阅读说明：本技术 一种聚硼酸盐粘结剂及其制备方法与应用 (Polyborate adhesive and preparation method and application thereof ) 是由 曾绍忠 韩培刚 于 2021-07-26 设计创作，主要内容包括：本发明公开了一种聚硼酸盐粘结剂及其制备方法与应用,其中,制备方法包括步骤：选取有机物配体,所述有机物配体包括的官能团为羟基、羧基和磺酸基中的一种或几种；将所述有机物配体与硼离子化合物加入到水溶剂中混合,反应制得所述聚硼酸盐粘结剂。本发明采用较廉价的原料合成的水溶性固有微孔导电聚硼酸盐粘结剂具有更强的粘结强度,并具有锂离子导电能力,用于硅基负极材料具有优异的效果,即使用于传统的磷酸铁锂、锰酸锂和石墨等电极材料,也具有非常明显的优势。而且,本发明所述粘结剂采用较廉价的商业化原料,通过简单可量产的工艺合成,具有巨大的应用前景。(The invention discloses a polyborate adhesive and a preparation method and application thereof, wherein the preparation method comprises the following steps: selecting an organic ligand, wherein the functional group of the organic ligand is one or more of hydroxyl, carboxyl and sulfonic group; and adding the organic ligand and the boron ion compound into a water solvent, mixing, and reacting to obtain the polyborate adhesive. The water-soluble inherent microporous conductive polyborate adhesive synthesized by adopting the cheap raw materials has stronger adhesive strength, has lithium ion conductive capability, has excellent effect when being used for silicon-based negative electrode materials, and has very obvious advantages even when being used for traditional electrode materials such as lithium iron phosphate, lithium manganate, graphite and the like. In addition, the adhesive is synthesized by adopting relatively cheap commercial raw materials through a simple mass production process, and has a huge application prospect.)

1. A method of preparing a polyborate binder, comprising the steps of:

selecting an organic ligand, wherein the functional group of the organic ligand is one or more of hydroxyl, carboxyl and sulfonic group;

and adding the organic ligand and the boron ion compound into a water solvent, mixing, and reacting to obtain the polyborate adhesive.

2. The method of preparing a polyborate binder of claim 1, wherein the organic ligand is one or more of ethylene glycol, propylene glycol, pentaerythritol, polyvinyl alcohol, sorbitol, xylitol, cyclodextrin, tartaric acid, phytic acid, polystyrene sulfonic acid, polyacrylic acid, polyethylene oxide, polyacrylamide, and a saccharide compound.

3. The method of preparing a polyborate binder of claim 2 wherein the sugar compound is one or more of glucose, fructose, sucrose and lactose.

4. The method of preparing a polyborate binder of claim 1 wherein the boron ion compound is one or more of boric acid, lithium hydroxide, lithium carbonate, lithium tetraborate, and lithium metaborate.

5. The method of preparing the polyborate binder of claim 1, wherein the molar ratio of the functional groups in the organic ligand to the boron ions in the boron ion compound is from 80:1 to 4: 1.

6. A polyborate binder, characterized by being prepared by the method of any one of claims 1 to 5.

7. Use of a polyborate binder as claimed in claim 6 for the production of batteries.

Technical Field

The invention relates to the technical field of electrochemistry and new energy materials, in particular to a polyborate adhesive and a preparation method and application thereof.

Background

Lithium ion batteries are widely used in smart phones, notebook computers, and electric vehicles due to their excellent properties such as high energy density, long life, and high voltage. With the development of smart phones and notebook computers, such as light weight, thinness, multiple functions, and large screen, and electric vehicles, the energy density requirement of batteries is higher.

Lithium ion batteries are typically manufactured using the following process: the battery is prepared by uniformly mixing powdery active substances, conductive agents and binders according to a certain proportion to prepare slurry, coating the slurry on a current collector such as an aluminum foil or a copper foil to form a pole piece, rolling the pole piece to form a more compact pole piece, winding or laminating a positive pole piece, a negative pole piece and a diaphragm together to form a battery core, putting the battery core into a battery box, injecting electrolyte and sealing the battery box to obtain the battery.

