solution, a step (b) solution is prepared; a compound having an aldehyde group (-CHO) and/or an amine group (-NH ₂ ) is added to the solution of the step (b) to prepare a step (c). a solution; wherein the preparation process is carried out in an acidic environment. The preparation method of claim 22, wherein the acidic solution is hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, phosphoric acid, citric acid, or a combination thereof by adding an acidic solution to form the aforementioned acidic environment. The preparation method of claim 22 is carried out at room temperature.