CN111341980A - A kind of sodium perfluorosulfonate ion battery electrolyte separator and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of solid electrolyte materials for sodium ion batteries, and in particular relates to an electrolyte diaphragm of a sodium perfluorosulfonate ion battery and a preparation method and application thereof. The preparation method uses calcium salts, aluminum salts and sulfur salts in specific proportions as raw materials, and is sintered at high temperature to prepare calcium sulfoaluminate; and then the caustic alkali and the calcium sulfoaluminate are made into calcium sulfoaluminate through low-temperature hydrothermal reaction sodium molecular sieve; finally, the sodium ion solid electrolyte membrane is prepared from the calcium sodium sulfoaluminate-containing molecular sieve and PFSA-Li powder. The finished product prepared by the preparation method can reduce or avoid the use of liquid electrolyte, significantly inhibit the generation of dendrites in the metal sodium negative electrode, and has high strength, and can be directly used as a sodium ion secondary battery separator for assembling batteries, which can significantly Enhance the conductivity of sodium ions and the cycling stability of high-current charge-discharge batteries.

Description

A kind of sodium perfluorosulfonate ion battery electrolyte separator and preparation method and application thereof

technical field

The invention belongs to the technical field of solid electrolyte materials for sodium ion batteries, and in particular relates to an electrolyte diaphragm of a sodium perfluorosulfonate ion battery and a preparation method and application thereof.

Background technique

Among many energy storage systems, lithium-ion batteries have developed rapidly in portable devices due to their high energy density, high power density, high discharge voltage, and low self-discharge rate. However, lithium resource is a relatively scarce resource, and its massive use has led to rising prices of lithium products. Although the energy density of sodium-ion batteries is lower than that of lithium-ion batteries, due to the abundant and easy availability of sodium resources, they still have good application prospects in fields that do not require high energy density.

However, organic liquid electrolytes are mostly used in sodium-ion batteries, and the electrolytes and electrode materials can damage the electrode materials during the charging and discharging process and cause irreversible attenuation of the battery capacity. Drying, leakage and other phenomena will seriously affect the battery life. On the other hand, due to factors such as the current density on the electrode surface and the uneven distribution of sodium ions, the extraction and insertion of ions during the battery cycle of sodium ion batteries will lead to the occurrence of side reactions in the electrode material, resulting in decomposition products and exfoliated electrode materials. , deposition can form uneven pores and dendrites. The dendrite will pierce the separator and contact the positive electrode, causing a series of safety hazards such as battery short circuit, thermal runaway, fire and explosion.

SUMMARY OF THE INVENTION

Aiming at the problems that the liquid electrolyte and the electrode will have side reactions, which will cause the battery capacity to decay and dendrites may cause safety hazards, the invention provides a preparation method of an electrolyte separator for a sodium perfluorosulfonate ion battery.

And, the present invention also provides an electrolyte separator for sodium perfluorosulfonate ion battery.

And, the present invention also provides the application of the above-mentioned sodium perfluorosulfonate ion battery electrolyte separator in the preparation of lithium ion battery.

In order to achieve the above-mentioned purpose of the invention, the embodiment of the present invention adopts the following technical solutions:

A preparation method of an electrolyte diaphragm of a sodium perfluorosulfonate ion battery, specifically comprising the following steps:

S1. Mix calcium salt, sulfate and aluminum salt, and sinter at 1300-1600 ° C to obtain porous layered calcium sulfoaluminate; in the calcium salt, sulfur salt and aluminum salt, the molar ratio of calcium element to aluminum element is 1:1.2～2, the molar ratio of the calcium element to the sulfur element is 4～10:1;

S2, placing the porous layered calcium sulfoaluminate in a caustic alkali solution and reacting at 110-160° C.; the molar amount of alkali metal ions in the caustic solution is the porous layered calcium sulfoaluminate 4 to 10 times the molar amount of calcium ions in calcium;

S3, the product obtained in S2 is made into a glue solution with polyethylene oxide (PEO), lithium perfluorosulfonate (PFSA-Li) and an organic solvent, and is dried after scraping.

The preparation method of the present invention firstly uses calcium salts, aluminum salts and sulfur salts whose ratios of calcium element, aluminum element and sulfur element are limited as raw materials in S1, and can prepare porous layered sulfoaluminate by high-temperature sintering at a specific temperature calcium.

Then in S2, the porous layered calcium sulfoaluminate prepared in S1 and the alkali metal in caustic soda undergo ion exchange through a low-temperature hydrothermal reaction at a specific temperature, so as to obtain sulfur-containing aluminate with uniform pore size and complete crystal form. Calcium sodium molecular sieve. The molecular sieve can selectively filter the decomposition products of the electrode side reaction and the electrode shedding, prevent them from passing through, and can significantly inhibit the generation of dendrites of the metal sodium negative electrode.