In order to further improve the energy density of the lithium ion battery, the adoption of a high specific capacity electrode material is the most fundamental solution, wherein the silicon-based negative electrode material has a theoretical specific capacity as high as 4200mAh/g and becomes the most promising next-generation negative electrode material, but because of the huge volume expansion of the silicon-based negative electrode material, the conventional binders such as polyvinylidene fluoride (PVDF), sodium carboxymethylcellulose (CMC)/styrene butadiene rubber latex (SBR), acrylonitrile-acrylic acid copolymer (LA133) and the like cannot meet the requirements, even the sodium alginate with stronger binding property is insufficient, and the development of novel high-strength multifunctional binders such as conductive binders, super-elastic binders and the like is urgently needed.

The ion conductive adhesive is not only an adhesive, but also has ion conductive capability, and is beneficial to reducing polarization and enhancing the rapid charge and discharge capability. In view of the requirements of the binder, only a few of the reported ion conductive binders have problems of expensive raw materials or complex process, and the like, and thus mass production cannot be realized.

Accordingly, the prior art is yet to be improved and developed.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide a polyborate adhesive, a preparation method and application thereof, and aims to solve the problems of low adhesive strength, poor conductivity and high preparation cost of the conventional adhesive.

The technical scheme of the invention is as follows:

a method of preparing a polyborate binder, comprising the steps of:

selecting an organic ligand, wherein the functional group of the organic ligand is one or more of hydroxyl, carboxyl and sulfonic group;

and adding the organic ligand and the boron ion compound into a water solvent, mixing, and reacting to obtain the polyborate adhesive.

The preparation method of the polyborate binder comprises the step of preparing a polyborate binder, wherein the organic matter ligand is one or more of ethylene glycol, propylene glycol, pentaerythritol, polyvinyl alcohol, sorbitol, xylitol, cyclodextrin, tartaric acid, phytic acid, polystyrene sulfonic acid, polyacrylic acid, polyethylene oxide, polyacrylamide and saccharide compounds.

The preparation method of the polyborate adhesive comprises the following step of mixing a polyborate adhesive with a sugar compound, wherein the sugar compound is one or more of glucose, fructose, sucrose and lactose.

The preparation method of the polyborate adhesive comprises the step of preparing a polyborate adhesive, wherein the boron ion compound is one or more of boric acid, lithium hydroxide, lithium carbonate, lithium tetraborate and lithium metaborate.

The preparation method of the polyborate adhesive comprises the step of preparing the polyborate adhesive, wherein the molar ratio of functional groups in the organic ligand to boron ions in the boron ion compound is 80:1-4: 1.

The invention relates to a polyborate adhesive, which is prepared by the preparation method of the polyborate adhesive.

Use of a polyborate binder for the preparation of a battery.

Has the advantages that: compared with the traditional PVDF, CMC/SBR, LA133, sodium alginate and other binders, the water-soluble inherent microporous conductive polyborate binder synthesized by adopting cheaper raw materials has stronger binding strength and lithium ion conductive capability, has excellent effect when being used for silicon-based negative electrode materials, and has very obvious advantages even being used for traditional electrode materials such as lithium iron phosphate, lithium manganate, graphite and the like. In addition, the adhesive is synthesized by adopting relatively cheap commercial raw materials through a simple mass production process, and has a huge application prospect.

Drawings

FIG. 1 is a flow diagram of a preferred embodiment of a method of making a polyborate binder of the present invention.

Fig. 2 is a graph comparing the effects of the polyborate binder and Sodium Alginate (SA) for a silicon carbon negative electrode material in example 1.

Fig. 3 is a graph comparing the effect of polyborate binder and LA133 for a graphite negative electrode in example 1.

