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CN-120518060-B - High-discharge-voltage fluorocarbon and preparation method and application thereof

CN120518060BCN 120518060 BCN120518060 BCN 120518060BCN-120518060-B

Abstract

The invention belongs to the technical field of primary batteries, and particularly relates to high-discharge voltage fluorocarbon and a preparation method and application thereof. The invention provides a preparation method of high-discharge-voltage fluorocarbon, which comprises the following steps of carrying out fluorination on amorphous carbon in a fluorine-containing atmosphere to obtain the high-discharge-voltage fluorocarbon, wherein the amorphous carbon has a multi-stage pore structure, the specific surface area of the amorphous carbon is not lower than 1000m 2 /g, and the fluorination temperature is 20-200 ℃. According to the invention, the carbon raw material is screened, so that the fluorination temperature is reduced, a low-temperature fluorination treatment process is adopted, the conductive network structure of an initial carbon source is reserved to the greatest extent, the electrochemical activity of fluorocarbon bonds is improved, the porous network structure of the carbon raw material is beneficial to shuttling of charges in a battery, and finally, the preparation of the high-voltage fluorocarbon material is realized.

Inventors

  • LI YU
  • XU HANG
  • PENG CONG

Assignees

  • 北京化工大学

Dates

Publication Date
20260508
Application Date
20250717

Claims (8)

  1. 1. A method for preparing high discharge voltage fluorocarbon, which is characterized by comprising the following steps: Fluorinating amorphous carbon in a fluorine-containing atmosphere to obtain the high discharge voltage fluorocarbon; the amorphous carbon has a hierarchical pore structure; The specific surface area of the amorphous carbon is 2331-3500 m 2 /g; the temperature of the fluorination is 20-50 ℃; The discharge voltage of the high discharge voltage fluorocarbon is 3.50-3.52V (vs. Li/Li + ).
  2. 2. The method according to claim 1, wherein the fluorination time is 12 to 36 hours.
  3. 3. The method according to claim 1, wherein the pressure of the fluorination is 0.01 to 0.5mpa.
  4. 4. The production method according to claim 1, wherein the fluorine-containing atmosphere comprises fluorine gas and a shielding gas, the shielding gas comprising at least one of nitrogen gas, argon gas, and helium gas; the volume ratio of fluorine gas in the fluorine-containing atmosphere is 10-30%.
  5. 5. The high discharge voltage fluorocarbon prepared by the preparation method of any one of claims 1 to 4.
  6. 6. The high discharge voltage fluorocarbon of claim 5 comprising 50 to 70 atomic percent carbon, 20 to 40 atomic percent fluorine and 5 to 20 atomic percent oxygen.
  7. 7. The high discharge voltage fluorocarbon of claim 5 having a specific surface area of not less than 300m 2 /g.
  8. 8. Use of the high discharge voltage fluorocarbon of any one of claims 5 to 7 as a positive electrode in a primary battery.

Description

High-discharge-voltage fluorocarbon and preparation method and application thereof Technical Field The invention belongs to the technical field of primary batteries, and particularly relates to high-discharge voltage fluorocarbon and a preparation method and application thereof. Background In the field of energy materials at present, the fluorocarbon material is a material which is attractive, has great application potential in a plurality of fields because of high theoretical energy density, is particularly used as a positive electrode material in a lithium/fluorocarbon battery, is regarded as a key material of a final lithium primary battery, and has important application prospect in the fields with extremely high requirements on battery performance such as aerospace, deep sea detection, medical implantation equipment and the like. While fluorocarbon materials play a critical role in high energy lithium primary batteries, their potential remains to be exploited further, especially for problems with discharge voltages well below thermodynamic theoretical values. According to an electrode reaction equation, the theoretical discharge voltage of the lithium/carbon fluoride battery is required to be 4.55V (vs. Li/Li +), however, the discharge voltage of the graphite fluoride which is commonly used at present is only 2.5-2.6V (vs. Li/Li +). This is mainly due to the fact that in the preparation of high fluorine-carbon ratio (F/C) graphite fluoride by high temperature (450-600 ℃) gas phase fluorination, each carbon atom forms a chemical bond with the fluorine atom, which results in the transition of the hybridization state of the carbon atom from sp 2 to sp 3. The fluorocarbon bond thus formed exhibits typical insulating properties of covalent compounds, and is the highest bond energy species among all covalent single bonds, thus consuming a large amount of energy to break the fluorocarbon bond upon discharge and form lithium fluoride with lithium ions, thereby deviating the actual discharge voltage from its thermodynamic theoretical value. In the prior art, the discharge voltage of the carbon fluoride is successfully improved by optimizing the selection of the carbon raw material and improving the fluorination process. Carbon nanomaterials with special nanotopography, such as graphene, carbon nanospheres or carbon nanofibers, are generally adopted, and a fluorination process is optimized, for example, nitrogen trifluoride (NF 3) which can be cracked at a high temperature to generate fluorine atoms is used as a fluorine source, and meanwhile, the temperature is reduced to 300-400 ℃, so that the discharge voltage of the prepared carbon fluoride nanomaterial is increased to 3.0-3.2V (vs. Li/Li +). This is mainly due to the unique spatial structure of the carbon nanomaterial and the appropriately reduced fluorocarbon ratio, resulting in the formation of fluorocarbon half-ionic bonds with lower bond energy, thereby reducing the energy required to break the fluorocarbon bonds during discharge, and ultimately increasing the discharge voltage of the fluorocarbon. However, the fluorination temperature is still further reduced in the above method, and the discharge voltage is still required to be further increased. Disclosure of Invention The invention aims to provide a high-discharge-voltage fluorocarbon, a preparation method and application thereof. In order to achieve the above object, the present invention provides the following technical solutions: The invention provides a preparation method of high discharge voltage fluorocarbon, which comprises the following steps: Fluorinating amorphous carbon in a fluorine-containing atmosphere to obtain the high discharge voltage fluorocarbon; the amorphous carbon has a hierarchical pore structure; The specific surface area of the amorphous carbon is not less than 1000m 2/g; The temperature of the fluorination is 20-200 ℃. Preferably, the specific surface area of the amorphous carbon is 1000-3500 m 2/g. Preferably, the fluorination time is 12-36 hours. Preferably, the pressure of the fluorination is 0.01-0.5 MPa. Preferably, the fluorine-containing atmosphere includes fluorine gas and a shielding gas including at least one of nitrogen gas, argon gas, and helium gas; the volume ratio of fluorine gas in the fluorine-containing atmosphere is 10-30%. The invention also provides the high discharge voltage fluorocarbon prepared by the preparation method. Preferably, the high discharge voltage fluorocarbon comprises 50-70% of carbon, 20-40% of fluorine and 5-20% of oxygen in atomic percent. Preferably, the specific surface area of the high discharge voltage fluorocarbon is not less than 300m 2/g. The invention also provides application of the high-discharge voltage fluorocarbon as the positive electrode in the primary battery. The invention provides a method for preparing high discharge voltage fluorocarbon. The invention adopts the amorphous carbon with the hierarchical pore structur