Non-acid system liquid-phase synthesis C/Ag, Zr/ZrF4 composite zirconium fluoride lithium ion battery positive electrode material and preparation method thereof

Abstract

The invention discloses a non-acid system liquid-phase synthesis C / Ag, Zr / ZrF4 composite zirconium fluoride lithium ion battery positive electrode material and a preparation method thereof. According to the method, through the mixing manner of reaction raw materials such as zirconium nitrate pentahydrate and ammonium fluoride, the adding manner of water and the design of adding speed, the addition of dilute nitric acid for inhibiting hydrolysis is avoided, and the risk that the dilute nitric acid reacts with the ammonium fluoride to generate high-toxicity hydrogen fluoride is avoided; moreover, cracking carbon is generated in the heat treatment process and a certain amount of zirconium and metallic silver are reduced in situ on the surfaces of zirconium fluoride particles, a homogeneous crystallization core is provided for the electrode material during discharging, and the kinetic blockage of new phase formation is reduced; the metallic silver can improve the discharge reaction rate; and moreover, various side reaction products such as double salts of zirconium fluoride are further prevented from being generated in a liquid-phase reaction, and the material has excellent electrochemical performance.

Description

technical field [0001] The invention relates to the technical field of a method for manufacturing a high-performance zirconium 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 aut...

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Problems solved by technology

The conventional synthesis method of zirconium fluoride is to react hydrogen fluoride gas with metal oxide / hydroxide or fluorine gas with 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.

The preparation of zirconium 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 zirconium nitrate in water has the risk of producing highly toxic hydrogen fluoride by reacting with ammonium fluoride.

Another negative characteristic of zirconium fluoride as a cathode material for lithium-ion secondary batteries is 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 zirconium 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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