Method for the preparation of nickel sulfide / cobalt sulfide based on sulfur-rich vacancies for nickel-zinc batteries

Abstract

The application discloses a preparation method of nickel sulfide / cobalt sulfide for a nickel-zinc battery based on sulfur vacancy enrichment, and is specifically implemented according to the following steps: step 1, preparing Ni-doped Co5(O 9.48 H 8.52 )NO3 nanosheet material; step 2, preparing Ni3S2 / Co3S4 nanosheet heterojunction material; and step 3, preparing Ni3S2 / Co3S4 nanosheet heterojunction material with sulfur vacancy enrichment. The positive electrode material is green and environment-friendly, has high specific surface area and high electrical conductivity, and has high power density and area specific capacity compared with other positive electrode materials of an alkaline Ni-Zn battery.

Description

Technical Field

[0001] This invention belongs to the field of alkaline Ni-Zn battery cathode material synthesis technology, specifically relating to a method for preparing nickel sulfide / cobalt sulfide based on sulfur-rich vacancies for nickel-zinc batteries. Background Technology

[0002] With the overexploitation and rapid consumption of fossil fuels, energy issues and environmental degradation have become major concerns. Developing clean, inexpensive, and environmentally friendly energy storage components to alleviate the current energy crisis is of great significance for national economic development and sustainable development. Currently, ammonium-ion hybrid capacitors are considered one of the effective approaches as emerging energy storage components. Research shows that: ① Compared to lithium-ion batteries, alkaline Ni-Zn battery materials have higher power density and can achieve rapid charging and discharging; ② Alkaline Ni-Zn battery materials are green, pollution-free, and environmentally friendly, making them valuable for applications in the power energy sector.

[0003] Methods for preparing Ni3S2 and Co3S4 nanomaterials as cathode materials for supercapacitors have been reported in the literature, but reports on the preparation of sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction materials for use in alkaline Ni-Zn battery systems are scarce. A hydrothermal method is used to construct Ni3S2 nanoparticles on Co3S4 nanosheets, forming a heterojunction at the interface layer. This significantly improves the structural stability and specific capacity of the Ni3S2 / Co3S4 nanosheet material. Simultaneously, sulfur vacancies are introduced at the heterojunction interface, resulting in a composite material with high electrical conductivity, enabling rapid charge-discharge of alkaline Ni-Zn battery systems. However, there are almost no reports on the use of sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction materials as cathode materials for alkaline Ni-Zn batteries. Summary of the Invention Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing nickel sulfide / cobalt sulfide based on sulfur-rich vacancies for nickel-zinc batteries. This cathode material is green and environmentally friendly, and has a high specific surface area and high conductivity. Compared with other cathode materials for alkaline Ni-Zn batteries, it has a high power density and areal specific capacity.

[0006] The technical solution adopted in this invention is a method for preparing nickel-zinc batteries based on sulfur-rich vacancy nickel sulfide / cobalt sulfide, specifically implemented according to the following steps:

[0007] Step 1: Preparation of Ni-doped Co5(O) 9.48 H 8.52 NO3 nanosheet materials;

[0008] Step 2: Prepare Ni3S2 / Co3S4 nanosheet heterojunction material;

[0009] Step 3: Prepare Ni3S2 / Co3S4 nanosheet heterojunction material with sulfur-rich vacancies.

[0010] The invention is further characterized in that,

[0011] Step 1 is implemented in the following steps:

[0012] Add 3–5 mmol of CoCl₂·6H₂O to 80–120 mL of deionized water until completely dissolved, yielding a pink solution, which is named Solution A. Dissolve 12–20 mmol of dimethylimidazole in 80–120 mL of deionized water to obtain a colorless and transparent solution, which is named Solution B. Slowly add Solution B to Solution A, stirring thoroughly to obtain a mixed solution. Let the mixed solution stand at room temperature for 20–24 hours. Centrifuge and wash the precipitate obtained from the reaction to obtain a green powder, which is named Powder C, i.e., Co₅(O₂)₂. 9.48 H 8.52 NO3;

