Preparation method for lithium titanate

Abstract

The invention discloses a preparation method for lithium titanate. The preparation method comprises the following steps: (1) preparing a slurry by using a titanium source, a lithium source, an inorganic additive, an organic additive and water; (2) atomizing and drying the slurry prepared by the first step into powder in an atomizing dryer; (3) roasting the powder prepared by the second step at the atmosphere of a hydrogen and nitrogen gas mixture for 5 to 10 hours; (4) cooling the roasted powder obtained by the third step at the atmosphere of the hydrogen and nitrogen gas mixture to room temperature, thereby obtaining the lithium titanate. The lithium titanate prepared by the preparation method is stable in quality; meanwhile, the product has high-rate discharge performance and cycling performance, and is an excellent lithium ion battery anode material.

Description

technical field [0001] The invention relates to a preparation method of lithium titanate, which belongs to the field of lithium ion battery materials. Background technique [0002] With the rapid development of transportation, communication and information industrialization, products such as electric vehicles, notebook computers and mobile communication tools have put forward higher and very urgent requirements for the development of new chemical power sources. The development of new secondary green batteries has become an inevitable need. Compared with the traditional secondary battery, lithium-ion battery has rapidly developed into one of the most Important and state-of-the-art secondary batteries. It has become an ideal power source for small and lightweight electronic devices such as cameras, mobile phones, notebook computers, and portable measuring instruments, and it is also the preferred power source for lightweight high-energy power batteries for future electric ve...

AI Technical Summary

Problems solved by technology

The solid-phase method is to mix the solid raw materials with ball milling and then roast them at high temperature, relying on the solid-phase diffusion between the various components of the raw materials to realize the synthesis. Chinese patent 200610109497.6 uses this method to grind various solid raw materials to a uniformly mixed solid powder, which is placed in a horse Calcination is carried out in a Furnace, the reaction temperature is 500-1200 ° C, and the reaction time is 6-16 hours. The advantages of the solid-phase method are that the process flow is short, simple and easy, and it is easy to produce on a large scale; the disadvantage is that the produced materials have poor performance. High-quality products are not easily available

The chemical precipitation method is to control the appropriate conditions in the aqueous solution of metal salts to make the precipitant react with metal ions to produce hydrated oxides or insoluble compounds, so that the solute is converted into a precipitate, and then separated, dried or calcined to obtain a super Particles, Wu Xianming et al. in "Preparation of Li by Solution Deposition 4 / 3 Ti 5 / 3 o 4 Thin films and their properties" disclosed in the preparation of Li 4 Ti 5 o 12 The method: dissolve the lithium acetate of stoichiometric ratio in ethylene glycol methyl ether, then add tetrabutyl titanate dropwise and keep stirring, filter the obtained solution to remove insoluble matter and other impurities, and obtain Li 4 / 3 Ti 5 / 3 o 4 Precursor solution, this method has a long process flow and high raw material cost, and the Li obtained by this method 4 / 3 Ti 5 / 3 o 4 There are technical defects such as poor conductivity and rapid specific capacity decay when working in a high-rate environment

Nano-Li prepared by sol-gel method 4 / 3 Ti 5 / 3 o 4 Potentially improved, but difficult to scale up

The hydrothermal method is one of the solvothermal methods. It is a method in which raw materials are placed in water to react at a higher temperature and pressure to synthesize products. This method can produce nano-scale Li 4 Ti 5 o 12 , the initial electrochemical performance has been improved, and the Chinese invention patent application CN102259911A involves the synthesis of nano-Li by hydrothermal method 4 Ti 5 o 12 : In step 1, fully mix nano-titanium dioxide and lithium hydroxide at a molar ratio of 5:4 to 5:4.3, put the mixture into a hydrothermal reactor and react at a temperature of 160 to 190°C for 10 to 24 hours to obtain the reaction Precursor; step 2, high-temperature solid-phase method crystallization: after drying the reaction precursor, calcining at 600°C-800°C for 2-5 hours to obtain spinel with a particle size of 0.1-1 μm structure of lithium titanate powder, but this method requires the raw material itself to reach the nanometer level, and the equipment requirements are very high, and it is not easy to produce on a large scale

There are also known examples of improving the above method. For example, Chinese patent CN102299313A discloses an improved solid-phase method. Lithium source, titanium source and surfactant are dispersed in absolute ethanol and ball milled for 4 to 12 hours, and then ball milled The obtained precursor is placed in an oven to dry, and pre-fired in a muffle furnace to obtain a pre-calcined product, which is then ground and pressed into tablets, and finally calcined in a muffle furnace at 700-800°C for 8-24 hours. The spinel-type lithium titanate product is obtained. The electrochemical performance of this method is better than that of the traditional solid-phase method. However, absolute ethanol is used in the process and dried in an oven, which is a problem in large-scale production. serious safety hazard

Another example is the Chinese patent application CN200910086946, which discloses a high specific energy spinel structure lithium titanate material and its preparation method, using cheap industrial titanium dioxide as raw material, and preparing titanium by ultrasonic chemical hydrothermal method and heat treatment under reducing atmosphere Lithium oxide nanotubes / wires, or lithium salt and titanium dioxide as raw materials, heat treatment under reducing atmosphere to prepare lithium titanate submicron particles, or prepare spinel structure lithium titanate under reducing atmosphere Compared with lithium titanate materials obtained by heat treatment in air, these high specific energy lithium titanate materials obtained by heat treatment in a reducing atmosphere can maintain higher capacity, better cycle stability and more Long service life, but the Li prepared by the above method 4 Ti 5 o 12 There are still some defects in the cycle performance of materials

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