A liquid phase synthesis b 3+ , la 3+ Doped orthogonal structure bismuth fluoride lithium ion battery positive electrode material and preparation method thereof

Abstract

The invention discloses a bismuth fluoride lithium ion cell anode material prepared through liquid phase synthesis and having a B<3+> and La<3+> doped orthorhombic structure and a preparation method of the bismuth fluoride lithium ion cell anode material. According to the method, the orthorhombic-structure bismuth fluoride is prepared by taking a liquid phase reaction, designing the technological conditions and introducing a plurality of auxiliaries; the specific capacity and the electronic conductivity of the material are improved by doping B<3+> and La<3+>; when the bismuth fluoride material is used as the lithium ion cell anode material, the specific capacity of the bismuth fluoride material is higher than 200 mAh / g<-1>. The method is low in equipment requirement, high in product purity, capable of avoiding generation of multiple side reaction products, such as double salt, of bismuth fluoride in the liquid phase reaction, and excellent in electrochemical performance.

Description

technical field [0001] The invention relates to the technical field of a method for manufacturing a high-capacity bismuth fluoride composite lithium battery cathode material. Background technique [0002] Lithium-ion secondary batteries have the absolute advantages of high volume, weight-to-energy ratio, high voltage, low self-discharge rate, no memory effect, long cycle life, and high power density. Currently, the global mobile power market has an annual share of more than 30 billion US dollars and Gradually grow at a rate of more than 10%. Especially in recent years, with the gradual depletion 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 a large amount of energy is used simultaneously to meet the needs of continuous power supply. Energy storage batteries; urban air quality problems caused by automobi...

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 by-product content is too high, and it is also uneconomical due to the high cost of waste liquid.

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.

[0007] In addition, the crystal form and morphology of bismuth fluoride have a great influence on the electron transport characteristics in the crystal lattice, so it is directly related to the electrochemical performance of lithium ion batteries such as charge and discharge speed, capacity and cycle capacity retention; ion doping is a It is an effective way to adjust the microstructure of the lattice and change the electron and ion transport characteristics of the lattice. However, the mechanism of ion doping or even multi-ion synergistic doping on the matrix is ​​very complicated, and the effect is often unpredictable.

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