1. A preparation method of a three-dimensional porous silicon dioxide negative electrode material for a lithium ion battery comprises the following steps:

1) weighing MXene, a metal framework compound precursor and methanol in certain mass, and magnetically stirring for 2-10 h; MXene is Ti₃C₂、MoNb₂SnC₂One kind of (1); the metal skeleton compound is ZIF-8, ZIF-67, Cu₃(HHTP)₂And Ni₃(HITP)₂One kind of (1); 0.001-1 molar ratio of metal framework compound to Mxene;

2) weighing the product obtained in the step 1), metal salt, surfactant, organic alkaline substance and water, mixing and stirring, and carrying out hydrothermal reaction for 2-20h at 70-150 ℃; the metal salt is one of soluble nickel, cobalt, manganese, tin and iron; the metal salt is 0.1-50 wt% of the product of the step 1); the organic base is one of hexamethylenetetramine, hexamethylenediamine, aniline, cyclohexylamine, ethylenediamine and methylamine;

3) placing the product in the step 2) for 2-10h at the temperature of 500-1000 ℃ under the argon atmosphere;

4) mixing the product obtained in the step 3) with organic silicon, water and a surfactant, and carrying out hydrothermal reaction for 1-20h at the temperature of 20-100 ℃; the molar ratio of the organic silicon to the Mxene is 0.1-20;

5) and (3) dipping the product obtained in the step (4) in concentrated hydrochloric acid for 1-40h, washing and drying to obtain the three-dimensional porous silicon dioxide cathode material for the lithium ion battery.

Background

SiO₂Has high theoretical specific capacity (about 2600mAh g^-1) To putLow voltage, and the like, and has good application prospect in the aspect of lithium ion batteries. SiO as with silicon cathode₂There are also problems of poor conductivity and volume expansion during charge and discharge. Adopts carbon material, conductive polymer and SiO with high conductivity and large specific surface area₂Compounding is to improve SiO₂An efficient way of electrochemical performance. Wangjianpin et al (Wangjianpin, Tianwenhuai, Yangdao, etc.) high-temperature pyrolysis preparation of silicon/carbon composite material and its electrochemical properties, proceedings of engineering science 2015(08):1044-1048.]Preparation of SiO by high-temperature pyrolysis₂A carbon composite; the material was at 0.2mA cm²Current density of 768mAh g of first charge capacity^-1The coulombic efficiency is 75.6 percent, and the reversible specific capacity after 70 cycles is 529mAh g^-1The average attenuation rate was 0.4%. Ren Yu Rong, etc. [ ren Yu Rong, Wei Heng Ma, Huang Xiao Bing, SiO₂The preparation and the performance of the/C composite cathode material are shown in the Chinese science of chemistry 2015(7) 733-739.]Coating nano SiO with polyaniline₂Preparing SiO by high-temperature carbonization₂a/C nanocomposite; the electrochemical test result shows that the concentration is 50mAg^-1The first discharge specific capacity under the current density reaches 830.5mAh g^-1The specific discharge capacity after 100 times of circulation is 510mAh g^-1The coulomb efficiency is kept above 98.0%.

MXene is an emerging two-dimensional material with ultra-thin thickness and large surface area. It is receiving increasing attention in the field of electrochemical energy storage due to its high electron conductivity and ion diffusion rate. Zhang F et al [ Zhang F, Jia Z, Wang C, et al Sandwich-like silicon/Ti3C2 MXene composition by electrostatic selection-analysis for high performance requirement basic. energy.2020.117047.]The sandwich silicon/MXene composite material is prepared by adopting an electrostatic self-assembly method, has good cycle performance and electrochemical capacity and is prepared at 300mA g^-1Can provide 1067.6mAh g at the current density of^-1The initial reversible specific capacity of the product is 643.8mAh g after 100 cycles^-1The specific capacity of (A). ZHao Q et al [ ZHao Q, Zhu Q, Miao J, et al. Flexible 3D ports MXene Foam for High-Performance Lithium-Ion batteries. Small,2019,15(51):1904293.]By passingMXene with a developed porous structure was prepared by a simple sulfur template method. This soft porous MXene was at 50mA g^-1The specific capacity of the alloy reaches 456mAh g under the current density^-1(ii) a At 1A g^-1The specific capacity is still 220mAh g after 3500 cycles^-1(ii) a At 18A g^-1Specific capacity of 101mAh g under current density^-1. However, to date, there is no report on SiO₂The application of the/Mxene composite material in the negative electrode material of the lithium ion battery.

