CN110148747B

CN110148747B - Preparation method of carbon fluoride anode material with anti-expansion function

Info

Publication number: CN110148747B
Application number: CN201910415216.7A
Authority: CN
Inventors: 李秀涛; 周晓猛; 张海军
Original assignee: Civil Aviation University of China
Current assignee: Civil Aviation University of China
Priority date: 2019-05-14
Filing date: 2019-05-14
Publication date: 2022-04-15
Anticipated expiration: 2039-05-14
Also published as: CN110148747A

Abstract

A preparation method of a carbon fluoride anode material with an anti-expansion function. Which comprises the following steps: carrying out high-temperature carbonization on the aluminum-based metal organic framework material in an inert gas atmosphere, and then cooling to room temperature to obtain a carbon fluoride precursor carbon source; placing a carbon source of a carbon fluoride precursor in a reaction kettle for drying, then introducing mixed gas consisting of fluorine gas and nitrogen gas, then carrying out a fluorination reaction under a heating condition, carrying out vacuum drying to obtain a crude product of the carbon fluoride anode material, and finally washing off metal fluoride in the crude product by using hydrofluoric acid to obtain the carbon fluoride anode material as a final product. The invention has the advantages that: the raw material cost is low, the fluorination temperature is low, the operation is simple, and the structural morphology of the carbon source can be regulated and controlled through synthesis conditions; the carbon fluoride anode material has a transverse or longitudinal carbon layer structure, can effectively prevent the expansion phenomenon of the carbon fluoride battery in the discharging process, can be applied to the fields of lithium ion batteries and the like, and has a very good application prospect.

Description

Preparation method of carbon fluoride anode material with anti-expansion function

Technical Field

The invention belongs to the technical field of carbon material synthesis, and particularly relates to a preparation method of a carbon fluoride anode material with an anti-expansion function.

Background

The carbon fluoride material has great application value, and can be widely applied to the fields of lithium battery positive electrode materials, solid lubricants, release agents, waterproof and oleophobic materials, surface paints and the like, wherein the lithium carbon fluoride battery prepared from the lithium battery positive electrode materials has the highest theoretical energy density in the existing primary batteries, and therefore, the lithium carbon fluoride battery is considered to be a main substitute of the future primary batteries.

The volume expansion of the existing lithium fluorocarbon battery is accompanied in the discharging process, and the restriction of the volume expansion inevitably causes larger stress in the battery. Research shows that amorphous LiF is continuously generated along with the discharge of the carbon fluoride material, the LiF is deposited on the inner surface of the activated carbon, and the deposition of the LiF on the inner surface of the carbon is a direct cause of electrode expansion. The calculation results show that CF before discharge_1.0The density of the material is 2.8g/cm³And the density of the generated LiF after discharge is 2.65g/cm³Carbon density of 2.0g/cm³The full-capacity discharge volume expansion is expected to be 41%. Therefore, the problem of expansion of the fluorocarbon electrode is one of the major factors affecting its wide use.

Disclosure of Invention

In order to solve the above problems, an object of the present invention is to provide a method for producing a fluorocarbon positive electrode material having an anti-swelling function.

In order to achieve the above object, the present invention provides a method for preparing a fluorocarbon positive electrode material having an anti-swelling function, comprising the following steps performed in order:

(1) carrying out high-temperature carbonization on the aluminum-based metal organic framework material in an inert gas atmosphere, and then cooling to room temperature to obtain a carbon fluoride precursor carbon source;

(2) placing the prepared carbon fluoride precursor carbon source in a reaction kettle for drying, then introducing mixed gas consisting of fluorine gas and nitrogen gas, then carrying out fluorination reaction under a heating condition, carrying out vacuum drying to obtain a carbon fluoride anode material crude product, and finally washing off metal fluoride in the carbon fluoride anode material by using hydrofluoric acid to obtain the carbon fluoride anode material as a final product.

In step (1), the aluminum-based metal organic framework material is selected from MIL-53(Al) and Al (OH) (1, 4-NDC). 2H₂At least one of O.

In the step (1), the temperature rise rate of the high-temperature carbonization is 1-5 ℃/min, and the carbonization temperature is 600-1000 ℃.

In the step (2), the volume fraction percentage of fluorine gas and nitrogen gas in the mixed gas is 10-40: 60-90.

In the step (2), the drying temperature is 150 ℃, the fluorination reaction temperature is 300-400 ℃, and the fluorination reaction time is 2-6 hours.

The preparation method of the carbon fluoride anode material with the expansion resistance function provided by the invention has the main technical principle that: because the aluminum-based metal organic framework material can form a transversely or longitudinally distributed carbon layer structure after carbonization, and a larger buffer space is arranged between carbon layers, the material is used as a carbon source, and a carbon fluoride material with an anti-anode expansion function can be obtained after fluorination.

