A kind of aluminum fluoride and its preparation method and application

Abstract

The invention discloses AlF3, and a preparation method and an application thereof. The preparation method includes: 1) heating an aluminum salt solution and adding a fluoride salt to form a mixed solution; 2) heating and crystallizing the mixed solution to obtain a precursor; 3) calcining the precursor to obtain the AlF3, wherein the aluminum salt and fluoride salt are both soluble. The preparation method is abundant in raw material source, is low in cost, is simple and reliable, has gentle reaction conditions and is easy to carry out in large-scale industrial production. Secondly, the methodis free of HF, so that the method is more environment-friendly and safe. Meanwhile, the AlF3 has excellent electrochemical performance, so that when being applied to batteries as a cathode active material, the AlF3 can reach 2.8-3.1 V in initial voltage and is higher than 300 mAh / g in specific capacity. Finally, the AlF3 has a special globular flower appearance.

Description

technical field [0001] The invention relates to the field of material preparation, in particular to an aluminum fluoride and its preparation method and application. Background technique [0002] At present, the industrial production processes of aluminum fluoride mainly include: 1. Hydrofluoric acid method, including dry process and wet process. The dry process is calcined at 500-600 ° C to obtain ɑ-A1F 3 ; Wet method is the first to get A1F 3 ·3H 2 O crystal, after high temperature calcination to obtain A1F 3 , the raw materials are hydrogen fluoride and aluminum hydroxide; 2. Fluosilicic acid method, using fluosilicic acid and aluminum hydroxide to react to produce aluminum fluoride products, the products are mainly square α-crystal form or hexagonal β-crystal form Aluminum fluoride monohydrate; 3. Aluminum salt method, which mainly uses aluminum chloride aqueous solution and hydrofluoric acid to heat to 400 ° C to obtain aluminum fluoride products; secondly, the prepar...

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Problems solved by technology

[0003] However, the above methods generally have the following problems: 1. Use hydrofluoric acid or hydrogen fluoride as a raw material to prepare aluminum fluoride. Hydrogen fluoride and its aqueous solution are toxic and easily deform bones and teeth, and hydrofluoric acid can also penetrate through the skin. Mucous membrane, respiratory tract and gastrointestinal tract absorption, which is not conducive to human health; 2. The traditional synthesis method of aluminum fluoride first obtains A1F 3 ·3H 2 O, then by calcining A1F 3 ·3H 2 O obtains anhydrous aluminum fluoride after removal of crystallization water, however, when the calcination temperature is higher than 300 °C, it will lead to A1F 3 ·3H 2 Hydrolysis of O to produce alumina (2A1F 3 ·3H 2 O=Al 2 o 3 +6HF), resulting in more impurities in the product

[0004] In addition, fluorine has the highest electronegativity, and the theoretical specific capacity of aluminum fluoride formed by combining with lightweight aluminum elements can be as high as 957mAh / g. Too low is generally only suitable for the aluminum electrolysis industry as a cosolvent and regulator, and cannot be used as an active material in batteries

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