A method for preparing electrode materials for low-temperature zinc-ion batteries and its application.

Abstract

This invention relates to the field of new energy zinc-vanadium battery materials technology, and in particular to a method for preparing electrode materials for low-temperature zinc-ion batteries and its application. Cobalt acetylacetone, water, and furfural are mixed and then subjected to heat treatment and centrifugation sequentially to obtain a precipitate. The precipitate is mixed with potassium hydroxide solution and calcined for the first time to obtain a calcined material. The calcined material is mixed with ammonium metavanadate and water, and then subjected to hydrothermal treatment and drying sequentially to obtain a dried material. The dried material is calcined a second time to obtain the electrode material. This invention uses a coupling strategy to prepare a V₂O₅ / nanoflower-like porous carbon-based zinc-ion cathode material, which exhibits good cycle stability in zinc-ion batteries. This is because the carbon material surface has more channels, promoting rapid diffusion of zinc ions to improve electrical and ionic conductivity, and enabling low-temperature applications.

Description

Technical Field

[0001] This invention relates to the field of new energy zinc-vanadium battery materials technology, and in particular to a method for preparing electrode materials for low-temperature zinc-ion batteries and their application. Background Technology

[0002] Among various energy storage devices, lithium-ion batteries (LIBs) have significant application value in portable electronic devices and electric vehicles due to their high energy density and long cycle life. However, the flammable organic electrolyte, scarce lithium resources, and high cost severely hinder the application of lithium-ion batteries as large-scale energy storage systems. To achieve the goals of high safety and low cost in rechargeable batteries, more research has focused on aqueous batteries, including aqueous lithium-ion batteries, aqueous sodium-ion batteries, vanadium redox flow batteries, and Zn-Br2 batteries. As a material for aqueous batteries, zinc has a high energy density of up to 820 mAh g / L. -1 Its theoretical specific capacity and low equilibrium redox potential (-0.76V) make it a promising candidate for use in aqueous zinc-ion batteries (ZIBs). Furthermore, zinc is inexpensive, abundant, and environmentally friendly.

[0003] As with other batteries, the electrode materials and their properties are crucial for improving the performance of zinc-ion batteries. Currently, research focuses on enhancing the efficient and rapid insertion / extraction of divalent zinc ions within the cathode material framework to achieve higher electrochemical performance. To date, various compounds have been used as cathodes for ZIBs, including manganese-based oxides, vanadium-based oxides, Prussian blue analogs, and organic conductive polymers. Among these, those with multiple oxidation states (V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10 ...2, V2, V2, V2, V2, V2, V2, V2, V2, V2, V2, V2, V2, V2, V 2+ V 3+ V 4+ V 5+ Vanadium-based oxides with an open-framework crystal structure possess high theoretical capacity and good cycling stability. Due to the high specific capacity (589 mAh g⁻¹) of the V₂O₅ cathode... -1 Therefore, V2O5 cathodes have been widely studied for the fabrication of aqueous zinc-ion batteries. Although V2O5 is an excellent electrode material, using V2O5 alone as a cathode presents problems such as poor conductivity and ionic conductivity, slow electrolyte transport rate, and poor stability. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a method for preparing electrode materials for low-temperature zinc-ion batteries and its application. This invention employs a coupling strategy to prepare V2O5 / nanoflower-like porous carbon-based zinc-ion cathode materials, which exhibit good cycle stability in zinc-ion batteries. This is because the presence of more channels on the surface of the carbon material promotes the rapid diffusion of zinc ions, thereby improving the conductivity of the electrode and enabling its application at low temperatures.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing electrode materials for low-temperature zinc-ion batteries, comprising the following steps:

[0007] 1) After mixing cobalt acetylacetone, water and furfural, the mixture was subjected to heat treatment and centrifugation in sequence to obtain a precipitate;

[0008] 2) The precipitate obtained in step 1) is mixed with potassium hydroxide and water and then calcined for the first time to obtain the calcined material;

[0009] The first calcination temperature is 650–850°C;

[0010] 3) The calcined material obtained in step 2) is mixed with ammonium metavanadate and water, and then subjected to hydrothermal treatment and drying in sequence to obtain dried material;

[0011] The hydrothermal treatment is performed at a temperature of 160–200°C for 12 hours.

[0012] 4) The dried material obtained in step 3) is calcined a second time to obtain the electrode material;

[0013] The second calcination was carried out at a temperature of 400°C for 30 minutes.

[0014] Preferably, the temperature of the hydrothermal treatment in step 3) is 180°C.

[0015] Preferably, in step 1), the mass ratio of cobalt acetylacetone, furfural, and water is 0.8:0.3:40.