Compared with the prior art, the preparation method of the carbon fluoride anode material with the expansion resistance function has the following advantages: (1) the method has the advantages of low cost of raw materials, low fluorination temperature and simple operation, and the structural morphology of the carbon source can be regulated and controlled through synthesis conditions; (2) the carbon fluoride anode material prepared by the invention has a transverse or longitudinal carbon layer structure, can effectively prevent the expansion phenomenon in the discharge process of the carbon fluoride battery, can be applied to the fields of lithium ion batteries and the like, and has a very good application prospect.

Drawings

FIG. 1 is a transmission electron microscope image of carbon fluoride prepared by using a carbonized aluminum-based metal organic framework material MIL-53(Al) as a carbon source.

FIG. 2 shows the Al (OH) (1, 4-NDC). 2H of the carbonized aluminum-based metal-organic framework material of the present invention₂Transmission electron microscopy of carbon fluoride prepared with O as carbon source.

Detailed Description

The present invention is further described in the following description of the specific embodiments, which is not intended to limit the invention, but various modifications and improvements can be made by those skilled in the art according to the basic idea of the invention, within the scope of the invention, as long as they do not depart from the basic idea of the invention.

Example 1

The preparation method of the fluorocarbon cathode material with the anti-swelling function provided by the embodiment comprises the following steps in sequence:

(1) 1.0g of MIL-53(Al) is carbonized at high temperature in a nitrogen atmosphere, the temperature rising speed is 5 ℃/min, the carbonization temperature is 1000 ℃, and then the carbon fluoride precursor carbon source is obtained after cooling to room temperature;

(2) placing the prepared carbon fluoride precursor carbon source in a reaction kettle, drying at the temperature of 150 ℃, introducing mixed gas consisting of 25 volume percent of fluorine gas and 75 volume percent of nitrogen gas, heating to 350 ℃, carrying out fluorination reaction for 4 hours, carrying out vacuum drying to obtain a carbon fluoride anode material crude product, and finally washing off metal fluoride in the carbon fluoride by using hydrofluoric acid to obtain the carbon fluoride anode material with the anti-expansion function. The material is of a laminated structure through a projection electron microscope test, as shown in figure 1, and through a soft package battery discharge test, the expansion rate of the positive electrode is less than 1.3%.

Example 2

(1) 1.0g of Al (OH) (1, 4-NDC). 2H was charged₂Carrying out high-temperature carbonization on O in a nitrogen atmosphere, wherein the temperature rise speed is 5 ℃/min, the carbonization temperature is 1100 ℃, and then cooling to room temperature to obtain a carbon source of a carbon fluoride precursor;

(2) placing the prepared carbon fluoride precursor carbon source in a reaction kettle, drying at the temperature of 150 ℃, introducing mixed gas consisting of 25 volume percent of fluorine gas and 75 volume percent of nitrogen gas, heating to 350 ℃, carrying out fluorination reaction for 4 hours, carrying out vacuum drying to obtain a carbon fluoride anode material crude product, and finally washing off metal fluoride in the carbon fluoride by using hydrofluoric acid to obtain the carbon fluoride anode material with the anti-expansion function. The material is of a laminated structure through a projection electron microscope test, as shown in figure 2, and the positive electrode expansion rate is less than 1.7% through a soft package battery discharge test.

Claims

1. A preparation method of a carbon fluoride anode material with an anti-expansion function is characterized by comprising the following steps: the preparation method comprises the following steps which are carried out in sequence:

2. The method for producing a fluorocarbon positive electrode material having an anti-swelling function according to claim 1, characterized in that: in step (1), the aluminum-based metal organic framework material is selected from MIL-53(Al) and Al (OH) (1, 4-NDC). 2H₂At least one of O.

3. The method for producing a fluorocarbon positive electrode material having an anti-swelling function according to claim 1, characterized in that: in the step (1), the temperature rise rate of the high-temperature carbonization is 1-5 ℃/min, and the carbonization temperature is 600-1000 ℃.

4. The method for producing a fluorocarbon positive electrode material having an anti-swelling function according to claim 1, characterized in that: in the step (2), the volume fraction percentage of fluorine gas and nitrogen gas in the mixed gas is 10-40: 60-90.

5. The method for producing a fluorocarbon positive electrode material having an anti-swelling function according to claim 1, characterized in that: in the step (2), the drying temperature of the carbon fluoride precursor carbon source is 150 ℃, the fluorination reaction temperature is 300-400 ℃, and the fluorination reaction time is 2-6 hours.