Disclosure of Invention
The invention provides a preparation method of an electrolyte diaphragm of a sodium perfluorosulfonate ion battery, aiming at the problems that the battery capacity is attenuated and potential safety hazards can be caused by dendritic crystals due to side reactions of a liquid electrolyte and an electrode.
The invention also provides a sodium perfluorosulfonate ion battery electrolyte diaphragm.
The invention also provides application of the sodium perfluorosulfonate ion battery electrolyte membrane in preparation of a sodium ion battery.
In order to achieve the purpose of the invention, the embodiment of the invention adopts the following technical scheme:
a preparation method of an electrolyte diaphragm of a sodium perfluorosulfonate ion battery specifically comprises the following steps:
s1, mixing the calcium salt, the sulfate and the aluminum salt, and sintering at 1300-1600 ℃ to obtain porous layered calcium sulphoaluminate; in the calcium salt, the sulfur salt and the aluminum salt, the molar ratio of calcium to aluminum is 1: 1.2-2, and the molar ratio of calcium to sulfur is 4-10: 1;
s2, placing the porous layered calcium sulphoaluminate into a caustic alkali solution, and reacting at the temperature of 110-160 ℃; the molar weight of alkali metal ions in the caustic alkali solution is 4-10 times of that of calcium ions in the porous layered calcium sulphoaluminate;
and S3, preparing a glue solution from the product obtained in S2, polyethylene oxide (PEO), lithium perfluorosulfonate (PFSA-Li) and an organic solvent, blade-coating, and drying to obtain the polyethylene terephthalate.
According to the preparation method, firstly, calcium salt, aluminum salt and sulfur salt with limited proportion of calcium element, aluminum element and sulfur element are used as raw materials in S1, and porous layered calcium sulphoaluminate can be prepared by high-temperature sintering at a specific temperature.
Then in S2, the porous calcium sulphoaluminate prepared in S1 and alkali metal in caustic soda undergo ion exchange through low-temperature hydrothermal reaction at a specific temperature, so that the sodium sulphoaluminate molecular sieve with uniform pore diameter and complete crystal form is prepared. The molecular sieve can selectively filter decomposition products of electrode side reactions and electrode falling objects, prevent the decomposition products from passing through and can remarkably inhibit the generation of dendritic crystals of the metal sodium cathode.
And finally, carrying out ion exchange reaction on the sulfur-containing calcium sodium aluminate molecular sieve and water-soluble PFSA-Li in glue solution in S3 to obtain calcium sodium sulphoaluminate molecular sieve modified PFSA-Na composite powder, and carrying out blade coating and drying to form a solid sulfur-containing PFSA-Na composite diaphragm, namely the sodium perfluorosulfonate ion battery electrolyte diaphragm. PFSA-Li is water soluble and has relaxed requirement on production environment, and low temperature film forming is performed, so that S3 has no need of high temperature and long reaction time. The framework structure of the molecular sieve obtained from S2 can also enhance the strength of the electrolyte membrane.
Compared with other polymer electrolyte diaphragms, the sodium perfluorosulfonate ion battery electrolyte diaphragm obtained by the invention can be directly used for assembling batteries without additionally adding liquid electrolyte, has good conductivity, does not have the conditions of collapse, melting and the like caused by the reaction of the liquid electrolyte and electrodes, and reduces the battery capacity attenuation caused by the use of the liquid electrolyte. Meanwhile, the obtained diaphragm can filter decomposition products of electrode side reaction and electrode falling objects, and can inhibit generation of dendritic crystals. The electrolyte diaphragm is used as a diaphragm of a sodium ion secondary battery, and can obviously enhance the conductivity of sodium ions and the cycle stability of a large-current charge-discharge battery.
The process flow diagram of the preparation method of the invention is shown in figure 1.
Preferably, the mixing is to treat the calcium salt, the sulfate and the aluminum salt together with the absolute ethyl alcohol in a ball mill until the materials are mixed uniformly.
Preferably, the sintering is carried out for 10-15 min at 1550-1600 ℃, and then the temperature is reduced to 1300-1400 ℃ for 2-10 h.
Preferably, the caustic is sodium hydroxide.
Preferably, the concentration of the sodium hydroxide solution is 10-80 g/L. At the concentration, the reaction time is preferably 6-24 h.
Preferably, the caustic alkali solution further contains carbonate of alkali metal, wherein the molar amount of the carbonate in the carbonate is 1/6-1/3 of the molar amount of the calcium element. The carbonate can remove part of calcium in the calcium sulphoaluminate, and can further form pores on the calcium sulphoaluminate.