[0013] Weigh 30–40 mg of powder C and disperse it in a mixed solution of ethanol and N,N-dimethylformamide (DMF) at a volume ratio of 1:1, with each component having a volume of 5–6 mL. Name the resulting solution D. Weigh 30–40 mg of NiCl₂·6H₂O and dissolve it in 2–5 mL of deionized water to obtain solution E. Then, slowly add solution E to solution D and mix thoroughly. Place the mixture in a reaction vessel and maintain the temperature at 80–100 °C for 8–10 hours. Centrifuge, wash, and dry the resulting precipitate to obtain a green powder named powder F, thus obtaining Ni / Co₅(O₂)₂. 9.48 H 8.52 NO3.

[0014] In step 1, the molar ratio of CoCl2·6H2O to dimethylimidazole is 1:3 to 5; the mass ratio of powder C to NiCl2·6H2O is 1:0.5 to 2.

[0015] Step 2 is implemented in the following steps:

[0016] Weigh 20-40 mg of the above powder F and fully disperse it in 10-20 mL of 30-60 mg of Na2S in a deionized water solution. Place the solution in a reaction vessel and maintain the temperature at 80-100℃ for 8-10 hours. Centrifuge, wash and dry the resulting precipitate to obtain a black powder named powder G, which is the Ni3S2 / Co3S4 nanosheet heterojunction material.

[0017] In step 2, the mass ratio of powder F to Na2S is 1:1 to 2.

[0018] Step 3 is implemented in the following steps:

[0019] Add 10-20 mL of 20-40 mg NaBH4 solution dropwise to solution H in step 3, stir magnetically for 0.5-1.5 hours, let stand for 20-24 hours, centrifuge, wash, and vacuum dry the solution to obtain sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction material.

[0020] The mass ratio of the black powder G and NaBH4 prepared in step 2 is 1:1.5 to 2.5.

[0021] The beneficial effects of this invention are that the method for preparing nickel-zinc batteries based on sulfur-vacancy-rich nickel / cobalt sulfide is simple and low-cost. The prepared alkaline Ni-Zn battery cathode material has high areal specific capacity and power density, and exhibits good electrochemical performance when assembled with Zn foil into an alkaline Ni-Zn battery device. Furthermore, this invention is the first to synthesize sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction material and apply it to alkaline Ni-Zn batteries, which is innovative; its good electrochemical performance also makes it practical. Attached Figure Description

[0022] Figure 1 Electron paramagnetic resonance spectrum of Ni3S2 / Co3S4 material surface;

[0023] Figure 2 Transmission electron microscope image of Ni3S2 / Co3S4 material;

[0024] Figure 3 The constant current charge-discharge curves of Ni3S2 / Co3S4 nanosheet heterojunction materials rich in sulfur vacancies are shown. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0026] This invention relates to a method for preparing nickel-zinc batteries using sulfur-vacancy-rich nickel sulfide / cobalt sulfide, specifically implemented according to the following steps:

[0027] Step 1: Preparation of Ni-doped Co5(O) 9.48 H 8.52 NO3 nanosheet materials;

[0028] Step 1 is implemented in the following steps:

[0029] All chemicals (analytical grade) were used as is, without further processing. 3–5 mmol of CoCl₂·6H₂O was added to 80–120 mL of deionized water until completely dissolved, yielding a pink solution, which was named Solution A. 12–20 mmol of dimethylimidazole was dissolved in 80–120 mL of deionized water, yielding a colorless, transparent solution, which was named Solution B. Solution B was slowly added to Solution A, and the mixture was stirred thoroughly to obtain a mixed solution. The mixed solution was left at room temperature for 20–24 hours. The resulting precipitate was centrifuged and washed to obtain a green powder, which was named Powder C, i.e., Co₅(O₂)₂. 9.48 H 8.52 NO3;

[0030] Weigh 30–40 mg of powder C and disperse it in a mixed solution of ethanol and N,N-dimethylformamide (DMF) at a volume ratio of 1:1, with each component having a volume of 5–6 mL. Name the resulting solution D. Weigh 30–40 mg of NiCl₂·6H₂O and dissolve it in 2–5 mL of deionized water to obtain solution E. Then, slowly add solution E to solution D and mix thoroughly. Place the mixture in a reaction vessel and maintain the temperature at 80–100 °C for 8–10 hours. Centrifuge, wash, and dry the resulting precipitate to obtain a green powder named powder F, thus obtaining Ni / Co₅(O₂)₂. 9.48 H 8.52 NO3.