Disclosure of Invention

Aiming at the defects of the prior technical scheme, the invention aims to provide a preparation method of a three-dimensional porous silicon dioxide cathode material for a lithium ion battery, which overcomes the defects of the prior preparation technology and improves the electrochemical performance of silicon dioxide.

In order to achieve the purpose, the technical scheme of the invention is as follows: a preparation method of a three-dimensional porous silicon dioxide negative electrode material for a lithium ion battery comprises the following steps:

1) weighing MXene, a metal framework compound precursor and methanol in certain mass, and magnetically stirring for 2-10 h; MXene is Ti₃C₂、MoNb₂SnC₂One kind of (1); the metal skeleton compound is ZIF-8, ZIF-67, Cu₃(HHTP)₂And Ni₃(HITP)₂One kind of (1); 0.001-1 molar ratio of metal framework compound to Mxene;

2) weighing the product obtained in the step 1), metal salt, surfactant, organic alkaline substance and water, mixing and stirring, and carrying out hydrothermal reaction for 2-20h at 70-150 ℃; the metal salt is one of soluble nickel, cobalt, manganese, tin and iron; the metal salt is 0.1-50 wt% of the product of the step 1); the organic base is one of hexamethylenetetramine, hexamethylenediamine, aniline, cyclohexylamine, ethylenediamine and methylamine;

3) placing the product in the step 2) for 2-10h at the temperature of 500-1000 ℃ under the argon atmosphere;

4) mixing the product obtained in the step 3) with organic silicon, water and a surfactant, and carrying out hydrothermal reaction for 1-20h at the temperature of 20-100 ℃; the molar ratio of the organic silicon to the Mxene is 0.1-20;

5) and (3) dipping the product obtained in the step (4) in concentrated hydrochloric acid for 1-40h, washing and drying to obtain the three-dimensional porous silicon dioxide cathode material for the lithium ion battery.

The patent designs a preparation method of a three-dimensional porous silicon dioxide cathode material for a lithium ion battery; the interlayer spacing of the two-dimensional material is enlarged through a metal framework compound; preparing hydroxide through salt hydrolysis, performing high-temperature treatment, and reacting carbon with metal oxide to obtain a three-dimensional porous structure; the deposition of silicon dioxide is regulated and controlled by taking a three-dimensional porous Mxene as a carrier; obtaining the three-dimensional porous silicon dioxide cathode material for the lithium ion battery. Compared with the prior art, the three-dimensional porous silicon dioxide cathode material for the lithium ion battery provided by the invention has the following advantages:

1) the preparation process is simple, the working procedures are controllable, and industrial production can be realized;

2) the Mxene has good conductivity, is compounded with silicon dioxide, and is beneficial to improving the electrochemical performance of the silicon dioxide;

3) the Mxene/carbon material is prepared by in-situ synthesis of a metal framework compound precursor on the surface of the Mxene and high-temperature sintering, so that the interlayer spacing of the Mxene is favorably expanded;

4) metal salt is adopted to deposit hydroxide in situ on the Mxene/carbon material, and the Mxene/carbon material with a three-dimensional network structure is obtained through the high-temperature thermal reduction reaction of carbon and metal hydroxide;

5) the silicon dioxide is deposited by using the Mxene/carbon material with a three-dimensional network structure to obtain the silicon dioxide cathode material for the lithium ion battery, and the material has good electrochemical performance. The electrochemical capacity of 100 cycles is higher than 1200mAh/g under the current density of 0.1C. The silicon dioxide cathode material has good application prospect in the field of lithium ion batteries.

Detailed Description

In order to further understand the contents, features and effects of the present invention, the following embodiments are described in detail as follows:

example 1

A preparation method of a three-dimensional porous silicon dioxide negative electrode material for a lithium ion battery comprises the following steps:

1) weighing MXene, a metal framework compound precursor and methanol in certain mass, and magnetically stirring for 5 hours;

2) weighing the product obtained in the step 1), metal salt, surfactant, organic alkaline substance and water, mixing and stirring, and carrying out hydrothermal reaction for 5h at 120 ℃;

3) standing the product obtained in the step 2) at 800 ℃ for 10 hours in an argon atmosphere;

4) mixing the product obtained in the step 3) with organic silicon, water and a surfactant, and carrying out hydrothermal reaction for 5 hours at 40 ℃;

5) and (3) soaking the product obtained in the step (4) in concentrated hydrochloric acid for 30 hours, washing and drying to obtain the three-dimensional porous silicon dioxide cathode material for the lithium ion battery.