[0016] Preferably, the conditions for the heat treatment in step 1) include: a temperature of 180°C and a time of 16 hours.

[0017] Preferably, the mass ratio of the precipitate to potassium hydroxide and water in step 2) is 4:1:10.

[0018] Preferably, the conditions for the first calcination in step 2) further include calcination for 1 hour in a nitrogen atmosphere.

[0019] Preferably, the mass ratio of the calcined material to ammonium metavanadate and water in step 3) is 1:2:40;

[0020] The drying conditions include a temperature of 60°C and a time of 12 hours.

[0021] The present invention also provides an electrode material for low-temperature zinc-ion batteries prepared by the preparation method described above.

[0022] The present invention also provides the application of the electrode material described in the above technical solution in the preparation of low-temperature zinc-ion batteries.

[0023] The present invention also provides a low-temperature zinc-ion battery, comprising a zinc foil anode and a cathode;

[0024] The cathode is prepared from the electrode material described in the above technical solution, acetylene black, polyvinylidene fluoride and N-methylpyrrolidone;

[0025] The mass ratio of the electrode material, acetylene black, polyvinylidene fluoride, and N-methylpyrrolidone is 70 mg: 20 mg: 10 mg: 150 μL.

[0026] The beneficial effects of this invention are:

[0027] This invention optimizes the surface pore structure of carbon particles using a one-step KOH activation method and then hydrothermally coats the surface of nanoflower-like carbon with vanadium pentoxide to obtain a V₂O₅ / nanoflower-like porous carbon composite material. Data comparison shows that this composite material exhibits interfacial coupling and efficient transport properties, effectively increasing interlayer spacing and achieving hydrated Zn. 2+ Rapid and reversible insertion / extraction improves cycle stability and enhances electrochemical performance, thereby expanding its application range. At a current density of 50 mA g... -1 At that time, the reversible specific capacity of the V2O5-180 cathode material was 244.4 mAh g. -1 Energy density is 171 Wh / kg -1 After 7000 cycles, V₂O₅-180 retained 92% of its original specific capacity and nearly 98% coulombic efficiency. Furthermore, the assembled zinc-vanadium battery exhibited excellent low-temperature performance and operability, with a specific capacity of 171 mAh g⁻¹ at -20°C. -1 It exhibits a specific capacity retention of 70% and good electrochemical reversibility. This coupling method promotes the diffusion or transport of multivalent ions, offering hope for the fabrication of next-generation water-rechargeable zinc ion energy storage devices.

[0028] 1. A V2O5 / nanoflower-like porous carbon-based zinc ion cathode material was prepared using a coupling strategy.

[0029] 2. It possesses excellent energy storage performance, including a current density of 50 mA g. -1 High capacity (244.35mAh g) -1 ) and high energy density (171Wh kg) -1 ).

[0030] 3. Satisfactory cycling stability, with a cycle life of up to 7,000 cycles and a capacity retention of 92%.

[0031] 4. High current density and low temperature applications (specific capacity of 171 mAh g) -1 (The specific capacity retention rate is 70% at -20℃). Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0033] Figure 1 SEM images of nanoflower-like carbon particles at different activation temperatures;

[0034] Figure 2 Wide-angle XRD patterns of samples at different hydrothermal temperatures;

[0035] Figure 3 The current density is 0.05Ag -1 GCD curves of different samples at different times;

[0036] Figure 4 V2O5-180 at 1.0Ag -1 Stability and coulomb efficiency under 7000 cycles;

[0037] Figure 5 The rate performance of V2O5-180 at different temperatures and current densities is shown. Detailed Implementation

[0038] This invention provides a method for preparing electrode materials for low-temperature zinc-ion batteries, comprising the following steps:

[0039] 1) After mixing cobalt acetylacetone, water and furfural, the mixture was subjected to heat treatment and centrifugation in sequence to obtain a precipitate;

[0040] 2) The precipitate obtained in step 1) is mixed with potassium hydroxide and water and then calcined for the first time to obtain the calcined material;

[0041] The first calcination temperature is 650–850°C;

[0042] 3) The calcined material obtained in step 2) is mixed with ammonium metavanadate and water, and then subjected to hydrothermal treatment and drying in sequence to obtain dried material;

[0043] The hydrothermal treatment is performed at a temperature of 160–200°C for 12 hours.

[0044] 4) The dried material obtained in step 3) is calcined a second time to obtain the electrode material;

[0045] The temperature of the second calcination is 400℃.

