A solid phase synthesis co 2+ ,cu 2+ Doped orthogonal structure bismuth fluoride lithium ion battery positive electrode material and preparation method thereof

Abstract

The invention relates to a solid-phase synthesis bismuth fluoride lithium ion battery anode material with a Co<2+> and Cu<2+> doped structure and a preparation method of the solid-phase synthesis bismuth fluoride lithium ion battery anode material. The preparation method comprises the following steps: a quaternary ammonium salt taking fluoride as an anion is taken as a raw material, the raw material is in solid-phase synthesis into bismuth fluoride with an orthorhombic structure directly through steric hindrance of a macroradical and the action of a specific additive, and at the same time, the average discharge potential of the material is improved through Cu<2+> doping, and the electronic conductivity of the material is improved through Co<2+> doping, and the bismuth fluoride material is taken as a lithium ion battery anode material and has specific capacity exceeding 200 mAh.g<-1>. The preparation method is low in equipment requirement, the product is high in purity, reaction by-products such as various complex salts for producing bismuth fluoride in the solid-phase reaction can be avoided, and the solid-phase synthesis oxygen bearing bismuth fluoride anode material is 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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