The composition design of the three-dimensional porous silicon dioxide anode material for the lithium ion battery comprises the following components:

1)Ti₃C₂,0.01mol；ZIF-67,0.001mol；NiCl₂.6H₂0.005mol of O; 0.05mol of tetraethoxysilane;

2)Ti₃C₂,0.01mol；ZIF-8,0.001mol；CoCl₂.6H₂0.005mol of O; 0.05mol of tetraethoxysilane;

3)Ti₃C₂,0.01mol；Cu₃(HHTP)₂,0.001mol；SnCl₂.2H₂0.005mol of O; 0.05mol of tetraethoxysilane;

4)Ti₃C₂,0.01mol；Ni₃(HITP)₂,0.001mol；FeCl₂.4H₂0.005mol of O; 0.05mol of tetraethoxysilane;

the electrochemical test results show that: the silicon dioxide cathode material has good electrochemical performance; the capacity of 100 cycles is higher than 1200ml/g at a current density of 0.1C.

Example 2

A preparation method of a three-dimensional porous silicon dioxide negative electrode material for a lithium ion battery comprises the following steps:

1) weighing MXene, a metal framework compound precursor and methanol in certain mass, and magnetically stirring for 8 hours;

2) weighing the product obtained in the step 1), metal salt, surfactant, organic alkaline substance and water, mixing and stirring, and carrying out hydrothermal reaction for 8h at 100 ℃;

3) standing the product obtained in the step 2) for 10 hours at the temperature of 1000 ℃ under the argon atmosphere;

4) mixing the product obtained in the step 3) with organic silicon, water and a surfactant, and carrying out hydrothermal reaction for 5 hours at 40 ℃;

5) and (3) soaking the product obtained in the step (4) in concentrated hydrochloric acid for 20 hours, washing and drying to obtain the three-dimensional porous silicon dioxide cathode material for the lithium ion battery.

The composition design of the three-dimensional porous silicon dioxide anode material for the lithium ion battery comprises the following components:

5)Ti₃C₂,0.01mol；ZIF-67,0.002mol；NiCl₂.6H₂0.005mol of O; 0.03mol of tetraethoxysilane;

6)Ti₃C₂,0.01mol；ZIF-67,0.003mol；NiCl₂.6H₂0.005mol of O; 0.04mol of tetraethoxysilane;

7)Ti₃C₂,0.01mol；ZIF-67,0.004mol；NiCl₂.6H₂0.005mol of O; 0.06mol of tetraethoxysilane;

8)Ti₃C₂,0.01mol；ZIF-67,0.005mol；NiCl₂.6H₂0.005mol of O; 0.07mol of tetraethoxysilane;

the electrochemical test results show that: the silicon dioxide cathode material has good electrochemical performance; the capacity of 100 cycles is higher than 1200ml/g at a current density of 0.1C.

Example 3

The procedure was as in example 1

9)MoNb₂SnC₂,0.01mol；ZIF-67,0.002mol；NiCl₂.6H₂0.005mol of O; 0.03mol of tetraethoxysilane;

10)MoNb₂SnC₂,0.01mol；ZIF-67,0.003mol；NiCl₂.6H₂0.005mol of O; 0.04mol of tetraethoxysilane;

11)MoNb₂SnC₂,0.01mol；ZIF-67,0.004mol；NiCl₂.6H₂0.005mol of O; 0.06mol of tetraethoxysilane;

12)MoNb₂SnC₂,0.01mol；ZIF-67,0.005mol；NiCl₂.6H₂0.005mol of O; 0.07mol of tetraethoxysilane;

the electrochemical test results show that: the silicon dioxide cathode material has good electrochemical performance; the capacity of 100 cycles is higher than 1200ml/g at a current density of 0.1C.

The above-described embodiments of the patent are intended to be illustrative, but not limiting, of the scope of the patent, which is included for the purpose of better understanding the patent by those skilled in the art; any equivalent alterations or modifications made according to the spirit of the disclosure of this patent are intended to be included in the scope of this patent.