[0031] In step 1, the molar ratio of CoCl2·6H2O to dimethylimidazole is 1:3 to 5; the mass ratio of powder C to NiCl2·6H2O is 1:0.5 to 2.

[0032] Step 2: Prepare Ni3S2 / Co3S4 nanosheet heterojunction material;

[0033] Step 2 is implemented in the following steps:

[0034] Weigh 20-40 mg of the above powder F and fully disperse it in 10-20 mL of 30-60 mg of Na2S in a deionized water solution. Place the solution in a reaction vessel and maintain the temperature at 80-100℃ for 8-10 hours. Centrifuge, wash and dry the resulting precipitate to obtain a black powder named powder G, which is the Ni3S2 / Co3S4 nanosheet heterojunction material.

[0035] In step 2, the mass ratio of powder F to Na2S is 1:1 to 2.

[0036] Step 3: Prepare Ni3S2 / Co3S4 nanosheet heterojunction material with sulfur-rich vacancies.

[0037] Step 3 is implemented in the following steps:

[0038] Add 10-20 mL of 20-40 mg NaBH4 solution dropwise to solution H in step 3, stir magnetically for 0.5-1.5 hours, let stand for 20-24 hours, centrifuge, wash, and vacuum dry the solution to obtain sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction material.

[0039] The mass ratio of the black powder G and NaBH4 prepared in step 2 is 1:1.5 to 2.5.

[0040] Figure 1 It can be seen that the Ni3S2 / Co3S4 composite material has a large number of sulfur vacancies.

[0041] Figure 2 It can be seen that the Ni3S2 / Co3S4 material has a nanosheet morphology and a heterostructure is formed at the interface.

[0042] Figure 3 The galvanostatic charge-discharge curves of the sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction material in an alkaline Ni-Zn battery are shown.

[0043] Reference Figure 1 As shown, electron paramagnetic resonance indicates that the vacancy signal intensity on the surface of Ni3S2 / Co3S4 material is significantly enhanced after step 3), successfully introducing a large number of sulfur vacancies into the Ni3S2 / Co3S4 composite material.

[0044] Reference Figure 2 As shown, Ni3S2 / Co3S4 materials form a heterojunction of Ni3S2 and Co3S4 at the interface of nanosheet morphology.

[0045] Reference Figure 3 As shown, the current density of the alkaline Ni-Zn battery device at 1, 2, 3, 4, and 5 Ag is... -1 The constant current charge-discharge spectrum under the corresponding conditions.

[0046] Example 1:

[0047] 1) Preparation of Ni-doped Co5(O) 9.48 H 8.52 NO3 nanosheet materials:

[0048] All chemicals (analytical grade) were used as is, without further processing. 4 mmol of CoCl₂·6H₂O was added to 100 mL of deionized water until completely dissolved, yielding a pink solution, which was named Solution A. 16 mmol of dimethylimidazole was dissolved in 100 mL of deionized water, yielding a colorless, transparent solution, which was named Solution B. Solution B was slowly added to Solution A, and the mixture was stirred thoroughly to obtain a mixed solution. This mixture was then left at room temperature for 24 hours. The resulting precipitate was centrifuged and washed to obtain a green powder, which was named Powder C, i.e., Co₅(O₂)₂. 9.48 H 8.52 NO3.

