阅读说明：本技术 一种金属钾的制备方法 (Preparation method of metal potassium ) 是由 梁升 陈捷 刘伶俐 周宁宁 胡磊 张全争 王黎丽 梁德伟 于 2021-07-21 设计创作，主要内容包括：一种金属钾的制备方法,涉及金属单质合成技术领域,以氢化锂和钾盐为原料,在惰性气氛保护下将氢化锂与钾盐按摩尔比1∶0.1～10混合,置于立式管式炉中,将混合物在真空条件下加热至200～700℃,并保温0.5～24h。待反应结束并冷却后,在惰性气氛保护下取出立式管式炉上端的产物,即金属钾单质。本发明利用氢化锂与钾盐在加热条件下反应生成钾单质,大大降低了钾的合成温度。方法简单易控、绿色环保、成本低廉、易于实现工业化生产。制备的金属钾可应用于钾钠合金和钾离子电池领域,制备的电池具有优异的电化学性能。(A preparation method of metal potassium relates to the technical field of metal simple substance synthesis, and comprises the steps of taking lithium hydride and potassium salt as raw materials, mixing the lithium hydride and the potassium salt according to a molar ratio of 1: 0.1-10 under the protection of inert atmosphere, placing the mixture in a vertical tube furnace, heating the mixture to 200-700 ℃ under a vacuum condition, and preserving heat for 0.5-24 hours. And after the reaction is finished and the reaction product is cooled, taking out a product at the upper end of the vertical tube furnace under the protection of inert atmosphere, namely the metal potassium simple substance. The invention utilizes the reaction of lithium hydride and potassium salt under the heating condition to generate the potassium simple substance, thereby greatly reducing the synthesis temperature of potassium. The method is simple and easy to control, green and environment-friendly, low in cost and easy to realize industrial production. The prepared metal potassium can be applied to the fields of potassium-sodium alloy and potassium ion batteries, and the prepared batteries have excellent electrochemical performance.)

1. The preparation method of the metal potassium is characterized in that lithium hydride and potassium salt are reacted under the heating condition to generate the metal potassium, and the preparation method specifically comprises the following steps:

(1) mixing lithium hydride and potassium salt according to the molar ratio of 1: 0.1-10 under the protection of inert atmosphere, and placing the mixture in a vertical tubular furnace;

(2) heating the mixture in the vertical tube furnace to 200-700 ℃ under a vacuum condition, and preserving heat for 0.5-24 h;

(3) and after the reaction is finished and the reaction product is cooled, taking out the product at the upper end of the vertical tube furnace under the protection of inert atmosphere, thus obtaining the metal potassium.

2. The method of claim 1, wherein: the inert gas mentioned in the step (1) means a gas which does not react with lithium hydride, potassium salt and potassium.

3. The method of claim 1, wherein: the potassium salt in the step (1) is at least one of potassium chloride, potassium oxide and potassium peroxide.

4. The method of claim 1, wherein: the heating rate of the heating process in the step (2) is 0.1-50 ℃/min.

5. The method of claim 1, wherein: the inert gas in the step (3) is a gas which does not react with the potassium metal.

Technical Field

The invention relates to the technical field of metal simple substance synthesis, in particular to a preparation method of metal potassium.

Background

The metal potassium is used as an active alkali metal and is widely applied to the fields of material chemical industry, biological medicine, potassium-sodium alloy, electronic information, potassium ion batteries and the like. The currently industrially predominant preparation process is to react sodium metal with potassium chloride at 850 ℃ (Na + KCl → NaCl + K) and to obtain potassium metal by one-step refining by fractional distillation. The reaction utilizes the difference of melting points between potassium (760 ℃) and sodium (883 ℃) to realize the preparation of potassium.

However, there are two major problems in this preparation process: 1. the prepared potassium contains a large amount of sodium, and the potassium with higher purity can be obtained by further fractionation; 2. the preparation process is usually carried out at 850 ℃, and the energy consumption is high. Therefore, the development of a novel, efficient, low-cost and low-energy-consumption preparation method of the metal potassium is of great significance.

Disclosure of Invention

The invention aims to provide a novel, efficient, low-cost, low-energy-consumption and easy-industrialized-production method for preparing the metal potassium.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a preparation method of metal potassium utilizes lithium hydride and potassium salt to react under heating condition to generate the metal potassium, and specifically comprises the following steps:

(1) mixing lithium hydride and potassium salt according to the molar ratio of 1: 0.1-10 under the protection of inert atmosphere, and placing the mixture in a vertical tubular furnace;

(2) heating the mixture in the vertical tube furnace to 200-700 ℃ under a vacuum condition, and preserving heat for 0.5-24 h;

(3) and after the reaction is finished and the reaction product is cooled, taking out the product at the upper end of the vertical tube furnace under the protection of inert atmosphere, thus obtaining the metal potassium.

As a preferred technical scheme of the invention, the preparation method comprises the following steps:

the inert gas mentioned in the step (1) means a gas which does not react with lithium hydride, potassium salt and potassium.

The potassium salt in the step (1) is at least one of potassium chloride, potassium oxide and potassium peroxide.

The heating rate of the heating process in the step (2) is 0.1-50 ℃/min.

The inert gas in the step (3) is a gas which does not react with the potassium metal.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention utilizes the reaction of lithium hydride and potassium salt under the heating condition to generate the metal potassium, and fills up the blank of the technology of preparing the metal potassium at lower temperature.

(2) The method is simple and easy to control, green and environment-friendly, low in cost and easy to realize industrial production.

(3) The metal potassium prepared by the method can be applied to the fields of potassium-sodium alloy and potassium ion batteries, and the prepared batteries have excellent electrochemical properties.

Drawings

FIG. 1 is an X-ray diffraction pattern of the product prepared in example 1.