Fig. 4 is a graph comparing the effects of the polyborate binder, PVDF, and LA133 in example 1 for a lithium iron phosphate positive electrode.

Detailed Description

The invention provides a polyborate adhesive and a preparation method and application thereof, and the invention is further described in detail below in order to make the purpose, technical scheme and effect of the invention clearer and clearer. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, fig. 1 is a flow chart of a preferred embodiment of a method for preparing a polyborate adhesive according to the present invention, which includes the steps of:

s10, selecting an organic ligand, wherein the organic ligand comprises one or more of hydroxyl, carboxyl and sulfonic acid groups as functional groups;

s20, adding the organic ligand and the boron ion compound into a water solvent, mixing, and reacting to obtain the polyborate adhesive.

In the embodiment, a commercial reagent is used as an organic ligand, or an organic ligand which can be synthesized only by 2-3 steps of reaction is selected, so that the raw materials are cheap and easy to obtain; the functional group contained in the organic matter ligand is one or more of hydroxyl, carboxyl and sulfonic group. In this embodiment, after the organic ligand and the boron ion compound are added to the aqueous solvent and mixed, the organic ligand may form a cyclic structure with trivalent boron ions through its functional group, so as to form the polyborate binder, and the boron ion in the boron ion compound is in a 4-coordinate configuration, similar to a spiro carbon atom. The polyborate adhesive prepared by the embodiment has stronger adhesive strength and lithium ion conductivity, and has excellent effect when being used for silicon-based negative electrode materials.

In some embodiments, the organic ligand is one or more of ethylene glycol, propylene glycol, pentaerythritol, polyvinyl alcohol, sorbitol, xylitol, cyclodextrin, tartaric acid, phytic acid, polystyrene sulfonic acid, polyacrylic acid, polyethylene oxide, polyacrylamide, and a saccharide compound, but is not limited thereto. In this embodiment, the sugar compound is one or more of glucose, fructose, sucrose and lactose, but is not limited thereto.

In some embodiments, the boron ion compound is one or more of boric acid, lithium hydroxide, lithium carbonate, lithium tetraborate, and lithium metaborate, but is not limited thereto.

In some embodiments, to ensure that the boron ions in the boron ion compound are sufficiently bound to the functional groups of the organic ligand, the molar ratio of the functional groups in the organic ligand to the boron ions in the boron ion compound is from 80:1 to 4: 1.

In some embodiments, a polyborate binder is also provided, wherein the polyborate binder is prepared by the method of the invention.

In some embodiments, there is also provided the use of a polyborate binder according to the present invention for the preparation of a battery.

A polyborate binder of the invention, its preparation and use are further illustrated by the following specific examples:

example 1

1. Synthesis of polyborate binder: 22.70 g of cyclodextrin and 4.228 g of lithium tetraborate are added to 200 g of water and the mixture is stirred at room temperature for 6 hours to obtain a colorless solution which is diluted to a solution with a solids content of 2%.

2. Manufacturing a battery: weighing 0.225 g of carbon-coated SiO negative electrode material, adding 0.045 g of Ketjen black conductive agent, uniformly mixing in an agate mortar, adding 1.50 g of the polyborate binder solution, grinding into uniform slurry, blade-coating the uniform slurry on copper foil, drying at 80 ℃, punching into a pole piece with the diameter of 12mm, vacuum-drying at 70 ℃ overnight, and assembling into a button cell in a glove box, wherein the negative electrode is a metal lithium piece, the electrolyte is 1mol/L LiPF6 solution (the solvent is ethylene carbonate and diethyl carbonate with the volume ratio of 1: 1, 2% of ethylene carbonate is added as a film-forming agent), and the diaphragm is cellgard2500

