阅读说明：本技术 一种导电聚合物-镁还原氧化亚硅负极材料的制备方法 (Preparation method of conductive polymer-magnesium reduction-silicon oxide negative electrode material ) 是由 齐美洲 郭钰静 许家齐 杨茂萍 于 2020-02-28 设计创作，主要内容包括：本发明公开了一种导电聚合物-镁还原氧化亚硅负极材料的制备方法包括以下步骤,(1)将氧化亚硅在高温下惰性气体中进行烧结,得到歧化型氧化亚硅；(2)将Mg粉与歧化型氧化亚硅按一定重量比进行混合,在高温下惰性气体中进行烧结,冷却后得到复合物A,使用酸对复合物进行浸泡,形成复合物B；(3)将复合物B溶于乙醇溶液中,加入硅烷偶联剂反应,调节PH值至3-7,再加入导电聚合物单体和氧化剂进行聚合反应,制得混合溶液,最后经洗涤、抽滤及真空干燥,得到导电聚合物-镁还原氧化亚硅负极材料。本发明工艺简单,实用性强,有利于促进氧化亚硅负极材料的工业化生产及应用性能的提升,并可推动镁热还原技术的推广和应用。(The invention discloses a preparation method of a conductive polymer-magnesium reduction silicon monoxide negative electrode material, which comprises the following steps of (1) sintering silicon monoxide in inert gas at high temperature to obtain disproportionation type silicon monoxide; (2) mixing Mg powder and disproportionated silicon monoxide according to a certain weight ratio, sintering in inert gas at high temperature, cooling to obtain a compound A, and soaking the compound A with acid to form a compound B; (3) and dissolving the compound B in an ethanol solution, adding a silane coupling agent for reaction, adjusting the pH value to 3-7, adding a conductive polymer monomer and an oxidant for polymerization reaction to obtain a mixed solution, and finally washing, filtering and drying in vacuum to obtain the conductive polymer-magnesium reduced silicon oxide negative electrode material. The method has simple process and strong practicability, is favorable for promoting the industrial production and the improvement of the application performance of the silicon monoxide cathode material, and can promote the popularization and the application of the magnesiothermic reduction technology.)

1. A preparation method of a conductive polymer-magnesium reduction monox negative electrode material is characterized by comprising the following steps,

(1) sintering the silicon monoxide in inert gas at high temperature to obtain disproportionated silicon monoxide;

(2) mixing Mg powder and the disproportionated silicon monoxide in the step (1) according to a certain weight ratio, sintering in inert gas at high temperature, cooling to obtain a compound A, and soaking the compound A by using acid to form a compound B;

(3) dissolving the compound B in an ethanol solution, adding a silane coupling agent for reaction, adjusting the pH value to 3-7, adding a conductive polymer monomer and an oxidant for polymerization reaction to obtain a mixed solution, and finally washing, filtering and drying in vacuum to obtain the conductive polymer-magnesium reduced silicon oxide negative electrode material.

2. The method for preparing a conductive polymer-magnesium reduced silica negative electrode material according to claim 1, wherein in the step (1), the sintering conditions are as follows: the inert gas adopts one of nitrogen, helium or argon, and the sintering process is as follows: heating to 900-.

3. The method for preparing a conductive polymer-magnesium reduced silica negative electrode material according to claim 1, wherein in the step (2), the sintering conditions are as follows: the inert gas adopts helium or argon, and the sintering process comprises the following steps: heating to 660-750 ℃ at the speed of 2-10 ℃/min, preserving the heat for 3-15h, and naturally cooling to room temperature.

4. The method for producing a conductive polymer-magnesium reduced silica negative electrode material according to claim 1, wherein in the step (2), the weight ratio of the Mg powder to the disproportionated silica is 0.04 to 0.25.

5. The method for preparing a conductive polymer-magnesium reduced silicon oxide negative electrode material according to claim 1, wherein in the step (2), the acid used for soaking is hydrochloric acid or nitric acid, and the soaking time is 1-20 h.