[0049] Weigh 30–40 mg of the above powder C and disperse it in a mixed solution of ethanol and N,N-dimethylformamide (DMF) (ethanol:DMF volume ratio 1:1, each volume 5–6 mL), and name this solution D. Weigh 30–40 mg of NiCl₂·6H₂O and dissolve it in 2–5 mL of deionized water to obtain solution E. Then, slowly add solution E to solution D and mix thoroughly. Place the mixture in a reaction vessel and maintain it at 80–100 °C for 8–10 hours. Centrifuge the resulting precipitate, wash it, and dry it to obtain a green powder, which is named powder F. This yields Ni / Co₅(O₂)₂. 9.48 H 8.52 NO3.

[0050] 2) Preparation of Ni3S2 / Co3S4 nanosheet heterojunction materials:

[0051] Weigh 20-40 mg of the above powder F and fully disperse it in 10-20 mL of 30-60 mg of Na2S in a deionized water solution. Place the solution in a reaction vessel and maintain it at 80-100°C for 8-10 hours. Centrifuge the resulting precipitate, wash it, and dry it to obtain a black powder, which is named powder G. Ni3S2 / Co3S4 can be obtained.

[0052] 3) Preparation of Ni3S2 / Co3S4 nanosheet heterojunction materials rich in sulfur vacancies:

[0053] Weigh 10–20 mg of the above powder G and fully disperse it in 40–60 mL of deionized water, denoted as solution H, to prepare 10–20 mL of 20–40 mg NaBH4 solution. Add the NaBH4 solution dropwise to solution H, stir magnetically for 1 hour, and let stand for 20 hours. Centrifuge the solution, wash, vacuum dry, and collect the sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction material.

[0054] Example 2:

[0055] 1) Preparation of Ni-doped Co5(O) 9.48 H 8.52NO3 nanosheet materials:

[0056] All chemicals (analytical grade) were used as is, without further processing. 3–5 mmol of CoCl₂·6H₂O was added to 80–120 mL of deionized water until completely dissolved, yielding a pink solution, which was named Solution A. 12–20 mmol of dimethylimidazole was dissolved in 80–120 mL of deionized water, yielding a colorless, transparent solution, which was named Solution B. Solution B was slowly added to Solution A, and the mixture was stirred thoroughly to obtain a mixed solution. This mixture was then left at room temperature for 24 hours. The resulting precipitate was centrifuged and washed to obtain a green powder, which was named Powder C, i.e., Co₅(O₂)₂. 9.48 H 8.52 NO3.

[0057] Weigh 30 mg of the above powder C and disperse it in a mixed solution of ethanol and N,N-dimethylformamide (DMF) (ethanol:DMF volume ratio 1:1, 6 mL each), and name this solution D. Weigh 30 mg of NiCl2·6H2O and dissolve it in 3 mL of deionized water to obtain solution E. Then, slowly add solution E to solution D and mix thoroughly. Place the mixture in a reaction vessel and maintain it at 80–100 °C for 8–10 hours. Centrifuge the resulting precipitate, wash it, and dry it to obtain a green powder, which is named powder F. This yields Ni / Co5(O) 9.48 H 8.52 NO3.

[0058] 2) Preparation of Ni3S2 / Co3S4 nanosheet heterojunction materials:

[0059] Weigh 20-40 mg of the above powder F and fully disperse it in 10-20 mL of 30-60 mg of Na2S in a deionized water solution. Place the solution in a reaction vessel and maintain it at 80-100°C for 8-10 hours. Centrifuge the resulting precipitate, wash it, and dry it to obtain a black powder, which is named powder G. Ni3S2 / Co3S4 can be obtained.

[0060] 3) Preparation of Ni3S2 / Co3S4 nanosheet heterojunction materials rich in sulfur vacancies:

[0061] Weigh 10–20 mg of the above powder G and fully disperse it in 40–60 mL of deionized water, denoted as solution H, to prepare 10–20 mL of 20–40 mg NaBH4 solution. Add the NaBH4 solution dropwise to solution H, stir magnetically for 1 hour, and let stand for 20 hours. Centrifuge the solution, wash, vacuum dry, and collect the sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction material.

