Method for manufacturing hybrid solid electrolyte porous silica nano-support particles for battery

Abstract

The present invention relates to a method for manufacturing spherical porous silica particles used as a support for an ionic liquid and a lithium salt liquid electrolyte inside a semi-solid or solid electrolyte, wherein a tetraalkoxysilane such as tetraethyl orthosilicate (TEOS) is used as a precursor of the porous silica, and a metal hydroxide such as LiOH is used as a base catalyst. In addition, the particles may contain a desired ionic liquid therein, and the particles having a diameter of 20-60 nm are each configured to have a pore diameter of 1-2 nm in order to maximize the supporting ability.

Description

Method for manufacturing hybrid solid electrolyte porous silica nano-support particles for batteries

[0001] The present invention relates to a method for producing spherical porous silica particles for use as an ionic liquid carrier within a solid electrolyte.

[0002] With the increasing demand for energy storage devices in electric vehicles and portable electronic devices, research on high-energy-density batteries is rapidly increasing. However, the use of liquid electrolytes within batteries poses several risks, including the risk of leakage, fire, and explosion due to high temperatures and impact.

[0003] To address these issues with liquid electrolytes, active research is being conducted on solid electrolytes. However, solid electrolytes also have several drawbacks, such as interfacial resistance and relatively low ionic conductivity compared to liquid electrolytes.

[0004] Recently, hybrid solid electrolytes have emerged to address the issues associated with these solid electrolytes. Hybrid solid electrolytes are a step forward from the traditional solid electrolytes, which were simply categorized into sulfide, oxide, and polymer electrolytes. These solid electrolytes are a mixture of various substances. Among these, the carrier-based hybrid solid electrolyte is a method of manufacturing a solid electrolyte by encapsulating an ionic liquid within a porous carrier.

[0005] Meanwhile, the porous silica used as the porous support in the present invention is widely used in catalysts, adsorbents, optical devices, drug delivery agents, and bio-fields depending on its various characteristics such as shape and size. By using the porous support, more ionic liquids can be supported inside the solid electrolyte. Ionic liquids are substances used as electrolytes due to their wide electrochemical window, high thermal stability, and conductivity. Since the solid electrolyte forms a wetting contact at the nanoscale, it can reduce the interfacial resistance, and higher ionic conductivity can be expected than other solid electrolytes due to the internal ionic liquid.

[0006] (Patent Document 1) 1. Republic of Korea Publication Patent No. 10-2012-0092428

[0007] (Non-patent Document 1) 1. Peng, S.; Luo, J.; Liu, W.; He, X.; Xie, F. Enhanced Capacity Retention of Li3V2(PO4)3-Cathode Based Lithium Metal Battery Using SiO2-Scaffold-Confined Ionic Liquid as Hybrid Solid-State Electrolyte. Molecules 2023, 28, 4896.

[0008] The purpose of the present invention is to manufacture an ionic liquid carrier for a hybrid solid electrolyte that combines the advantages of a liquid electrolyte and the advantages of a solid electrolyte and compensates for their disadvantages.

[0009] The present invention is characterized by spherical porous silica nanoparticles having a diameter of 20 to 60 nm and pores of 1 to 2 nm as an ionic liquid carrier of a hybrid solid electrolyte for a secondary battery.

[0010] The spherical porous silica nanoparticles of the present invention have a BET specific surface area of ​​300 to 1000 m 2 / s, and is characterized by an oil absorption rate of 1.0 to 2.5 ml / g and a water absorption rate of 1.5 to 3.5 ml / g.

[0011] In addition, the present invention is characterized by providing a hybrid solid electrolyte comprising the porous silica nanoparticles.

[0012] Due to the structure of the above porous silica particles, more ionic liquid can be contained within the solid electrolyte, and since the solid electrolyte forms wet contact at the nano level, the interfacial resistance can be reduced, and higher ionic conductivity than other solid electrolytes can be expected due to the internal ionic liquid.

[0013] Meanwhile, a method for manufacturing spherical porous silica nanoparticles as an ionic liquid carrier for a hybrid solid electrolyte for secondary batteries is provided.

