Preparation process of lithium bis (oxalato) borate

Abstract

The invention provides a preparation process of lithium bis (oxalato) borate. The preparation process comprises the following step of: carrying out a water-phase synthesis reaction through a one-step method or a two-stage method. In the one-step method, firstly adding boric acid and lithium carbonate, and then adding oxalic acid; in the two-stage method, the front stage is a water-phase synthesis process which is carried out in an enamel kettle, the rear stage is a high-temperature dehydration process which is carried out in a 316L stainless steel reaction kettle, and dissolving, filtering, settling, crystallizing and drying are carried out after synthesis. According to the preparation process of the invention, the traditional process and equipment are changed, and the battery-grade lithium bis (oxalato) borate meeting the requirements is prepared through the preparation process of one-step synthesis or two-stage synthesis; the problems that metal ions in the product exceed the standard and equipment is corroded in the production process can be solved, meanwhile, a high-cost coating and the maintenance cost and the time cost brought after the coating is abraded are avoided, the production efficiency and the product quality can be improved, and the production cost is reduced.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a preparation process of lithium bisoxalate borate. Background technique [0002] Lithium bisoxalate borate is an additive used in the electrolyte of lithium-ion batteries. It can form SEI films on its positive and negative electrodes to avoid the decomposition of solvents on the electrode surface. It is especially widely used in manganese-based batteries. High-temperature storage, high-temperature cycle and other performance have very good effect. [0003] The synthesis method of bisoxalate lithium borate includes solid-phase synthesis method and liquid-phase synthesis method. The main raw materials for synthesis include oxalic acid, boric acid and lithium salt, and the reaction temperature can reach up to 220-260°C. The liquid-phase synthesis method is mainly a water-phase synthesis, that is, the three substances are mixed and reacted in the water phase, and the reac...

AI Technical Summary

Problems solved by technology

[0004] ① Even 316L stainless steel can only withstand oxalic acid corrosion at a concentration of less than 10% at room temperature; while in the aqueous phase preparation process of lithium bisoxalate borate, the concentration of oxalic acid is extremely high (saturated state), and the temperature can reach up to 200 Above ℃, at high concentration of oxalic acid and high temperature, due to the complexation and corrosion of oxalic acid, the traditional 316L stainless steel reactor will be corroded, and the metal ions in the product will increase, making it difficult to apply to lithium-ion batteries; this also leads to 316L stainless steel is difficult to apply to the synthesis process of lithium bisoxalate borate;

[0005] ②The enamel kettle can solve the problem of corrosion, but due to the high reaction temperature, it is prone to cracking during rapid cooling and rapid heating, and the strength of the enamel kettle stirring paddle is difficult to solve the degree of mass industrial production;

[0006] ③High temperature resistant coating can solve corrosion and high temperature problems, but it will increase the cost, and long-term high temperature conditions may cause the coating to peel off, increasing the difficulty of repair and time cost

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