6. The method for preparing the conductive polymer-magnesium reduced silicon oxide negative electrode material of claim 1, wherein in the step (3), the conductive polymer monomer is pyrrole or thiophene, and the oxidant is one or two of hydrogen peroxide and ferric trichloride.

7. The method for preparing a conductive polymer-magnesium reduced silica negative electrode material according to claim 1 or 6, wherein in the step (3), the weight ratio of the oxidizing agent to the conductive polymer monomer is 0.005 to 0.015.

8. The method for preparing a conductive polymer-magnesium reduced silica negative electrode material according to claim 1, wherein the weight ratio of the silane coupling agent to the composite B in the step (3) is 0.005 to 0.01.

9. The method for preparing a conductive polymer-magnesium reduced silica anode material according to claim 1, wherein in the step (3), the polymerization reaction is carried out at a reaction temperature of 80-95 ℃ for 10-20 hours.

10. The method for preparing a conductive polymer-magnesium reduced silica negative electrode material according to claim 1, wherein in the step (3), the silane coupling agent is one or both of 3-aminopropyltrimethoxysilane and 3-ureidopropyltrimethoxysilane.

Technical Field

The invention belongs to the technical field of negative electrode materials, and particularly relates to a preparation method of a conductive polymer-magnesium reduced silicon oxide negative electrode material.

Background

At present, the commercial power battery negative electrode material is mainly graphite, but the theoretical gram capacity of the graphite is low, and the requirement of the high specific capacity lithium ion power battery cannot be met, in the high capacity negative electrode material, the silicon-based material has very high capacity, wherein, the silicon oxide has higher theoretical capacity (2400 mAh/g) and relatively lower volume expansion effect (200%), and is a novel lithium ion battery negative electrode material, but compared with the graphite, the volume expansion effect is still an important obstacle limiting the application of the lithium ion battery negative electrode material in the charging and discharging process, and simultaneously, due to the existence of oxygen element, a large amount of lithium ions can be consumed in the first charging and discharging process, so that the first efficiency is lower.

Disclosure of Invention

The invention aims to provide a preparation method of a conductive polymer-magnesium reduced silicon oxide negative electrode material, which overcomes the technical problems.

The technical purpose of the invention is realized by the following technical scheme:

a preparation method of a conductive polymer-magnesium reduction monox negative electrode material comprises the following steps,

(1) sintering the silicon monoxide in inert gas at high temperature to obtain disproportionated silicon monoxide;

(2) mixing Mg powder and the disproportionated silicon monoxide in the step (1) according to a certain weight ratio, sintering in inert gas at high temperature, cooling to obtain a compound A, and soaking the compound A by using acid to form a compound B;

(3) dissolving the compound B in an ethanol solution, adding a silane coupling agent for reaction, adjusting the pH value to 3-7, adding a conductive polymer monomer and an oxidant for polymerization reaction to obtain a mixed solution, and finally washing, filtering and drying in vacuum to obtain the conductive polymer-magnesium reduced silicon oxide negative electrode material.

Further, in the step (1), the sintering conditions are as follows: the inert gas adopts one of nitrogen, helium or argon, and the sintering process is as follows: heating to 900-.

Further, in the step (2), the sintering conditions are as follows: the inert gas adopts helium or argon, and the sintering process comprises the following steps: heating to 660-750 ℃ at the speed of 2-10 ℃/min, preserving the heat for 3-15h, and naturally cooling to room temperature.

Further, in the step (2), the weight ratio of the Mg powder to the disproportionated silica is 0.04-0.25.

Further, in the step (2), the acid used for soaking is hydrochloric acid or nitric acid, and the soaking time is 1-20 h.

Further, in the step (3), the conductive polymer monomer is pyrrole or thiophene, and the oxidant is one or two of hydrogen peroxide and ferric trichloride.

Further, in the step (3), the weight ratio of the oxidizing agent to the conductive polymer monomer is 0.005-0.015.

Further, in the step (3), the weight ratio of the silane coupling agent to the composite B is 0.005 to 0.01.