3. And (3) performance testing: performing charge and discharge test by adopting a current density of 150mA/g within the range of 0.01-1.5V, and measuring that the first lithium intercalation capacity is 1756mAh/g, the first efficiency is 66%, and the specific capacity is 1247mAh/g after 100 times of circulation; for comparison, the silicon-carbon negative electrode material adopting the sodium alginate binder has the lithium intercalation capacity of 1636mAh/g for the first time, the first efficiency of 63 percent, and the specific capacity of 821mAh/g after 100 times of circulation, and the comparison effect is shown in figure 2, wherein PLB161, PLB121, PLB81 and PLB41 represent cyclodextrin and lithium tetraborate in different proportions. In order to further prove the excellent effect of the lithium ion conductive binder, PLB41 and LA133 are respectively used as graphite negative electrode binders, the cycle performance of the graphite negative electrode binders is shown in fig. 3, the first efficiency of the PLB41 binder is 74%, the first lithium intercalation specific capacity is 281mAh/g, the first efficiency of the LA133 is 70%, and the first lithium intercalation specific capacity is 440mAh/g, although the specific capacity of the PLB41 is lower than that of the LA133 before 250 cycles, the specific capacity of the PLB41 binder is gradually increased along with the increase of the cycle number, is obviously greater than that of the latter after 250 cycles, and the specific capacity of the latter is gradually reduced along with the increase of the cycle number and is sharply reduced after 250 cycles. Fig. 4 further shows the performance of the PLB binder for the lithium iron phosphate positive electrode, compared to the conventional binders such as PVDF and LA133, although the specific capacity of PLB41 is relatively low, the PLB41 has the highest energy conversion efficiency and better cycle stability, and the energy conversion efficiency is not reduced with the increase of the cycle number and is always stabilized at 94%. In comparison, the initial energy conversion efficiency of PVDF is only 89%, then it decreases gradually, only 85% after 320 cycles.

Example 2

1. Synthesis of the binder: to 200 g of water were added 15.00 g of tartaric acid and 0.4975 g of metaboric acid, and the mixture was stirred at room temperature for 6 hours to obtain a colorless solution, which was diluted to a solution having a solid content of 2%.

2. Manufacturing a battery: weighing 0.225 g of carbon-coated SiO negative electrode material, adding 0.045 g of Ketjen black conductive agent, uniformly mixing in an agate mortar, adding 1.50 g of the binder solution, grinding into uniform slurry, blade-coating the slurry on copper foil, drying at 80 ℃, punching into a pole piece with the diameter of 12mm, drying at 70 ℃ in vacuum overnight, and assembling into a button cell in a glove box, wherein the negative electrode is a metal lithium piece, the electrolyte is 1mol/L LiPF6 solution (the solvent is ethylene carbonate and diethyl carbonate with the volume ratio of 1: 1, 2% of ethylene carbonate is added as a film forming agent), and the diaphragm is cellgard 2500.

3. And (3) performance testing: performing charge and discharge tests by adopting a current density of 150mA/g within the range of 0.01-1.5V, and measuring that the first lithium intercalation capacity is 1700mAh/g, the first efficiency is 63 percent, and the specific capacity is 985mAh/g after circulation for 100 times; for comparison, the silicon-carbon negative electrode material adopting the sodium alginate adhesive has the lithium intercalation capacity of 1636mAh/g for the first time, the first efficiency of 63 percent and the specific capacity of 821mAh/g after 100 times of circulation.

Example 3

1. Synthesis of the binder: 18.20 g of sorbitol and 0.8456 g of lithium tetraborate are added into 200 g of water, stirred and reacted for 6 hours at room temperature to obtain a colorless solution, and the colorless solution is diluted to a solution with the solid content of 2%.

2. Manufacturing a battery: weighing 0.225 g of carbon-coated SiO negative electrode material, adding 0.045 g of Ketjen black conductive agent, uniformly mixing in an agate mortar, adding 1.50 g of the binder solution, grinding into uniform slurry, blade-coating the slurry on copper foil, drying at 80 ℃, punching into a pole piece with the diameter of 12mm, drying at 70 ℃ in vacuum overnight, and assembling into a button cell in a glove box, wherein the negative electrode is a metal lithium piece, the electrolyte is 1mol/L LiPF6 solution (the solvent is ethylene carbonate and diethyl carbonate with the volume ratio of 1: 1, 2% of ethylene carbonate is added as a film forming agent), and the diaphragm is cellgard 2500.