[0062] Example 3:

[0063] 1) Preparation of Ni-doped Co5(O) 9.48 H 8.52 NO3 nanosheet materials:

[0064] All chemicals (analytical grade) were used as is, without further processing. 3–5 mmol of CoCl₂·6H₂O was added to 80–120 mL of deionized water until completely dissolved, yielding a pink solution, which was named Solution A. 12–20 mmol of dimethylimidazole was dissolved in 80–120 mL of deionized water, yielding a colorless, transparent solution, which was named Solution B. Solution B was slowly added to Solution A, and the mixture was stirred thoroughly to obtain a mixed solution. This mixture was then left at room temperature for 24 hours. The resulting precipitate was centrifuged and washed to obtain a green powder, which was named Powder C, i.e., Co₅(O₂)₂. 9.48 H 8.52 NO3.

[0065] Weigh 30–40 mg of the above powder C and disperse it in a mixed solution of ethanol and N,N-dimethylformamide (DMF) (ethanol:DMF volume ratio 1:1, each volume 5–6 mL), and name this solution D. Weigh 30–40 mg of NiCl₂·6H₂O and dissolve it in 2–5 mL of deionized water to obtain solution E. Then, slowly add solution E to solution D and mix thoroughly. Place the mixture in a reaction vessel and maintain it at 80–100 °C for 8–10 hours. Centrifuge the resulting precipitate, wash it, and dry it to obtain a green powder, which is named powder F. This yields Ni / Co₅(O₂)₂. 9.48 H 8.52 NO3.

[0066] 2) Preparation of Ni3S2 / Co3S4 nanosheet heterojunction materials:

[0067] Weigh 30 mg of the above powder F and fully disperse it in 15 mL of 45 mg Na2S deionized water solution. Place it in a reaction vessel and maintain it at 80-100℃ for 8-10 hours. Centrifuge the obtained precipitate, wash it, and dry it to obtain a black powder, which is named powder G. Ni3S2 / Co3S4 can be obtained.

[0068] 3) Preparation of Ni3S2 / Co3S4 nanosheet heterojunction materials rich in sulfur vacancies:

[0069] Weigh 10–20 mg of the above powder G and fully disperse it in 40–60 mL of deionized water, denoted as solution H, to prepare 10–20 mL of 20–40 mg NaBH4 solution. Add the NaBH4 solution dropwise to solution H, stir magnetically for 1 hour, and let stand for 20 hours. Centrifuge the solution, wash, vacuum dry, and collect the sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction material.

[0070] Example 4:

[0071] 1) Preparation of Ni-doped Co5(O) 9.48 H 8.52 NO3 nanosheet materials:

[0072] All chemicals (analytical grade) were used as is, without further processing. 3–5 mmol of CoCl₂·6H₂O was added to 80–120 mL of deionized water until completely dissolved, yielding a pink solution, which was named Solution A. 12–20 mmol of dimethylimidazole was dissolved in 80–120 mL of deionized water, yielding a colorless, transparent solution, which was named Solution B. Solution B was slowly added to Solution A, and the mixture was stirred thoroughly to obtain a mixed solution. This mixture was then left at room temperature for 24 hours. The resulting precipitate was centrifuged and washed to obtain a green powder, which was named Powder C, i.e., Co₅(O₂)₂. 9.48 H 8.52 NO3.

[0073] Weigh 30–40 mg of the above powder C and disperse it in a mixed solution of ethanol and N,N-dimethylformamide (DMF) (ethanol:DMF volume ratio 1:1, each volume 5–6 mL), and name this solution D. Weigh 30–40 mg of NiCl₂·6H₂O and dissolve it in 2–5 mL of deionized water to obtain solution E. Then, slowly add solution E to solution D and mix thoroughly. Place the mixture in a reaction vessel and maintain it at 80–100 °C for 8–10 hours. Centrifuge the resulting precipitate, wash it, and dry it to obtain a green powder, which is named powder F. This yields Ni / Co₅(O₂)₂. 9.48 H 8.52 NO3.