Preferably, the organic solvent is Dimethylformamide (DMF).
Preferably, the method for preparing the glue solution comprises the following steps: and (3) preparing the product obtained in the step (S2), the polyoxyethylene, the lithium perfluorosulfonate and the organic solvent into slurry, and dispersing the slurry to form uniform glue solution at the temperature of 45-65 ℃.
Preferably, the dispersion is on a magnetic stirrer. Under magnetic stirring, the positive charge of the molecular sieve is close to the magnetic field of the negative electrode, so that the molecular sieve with one-way permeability is obtained, and the passing of substances has selectivity.
Preferably, the drying temperature is 80-100 ℃.
Preferably, the thickness of the blade coating is 30-40 μm.
The embodiment of the invention also provides a sodium perfluorosulfonate ion battery electrolyte diaphragm, which is prepared by the preparation method of the sodium perfluorosulfonate ion battery electrolyte diaphragm.
The embodiment of the invention also provides application of the sodium perfluorosulfonate ion battery electrolyte membrane in preparation of a sodium ion battery. The sodium ion battery prepared by using the sodium perfluorosulfonate ion battery electrolyte membrane can keep stable structure after repeated cyclic charge and discharge, the battery capacity is not obviously attenuated, and the dendritic crystal can be effectively inhibited. And the battery assembled by the separator has good conductivity and good performance even at relatively high working temperature.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
The embodiment provides an electrolyte diaphragm of a sodium perfluorosulfonate ion battery, which comprises the following steps:
s1, taking calcium carbonate, aluminum sulfate and aluminum hydroxide as raw materials, mixing and mixing according to the molar ratio of calcium element to aluminum element to sulfur element of 10:17:2, putting the mixed material and absolute ethyl alcohol into a high-energy ball mill for treatment for 12 hours, then making the treated material into a cake shape, putting the cake shape into a high-temperature sintering furnace for sintering at 1600 ℃ for 10 minutes, cooling to 1350 ℃ and preserving heat for 6 hours to obtain the porous layered calcium sulphoaluminate.
S2, putting the porous layer calcium sulphoaluminate prepared in the S1 into a hydrothermal kettle containing 25g/L of NaOH aqueous solution for carrying out sodium treatment and pore-forming treatment, wherein the molar weight of NaOH is 6 times of that of calcium ions in the porous layer calcium sulphoaluminate, the hydrothermal temperature is 135 ℃, and the hydrothermal time is 8 hours, so that the sodium calcium sulphoaluminate molecular sieve with uniform pore diameter and complete crystal form is prepared.
S3, preparing the sodium calcium aluminate containing sulfur prepared in the S2, PEO, PFSA-Li and DMF into slurry, and uniformly dispersing the slurry on a magnetic stirrer at the temperature of 55 ℃ in the dispersing process for 12 hours to form uniform glue solution. And finally, carrying out blade coating on the obtained glue solution (the thickness is 35 mu m), and drying at 90 ℃ for 8h to obtain the sulfur-containing PFSA-Na compound diaphragm modified by the sodium calcium sulphoaluminate molecular sieve.
Example 2
The embodiment provides a sodium perfluorosulfonate ion battery electrolyte membrane, and the preparation method comprises the following steps:
s1, taking calcium carbonate, aluminum sulfate and aluminum hydroxide as raw materials, mixing and mixing according to the molar ratio of calcium element to aluminum element to sulfur element of 10:17:2, putting the mixed material and absolute ethyl alcohol into a high-energy ball mill for treatment for 12 hours, then making the treated material into a cake shape, putting the cake shape into a high-temperature sintering furnace for sintering at 1600 ℃ for 10 minutes, cooling to 1350 ℃ and preserving heat for 6 hours to obtain the porous layered calcium sulfoaluminate, wherein the microscopic appearance of the porous layered calcium sulfoaluminate is shown in figure 2.
S2, placing the porous calcium sulphoaluminate prepared by S1 into a container containing 25g/L NaOH aqueous solution and 4.1g/L Na 2 CO 3 Carrying out sodium treatment and pore-forming treatment in a hydrothermal kettle of the aqueous solution, wherein the molar weight of NaOH is 4 times of that of calcium ions in the porous calcium sulphoaluminate, the hydrothermal temperature is 135 ℃, the hydrothermal time is 8 hours, and the prepared sulfur-containing calcium sodium aluminate molecular sieve with uniform aperture and complete crystal form is shown in figure 3.
