Composite material of lithium tetrachloroaluminate and carbon nanotube-coated lithium titanate, preparation method and application thereof

Abstract

The invention relates to a composite material of lithium tetrachloroaluminate and carbon nanotube-coated lithium titanate, its preparation method and application. The composite material includes a composite particle composed of a lithium titanate inner core and a lithium tetrachloroaluminate coating layer coated on the surface of the inner core, and a carbon nanotube layer coated on the surface of the composite particle. The method comprises: 1) using an ALD method to alternately deposit lithium chloride and aluminum trichloride on the surface of lithium titanate particles, forming a lithium tetrachloroaluminate coating layer on the surface of lithium titanate particles to obtain composite particles; 2 ) adding composite particles and carbon nanotubes into a water-alcohol mixed solvent, ball milling, and spray drying to obtain a composite material. The composite material of the invention has a double-layer coating structure, and has the characteristics of stable structure, high gram capacity, good rate performance and electrical conductivity, excellent cycle performance, and good lithium intercalation and delithiation capabilities. The method of the invention is easy to operate, friendly to the environment and easy to realize industrialized production.

Description

technical field [0001] The invention belongs to the field of negative electrode materials for lithium ion batteries, and relates to a composite material of lithium tetrachloroaluminate and carbon nanotube-coated lithium titanate, a preparation method thereof, and a lithium ion battery comprising the composite material. Background technique [0002] Lithium-ion batteries include electrode materials, electrolytes, separators, casings, etc. Compared with other types of batteries, lithium-ion batteries are considered to be due to their high energy density, high operating voltage, long cycle life, no memory effect, and environmental friendliness. It is an excellent power source for power batteries and energy storage systems. As a platform for battery charging and discharging, the performance of electrode materials is crucial for lithium batteries. [0003] Commercial lithium-ion batteries mainly use carbon as the negative electrode material. Since the carbon negative electrode m...

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Problems solved by technology

The advantages of the solid-phase method are simple process, low equipment requirements, low cost, and easy realization of large-scale industrial production; The requirements for raw materials and equipment are high, and it is not easy to produce on a large scale; the properties of the samples obtained by the sol-gel method and the chemical precipitation method are improved compared with the previous two methods, but the process is long and the cost of raw materials is high, so it is not easy to produce on a large scale; Therefore, the solid phase reaction method is more suitable for industrial production

However, the electrical conductivity of the lithium titanate negative electrode material is very poor, resulting in a very low rate performance of the battery prepared by it. At the same time, the lithium battery with lithium titanate as the negative electrode has the problem of flatulence during use. Yanbing He, Baohua Li, Ming Liu et al. Gassing in Li 4 Ti 5 o 12 -based batteries and its remedy" analyzed the reasons in detail. The flatulence is mainly due to the reaction between the surface of lithium titanate particles and the electrolyte to generate H 2 , CO 2 and CO

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