3. And (3) performance testing: performing charge and discharge test by adopting a current density of 150mA/g within the range of 0.01-1.5V, and measuring that the first lithium intercalation capacity is 1737mAh/g, the first efficiency is 64 percent, and the specific capacity is 1213mAh/g after circulation for 100 times; for comparison, the silicon-carbon negative electrode material adopting the sodium alginate adhesive has the lithium intercalation capacity of 1636mAh/g for the first time, the first efficiency of 63 percent and the specific capacity of 821mAh/g after 100 times of circulation.

Example 4

1. Synthesis of the binder: to 200 g of water were added 14.40 g of polyacrylic acid and 8.80 g of polyvinyl alcohol, 6.183 g of boric acid and 3.6940 g of lithium carbonate, and the mixture was stirred at room temperature for 6 hours to react to obtain a colorless solution, which was diluted to a solution having a solid content of 2%.

2. Manufacturing a battery: weighing 0.225 g of carbon-coated SiO negative electrode material, adding 0.045 g of Ketjen black conductive agent, uniformly mixing in an agate mortar, adding 1.50 g of the binder solution, grinding into uniform slurry, blade-coating the slurry on copper foil, drying at 80 ℃, punching into a pole piece with the diameter of 12mm, drying at 70 ℃ in vacuum overnight, and assembling into a button cell in a glove box, wherein the negative electrode is a metal lithium piece, the electrolyte is 1mol/L LiPF6 solution (the solvent is ethylene carbonate and diethyl carbonate with the volume ratio of 1: 1, 2% of ethylene carbonate is added as a film forming agent), and the diaphragm is cellgard 2500.

3. And (3) performance testing: performing charge and discharge tests by adopting a current density of 150mA/g within the range of 0.01-1.5V, and measuring that the first lithium intercalation capacity is 1619mAh/g, the first efficiency is 63 percent, and the specific capacity is 867mAh/g after circulation for 100 times; for comparison, the silicon-carbon negative electrode material adopting the sodium alginate adhesive has the lithium intercalation capacity of 1636mAh/g for the first time, the first efficiency of 63 percent and the specific capacity of 821mAh/g after 100 times of circulation.

Example 5

1. Synthesis of the binder: 19.62 g of gluconic acid and 4.975 g of lithium metaborate are added into 200 g of water, stirred and reacted for 6 hours at room temperature to obtain a colorless solution, and the colorless solution is diluted to a solution with the solid content of 2%.

2. Manufacturing a battery: weighing 0.225 g of carbon-coated SiO negative electrode material, adding 0.045 g of Ketjen black conductive agent, uniformly mixing in an agate mortar, adding 1.50 g of the binder solution, grinding into uniform slurry, blade-coating the slurry on copper foil, drying at 80 ℃, punching into a pole piece with the diameter of 12mm, drying at 70 ℃ in vacuum overnight, and assembling into a button cell in a glove box, wherein the negative electrode is a metal lithium piece, the electrolyte is 1mol/L LiPF6 solution (the solvent is ethylene carbonate and diethyl carbonate with the volume ratio of 1: 1, 2% of ethylene carbonate is added as a film forming agent), and the diaphragm is cellgard 2500.

3. And (3) performance testing: performing charge and discharge test at a current density of 150mA/g within a range of 0.01-1.5V, and measuring that the first lithium intercalation capacity is 1698mAh/g, the first efficiency is 64%, and the specific capacity is 978mAh/g after circulation for 100 times; for comparison, the silicon-carbon negative electrode material adopting the sodium alginate adhesive has the lithium intercalation capacity of 1636mAh/g for the first time, the first efficiency of 63 percent and the specific capacity of 821mAh/g after 100 times of circulation.