[0046] In this invention, cobalt acetylacetone, water, and furfural are mixed and then subjected to heat treatment and centrifugation sequentially to obtain a precipitate. In this invention, the preferred mass ratio of cobalt acetylacetone, furfural, and water is 0.8:0.3:40. In this invention, the preferred heat treatment conditions include a temperature of 180°C and a time of 16 hours.

[0047] In this invention, the obtained precipitate is mixed with a potassium hydroxide solution and then subjected to a first calcination to obtain a calcined material; the temperature of the first calcination is 650–850°C. In this invention, the precipitate is mixed with potassium hydroxide and water at a mass ratio of 4:1:10. In this invention, the conditions for the first calcination preferably include calcination under a nitrogen atmosphere for 1 hour.

[0048] In this invention, the obtained calcined material is mixed with ammonium metavanadate and water, and then subjected to hydrothermal treatment and drying sequentially to obtain a dried material. The hydrothermal treatment temperature is 160–200°C, and the time is 12 hours. Preferably, the hydrothermal treatment temperature is 180°C. The mass ratio of the calcined material to ammonium metavanadate and water is 1:2:40. The drying conditions preferably include a temperature of 60°C and a time of 12 hours.

[0049] The present invention involves subjecting the obtained dried material to a second calcination to obtain electrode material; the second calcination temperature is 400℃ and the time is 30min.

[0050] In this invention, furfural, cobalt acetylacetonate, potassium hydroxide, ammonium metavanadate, and zinc perchlorate were purchased from Aladdin (Shanghai, China). All chemicals were used as is without further purification.

[0051] The present invention also provides an electrode material for low-temperature zinc-ion batteries prepared by the preparation method described above.

[0052] The present invention also provides the application of the electrode material described in the above technical solution in the preparation of low-temperature zinc-ion batteries.

[0053] The present invention also provides a low-temperature zinc-ion battery, comprising a zinc foil anode and a cathode; the cathode is prepared from the electrode material described in the above technical solution, acetylene black, polyvinylidene fluoride and N-methylpyrrolidone; the mass ratio of the electrode material, the mass of acetylene black, the mass of polyvinylidene fluoride and the volume ratio of N-methylpyrrolidone is 70mg:20mg:10mg:150μL.

[0054] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0055] Example 1

[0056] Dissolve 0.8 g of cobalt acetylacetonate in 40 ml of water and stir at 80 °C for at least 5 minutes. Add 0.3 g of furfural to the dissolved cobalt acetylacetonate solution and stir continuously until fully mixed. Perform hydrothermal treatment at 180 °C for 16 h and centrifuge at 4000 r / min to obtain the solid sample.

[0057] The sample was mixed with potassium hydroxide and water at a mass ratio of 4:1:10. The mixture was then calcined at 650°C under a nitrogen atmosphere for 1 hour to obtain an activated sample.

[0058] Example 2

[0059] Dissolve 0.8 g of cobalt acetylacetonate in 40 ml of water and stir at 80 °C for at least 5 minutes. Add 0.3 g of furfural to the dissolved cobalt acetylacetonate solution and stir continuously until fully mixed. Perform hydrothermal treatment at 180 °C for 16 h and centrifuge at 4000 r / min to obtain the solid sample.

[0060] The sample was mixed with potassium hydroxide and water at a mass ratio of 4:1:10. The mixture was then calcined at 750°C under a nitrogen atmosphere for 1 hour to obtain an activated sample.

[0061] Example 3

[0062] Dissolve 0.8 g of cobalt acetylacetonate in 40 ml of water and stir at 80 °C for at least 5 minutes. Add 0.3 g of furfural to the dissolved cobalt acetylacetonate solution and stir continuously until fully mixed. Perform hydrothermal treatment at 180 °C for 16 h and centrifuge at 4000 r / min to obtain the solid sample.

[0063] The sample was mixed with potassium hydroxide and water at a mass ratio of 4:1:10. The mixture was then calcined at 850°C under a nitrogen atmosphere for 1 hour to obtain an activated sample.

[0064] Example 4

[0065] Dissolve 0.8 g of cobalt acetylacetonate in 40 ml of water and stir at 80 °C for at least 5 minutes. Add 0.3 g of furfural to the dissolved cobalt acetylacetonate solution and stir continuously until fully mixed. Perform hydrothermal treatment at 180 °C for 16 h and centrifuge at 4000 r / min to obtain the solid sample.

[0066] The sample was mixed with potassium hydroxide and water at a mass ratio of 4:1:10. The mixture was then calcined at 750°C under a nitrogen atmosphere for 1 hour to obtain an activated sample.

