Preparation method of regular octahedral bismuth fluoride material

Abstract

The invention relates to a preparation method of a regular octahedral bismuth fluoride material. The method comprises the following steps: (1) dissolving bismuth fluoride into deionized water, adding concentrated nitric acid and preparing a bismuth nitrate solution with the molar concentration of 45-55mM; (2) dissolving sodium fluoride into the deionized water and adding polyvinylpyrrolidone to prepare a sodium fluoride solution with the molar concentration of 37.5-125mM; (3) adding the bismuth nitrate solution to the sodium fluoride solution, carrying out standing reaction at 20-30 DEG C to obtain a sediment, wherein the volume ratio of the bismuth nitrate solution to the sodium fluoride solution is 1 to (3.5-4.5); and (4) filtering, washing and drying the sediment obtained in the step (3) to obtain the regular octahedral bismuth fluoride material. According to the preparation method, the regular octahedral bismuth fluoride material can be synthesized by one-step reaction; the cost is saved; the environment is protected; and the product is high in purity, uniform and regular in shape and size, and beneficial to large-scale mass production in future.

Description

technical field [0001] The invention relates to a preparation method of bismuth fluoride, in particular to a preparation method of a regular octahedral bismuth fluoride material. Background technique [0002] In recent years, Bi-based compounds have attracted attention due to their special layered structures and appropriate bandgap widths. As a metal fluoride cathode material, BiF 3 High storage capacity is achieved through reversible switching reactions. Although BiF 3 Its mass specific energy is only 905Wh / kg, but its volume specific energy is as high as 7170Wh / l. BiF 3 As a typical ionic compound, it can be doped with carbon and silver to make the positive electrode material of the secondary battery, and can make full use of all the valence of the material, so that the electrode process has more exchange electrons, high battery voltage and energy. density and other advantages, with more in-depth research on it, BiF 3 It will become a promising anode material for a n...

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Problems solved by technology

This type of reaction is time-consuming, energy-consuming and environmentally polluting, so the product is expensive

In addition, bismuth (III) ions in bismuth nitrate pentahydrate were chelated by mannitol to precipitate bismuth hydroxide in alkaline solution, and bismuth hydroxide was stirred in HF solution for 12 hours to undergo a solid-liquid reaction to form BiF 3 The method is theoretically feasible, but the actual yield is very low, there are many impurities and the product is unstable

[0004] Chinese invention patent (CN101212050A) discloses a preparation method of bismuth fluoride cathode material for lithium secondary batteries, which specifically includes dissolving bismuth salt in acetic acid solution to prepare bismuth salt acetic acid solution, adding a surfactant; and preparing soluble fluoride salt or HF ethanol at the same time aqueous solution to obtain a mixed solution of alcohol and fluorine; mix the two solutions at 0-45°C to obtain BiF 3 The precipitate was then filtered, washed and dried to obtain BiF 3 products, but this preparation method cannot obtain bismuth fluoride with specific morphology

Therefore, at present, there is no report on the synthesis technology of octahedral bismuth fluoride materials at room temperature.

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