Finally, the above-mentioned calcium-sodium sulfoaluminate-containing molecular sieve is ion-exchanged with water-soluble PFSA-Li in S3 to obtain a PFSA-Na composite powder modified by calcium-sodium sulfoaluminate molecular sieve. A solid-state sulfur-containing PFSA-Na composite separator, that is, an electrolyte separator for a sodium perfluorosulfonate ion battery, can be formed. PFSA-Li is water-soluble, and has relatively loose requirements on the production environment, and can form a film at low temperature, so the reaction process of S3 does not require high temperature and long reaction time. The framework structure of the molecular sieve obtained by S2 can also enhance the strength of the electrolyte separator.

Compared with other polymer electrolyte membranes, the perfluorosulfonate sodium ion battery electrolyte membrane obtained by the present invention does not need to add additional liquid electrolyte, can be directly used for assembling batteries, has good electrical conductivity, and will not cause the liquid electrolyte to react with the electrode. Causes collapse, melting, etc., and also reduces battery capacity fading due to the use of liquid electrolytes. At the same time, the obtained separator can filter the decomposition products of the electrode side reaction and the electrode exfoliation, and can suppress the generation of dendrites. Using this electrolyte separator as a separator for sodium ion secondary batteries can significantly enhance the electrical conductivity of sodium ions and the cycle stability of high-current charge-discharge batteries.

The process flow diagram of the preparation method of the present invention is shown in FIG. 1 .

Preferably, the mixing is to process the calcium salt, sulfate and aluminum salt together with absolute ethanol in a ball mill until the materials are uniformly mixed.

Preferably, the sintering is carried out at 1550-1600°C for 10-15 minutes, and then the temperature is lowered to 1300-1400°C for 2-10 hours.

Preferably, the caustic is sodium hydroxide.

Preferably, the concentration of the sodium hydroxide solution is 10-80 g/L. At this concentration, the preferred reaction time is 6 to 24 hours.

Preferably, the caustic alkali solution also contains carbonate of alkali metal, and the molar amount of carbonate in the carbonate is 1/6-1/3 of the molar amount of the calcium element. Carbonate can remove part of calcium in calcium sulfoaluminate, and can further pore for calcium sulfoaluminate.

Preferably, the organic solvent is dimethylformamide (DMF).

Preferably, the method for preparing the glue solution is as follows: the product obtained from S2, the polyethylene oxide, the lithium perfluorosulfonate and the organic solvent are made into a slurry, and the slurry is dispersed to a temperature of 45-65° C. It forms a homogeneous glue.

Preferably, the dispersion is on a magnetic stirrer. Under magnetic stirring, the positive charge of the molecular sieve is close to the negative magnetic field, thereby obtaining a molecular sieve with unidirectional permeability, which makes the material pass through selectively.

Preferably, the drying temperature is 80-100°C.

Preferably, the thickness of the blade coating is 30-40 μm.

And, the embodiment of the present invention also provides an electrolyte diaphragm of a sodium perfluorosulfonate ion battery, and the electrolyte diaphragm of a sodium perfluorosulfonate ion battery is prepared by the above-mentioned preparation method of an electrolyte diaphragm of a sodium perfluorosulfonate ion battery.

And, the embodiment of the present invention also provides the application of the above-mentioned sodium perfluorosulfonate ion battery electrolyte separator in the preparation of lithium ion battery. The sodium ion battery prepared by using the above-mentioned sodium perfluorosulfonate sodium ion battery electrolyte separator can maintain a stable structure after multiple cycles of charge and discharge, the battery capacity does not experience obvious attenuation, and dendrites can be effectively suppressed. And the battery assembled with the separator still has good conductivity and good performance even at a relatively high working temperature.

Description of drawings

Fig. 1 is the process flow schematic diagram of the present invention;

Fig. 2 is the microstructure of calcium sulfoaluminate prepared by S1 in Example 2 of the present invention;

Fig. 3 is the microstructure of calcium sodium aluminate containing sulfur obtained by S2 in Example 2 of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

Example 1

The present embodiment provides a sodium perfluorosulfonate ion battery electrolyte diaphragm, and its preparation method is:

S1, using calcium carbonate, aluminum sulfate and aluminum hydroxide as raw materials, according to the ratio of calcium element, aluminum element and sulfur element molar ratio of 10:17:2, carry out batching and mixing, and put the mixed material and absolute ethanol into the high-energy ball mill After treatment for 12h, the treated material was made into cake shape, put into a high temperature sintering furnace, sintered at 1600°C for 10min, cooled to 1350°C and kept for 6h to obtain porous layered calcium sulfoaluminate.