S3, preparing the sodium calcium aluminate containing sulfur prepared in the S2, PEO, PFSA-Li and DMF into slurry, and uniformly dispersing the slurry on a magnetic stirrer at the temperature of 55 ℃ in the dispersing process for 12 hours to form uniform glue solution. And finally, carrying out blade coating on the obtained glue solution (the thickness is 35 mu m), and drying at 90 ℃ for 8h to obtain the sulfur-containing PFSA-Na compound diaphragm modified by the sodium calcium sulphoaluminate molecular sieve.
Example 3
The embodiment provides a sodium perfluorosulfonate ion battery electrolyte membrane, and the preparation method comprises the following steps:
s1, taking calcium hydroxide, aluminum sulfate and aluminum carbonate as raw materials, mixing and mixing according to the molar ratio of calcium element to aluminum element to sulfur element of 10:15:2, putting the mixed material and absolute ethyl alcohol into a high-energy ball mill for treatment for 12 hours, then making the treated material into a cake shape, putting the cake shape into a high-temperature sintering furnace for sintering at 1550 ℃ for 15 minutes, and cooling to 1320 ℃ for heat preservation for 4 hours to obtain the porous layered calcium sulfoaluminate.
S2, placing the porous calcium sulphoaluminate prepared by S1 into a container containing10g/L NaOH aqueous solution and 0.4g/L Na 2 CO 3 Carrying out sodium treatment and pore-forming treatment in a hydrothermal kettle of the aqueous solution, wherein the molar weight of NaOH is 10 times of that of calcium ions in the porous calcium sulphoaluminate, the hydrothermal temperature is 160 ℃, and the hydrothermal time is 6 hours, so as to prepare the sodium calcium sulphoaluminate molecular sieve with uniform aperture and complete crystal form.
S3, preparing the sodium calcium aluminate containing sulfur prepared in the S2, PEO, PFSA-Li and DMF into slurry, and uniformly dispersing the slurry on a magnetic stirrer at the temperature of 45 ℃ in the dispersing process for 12 hours to form uniform glue solution. And finally, carrying out blade coating on the obtained glue solution (the thickness is 35 mu m), and drying at 80 ℃ for 9h to obtain the sulfur-containing PFSA-Na compound diaphragm modified by the sodium calcium sulphoaluminate molecular sieve.
Example 4
The embodiment provides a sodium perfluorosulfonate ion battery electrolyte membrane, and the preparation method comprises the following steps:
s1, taking calcium sulfate, calcium hydroxide and aluminum carbonate as raw materials, mixing and mixing according to the molar ratio of calcium element to aluminum element to sulfur element of 10:16:2, putting the mixed material and absolute ethyl alcohol into a high-energy ball mill for treatment for 12 hours, then making the treated material into a cake shape, putting the cake shape into a high-temperature sintering furnace for sintering at 1600 ℃ for 12 minutes, cooling to 1300 ℃ and preserving heat for 8 hours to obtain the porous layered calcium sulfoaluminate.
S2, placing the porous calcium sulfoaluminate prepared in S1 into a solution containing 30g/L NaOH water solution and 2.5g/L Na 2 CO 3 Carrying out sodium treatment and pore-forming treatment in a hydrothermal kettle of the aqueous solution, wherein the molar weight of NaOH is 8 times of that of calcium ions in the porous calcium sulphoaluminate, the hydrothermal temperature is 145 ℃, and the hydrothermal time is 10h, so as to prepare the sodium calcium sulphoaluminate molecular sieve with uniform aperture and complete crystal form.
S3, preparing the S2 sodium calcium aluminate containing sulfur, PEO, PFSA-Li and DMF into slurry, and uniformly dispersing the slurry on a magnetic stirrer at the temperature of 50 ℃ in the dispersing process for 12 hours to form uniform glue solution. Finally, the obtained glue solution is subjected to blade coating (the thickness is 40 mu m), and then is dried for 7 hours at the temperature of 100 ℃, so as to prepare the sulfur-containing PFSA-Na composite diaphragm modified by the calcium sulphoaluminate sodium molecular sieve.