Example 6

1. Synthesis of the binder: to 200 g of water were added 20.22 g of polystyrenesulfonic acid, 0.6183 g of boric acid and 0.4196 g of lithium hydroxide monohydrate, and the mixture was stirred at room temperature for 6 hours to react to obtain a colorless solution, which was diluted to a solution having a solid content of 2%.

2. Manufacturing a battery: weighing 0.225 g of carbon-coated SiO negative electrode material, adding 0.045 g of Ketjen black conductive agent, uniformly mixing in an agate mortar, adding 1.50 g of the binder solution, grinding into uniform slurry, blade-coating the slurry on copper foil, drying at 80 ℃, punching into a pole piece with the diameter of 12mm, drying at 70 ℃ in vacuum overnight, and assembling into a button cell in a glove box, wherein the negative electrode is a metal lithium piece, the electrolyte is 1mol/L LiPF6 solution (the solvent is ethylene carbonate and diethyl carbonate with the volume ratio of 1: 1, 2% of ethylene carbonate is added as a film forming agent), and the diaphragm is cellgard 2500.

3. And (3) performance testing: performing charge and discharge tests by adopting a current density of 150mA/g within the range of 0.01-1.5V, and measuring that the first lithium intercalation capacity is 1656mAh/g, the first efficiency is 65%, and the specific capacity is 1179mAh/g after circulation for 100 times; for comparison, the silicon-carbon negative electrode material adopting the sodium alginate adhesive has the lithium intercalation capacity of 1636mAh/g for the first time, the first efficiency of 63 percent and the specific capacity of 821mAh/g after 100 times of circulation.

Example 7

1. Synthesis of the binder: to 200 g of water were added 15.22 g of xylitol and 4.228 g of lithium tetraborate, and the mixture was stirred at room temperature for 6 hours to obtain a colorless solution, which was diluted to a solution having a solid content of 2%.

2. Manufacturing a battery: weighing 0.225 g of carbon-coated SiO negative electrode material, adding 0.045 g of Ketjen black conductive agent, uniformly mixing in an agate mortar, adding 1.50 g of the binder solution, grinding into uniform slurry, blade-coating the slurry on copper foil, drying at 80 ℃, punching into a pole piece with the diameter of 12mm, drying at 70 ℃ in vacuum overnight, and assembling into a button cell in a glove box, wherein the negative electrode is a metal lithium piece, the electrolyte is 1mol/L LiPF6 solution (the solvent is ethylene carbonate and diethyl carbonate with the volume ratio of 1: 1, 2% of ethylene carbonate is added as a film forming agent), and the diaphragm is cellgard 2500.

3. And (3) performance testing: performing charge and discharge test at a current density of 150mA/g within a range of 0.01-1.5V, and measuring that the first lithium intercalation capacity is 1725mAh/g, the first efficiency is 65%, and the specific capacity is 1113mAh/g after 100 times of circulation; for comparison, the silicon-carbon negative electrode material adopting the sodium alginate adhesive has the lithium intercalation capacity of 1636mAh/g for the first time, the first efficiency of 63 percent and the specific capacity of 821mAh/g after 100 times of circulation.

Example 8

1. Synthesis of the binder: 13.62 g of pentaerythritol and 0.2114 g of lithium tetraborate were added to 200 g of water, and the mixture was stirred at room temperature for 6 hours to obtain a colorless solution, which was diluted to a solution having a solid content of 2%.

2. Manufacturing a battery: weighing 0.225 g of carbon-coated SiO negative electrode material, adding 0.045 g of Ketjen black conductive agent, uniformly mixing in an agate mortar, adding 1.50 g of the binder solution, grinding into uniform slurry, blade-coating the slurry on copper foil, drying at 80 ℃, punching into a pole piece with the diameter of 12mm, drying at 70 ℃ in vacuum overnight, and assembling into a button cell in a glove box, wherein the negative electrode is a metal lithium piece, the electrolyte is 1mol/L LiPF6 solution (the solvent is ethylene carbonate and diethyl carbonate with the volume ratio of 1: 1, 2% of ethylene carbonate is added as a film forming agent), and the diaphragm is cellgard 2500.