S2, put the porous layered calcium sulfoaluminate obtained from S1 into the hydrothermal kettle containing 25g/L NaOH aqueous solution and carry out sodiumization and pore-forming treatment, and the molar weight of NaOH is the calcium ion in the porous layered calcium sulfoaluminate Molecular weight is 6 times, the hydrothermal temperature is 135℃, and the hydrothermal time is 8h, and the molecular sieve containing calcium sodium aluminate with uniform pore size and complete crystal form is prepared.

S3. Prepare a slurry containing calcium sodium aluminate, PEO, PFSA-Li and DMF obtained from S2, and uniformly disperse on a magnetic stirrer. The temperature of the dispersion process is 55 °C, and a uniform glue is formed after dispersing for 12 hours. . Finally, the obtained glue solution was scraped (35 μm in thickness) and dried at 90 °C for 8 h to obtain a sulfur-containing PFSA-Na composite membrane modified by calcium sodium sulfoaluminate molecular sieve.

Example 2

The present embodiment provides a sodium perfluorosulfonate ion battery electrolyte diaphragm, and its preparation method is:

S1, using calcium carbonate, aluminum sulfate and aluminum hydroxide as raw materials, according to the ratio of calcium element, aluminum element and sulfur element molar ratio of 10:17:2, carry out batching and mixing, and put the mixed material and absolute ethanol into the high-energy ball mill After treatment for 12h, the treated material was made into cake shape, put into a high temperature sintering furnace, sintered at 1600°C for 10min, cooled to 1350°C and kept for 6h to obtain porous layered calcium sulfoaluminate. Its microscopic morphology is shown in the figure. 2 shown.

S2, the porous layered calcium sulfoaluminate obtained from S1 is put into the hydrothermal still containing 25g/L NaOH aqueous solution and 4.1g/L Na ₂ CO ₃ aqueous solution to carry out sodiumization and pore-forming treatment, and the molar weight of NaOH is 4 times the molar amount of calcium ions in porous layered calcium sulfoaluminate, the hydrothermal temperature is 135 °C, and the hydrothermal time is 8 h, a molecular sieve containing calcium and sodium sulfoaluminate with uniform pore size and complete crystal form is obtained. Its microscopic morphology As shown in Figure 3.

S3. Prepare a slurry containing calcium sodium aluminate, PEO, PFSA-Li and DMF obtained from S2, and uniformly disperse on a magnetic stirrer. The temperature of the dispersion process is 55 °C, and a uniform glue is formed after dispersing for 12 hours. . Finally, the obtained glue solution was scraped (35 μm in thickness) and dried at 90 °C for 8 h to obtain a sulfur-containing PFSA-Na composite membrane modified by calcium sodium sulfoaluminate molecular sieve.

Example 3

The present embodiment provides a sodium perfluorosulfonate ion battery electrolyte diaphragm, and its preparation method is:

S1. Use calcium hydroxide, aluminum sulfate and aluminum carbonate as raw materials, carry out batching and mixing according to the molar ratio of calcium element, aluminum element and sulfur element as 10:15:2, and put the mixed material and absolute ethanol into the high-energy ball mill After treatment for 12h, the treated material was made into cake shape, put into a high-temperature sintering furnace, sintered at 1550°C for 15min, cooled to 1320°C and kept for 4h to obtain porous layered calcium sulfoaluminate.

S2, the porous layered calcium sulfoaluminate obtained from S1 is put into a hydrothermal still containing 10g/L NaOH aqueous solution and 0.4g/L Na ₂ CO ₃ aqueous solution to carry out sodiumization and pore-forming treatment, and the molar weight of NaOH is 10 times the molar amount of calcium ions in the porous layered calcium sulfoaluminate, the hydrothermal temperature is 160 °C, and the hydrothermal time is 6 h, a molecular sieve containing calcium sodium sulfoaluminate with uniform pore size and complete crystal form is prepared.

S3. Prepare a slurry containing calcium sodium sulfoaluminate, PEO, PFSA-Li and DMF obtained from S2, and uniformly disperse on a magnetic stirrer. The temperature of the dispersion process is 45 °C, and a uniform glue is formed after dispersing for 12 hours. . Finally, the obtained glue solution was scraped (35 μm in thickness) and dried at 80 °C for 9 h to obtain a sulfur-containing PFSA-Na composite membrane modified by calcium sodium sulfoaluminate molecular sieve.

