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KR-102962381-B1 - MANUFACTURING METHOD OF COMPOSITE CATHODE MATERIAL FOR SODIUM IONS SECONDARY BATTERIES AND COMPOSITE CATHODE MATERIAL THEREBY

KR102962381B1KR 102962381 B1KR102962381 B1KR 102962381B1KR-102962381-B1

Abstract

The present invention relates to a method for manufacturing a composite negative electrode material for a sodium ion secondary battery and a composite negative electrode material manufactured thereby. A method for manufacturing a composite negative electrode material for a sodium-ion secondary battery according to one embodiment of the technical concept of the present invention comprises: a graphene oxide powder dispersion step (S100) of preparing graphene oxide powder by calcining and grinding graphene oxide and then washing, and dispersing the graphene oxide powder in distilled water by ultrasonically treating the graphene oxide powder; a graphene oxide powder stirring step (S200) of adding ascorbic acid powder to the graphene oxide powder dispersed in distilled water and stirring; a graphene oxide powder reduction step (S300) of reducing the stirred graphene oxide powder by heat treating the stirred graphene oxide powder; and a reduced graphene oxide powder manufacturing step (S400) of preparing reduced graphene oxide powder by washing the heat-treated reduced graphene oxide powder and then freeze-drying it. The method comprises: a black phosphorus powder manufacturing step (S500) in which red phosphorus is prepared and then the prepared red phosphorus is crushed under an air atmosphere to synthesize black phosphorus powder; an oxidized black phosphorus powder manufacturing step (S600) in which the synthesized black phosphorus powder is oxidized under an air atmosphere to produce oxidized black phosphorus powder; an oxidized black phosphorus and reduced graphene oxide powder mixing step (S700) in which the oxidized black phosphorus powder and reduced graphene oxide powder are mixed to produce a mixed powder; and an oxidized black phosphorus and reduced graphene oxide composite manufacturing step (S800) in which the mixed powder consisting of the oxidized black phosphorus powder and the reduced graphene oxide powder is crushed under an air atmosphere to produce an oxidized black phosphorus and reduced graphene oxide composite. According to the above configuration, the method for manufacturing a composite negative electrode material for a sodium-ion secondary battery according to various embodiments of the technical concept of the present invention can manufacture a composite negative electrode material that has high electrical conductivity, excellent mechanical strength, stability in the atmosphere, and volume expansion suppression characteristics during charging and discharging by manufacturing a black phosphorus (BP) and graphene composite and then using it as a negative electrode material for a sodium-ion secondary battery.

Inventors

  • 김현경
  • 유성보
  • 정상원
  • 장은서

Assignees

  • 강원대학교산학협력단

Dates

Publication Date
20260508
Application Date
20240220
Priority Date
20230220

Claims (12)

  1. Graphene oxide is introduced into a calcination furnace and calcined by heating at a temperature of 1,600 to 1,800°C for 30 to 90 minutes , then ground using a grinder, and then graphene oxide powder is prepared by washing with a washing solution consisting of 5 to 15 wt% ethanol, 1 to 3 wt% sodium benzoate, 1 to 3 wt% sodium persulfate (Na₂S₂O₅ ) , 2 to 6 wt% peracetic acid, 3 to 7 wt% ceric ammonium nitrate (Ce( NH₄ ) ₂ ( NO₃ ) ₆ ), 1 to 5 wt% oxalic acid, 1 to 5 wt% oxalic acid, and 100 wt% deionized water satisfying these requirements; and 20 to 30 parts by weight of the graphene oxide powder is mixed with 450 to 500 ml of distilled water, and then for 30 to 70 minutes A graphene oxide powder dispersion step (S100) in which the powder is dispersed by treating it with ultrasound of 40 to 50 kHz intensity during the process; A graphene oxide powder stirring step (S200) in which ascorbic acid powder is added to the graphene oxide powder dispersed in the above distilled water at a ratio of 450 to 550 mg and stirred for 40 to 80 minutes; A graphene oxide powder reduction step (S300) in which the stirred graphene oxide powder is heat-treated at a temperature of 65 to 75°C for 20 to 30 hours to reduce the stirred graphene oxide powder; A step for manufacturing reduced graphene oxide powder (S400), wherein the heat-treated reduced graphene oxide powder is washed with pure water (DI Water) to remove impurities, and then freeze-dried at a temperature of -50 to -60℃ for 1 to 5 hours to produce reduced graphene oxide powder; A black phosphorus powder manufacturing step (S500) in which red phosphorus is prepared, and then the prepared red phosphorus is crushed under an air atmosphere to synthesize black phosphorus powder; A step for manufacturing oxidized black phosphorus powder (S600), wherein the synthesized black phosphorus powder is immersed in an immersion solution for 1 to 10 minutes, separated, and the separated black phosphorus powder is oxidized by performing a gas-phase oxidation reaction under an air atmosphere for 20 to 60 minutes to produce oxidized black phosphorus powder; A step of mixing black phosphorus oxide and reduced graphene oxide powder (S700) for preparing a mixed powder by mixing the black phosphorus oxide powder in a weight ratio of 30 to 70 weight% and the reduced graphene oxide powder in a weight ratio of 30 to 70 weight%; and The method includes a step (S800) for manufacturing a black phosphorus oxide and reduced graphene oxide composite by grinding a mixed powder composed of the black phosphorus oxide powder and the reduced graphene oxide powder under an air atmosphere to produce a black phosphorus oxide and reduced graphene oxide composite. A method for manufacturing a composite negative electrode material for a sodium ion secondary battery, characterized in that, in the step of manufacturing black phosphorus oxide powder (S600) above, the immersion solution comprises 100 to 200 g/l of benzotriazole, 300 to 400 ml/l of formic acid, 100 to 200 ml/l of citric acid, 50 to 150 g/l of a glycol derivative, and 30 to 70 ml/l of a thio compound per 1 L (liter) of purified water.
  2. In Article 1, The above black phosphorus powder manufacturing step (S500) is, A method for manufacturing a composite negative electrode material for a sodium ion secondary battery, characterized by synthesizing black phosphorus powder by grinding the above-mentioned prepared red phosphorus under an air atmosphere with a ball-to-powder mass ratio of 40:1.
  3. A composite negative electrode material for a sodium ion secondary battery characterized by being manufactured by any one of the methods selected from claims 1 to 2.
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Description

