KR-102964444-B1 - PREPARING METHOD FOR ELECTROLYTE SALT

KR102964444B1KR 102964444 B1KR102964444 B1KR 102964444B1KR-102964444-B1

Abstract

The present invention relates to a method for manufacturing an electrolytic salt, and more specifically, is characterized by grinding a lithium compound and a boron compound into particles having a specific range of sizes, dispersing the ground material and an oxalic acid compound in water, and then reacting the reactants dispersed in water to produce a lithium-boron complex salt. The present invention can produce an electrolyte salt with a more improved yield and provide the effect of further improving battery performance when the electrolyte salt is added to the electrolyte of a battery.

Inventors

이승현
이상원
안석진
손정익

Assignees

솔브레인 주식회사

Dates

Publication Date: 20260513
Application Date: 20200909

Claims (14)

i) a step of forming a pulverized material by individually pulverizing the lithium compound and the boron compound using separate grinders, respectively, to form particles having a number average particle size (D n50 ) of 0.5 to 100 μm and a maximum particle size (D n99 ) of 250 to 500 μm; ii) a step of adding the pulverized lithium compound and boron compound to water and dispersing them together (ii-1), and a step of adding and dispersing an oxalic acid compound to the water in which the pulverized material is dispersed to form a dispersion mixture (ii-2); and iii) a step of reacting the above dispersion mixture to produce a lithium-boron complex salt; comprising, In step ii) above, the lithium compound, boron compound, and oxalic acid compound are dispersed in water at a concentration of 40 to 95 weight percent based on the total solid content. Method for manufacturing electrolytic salt.
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In paragraph 1, The above grinder is characterized by being selected from the group consisting of ball milling machines and air jet milling machines. Method for manufacturing electrolytic salt.
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In paragraph 1, In step ii) above, the lithium compound, boron compound, and oxalic acid compound are dispersed in water at a concentration of 50 to 90 weight percent based on the total solid content. Method for manufacturing electrolytic salt.
In paragraph 1, Characterized by the molar ratio of the lithium compound, boron compound, and oxalic acid compound added to the above reaction being 1:0.5 to 2:1 to 3. Method for manufacturing electrolytic salt.
In paragraph 1, The above lithium compound is characterized as being lithium hydroxide, lithium hydroxide hydrate, lithium carbonate, or lithium oxide. Method for manufacturing electrolytic salt.
In paragraph 1, The above boron compound is characterized as being boric acid, boric acid ester, or borate. Method for manufacturing electrolytic salt.
In paragraph 1, The above oxalic acid compound is characterized as being oxalic acid, oxalic acid hydrate, or oxalate. Method for manufacturing electrolytic salt.
In paragraph 1, The above lithium-boron complex salt is characterized as being LiBC₄O₅ . Method for manufacturing electrolytic salt.
In paragraph 1, The reaction in step iii) above is characterized by being carried out at a temperature of 30 to 240°C for 5 to 20 hours. Method for manufacturing electrolytic salt.
In paragraph 1, The method further comprises the step of obtaining lithium-boron complex salt powder by drying the lithium-boron complex salt produced in step iii) at a temperature of 80 to 320°C and a pressure of 0.1 to 1 atm for 5 to 24 hours. Method for manufacturing electrolytic salt.
In Paragraph 12, The method is further characterized by comprising the step of dissolving the obtained lithium-boron complex salt powder in a carbonate-based solvent and then filtering the solution to obtain a lithium-boron complex salt solution with a concentration of 2 to 20 weight%. Method for manufacturing electrolytic salt.
In Paragraph 13, The above carbonate-based solvent is characterized by being one or more selected from the group consisting of ethylene carbonate (EC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PC), dipropyl carbonate (DPC), butylene carbonate, methylpropyl carbonate, and ethylpropyl carbonate. Method for manufacturing electrolytic salt.

Description

Preparation Method for Electrolyte Salt The present invention relates to a method for manufacturing an electrolyte salt, and more specifically, to a method for manufacturing a lithium-boron complex salt that can produce an electrolyte salt added to an electrolyte to improve the efficiency and lifespan of a battery with an improved yield, and can further improve the battery performance enhancement effect when added to the electrolyte of a battery. Lithium secondary batteries enable the smooth movement of lithium ions by placing an electrolyte between the positive and negative electrodes, and facilitate the use of electrical energy through a method in which electricity is generated or consumed by oxidation-reduction reactions resulting from insertion and extraction at the positive and negative electrodes. Lithium secondary batteries have been actively used due to the proliferation of small mobile devices, and as their use is gradually expanding to large devices such as electric vehicles, various methods are being attempted to improve battery performance, such as increasing battery output and capacity, improving output at high and low temperatures, and extending battery life. Lithium secondary batteries generally contain LiPF6 , which has high conductivity and excellent electrochemical stability, as a lithium salt. However, during storage or use of the battery, the lithium salt in the electrolyte decomposes, leading to deterioration of battery performance or the generation of corrosive byproducts, which reduces battery stability and shortens the battery's lifespan. To address this, an electrolyte additive capable of preventing the decomposition of the electrolyte is used. Lithium bisoxalate toborate (LiBOB), which is widely used as an electrolyte additive, has a manufacturing method introduced in Korean Patent Document 10-0716373. The aforementioned document discloses a method of manufacturing by mixing and reacting a lithium compound, oxalic acid, and boric acid in an aqueous solution state; however, the concentration of the reaction mixture solution is approximately 2-3 weight%, which results in a dilute concentration in the reaction vessel, leading to low productivity and an uneconomical problem. Furthermore, if an organic solvent that forms an azeotropic mixture with water is used as the reaction solvent, residual solvent may remain within the manufactured LiBOB granules, potentially degrading battery performance when added to the electrolyte. Moreover, the LiBOB granules manufactured by the above method do not have sufficient solubility in the battery electrolyte, resulting in a long dissolution time and the precipitation of insoluble crystals. Meanwhile, in an attempt to solve the above-mentioned problem, a method was attempted in which the reaction raw materials were mixed in powder form without dissolving them. However, in this case, mixing acidic raw materials such as oxalic acid and basic raw materials such as lithium hydroxide resulted in the generation of water, causing the reaction raw material powder to gradually become wet. Consequently, the reaction raw material powder became thick, making it difficult to achieve uniform mixing. Therefore, there is a problem in that contact between the reaction raw materials is not smooth, leading to reduced reaction efficiency and the generation of by-products, resulting in low purity and reduced reaction yield. Figure 1 shows the XRD determination pattern measurement results of Example 1(a) and Comparative Example 2(b) of the present invention. The present invention will be described in detail below. While researching a method to manufacture an electrolyte salt added to a lithium secondary battery to improve battery performance with greater stability and higher yield, and to improve its purity, the inventors confirmed that all of the above objectives could be achieved by grinding a lithium source and a substance that reacts with lithium into particles of a certain size and reacting them in a dispersion medium, and based on this, completed the present invention. A method for manufacturing an electrolytic salt according to embodiments of the present invention is characterized by comprising: i) a step of forming a pulverized material by grinding a lithium compound and a boron compound into particles having a number average particle size (D n50 ) of 0.5 to 100 μm and a maximum particle size (D n99 ) of 250 to 500 μm; ii) a step of forming a dispersion mixture by dispersing the pulverized material in water together with an oxalic acid compound; and iii) a step of producing a lithium-boron complex salt by reacting the dispersion mixture. As described above, the present invention has the excellent effect of enabling the stable production of a desired electrolytic salt with a superior yield and obtaining a high-purity electrolytic salt by first grinding the reaction raw materials, a lithium compound and a boron compound, into particles of a specific size, then disper