[0074] 2) Preparation of Ni3S2 / Co3S4 nanosheet heterojunction materials:

[0075] Weigh 20-40 mg of the above powder F and fully disperse it in 10-20 mL of 30-60 mg of Na2S in a deionized water solution. Place the solution in a reaction vessel and maintain it at 80-100°C for 8-10 hours. Centrifuge the resulting precipitate, wash it, and dry it to obtain a black powder, which is named powder G. Ni3S2 / Co3S4 can be obtained.

[0076] 3) Preparation of Ni3S2 / Co3S4 nanosheet heterojunction materials rich in sulfur vacancies:

[0077] Weigh 15 mg of the above powder G and fully disperse it in 50 mL of deionized water, denoted as solution H, to prepare 15 mL of 30 mg NaBH4 solution. Add the NaBH4 solution dropwise to solution H, stir magnetically for 1 hour, and let stand for 20 hours. Centrifuge the solution, wash, vacuum dry, and collect the sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction material.

Claims

1. A method for preparing nickel-zinc batteries based on sulfur-rich vacancy nickel sulfide / cobalt sulfide, characterized in that, The specific steps are as follows: Step 1: Preparation of Ni-doped Co5(O) 9.48 H 8.52 NO3 nanosheet materials; Step 1 is implemented in the following steps: Add 3-5 mmol of CoCl₂·6H₂O to 80-120 mL of deionized water until completely dissolved, obtaining a pink solution, which is named Solution A. Dissolve 12-20 mmol of dimethylimidazole in 80-120 mL of deionized water to obtain a colorless and transparent solution, which is named Solution B. Slowly add Solution B to Solution A, stirring thoroughly to obtain a mixed solution. Let the mixed solution stand at room temperature for 20-24 h. Centrifuge and wash the precipitate obtained from the reaction to obtain a green powder, which is named Powder C, i.e., Co₅(O₂)₂. 9.48 H 8.52 NO3; Weigh 30-40 mg of powder C and disperse it in a mixed solution of ethanol and N,N-dimethylformamide (volume ratio 1:1, volume 5-6 mL). Name the resulting solution D. Weigh 30-40 mg of NiCl₂·6H₂O and dissolve it in 2-5 mL of deionized water to obtain solution E. Then, slowly add solution E to solution D and mix thoroughly. Place the mixture in a reaction vessel and maintain the temperature at 80-100 °C for 8-10 hours. Centrifuge, wash, and dry the resulting precipitate to obtain a green powder named powder F, thus obtaining Ni / Co₅(O₂)₂. 9.48 H 8.52 NO3; In step 1, the molar ratio of CoCl2·6H2O to dimethylimidazole is 1:3~5; the mass ratio of powder C to NiCl2·6H2O is 1:0.5~2. Step 2: Prepare Ni3S2 / Co3S4 nanosheet heterojunction material; Step 2 is implemented in the following steps: Weigh 20-40 mg of the above powder F and fully disperse it in 10-20 mL of 30-60 mg of Na2S in a deionized water solution. Place it in a reaction vessel and maintain the temperature at 80-100 °C for 8-10 hours. Centrifuge, wash and dry the resulting precipitate to obtain a black powder named powder G, which is the Ni3S2 / Co3S4 nanosheet heterojunction material. In step 2, the mass ratio of powder F to Na2S is 1:1~2; Step 3: Prepare Ni3S2 / Co3S4 nanosheet heterojunction material with sulfur-rich vacancies; Step 3 is implemented in the following steps: 10-20 mL of 20-40 mg NaBH4 solution was added dropwise to solution H in step 3. After stirring magnetically for 0.5-1.5 hours, the solution was allowed to stand for 20-24 hours. The solution was then centrifuged, washed, and vacuum dried to obtain sulfur-vacancy-rich Ni3S2 / Co3S4 nanosheet heterojunction material. The mass ratio of the black powder G and NaBH4 prepared in step 2 is 1:1.5~2.5.

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