Manufacturing Method of Composite Cathode Material for Sodium Ion Secondary Batteries and Composite Cathode Material Manufactured Thereby The present invention relates to a method for manufacturing a composite negative electrode material for a sodium ion secondary battery and a composite negative electrode material manufactured thereby. More specifically, the invention relates to a method for manufacturing a composite negative electrode material for a sodium ion secondary battery and a composite negative electrode material manufactured thereby, wherein a black phosphorus and graphene composite is manufactured and then used as a negative electrode material for a sodium ion secondary battery, thereby ensuring high electrical conductivity, excellent mechanical strength, stability in the atmosphere, and volume expansion suppression characteristics during charging and discharging. Lithium-ion batteries are used in most IT devices, such as smartphones and tablet PCs, due to their superior long lifespan and energy density. Furthermore, the demand for lithium-ion batteries has recently been rapidly expanding into medium-to-large markets, including electric vehicles (EVs) and energy storage systems (ESS). However, concerns are rising regarding battery prices due to limited lithium reserves and the increasing demand for high-capacity batteries, making the development of next-generation energy sources essential to address this issue. Among next-generation energy sources, sodium ion batteries have battery components similar to lithium ion batteries and are devices that store energy by inserting and extracting sodium ions (Na + ) into and out of the electrodes instead of lithium ions (Li + ). Sodium ion batteries are currently receiving a lot of attention due to the advantage of being inexpensive because of abundant raw materials. However, sodium-ion batteries have the disadvantage of having a lower energy density compared to lithium-ion batteries due to their heavy atomic weight (23.0 g/mol) and standard reduction potential characteristics that are 0.3 V higher than that of lithium (~7.0 g/mol). In addition, carbon-based materials commercialized for lithium-ion batteries have limitations in capacity, lifespan, and output characteristics when applied to sodium-ion batteries because the difference in ionic radii between sodium ions (1.02 Å) and lithium ions (0.76 Å) prevents reversible insertion/extraction of ions into and out of the electrode. Therefore, from the perspective of anode materials, the development of materials with high capacity, high stability, and long lifespan characteristics is essential. Meanwhile, black phosphorus (BP), an isotope of phosphorus (P) with a two-dimensional structure, has an interlayer channel size of 3.08 Å, an electrode potential of 0.3 V vs Na/Na + , and a high theoretical specific capacity of 2596 mAh/g, making it a subject of interest as a negative electrode material for sodium-ion batteries. However, in order to use BP as a cathode material, problems caused by low electrical conductivity (~ 10⁻¹² S/m), instability in the atmosphere, and large volume expansion (490%) during charging and discharging must be resolved, and various studies are underway regarding this. First, research is underway to mitigate problems caused by expansion by preventing the separation of the electrode from the current collector due to volume expansion through binder design. Methods utilizing cross-linking with binders such as cNaCMC and PAA have been reported; however, these require a large amount of binder inside the electrode, which leads to a decrease in electrical conductivity. Secondly, there is research on methods for compounding with other materials. Currently, methods have been reported to improve electrical conductivity and mitigate problems caused by expansion by using carbon-based materials (Graphite, CNT) and metals (Sn, Ti) as composite materials. However, current BP composite materials have limitations in lifespan and output characteristics, making commercialization difficult, and additional research on composite materials is required. FIG. 1 is a flowchart schematically illustrating a method for manufacturing a composite negative electrode material for a sodium ion secondary battery according to one embodiment of the technical concept of the present invention. Figure 2 is a graph showing the results of X-ray diffraction analysis of a black phosphorus oxide and reduced graphene oxide composite (BP/RGO) according to an example. Figure 3 is a transmission electron microscope (TEM) image of a black phosphorus oxide and reduced graphene oxide composite (BP/RGO) according to an example. Figure 4 is a graph showing the analysis of black phosphorus oxide and reduced graphene oxide composites (BP/RGO) according to the example using X-ray photoelectron spectroscopy (XPS). Figure 5 is a graph showing the analysis of black phosphorus oxide and reduced graphene oxide composites (BP/RGO) according to the e