Example 4

The present embodiment provides a sodium perfluorosulfonate ion battery electrolyte diaphragm, and its preparation method is:

S1, take calcium sulfate, calcium hydroxide and aluminum carbonate as raw materials, carry out batching and mixing according to the molar ratio of calcium element, aluminum element and sulfur element as 10:16:2, put the mixed material and absolute ethanol into the high-energy ball mill After treatment for 12h, the treated material was made into cake shape, put into a high-temperature sintering furnace, sintered at 1600°C for 12min, cooled to 1300°C and kept for 8h to obtain porous layered calcium sulfoaluminate.

S2, the porous layered calcium sulfoaluminate obtained from S1 is put into the hydrothermal still containing 30g/L NaOH aqueous solution and 2.5g/L Na ₂ CO ₃ aqueous solution to carry out sodiumization and pore-forming treatment, and the molar weight of NaOH is The molar amount of calcium ions in the porous layered calcium sulfoaluminate is 8 times, the hydrothermal temperature is 145 °C, and the hydrothermal time is 10 h, and the molecular sieve containing calcium sodium sulfoaluminate with uniform pore size and complete crystal form is prepared.

S3. Prepare a slurry containing calcium sodium sulfoaluminate, PEO, PFSA-Li and DMF obtained from S2, and uniformly disperse on a magnetic stirrer. The temperature of the dispersion process is 50 °C, and a uniform glue is formed after dispersing for 12 hours. . Finally, the obtained glue solution was scraped (40 μm thick) and dried at 100 °C for 7 h to obtain a sulfur-containing PFSA-Na composite membrane modified by calcium sodium sulfoaluminate molecular sieve.

Example 5

The present embodiment provides a sodium perfluorosulfonate ion battery electrolyte diaphragm, and its preparation method is:

S1. Use calcium hydroxide, aluminum sulfate and aluminum hydroxide as raw materials, carry out batching and mixing according to the molar ratio of calcium element, aluminum element and sulfur element as 10:12:2.5, and put the mixed material and absolute ethanol into high-energy After treatment in a ball mill for 12 hours, the treated material was made into a cake shape, placed in a high-temperature sintering furnace, sintered at 1570 °C for 13 minutes, cooled to 1350 °C and kept for 8 hours to obtain porous layered calcium sulfoaluminate.

S2, the porous layered calcium sulfoaluminate obtained from S1 is put into the hydrothermal still containing 45g/L NaOH aqueous solution and 4.8g/L Na ₂ CO ₃ aqueous solution to carry out sodiumization and pore-forming treatment, and the molar weight of NaOH is Porous layered calcium sulfoaluminate contains 5 times the molar amount of calcium ions, the hydrothermal temperature is 125 °C, and the hydrothermal time is 18 h, to obtain a calcium-sodium sulfoaluminate molecular sieve with uniform pore size and complete crystal form.

S3. Prepare a slurry containing calcium sodium aluminate, PEO, PFSA-Li and DMF obtained from S2, and uniformly disperse on a magnetic stirrer. The temperature of the dispersion process is 55 °C, and a uniform glue is formed after dispersing for 12 hours. . Finally, the obtained glue solution was scraped (35 μm in thickness) and dried at 95 °C for 8 h to obtain a sulfur-containing PFSA-Na composite membrane modified by calcium sodium sulfoaluminate molecular sieve.

Example 6

The present embodiment provides a sodium perfluorosulfonate ion battery electrolyte diaphragm, and its preparation method is:

S1. Use calcium sulfate, calcium carbonate and aluminum carbonate as raw materials, carry out batching and mixing according to the molar ratio of calcium element, aluminum element and sulfur element as 10:20:1, and put the mixed material and absolute ethanol into the high-energy ball mill After treatment for 12h, the treated material was made into cake shape, put into a high temperature sintering furnace, sintered at 1520°C for 15min, cooled to 1400°C and kept for 2h to obtain porous layered calcium sulfoaluminate.

S2, the porous layered calcium sulfoaluminate obtained from S1 is put into the hydrothermal still containing 80g/L NaOH aqueous solution and 17.7g/L Na ₂ CO ₃ aqueous solution to carry out sodiumization and pore-forming treatment, and the molar weight of NaOH is The molar amount of calcium ions in the porous layered calcium sulfoaluminate is 4 times, the hydrothermal temperature is 110 °C, and the hydrothermal time is 24 h, and the molecular sieve containing calcium sodium sulfoaluminate with uniform pore size and complete crystal form is prepared.