Further, in the step (3), the reaction temperature of the polymerization reaction is 80-95 ℃ and the reaction time is 10-20 h.

Further, in the step (3), the silane coupling agent is one or two of 3-aminopropyltrimethoxysilane and 3-ureidopropyltrimethoxysilane.

Has the advantages that:

in the invention, before Mg powder is thermally reduced, the silicon monoxide is disproportionated at high temperature, and the disproportionated silicon monoxide consists of Si and SiO₂The disproportionation type silicon monoxide and Mg powder are favorable for Mg and SiO reduction₂So that the compound A has relatively high MgO content and Mg₂SiO₄Relatively low, so that after removal of MgO with acid, there is only a small amount of Mg₂SiO₄Residue is beneficial to improving gram capacity exertion of the material, and the first charge-discharge efficiency of the material is obviously improvedRate of residual Mg₂SiO₄Can be used as an inert phase and a buffer medium in the charge and discharge process, and is beneficial to reducing the volume expansion effect;

in addition, in the thermal reaction process of Mg powder, obvious volume shrinkage occurs in the particles, so that micro channels are formed, at the moment, after the particles are soaked by acid, the acid can permeate into the particles through the micro channels to react, so that a large number of holes are formed in the position of MgO, and the formed holes can provide good attachment points for conductive polymer monomers in the subsequent polymerization reaction, so that the magnesium reduction-silicon oxide negative electrode material penetrated by the conductive polymer can be formed;

and the network structure formed by the conductive polymer is beneficial to increasing the conductivity inside the particles and exerting gram capacity, and meanwhile, the network structure intertwined with each other can further reduce the volume expansion effect of the silicon protoxide material in the charge-discharge process of the material, so that the cycle performance of the silicon protoxide material is improved.

Drawings

FIG. 1 is a graph of cycle number versus capacity retention for examples of the present invention and comparative examples;

FIG. 2 is a SEM photograph of example 1 of the present invention;

FIG. 3 is a sectional SEM photograph of example 1 of the present invention;

FIG. 4 is an XRD spectrum of composite A particles prepared in example 1 of the present invention;

fig. 5 is an XRD spectrum of the composite B particle prepared in example 1 of the present invention.

Detailed Description

In the description of the present invention, unless otherwise specified, the terms "upper", "lower", "left", "right", "front", "rear", and the like, indicate orientations or positional relationships only for the purpose of describing the present invention and simplifying the description, but do not indicate or imply that the designated device or structure must have a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The preparation method of the conductive polymer-magnesium reduction monox cathode material comprises the following steps,

(1) sintering the silicon monoxide in inert gas at high temperature, wherein the inert gas adopts one of nitrogen, helium or argon, and the sintering process comprises the following steps: heating to 900-;

(2) mixing Mg powder with the disproportionated silicon monoxide in the step (1) according to the weight ratio of 0.04-0.25, and sintering in inert gas at high temperature, wherein the inert gas adopts helium or argon, and the sintering process is as follows: heating to 660-;

(3) dissolving a compound B in an ethanol solution, and adding a silane coupling agent for reaction, wherein the weight ratio of the silane coupling agent to the compound B is 0.005-0.01, and the silane coupling agent is one or two of 3-aminopropyltrimethoxysilane and 3-urea propyl trimethoxysilane; adjusting the pH value to 3-7 by using hydrochloric acid, adding a conductive polymer monomer and an oxidant to perform polymerization reaction at the temperature of 80-95 ℃ for 10-20h, wherein the conductive polymer monomer is pyrrole or thiophene, the oxidant is one or two of hydrogen peroxide and ferric trichloride, the weight ratio of the oxidant to the conductive polymer monomer is 0.005-0.015, so as to prepare a mixed solution, and finally, washing, filtering and vacuum drying are performed to obtain the conductive polymer-magnesium reduced silicon oxide negative electrode material, wherein the conductive polymer in the conductive polymer-magnesium reduced silicon oxide negative electrode material is 2-15% of the weight of the negative electrode material, and the Mg element accounts for 1-20% of the weight of the negative electrode material.