Preparation method of lithium difluoro(oxalato)borate

Abstract

The invention relates to the technical field of lithium difluoro(oxalato)borate production, and particularly discloses a preparation method of lithium difluoro(oxalato)borate. The method comprises the following steps: 1) heating and mixing raw materials; 2) adding a reaction accelerator, and continuously conducting stirring for reaction; (3) discharging the reacted liquid into a filter tank for filtering, pumping the filtered liquid into a concentration and crystallization kettle, pumping the inside of the concentration and crystallization kettle to negative pressure through a vacuumizing pump, conducting heating to perform negative pressure concentration on the filtrate, and then introducing cooling water into a water cooling jacket so as to perform cooling crystallization on the concentrated solution; and 4) in the negative pressure concentration process, introducing steam into a condensation reflux device for cooling reflux, then filtering the concentrated solution, and re-pumping the filtrate into a stirring and mixing tank through a third liquid pump. According to the preparation method of the lithium difluoro(oxalato)borate, disclosed by the invention, the efficiency of producing the lithium difluoro(oxalato)borate is higher, the utilization rate of raw materials is also greatly improved, and the production cost of preparing the lithium difluoro(oxalato)borate is reduced.

Description

technical field [0001] The invention relates to the technical field of lithium difluorooxalate borate production, and specifically discloses a preparation method of lithium difluorooxalate borate. Background technique [0002] Lithium-ion batteries have the characteristics of high energy density, long cycle life and no pollution, so they are widely used in various electrical appliances and electric equipment. Electrolyte is one of the main components of lithium-ion batteries and one of the key materials affecting the performance of lithium-ion batteries. The current research on new lithium salts mainly focuses on lithium borate complexes and lithium phosphate complexes, among which lithium difluorooxalate borate (LiODFB) attracts the most attention. Its unique chemical structure makes it combine the advantages of lithium bisoxalate borate and lithium tetrafluoroborate, so that it has good high and low temperature performance, rate performance and cycle performance at the sa...

AI Technical Summary

Problems solved by technology

Among them, the BF3 complex method is to use BF3 complex and Li2C2O4 as raw materials, and use ether or carbonate as a solvent to heat and reflux to obtain the LiODFB crude product. After multiple crystallization, the target product is obtained. This method has the advantage of low cost, but the reaction time Long, low production efficiency, and its products are lithium difluorooxalate borate and lithium tetrafluoroborate, both of which are dissolved in purification solvents such as dimethyl carbonate (DMC), and the purification process is complicated

The LiBF4 method is to use LiBF4 and H2C2O4 as raw materials, with acetonitrile or carbonate as a solvent, plus a reaction aid, the same heating and reflux process is used to obtain LiODFB. The product prepared by this method is only lithium difluorooxalate borate, and the purification is simple. But the disadvantage is that the cost of raw materials is high, especially the solution in the process of crystallization and recrystallization cannot be effectively and fully reused, which further increases the cost of preparing lithium difluorooxalate borate

Images