3. And (3) performance testing: performing charge and discharge test at a current density of 150mA/g within a range of 0.01-1.5V, and measuring that the first lithium intercalation capacity is 1692mAh/g, the first efficiency is 65%, and the specific capacity is 1017mAh/g after circulation for 100 times; for comparison, the silicon-carbon negative electrode material adopting the sodium alginate adhesive has the lithium intercalation capacity of 1636mAh/g for the first time, the first efficiency of 63 percent and the specific capacity of 821mAh/g after 100 times of circulation.

Example 9

1. Synthesis of the binder: to 200 g of water were added 18.02 g of sorbose, 6.183 g of boric acid and 4.196 g of lithium hydroxide monohydrate, and the mixture was stirred at room temperature for 6 hours to obtain a colorless solution, which was diluted to a solution having a solid content of 2%.

2. Manufacturing a battery: weighing 0.225 g of carbon-coated SiO negative electrode material, adding 0.045 g of Ketjen black conductive agent, uniformly mixing in an agate mortar, adding 1.50 g of the binder solution, grinding into uniform slurry, blade-coating the slurry on copper foil, drying at 80 ℃, punching into a pole piece with the diameter of 12mm, drying at 70 ℃ in vacuum overnight, and assembling into a button cell in a glove box, wherein the negative electrode is a metal lithium piece, the electrolyte is 1mol/L LiPF6 solution (the solvent is ethylene carbonate and diethyl carbonate with the volume ratio of 1: 1, 2% of ethylene carbonate is added as a film forming agent), and the diaphragm is cellgard 2500.

3. And (3) performance testing: performing charge and discharge tests by adopting a current density of 150mA/g within the range of 0.01-1.5V, and measuring that the first lithium intercalation capacity is 1743mAh/g, the first efficiency is 63 percent, and the specific capacity is 1052mAh/g after circulation for 100 times; for comparison, the silicon-carbon negative electrode material adopting the sodium alginate adhesive has the lithium intercalation capacity of 1636mAh/g for the first time, the first efficiency of 63 percent and the specific capacity of 821mAh/g after 100 times of circulation.

Example 10

1. Synthesis of the binder: 22.00 g of polyvinyl alcohol and 0.2114 g of lithium tetraborate are added into 200 g of water, stirred and reacted for 6 hours at room temperature to obtain a colorless solution, and the colorless solution is diluted to a solution with the solid content of 2%.

2. Manufacturing a battery: weighing 0.225 g of carbon-coated SiO negative electrode material, adding 0.045 g of Ketjen black conductive agent, uniformly mixing in an agate mortar, adding 1.50 g of the binder solution, grinding into uniform slurry, blade-coating the slurry on copper foil, drying at 80 ℃, punching into a pole piece with the diameter of 12mm, drying at 70 ℃ in vacuum overnight, and assembling into a button cell in a glove box, wherein the negative electrode is a metal lithium piece, the electrolyte is 1mol/L LiPF6 solution (the solvent is ethylene carbonate and diethyl carbonate with the volume ratio of 1: 1, 2% of ethylene carbonate is added as a film forming agent), and the diaphragm is cellgard 2500.

3. And (3) performance testing: performing charge and discharge tests by adopting a current density of 150mA/g within the range of 0.01-1.5V, and measuring that the first lithium intercalation capacity is 1689mAh/g, the first efficiency is 65%, and the specific capacity is 927mAh/g after circulation for 100 times; for comparison, the silicon-carbon negative electrode material adopting the sodium alginate adhesive has the lithium intercalation capacity of 1636mAh/g for the first time, the first efficiency of 63 percent and the specific capacity of 821mAh/g after 100 times of circulation.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.