[0014] A step of dissolving a surfactant and a basic catalyst in super-purified water (SPW) by heating it to 70℃;

[0015] A step of synthesizing porous silica by adding a silica precursor to the above mixed solution and stirring at 60 to 80°C for 2 to 4 hours;

[0016] A step of removing the surfactant from the above-mentioned synthesized mixture using nitric acid diluted to 0.3 to 0.5 M, and then washing using distilled water and ethanol;

[0017] It includes a step of drying at 60 to 90°C for 48 to 72 hours after the above washing step.

[0018] In the above manufacturing method, the basic catalyst is characterized by using a metal hydroxide such as lithium hydroxide (LiOH), sodium hydroxide (NaOH), or potassium hydroxide (KOH), and the surfactant is characterized by using cetrimonium bromide (CTAB) or cetyltrimethylammonium chloride (CTACl).

[0019] Meanwhile, the silica precursor is characterized as being tetramethyl orthosilicate (TMOS) or tetraethyl orthosilicate (TEOS).

[0020] In Non-patent Document 1, monovalent cations and surfactants were removed through a Reflux process using 1,4-dioxane, but this method is not only unsuitable for mass production, but also has the disadvantage of low yield. In contrast, the manufacturing method of the present invention removes surfactants through nitric acid washing, produces spherical porous silica, and uses it as a carrier for a solid electrolyte, thereby enabling an ionic liquid to be supported inside the carrier.

[0021] In addition, due to the structure of the silica particles of the present invention, more ionic liquid can be contained within the solid electrolyte, and since the solid electrolyte forms wet contact at the nano level, the interfacial resistance can be reduced, and higher ionic conductivity than other solid electrolytes can be expected due to the internal ionic liquid.

[0022] The present invention can manufacture a solid electrolyte using spherical porous silica as an ionic liquid carrier, and the ionic liquid has a wide electrochemical window, high thermal stability, and ionic conductivity, making it advantageous for various electrolyte applications.

[0023] Figure 1 is a flowchart showing the steps of the manufacturing process of the present invention.

[0024] Figure 2 is a TEM image of Example 1, taken at 50k and 100k magnifications.

[0025] Figure 3 is an SEM image of Example 1, taken at 50k and 100k magnifications.

[0026] To achieve the above purpose, the present invention provides spherical porous silica as an ionic liquid carrier of a solid electrolyte.

[0027]

[0028] 1. Raw material input stage: The stage of dissolving raw materials in a solvent.

[0029] This is the step of dissolving a surfactant and a basic catalyst by adding super purified water (SPW) to the reactor.

[0030] The amount of SPW input is approximately 330 times the theoretical yield. For the surfactant, cetrimonium bromide (CTAB) is used at 50-80% of the theoretical yield. Metal hydroxides are used as the basic catalyst, and lithium hydroxide (LiOH) is used at 3-10% of the theoretical yield. At this time, the size of the porous silica can be controlled by adjusting the input amount of the basic catalyst. After inputting the above two raw materials, the temperature is raised to 70℃, the synthesis temperature, and they are dissolved.

[0031]

[0032] 2. Porous silica synthesis step: Aging step after adding silica precursor.

[0033] This is a step of synthesizing porous silica by adding a silica precursor to a solution containing the above raw materials and stirring at 60 to 80°C for 2 to 3 hours. The silica precursor uses tetramethyl orthosilicate (TMOS) and tetraethyl orthosilicate (TEOS), and is used in an amount 3.5 times greater than the theoretical yield.

[0034]

[0035] 3. Surfactant removal and cleaning step

[0036] The above-mentioned synthesized mixture is filtered through diluted nitric acid to remove the surfactant, then washed with distilled water and ethanol. Nitric acid diluted to 0.3–0.5 M is used to remove the surfactant. After removing the surfactant, the remaining ions are washed with distilled water, and the internal distilled water is removed with ethanol. (The lower the conductivity of the cleaning solution, the better, and the pH is between 6 and 10.)

[0037]

[0038] 4. Drying stage

[0039] After the above washing step, it is dried in a dryer at 60 to 90°C for 48 to 72 hours, and the residual solvent inside the porous silica is removed through the drying process.

[0040] Hereinafter, the present invention will be described in more detail with examples.

[0041]

[0042]

[0043] Examples 1-4, Preparation of porous silica

[0044] According to the manufacturing method of the present invention, porous silica was synthesized using TEOS as a silica precursor and NaOH or LiOH as a basic catalyst. The particle size of the synthesized porous silica can be controlled by adjusting the amount of the basic catalyst added.

