Preparation method and device of passivated lithium microspheres and application

Abstract

The invention provides a preparation method and device of passivated lithium microspheres and an application of the passivated lithium microspheres. The preparation method of the passivated lithium microspheres comprises the following steps: 1) carrying out dispersion treatment on molten-state metal lithium jet flow by utilizing a fluid vibration nozzle to obtain metal lithium liquid drops; 2) applying static electricity to the metal lithium liquid drops to obtain metal lithium microspheres; and 3) placing the metal lithium microspheres in a passivation solution, and stirring to obtain the passivated lithium microspheres. According to the preparation method of the invention, a microcapsule granulation technology is adopted, the superposition vibration principle and the specific passivation technology are utilized, and the passivated lithium microspheres which are small in size, adjustable in size, narrow in particle size distribution, adjustable in passivation layer composition and thickness and high in coating rate can be prepared.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and relates to a preparation method of passivated lithium microspheres, a device and an application thereof. Background technique [0002] Lithium-ion batteries have the advantages of high voltage, high specific energy, and good safety performance, and have been widely used in portable electronic products and electric vehicles. With the rapid development of new energy vehicles, smart grids, and distributed energy storage, higher requirements are placed on the energy density of new energy devices, and there is an urgent need to study high-capacity electrode materials. At present, the negative electrodes of commercial lithium-ion batteries are mainly graphite and silicon carbon materials. However, the potential of graphite and silicon-carbon materials is located outside the electrolyte’s voltage stabilization window, and the electrolyte will be reduced during charging to form a solid...

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Problems solved by technology

[0004] At present, the preparation method of passivated lithium powder mainly follows the strong mechanical shear "microemulsion" method reported by FMC Company, specifically, using an inert high-boiling point organic solvent as a protective solvent, melting metallic lithium at a higher temperature, and stirring at a high speed The high shear force generated makes the molten metal lithium "micro-emulsified", and passivation additives are added to obtain passivated lithium powder. However, the method of preparing lithium powder through mechanical shear "micro-emulsification" requires a high-speed stirring device and a heating device, and the equipment is complicated. The degree is high, and the size of the obtained passivated lithium powder is usually large (tens to thousands of microns), and the large-sized passivated lithium powder increases the difficulty of uniform dispersion of lithium powder in the pre-lithiation process

[0005] The spray drying method is also a common method for preparing passivated lithium powder. This method uses a dry lithium melting tank to melt solid metal lithium into liquid metal lithium, and atomizes the liquid metal lithium into fine particles in the dry passivation tank. The metal lithium droplets disperse and fall, and meet the cooling passivation airflow during the falling process, condense and solidify into metal lithium microspheres, and react with the passivation agent to form a passivation film on the surface of the metal lithium microspheres, and obtain passivation. However, the coating layer of lithium metal microspheres prepared by spray drying method has poor selectivity, poor process controllability, and wide particle size distribution.

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