[0067] Then, 0.0025 mol ammonium metavanadate and 0.14625 g of activated sample were added to 40 ml of water, heated and stirred for 30 min, and then the hydrothermal temperature was set at 160 ℃ for 12 h. The mixture was then placed in a vacuum drying oven and heated at 60 ℃ for 12 h. Finally, it was calcined at 400 ℃ for 30 min in air atmosphere to obtain a V2O5-coated nano-flower-like porous carbon composite material, denoted as V2O5-160.

[0068] Example 5

[0069] Dissolve 0.8 g of cobalt acetylacetonate in 40 ml of water and stir at 80 °C for at least 5 minutes. Add 0.3 g of furfural to the dissolved cobalt acetylacetonate solution and stir continuously until fully mixed. Perform hydrothermal treatment at 180 °C for 16 h and centrifuge at 4000 r / min to obtain the solid sample.

[0070] The sample was mixed with potassium hydroxide and water at a mass ratio of 4:1:10. The mixture was then calcined at 750°C under a nitrogen atmosphere for 1 hour to obtain an activated sample.

[0071] Then, 0.0025 mol ammonium metavanadate and 0.14625 g of activated sample were added to 40 ml of water, heated and stirred for 30 min, and then the hydrothermal temperature was set at 180℃ for 12 h. The mixture was then placed in a vacuum drying oven and heated at 60℃ for 12 h. Finally, it was calcined at 400℃ for 30 min in air atmosphere to obtain a V2O5-coated nano-flower-like porous carbon composite material, denoted as V2O5-180.

[0072] Example 6

[0073] Dissolve 0.8 g of cobalt acetylacetonate in 40 ml of water and stir at 80 °C for at least 5 minutes. Add 0.3 g of furfural to the dissolved cobalt acetylacetonate solution and stir continuously until fully mixed. Perform hydrothermal treatment at 180 °C for 16 h and centrifuge at 4000 r / min to obtain the solid sample.

[0074] The sample was mixed with potassium hydroxide and water at a mass ratio of 4:1:10. The mixture was then calcined at 750°C under a nitrogen atmosphere for 1 hour to obtain an activated sample.

[0075] Then, 0.0025 mol ammonium metavanadate and 0.14625 g of activated sample were added to 40 ml of water, heated and stirred for 30 min, and then the hydrothermal temperature was set at 200℃ for 12 h. The mixture was then placed in a vacuum drying oven and heated at 60℃ for 12 h. Finally, it was calcined at 400℃ for 30 min in air atmosphere to obtain a V2O5-coated nano-flower-like porous carbon composite material, designated as V2O5-200.

[0076] Comparative Example 1

[0077] The sample that was not activated by the activator in Example 2 was named V2O5-NO, and the amorphous carbon sample that was not activated by the activator in Example 2 was named V2O5-C.

[0078] Material characterization testing:

[0079] The morphology of the samples was measured using a field emission scanning electron microscope (SEM, Thermo Scientific, USA) at a working voltage of 100 kV. The crystal phase of the prepared materials was analyzed using a wide-angle X-ray diffractometer (XRD, PANalytical BV, Netherlands) with a Ni-filtered Cu-Ka radiation source on an X'Pert PRO MPD X-ray diffractometer.

[0080] Electrochemical characterization tests:

[0081] The mass of V2O5-x, acetylene black, polyvinylidene fluoride (PVDF), and N-methylpyrrolidone (NMP) were mixed uniformly at a ratio of 70 mg:20 mg:10 mg:150 μL. The slurry was then scraped onto a stainless steel sheet to a thickness of 300 μm using a preparation device. The sheet was dried in a vacuum oven at 80 °C for 12 h, and then cut into circular electrode plates with a diameter of 14 mm using a slicer.

[0082] Electrochemical performance was tested using CR2032 coin cells. The CR2032 coin cell consists of a zinc foil anode (100 μm, polished with fine-grained sandpaper) and a V2O5-x cathode, with a 3M Zn(ClO4)2 electrolyte. Galvanostatic charge-discharge (GCD) tests were performed on a CHI660E electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd., China). The GCD test current density ranged from 0.05 to 1 Ag. -1 The potential window is 0.2–1.6V (vs. Zn). 2+ Cyclic stability tests were performed on the Land CT2001A battery testing system (Wuhan, China).

[0083] Performance testing:

[0084] First, a one-step hydrothermal method was used to synthesize nano-flower-like spherical carbon particles, such as... Figure 1 As shown, the carbon particles are uniform in size (approximately 5 μm in diameter) and have a petal-like surface. To further improve the pore structure of the carbon material, the pore structure was adjusted by calcining KOH at different activation temperatures. Figure 1 Images a, b, and c show SEM images of nanoflower-like carbon particles at different activation temperatures of 650℃, 750℃, and 850℃. It can be observed that... Figure 1 In the middle d, the nanoflower-like structure on the surface of the carbon particles is assembled from sheet-like structural units with a thickness of about 150 nm, and the surface is slightly etched by KOH.