[0045] In measuring oil absorption, linseed oil is used, and the measuring method is as follows.

[0046] 1) Weigh 1,000g of sample on a scale and place it on a glass plate.

[0047] 2) Put linseed oil into the syringe and measure the mass.

[0048] 3) Add linseed oil one drop at a time to the sample using a syringe and knead using a spatula.

[0049] 4) Repeat 3) until the surface becomes smooth.

[0050] 5) Calculate the absorption amount based on the mass of linseed oil used.

[0051] The method for measuring water absorption is the same as for measuring oil absorption, but ultrapure water is used instead of linseed oil.

[0052] Comparative Example 1: Spherical silica without pores (Korean Patent Publication No. 10-2012-0092428)

[0053] In a 500 mL flask, 120 mL of water, 250 mL of ethyl alcohol, and 8 mL of ammonia water were added, and the transparent mixture was heated while stirring to 45°C. 22 g of tetraethyl silicate (TEOS) was measured into another 100 mL beaker. High-purity TEOS was added all at once to the above solution (transparent mixture), and a polycondensation reaction of the hydrolyzate was performed for 4 hours. The temperature of the silica mixture solution was maintained at 45°C during the reaction. The silica microparticles thus obtained were pre-dried at 60°C for 1 hour and then dried at 100°C for 24 hours. The dried silica microparticles were calcined at 1000°C for 6 hours to have a crystalline phase.

[0054] Comparative Example 1 vs. Example 1; Comparison of the presence or absence of pores in similar-sized particles

[0055] : In order to determine the BET and the amount of support according to the presence or absence of porosity, the following silica synthesis method was cited and compared with Example 1.

[0056] Example 1 vs. Example 2; Comparison according to porous silica particle size

[0057] : Porous silica of different sizes was synthesized by controlling the content of the basic catalyst LiOH. In Example 1, 5% of the theoretical yield was added, and in Example 2, 10% of the theoretical yield was added.

[0058] Example 1 vs. Example 3; Comparison according to the type of porous silica base catalyst

[0059] : In Example 1, LiOH was used as a base catalyst, and in Example 3, NaOH was used to synthesize porous silica. In the case of NaOH, 1.91 times the mass of LiOH was used. The ratio of LiOH and NaOH was the same amount of 0.35 MH - After titration for 2SO4, the corresponding ratio was used.

Claims

1. Spherical porous silica nanoparticles having a diameter of 20 to 60 nm and pores of 1 to 2 nm as an ionic liquid carrier for a hybrid solid electrolyte for secondary batteries.

2. In paragraph 1, the BET specific surface area is 300 to 1000 m 2 / s spherical porous silica nanoparticles.

3. In the first paragraph, spherical porous silica nanoparticles having an oil absorption rate of 1.0 to 2.5 ml / g and a water absorption rate of 1.5 to 3.5 ml / g.

4. A hybrid solid electrolyte comprising the porous silica nanoparticles of any one of claims 1 to 3.

5. Step of dissolving a surfactant and a basic catalyst in super-purified water (SPW) by heating it to 70℃; A step of synthesizing porous silica by adding a silica precursor to the above mixed solution and stirring at 60 to 80°C for 2 to 4 hours; A step of removing the surfactant from the above-mentioned synthesized mixture using nitric acid diluted to 0.3 to 0.5 M, and then washing using distilled water and ethanol; A method for producing spherical porous silica nanoparticles as an ionic liquid carrier for a hybrid solid electrolyte for a secondary battery, comprising: a step of drying at 60 to 90°C for 48 to 72 hours after the above-mentioned washing step.

6. A manufacturing method characterized in that in paragraph 5, the basic catalyst is a metal hydroxide such as lithium hydroxide (LiOH), sodium hydroxide (NaOH), or potassium hydroxide (KOH).

7. A manufacturing method according to claim 5, characterized in that the surfactant is cetrimonium bromide (CTAB) or cetyltrimethylammonium chloride (CTACl).

8. A manufacturing method according to claim 5, characterized in that the silica precursor is tetramethyl orthosilicate (TMOS) or tetraethyl orthosilicate (TEOS).

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