Lithium bis(oxalato)borate preparation method

[0016] Example 1

[0017] A method for preparing lithium bis-oxalate borate, weighing each substance at a molar ratio of lithium hydroxide, oxalic acid and boric acid of 1:2:1, and then placing the lithium hydroxide and boric acid in an oven at 60°C for 4 hours Put the oxalic acid in an oven with a temperature of 120°C for 4 hours, then place the dried lithium hydroxide and oxalic acid in a ball mill for 15 minutes, and then add the dried boric acid to the ball mill for 15 minutes until a uniform The mixture was then dry-pressed into tablets under a pressure of 0.2 MPa, and then put into a container, first placed in a vacuum box with a temperature of 120°C for 6 hours, and then the temperature of the vacuum box was increased to 150°C so that the mixture was placed at a temperature of After 15 hours of reaction in a vacuum box at 150°C, a crude product of lithium bisoxalate borate is obtained. The crude product of lithium bisoxalate borate is then ground into a powder and fully dissolved in distilled anhydrous acetonitrile. The filtrate is obtained after filtration, and the filtrate is evaporated. Concentrate until the residual liquid is 1% of the total filtrate, finally discard the residual liquid, and place the product obtained by evaporation and concentration of the filtrate in a vacuum drying oven at a temperature of 120° C. for drying for 10 hours to obtain lithium bis-oxalate borate (LiBOB).

[0018] The specific preparation process of distilled anhydrous acetonitrile is as follows: put anhydrous acetonitrile in a container, then add phosphorus pentoxide to the container, reflux treatment at a temperature of 94℃ for 4h, and finally at a temperature of 100℃ Lower distillation treatment until evaporated to dryness.

[0019] The lithium bisoxalate borate prepared by the method in Example 1 was subjected to infrared analysis, and its infrared spectrum was as follows figure 1 Shown, according to figure 1 The peak positions of the obtained infrared spectrum of lithium bisoxalate borate and the list of corresponding functional groups are shown in Table 1, combined with Table 1 and figure 1 It can be seen that the lithium bisoxalate borate prepared by the method of Example 1 has good performance and meets the requirements for the use of lithium battery electrolyte.

[0020] Table 1 The infrared spectrum of lithium bisoxalate borate shows the peak positions and their corresponding functional groups

[0021] Peak position/(cm -1 )

[0022] Example 2

[0023] A method for preparing lithium bisoxalate borate, the steps of which are basically the same as those of the method for preparing lithium bisoxalate borate in Example 1, and the difference lies in:

[0024] 1. Lithium hydroxide and boric acid are placed in an oven at 50°C for 6 hours, and oxalic acid is placed in an oven at 130°C for 4.5 hours;

[0025] 2. The ball milling time of lithium hydroxide and oxalic acid is 25min, and the ball milling after boric acid is added is 25min;

[0026] 3. The mixture is dry pressed into tablets under a pressure of 0.22 MPa and then put into a container, first placed in a vacuum box with a temperature of 130°C for 5 hours, and then the temperature of the vacuum box is increased to 170°C so that the mixture is placed at 170°C Reaction in a vacuum box for 12 hours to obtain a crude product of lithium bisoxalate borate;

[0027] 4. Evaporate and concentrate the filtrate until the remaining liquid is 2% of the total filtrate;

[0028] 5. The product obtained by evaporation and concentration of the filtrate is placed in a vacuum drying oven at a temperature of 130°C and dried for 8 hours to obtain lithium bisoxalate borate;

[0029] 6. The preparation process of distilled anhydrous acetonitrile is specifically as follows: put anhydrous acetonitrile in a container, then add phosphorus pentoxide to the container, reflux treatment at a temperature of 96℃ for 4.5h, and finally at a temperature of It is obtained by distillation at 105°C until it is evaporated to dryness.

[0030] Example 3

[0031] A method for preparing lithium bisoxalate borate, the steps of which are basically the same as those of the method for preparing lithium bisoxalate borate in Example 1, and the difference lies in:

[0032] 1. Lithium hydroxide and boric acid are placed in an oven at 70℃ for 4.5 hours, and oxalic acid is placed in an oven at 105℃ for 6 hours;

[0033] 2. The ball milling time of lithium hydroxide and oxalic acid is 10 minutes, and the ball milling time after boric acid is added is 25 minutes;

[0034] 3. The mixture is dry pressed into tablets under a pressure of 0.25 MPa and then put into a container, first placed in a vacuum box with a temperature of 105°C for 8 hours, and then the temperature of the vacuum box is increased to 140°C so that the mixture is placed at a temperature of 140°C Reaction in a vacuum box for 24 hours to obtain a crude product of lithium bisoxalate borate;

[0035] 4. Evaporate and concentrate the filtrate until the remaining liquid is 1.5% of the total filtrate;

[0036] 5. The product obtained by evaporation and concentration of the filtrate is placed in a vacuum drying oven at a temperature of 105°C and dried for 12 hours to obtain lithium bisoxalate borate;

[0037] 6. The preparation process of distilled anhydrous acetonitrile is specifically as follows: put anhydrous acetonitrile in a container, then add phosphorus pentoxide to the container, reflux treatment at a temperature of 90℃ for 5h, and finally at a temperature of 110 It is obtained by distillation treatment at ℃ until evaporated to dryness.