Example 5
The embodiment provides a sodium perfluorosulfonate ion battery electrolyte membrane, and the preparation method comprises the following steps:
s1, taking calcium hydroxide, aluminum sulfate and aluminum hydroxide as raw materials, mixing and mixing according to the molar ratio of calcium element to aluminum element to sulfur element of 10:12:2.5, putting the mixed material and absolute ethyl alcohol into a high-energy ball mill for treatment for 12 hours, then making the treated material into a cake shape, putting the cake shape into a high-temperature sintering furnace for sintering at 1570 ℃ for 13 minutes, cooling to 1350 ℃ and preserving heat for 8 hours to obtain the porous layered calcium sulphoaluminate.
S2, placing the porous calcium sulphoaluminate prepared by S1 into a container containing 45g/L NaOH aqueous solution and 4.8g/L Na 2 CO 3 Carrying out sodium treatment and pore-forming treatment in a hydrothermal kettle of the aqueous solution, wherein the molar weight of NaOH is 5 times of that of calcium ions in the porous calcium sulphoaluminate, the hydrothermal temperature is 125 ℃, and the hydrothermal time is 18h, so as to prepare the sodium calcium sulphoaluminate molecular sieve with uniform aperture and complete crystal form.
S3, preparing the S2 sodium calcium aluminate containing sulfur, PEO, PFSA-Li and DMF into slurry, and uniformly dispersing the slurry on a magnetic stirrer at the temperature of 55 ℃ in the dispersing process for 12 hours to form uniform glue solution. And finally, carrying out blade coating on the obtained glue solution (the thickness is 35 mu m), and drying at 95 ℃ for 8h to obtain the sulfur-containing PFSA-Na compound diaphragm modified by the sodium calcium sulphoaluminate molecular sieve.
Example 6
The embodiment provides a sodium perfluorosulfonate ion battery electrolyte membrane, and the preparation method comprises the following steps:
s1, taking calcium sulfate, calcium carbonate and aluminum carbonate as raw materials, mixing and mixing according to the molar ratio of calcium element to aluminum element to sulfur element of 10:20:1, putting the mixed material and absolute ethyl alcohol into a high-energy ball mill for treatment for 12 hours, then making the treated material into a cake shape, putting the cake shape into a high-temperature sintering furnace for sintering at 1520 ℃ for 15 minutes, and cooling to 1400 ℃ for heat preservation for 2 hours to obtain the porous layered calcium sulfoaluminate.
S2, placing the porous calcium sulfoaluminate prepared in S1 into a solution containing 80g/L NaOH aqueous solution and 17.7g/L Na 2 CO 3 Performing sodium treatment and pore-forming treatment in a hydrothermal kettle of aqueous solution, and preparing NaOHThe molar weight of the molecular sieve is 4 times of that of calcium ions in the porous calcium sulphoaluminate, the hydrothermal temperature is 110 ℃, the hydrothermal time is 24 hours, and the sulfur-containing calcium sodium sulphoaluminate molecular sieve with uniform aperture and complete crystal form is prepared.
S3, preparing the sodium calcium aluminate containing sulfur prepared in the S2, PEO, PFSA-Li and DMF into slurry, and uniformly dispersing the slurry on a magnetic stirrer at the temperature of 65 ℃ in the dispersing process for 12 hours to form uniform glue solution. And finally, carrying out blade coating on the obtained glue solution (the thickness is 30 mu m), and drying at 85 ℃ for 9h to obtain the sulfur-containing PFSA-Na compound diaphragm modified by the sodium calcium sulphoaluminate molecular sieve.
Example 7
The embodiment provides application of an electrolyte membrane of a sodium perfluorosulfonate ion battery in preparation of a sodium ion battery.
And assembling the CR2032 button cell by using sodium iron phosphate as a positive electrode, metal sodium as a negative electrode and the finished product obtained in the example 2 as a diaphragm, wherein the test voltage range is 1.2-3.6V. The specific discharge capacity of the first ring of the battery reaches 128 mAh.g -1 The battery has excellent performance, the contact ratio of charge and discharge curves after 100, 500 and 1000 cycles of circulation is higher, the capacity retention rates are respectively 99.32%, 98.75% and 96.58%, and the polarization is smaller, which indicates that the battery has good reversibility in the circulation process. Meanwhile, the conductivity of the assembled battery measured at the working temperature of 40-50 ℃ is close to 10 -3 S/cm, which shows that the performance is good.
After 1000 cycles of circulation, the assembled battery is disassembled, no obvious sodium dendrite is generated on the sodium metal cathode close to one side of the diaphragm, and trace 10-35 nm small particles are attached to the diaphragm close to one side of the anode material, which shows that the diaphragm can effectively inhibit the generation of dendrite.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents or improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.