S3. Prepare a slurry containing calcium sodium sulfoaluminate, PEO, PFSA-Li and DMF obtained from S2, and uniformly disperse on a magnetic stirrer. The temperature of the dispersion process is 65 °C, and a uniform glue is formed after dispersing for 12 hours. . Finally, the obtained glue solution was scraped (30 μm in thickness) and dried at 85 °C for 9 h to obtain a sulfur-containing PFSA-Na composite membrane modified by calcium sodium sulfoaluminate molecular sieve.

Example 7

This embodiment provides an application of an electrolyte separator for a sodium perfluorosulfonate ion battery in the preparation of a sodium ion battery.

Using sodium iron phosphate as the positive electrode and sodium metal as the negative electrode, and using the finished product obtained in Example 2 as the separator to assemble a CR2032 button battery, the test voltage range is 1.2-3.6V. The discharge specific capacity of the battery in the first cycle reaches 128mAh·g ^-1 , and the performance is excellent. After 100, 500 and 1000 cycles, the charge-discharge curves have a high degree of overlap, and the capacity retention rates are 99.32%, 98.75%, and 96.58%, respectively. small, indicating that the battery has good reversibility during cycling. At the same time, the measured conductivity of the assembled battery is close to 10 ^-3 S/cm when the working temperature is 40-50° C., indicating that its performance is good.

After 1000 cycles, the assembled battery was disassembled. There was no obvious sodium dendrite formation on the sodium metal negative electrode on the side near the diaphragm, and a small amount of 10-35 nm small particles were attached to the diaphragm on the side near the positive electrode material, indicating that the diaphragm can effectively inhibit Generation of dendrites.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (10)

1. a preparation method of sodium perfluorosulfonate ion battery electrolyte diaphragm, is characterized in that, specifically comprises the following steps: S1. Mix calcium salt, sulfate and aluminum salt, and sinter at 1300-1600 ° C to obtain porous layered calcium sulfoaluminate; in the calcium salt, sulfur salt and aluminum salt, the molar ratio of calcium element to aluminum element is 1:1.2～2, the molar ratio of the calcium element to the sulfur element is 4～10:1; S2, placing the porous layered calcium sulfoaluminate in a caustic alkali solution and reacting at 110-160° C.; the molar amount of alkali metal ions in the caustic solution is the porous layered calcium sulfoaluminate 4 to 10 times the molar amount of calcium ions in calcium; S3, the product obtained in S2 is made into a glue solution with polyethylene oxide, lithium perfluorosulfonate and an organic solvent, and is dried after scraping. 2. according to the preparation method of the described sodium perfluorosulfonate ion battery electrolyte diaphragm of claim 1, it is characterized in that, described mixing is that described calcium salt, sulfate and aluminium salt and dehydrated alcohol are jointly processed in ball mill to The materials are mixed evenly. 3. The preparation method of the electrolyte diaphragm of a sodium perfluorosulfonate ion battery according to claim 1, wherein the sintering is carried out at 1550-1600 ℃ for 10-15 min, and then cooled to 1300-1400 ℃ for 2-10 h . 4. the preparation method of the electrolyte membrane of sodium perfluorosulfonate ion battery according to claim 1, is characterized in that, described caustic is sodium hydroxide; And/or The caustic alkali solution also contains alkali metal carbonate, and the molar amount of carbonate in the carbonate is 1/6 to 1/3 of the molar amount of the calcium element. 5 . The method for preparing an electrolyte membrane for a sodium perfluorosulfonate ion battery according to claim 4 , wherein the concentration of the sodium hydroxide solution is 10-80 g/L. 6 . 6. the preparation method of perfluorosulfonate sodium ion battery electrolyte diaphragm according to claim 1, is characterized in that, described organic solvent is dimethylformamide; And/or The method for preparing the glue solution is as follows: the product obtained from S2 and the polyethylene oxide, lithium perfluorosulfonate and dimethylformamide are made into a slurry, and the slurry is dispersed to a temperature of 45-65° C. It forms a homogeneous glue. 7. The preparation method of the electrolyte diaphragm of sodium perfluorosulfonate ion battery according to claim 6, wherein the dispersion is dispersed on a magnetic stirrer. 8. The preparation method of the electrolyte membrane of a sodium perfluorosulfonate ion battery according to claim 1, wherein the drying temperature is 80-100°C; and/or The thickness of the blade coating is 30-40 μm. 9 . An electrolyte diaphragm of a sodium perfluorosulfonate ion battery, wherein the electrolyte diaphragm of a sodium perfluorosulfonate ion battery is made of the electrolyte diaphragm of a sodium perfluorosulfonate ion battery according to any one of claims 1 to 8 prepared by the method of preparation. 10. The application of the sodium perfluorosulfonate ion battery electrolyte separator of claim 9 in the preparation of lithium ion batteries.

Images