FIG. 2 shows the preparation of potassium metal and FeSe by example 1₂And assembling the battery into a cycle performance diagram.

FIG. 3 shows the preparation of potassium metal and FeSe by example 1₂And assembling into a rate performance graph of the battery.

FIG. 4 shows potassium metal and FeSe prepared by example 1₂And assembling the first three charge-discharge curves of the battery.

Detailed Description

Example 1

0.1031g of lithium hydride and 0.9426g of potassium chloride were introduced into a vertical tube furnace under an argon atmosphere, sealed and evacuated. The mixture was raised to 550 ℃ at a rate of 10 ℃/min and held for 2 h. After the reaction is finished and the reaction product is cooled, collecting gas in the vertical tubular furnace, and taking out the solid product from the upper end of the vertical tubular furnace (the temperature of the upper end of the vertical tubular furnace is lower, and the metal potassium is preferentially deposited at the upper end) under the protection of argon atmosphere to obtain the metal potassium.

FIG. 1 is an X-ray diffraction pattern of the product prepared in example 1, and it can be seen from FIG. 1 that the positions of diffraction peaks of the sample completely correspond to the PDF # -01-0500 cards of potassium, indicating that the invention successfully synthesizes metallic potassium.

With FeSe₂As a positive electrode, the metal potassium synthesized in the example 1 is used as a negative electrode, glass fiber is used as a diaphragm, and 3M KFSI solute is dissolved in an EC/DEC solvent to assemble a battery for electrochemical performance test.

FIG. 2 shows the preparation of potassium metal and FeSe by example 1₂Cycle performance diagram of assembled battery, which is 0.1A g^-1The first discharge capacity of the lithium ion battery reaches up to 660mAh g^-1After 60 times of circulation, the product still keeps up to 200mAh g^-1The reversible capacity of (a).

FIG. 3 shows the preparation of potassium metal and FeSe by example 1₂Rate performance diagram of assembled battery, which is 0.1A g^-1、0.3A g^-1、0.5A g^-1、1.0A g^-1、2.0A g^-1Respectively shows 360mAh g at a current density of^-1、300mAh g^-1、280mAh g^-1、180mAh g^-1、150mAh g^-1And when the current density returns to 0.1A g again^-1Then, the capacity was maintained at 320mAh g^-1Showing that it possesses excellent rate capability.

FIG. 4 shows potassium metal and FeSe prepared by example 1₂The first three times of charging and discharging curve chart of the assembled battery has unobvious discharging platform and conforms to FeSe₂The second and third charge-discharge curves of the compound are basically coincident, and the excellent stability of the compound is proved.

Example 2

0.1031g of lithium hydride and 0.5g of potassium chloride were charged into a vertical tube furnace under a nitrogen atmosphere, sealed and evacuated. The mixture was raised to 600 ℃ at a rate of 5 ℃/min and held for 6 h. After the reaction is finished and the reaction product is cooled, collecting gas in the vertical tube furnace, and taking out the solid product from the upper end of the vertical tube furnace under the protection of helium atmosphere to obtain the metal potassium.

Example 3

Under a nitrogen/argon mixed atmosphere, 1g of lithium hydride and 8g of potassium chloride were charged into a vertical tube furnace, sealed and evacuated. The mixture was heated to 450 ℃ at a heating rate of 6 ℃/min and held for 10 h. And after the reaction is finished and the reaction product is cooled, collecting the gas in the vertical tube furnace, and taking out the solid product from the upper end of the vertical tube furnace under the protection of helium/argon mixed atmosphere to obtain the metal potassium.

Example 4

Under a helium atmosphere, 0.5g of lithium hydride and 2g of potassium chloride were charged into a vertical tube furnace, sealed and evacuated. The mixture was warmed to 620 ℃ at a rate of 3 ℃/min and held for 0.5 h. After the reaction is finished and the reaction product is cooled, collecting gas in the vertical tube furnace, and taking out the solid product from the upper end of the vertical tube furnace under the protection of helium atmosphere to obtain the metal potassium.

Example 5

Under an argon atmosphere, 2g of lithium hydride and 8g of potassium chloride were charged into a vertical tube furnace, sealed and evacuated. The mixture was raised to 650 ℃ at a temperature rise rate of 15 ℃/min and held for 0.2 h. And after the reaction is finished and the reaction product is cooled, collecting the gas in the vertical tube furnace, and taking out the solid product from the upper end of the vertical tube furnace under the protection of the nitrogen/argon mixed atmosphere to obtain the metal potassium.

Example 6

Under a helium/argon mixed atmosphere, 3g of lithium hydride and 9g of potassium peroxide were charged into a vertical tube furnace, sealed and evacuated. The mixture was raised to 700 ℃ at a rate of 9 ℃/min and held for 1 h. And after the reaction is finished and the reaction product is cooled, collecting the gas in the vertical tube furnace, and taking out the solid product from the upper end of the vertical tube furnace under the protection of a helium/argon mixed atmosphere to obtain the metal potassium.

Example 7

Under a helium/argon mixed atmosphere, 3g of lithium hydride and 9g of potassium oxide were charged into a vertical tube furnace, sealed and evacuated. The mixture was raised to 680 ℃ at a rate of 20 ℃/min and held for 1.5 h. And after the reaction is finished and the reaction product is cooled, collecting the gas in the vertical tube furnace, and taking out the solid product from the upper end of the vertical tube furnace under the protection of the nitrogen/argon mixed atmosphere to obtain the metal potassium.

The foregoing is merely exemplary and illustrative of the principles of the present invention and various modifications, additions and substitutions of the specific embodiments described herein may be made by those skilled in the art without departing from the principles of the present invention or exceeding the scope of the claims set forth herein.