[0085] Figure 2 The XRD patterns of the samples at different hydrothermal temperatures are shown. The characteristic peak diffraction angles of the materials prepared at different hydrothermal temperatures are 21.70°, 26.3°, and 45.4°, respectively, corresponding to the (110), (101), and (411) crystal planes of cubic V₂O₅ (PDF#41-1426). The results show that orthorhombic vanadium pentoxide was successfully synthesized. According to the Bragg equation, the d-intervals of the (110) and (101) peaks are approximately 4.2 Å and 3.4 Å, respectively. The d-interval of the (101) peak is due to the diffraction of amorphous carbon (002)V₂O₅-C. At high temperatures, the interlayer spacing increases when nano-flower-like porous carbon is combined with V₂O₅. With the increase of hydrothermal temperature, the diffraction peaks of V₂O₅-200 gradually broaden, indicating that its crystallinity is relatively poor.

[0086] Depend on Figure 3 It can be seen that the GCD curves of different samples at different hydrothermal temperatures are almost symmetrical, indicating that the electrode material has good electrochemical reversibility. The specific capacities of samples V2O5-C, V2O5-NO, V2O5-160, and V2O5-200 are 54.5, 95, 152.4, and 122.3 mAh g, respectively. -1 The V2O5-180 sample exhibited a significantly longer charge-discharge time, indicating that it had the highest specific capacity, with a discharge capacity as high as 244.4 mAh g⁻¹. -1 .

[0087] like Figure 4 As shown, at 1.0A g -1 The stability and coulombic efficiency of V2O5-180 were tested for 7000 cycles at different current densities. After 7000 cycles, V2O5-180 still maintained 92% of its original specific capacity and the coulombic efficiency was close to 98%, indicating that V2O5-180 has good electrochemical variability and excellent cycling stability as an electrode material.

[0088] like Figure 5 As shown, the prepared V2O5-180 has a specific capacity of 171 mAh g at -20℃. -1 The specific capacity retention rate is 70%, indicating that the interlayer spacing of the V2O5-180 composite material can be adjusted by Zn. 2+ Storage capacity, while larger pore sizes and interlayer spacing increase ion diffusion and Zn 2+ Storage dynamics.

[0089] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing an electrode material for a low-temperature zinc-ion battery, characterized in that, Includes the following steps: 1) After mixing cobalt acetylacetone, water and furfural, the mixture was subjected to heat treatment and centrifugation in sequence to obtain a precipitate; 2) The precipitate obtained in step 1) is mixed with potassium hydroxide and water and then calcined for the first time to obtain the calcined material; The temperature of the first calcination is 650~850℃; 3) After mixing the calcined material obtained in step 2) with ammonium metavanadate and water, the mixture is subjected to hydrothermal treatment and drying in sequence to obtain the dried material; The hydrothermal treatment is performed at a temperature of 160~200℃ for 12 hours. 4) The dried material obtained in step 3) is calcined a second time to obtain the electrode material; The second calcination was carried out at a temperature of 400°C for 30 minutes. Step 1) The mass ratio of cobalt acetylacetone, furfural, and water is 0.8:0.3:40; Step 1) The heat treatment conditions include: temperature of 180℃ and time of 16h; Step 2) The mass ratio of the precipitate to potassium hydroxide and water is 4:1:10; Step 3) The mass ratio of the calcined material to ammonium metavanadate and water is 1:2:40; The drying conditions include a temperature of 60°C and a time of 12 hours.

2. The preparation method according to claim 1, characterized in that, Step 3) The temperature for hydrothermal treatment is 180℃.

3. The preparation method according to claim 1, characterized in that, Step 2) The conditions for the first calcination also include: calcining for 1 hour in a nitrogen atmosphere.

4. An electrode material for a low-temperature zinc-ion battery prepared by the preparation method according to any one of claims 1 to 3.

5. The application of the electrode material according to claim 4 in the preparation of low-temperature zinc-ion batteries.

6. A low-temperature zinc-ion battery, characterized in that... Includes zinc foil anode and cathode; The cathode is prepared from the electrode material described in claim 4, acetylene black, polyvinylidene fluoride and N-methylpyrrolidone; The mass ratio of the electrode material, acetylene black, polyvinylidene fluoride, and N-methylpyrrolidone is 70 mg: 20 mg: 10 mg: 150 µL.

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