Integral conductive in-situ C / Bi / BiF3 composite bismuth fluoride lithium ion battery positive electrode material and preparation method thereof

A technology for compounding bismuth fluoride and lithium ion batteries, which is applied to battery electrodes, circuits, electrical components, etc., can solve the problems of high polarization voltage, charge and discharge capacity, discharge potential charge and discharge capacity retention ability, and high price. , to achieve the effect of improving electronic conductivity, excellent electrochemical performance, and reducing kinetic hindrance

Inactive Publication Date: 2017-06-20
宁波吉电鑫新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The conventional synthesis method of bismuth fluoride is to react with hydrogen fluoride gas and metal oxide / hydroxide or fluorine gas and metal element at high temperature. The process conditions are harsh, the equipment requirements are very high, and the energy consumption is high, so the price is very expensive.
However, the preparation of bismuth fluoride by liquid phase reaction is often unable to be used as a positive electrode material because the content of by-products is too high. At the same time, the dilute nitric acid added to inhibit the hydrolysis of bismuth nitrate in water has the risk of producing highly toxic hydrogen fluoride by reacting with ammonium fluoride.
Bismuth fluoride, as a cathode material for lithium-ion secondary batteries, also has a negative characteristic that its electronic conductivity is extremely low, so it will cause a high polarization voltage during charge and discharge.
Although some researchers have used carbon black mixed with ball milling to increase the electrical conductivity of the material, it is still difficult for granular carbon black to form a complete conductive link, which greatly improves its electronic conductivity.
Finally, the material produces a new phase of metal bismuth and lithium fluoride during discharge, and the small particles of the new phase are kinetically disadvantaged in the initial stage of formation, so the maintenance of the subsequent charge and discharge capacity, discharge potential, and charge and discharge capacity ability to adversely affect

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  • Integral conductive in-situ C / Bi / BiF3 composite bismuth fluoride lithium ion battery positive electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013]Example 1: The initial aqueous solution of 5wt% bismuth nitrate, 0.5wt% nitric acid, 6wt% acrylamide, 1wt% N,N'-methylenebisacrylamide was prepared, using a polytetrafluoroethylene stirring paddle at 900rpm Mix at speed for 5 minutes. The starting aqueous solution was raised to 75°C at a rate of 5°C / min and maintained at this temperature until the starting aqueous solution became a jelly-like gel. The formed gel is dried in a low temperature and high vacuum environment. The drying process adopts the finished freeze dryer on the market. Put the gel into the freeze dryer sample tray and start the refrigerator. Wait for the temperature of the gel on the sample tray. When the temperature drops to minus 46°C, turn on the vacuum pump to increase the vacuum degree. When the gas pressure in the system drops below 27Pa, turn on the temperature control of the separator to start dehydration and drying. After drying, the material is immersed in an ammonium fluoride aqueous solution...

Embodiment 2

[0014] Example 2: Prepare an initial aqueous solution of 15wt% bismuth nitrate, 1wt% nitric acid, 12wt% acrylamide, 2wt% N,N'-methylenebisacrylamide, and stir at a speed of 1200 rpm using a polytetrafluoroethylene stirring paddle 14 minutes. The starting aqueous solution was raised to 85°C at a rate of 10°C / min and maintained at this temperature until the starting aqueous solution became a jelly-like gel. The formed gel is dried in a low temperature and high vacuum environment. The drying process adopts the finished freeze dryer on the market. Put the gel into the freeze dryer sample tray and start the refrigerator. Wait for the temperature of the gel on the sample tray. Lower the temperature to minus 50°C, turn on the vacuum pump to increase the vacuum degree, and when the gas pressure in the system drops below 34Pa, turn on the separator temperature control to start dehydration and drying. After drying, the material was immersed in an ammonium fluoride aqueous solution with...

Embodiment 3

[0015] Example 3: Formulation of an initial aqueous solution consisting of 12wt% bismuth nitrate, 0.8wt% nitric acid, 9wt% acrylamide, 1.5wt% N,N'-methylenebisacrylamide, using a Teflon stirring paddle at 1100rpm speed for 9 minutes. The starting aqueous solution was raised to 80°C at a rate of 7°C / min and maintained at this temperature until the starting aqueous solution became a jelly-like gel. The formed gel is dried in a low temperature and high vacuum environment. The drying process adopts the finished freeze dryer on the market. Put the gel into the freeze dryer sample tray and start the refrigerator. Wait for the temperature of the gel on the sample tray. When the temperature drops to minus 48°C, turn on the vacuum pump to increase the vacuum degree. When the gas pressure in the system drops below 30Pa, turn on the separator temperature control to start dehydration and drying. After drying, the material is immersed in an ammonium fluoride aqueous solution with a concen...

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Abstract

The invention discloses an integral conductive in-situ C / Bi / BiF3 composite bismuth fluoride lithium ion battery positive electrode material and a preparation method thereof. According to the preparation method of the integral conductive in-situ C / Bi / BiF3 composite bismuth fluoride lithium ion battery positive electrode material, the bismuth nitrate is fixed on a highly conductive continuous carbon film with a void and interspace structure through the drying process at a low temperature and high vacuum condition and the heat treatment process; meanwhile, a certain amount of metallic bismuth is reduced on the surface of the bismuth fluoride particles during the heat treatment process, therefore, a homogeneous crystalline core is provided for the discharge of the electrode materials, and the kinetics barrier to the formation of new phases is reduced; and the formation of the side reaction products such as a variety of the complex salt of bismuth fluoride in a liquid phase reaction is avoided by the immobilization of the reaction raw materials, and the electrochemical performance is excellent.

Description

technical field [0001] The invention relates to the technical field of a manufacturing method for a high-performance bismuth fluoride composite lithium battery positive electrode material. Background technique [0002] Lithium-ion secondary batteries have the absolute advantages of high volume, high weight-to-energy ratio, high voltage, low self-discharge rate, no memory effect, long cycle life, and high power density. Gradually grow at a rate of over 10%. Especially in recent years, with the gradual exhaustion of fossil energy, new energy sources such as solar energy, wind energy, and biomass energy have gradually become alternatives to traditional energy sources. Among them, wind energy and solar energy are intermittent, and in order to meet the needs of continuous power supply, a large number of Energy storage batteries; the urban air quality problem caused by automobile exhaust is becoming more and more serious, and the vigorous advocacy and development of electric vehi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/36H01M4/583H01M4/38H01M4/1397
CPCH01M4/1397H01M4/362H01M4/38H01M4/582H01M4/583Y02E60/10
Inventor 水淼
Owner 宁波吉电鑫新材料科技有限公司
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