A kind of Na2 [Ni (EDTA) ] additive based on nickel plating waste liquid and its preparation method and application in perovskite battery active layer

Abstract

The application belongs to the technical field of industrial waste liquid resource utilization, and particularly relates to a Na2[Ni(EDTA)] additive based on nickel plating waste liquid and a preparation method and application thereof in a perovskite battery active layer. 2‑ The additive has three functions of defect passivation, energy level regulation and colloid stability, and when used in the perovskite solar cell active layer, can efficiently passivate bulk phase and interface defects, and inhibit non-radiation recombination of carriers and ion migration. The application realizes cross-field cooperation of harmless treatment of industrial hazardous waste, high-value utilization of resources and photovoltaic performance upgrading, and has simple process, easy scaling, and remarkable environmental, economic and social benefits.

Description

Technical Field

[0001] This invention belongs to the technical field of industrial waste liquid resource utilization, specifically relating to a Na2[Ni(EDTA)] additive based on nickel plating waste liquid, its preparation method, and its application in the active layer of perovskite solar cells. Background Technology

[0002] Chemical nickel plating and electroplating are widely used in industries such as electronics, machinery, automobiles, and aerospace. These processes release large amounts of Ni (EDTA) during production. 2- Industrial waste liquids. This type of waste liquid belongs to difficult-to-treat industrial hazardous waste. Traditional treatment technologies generally adopt processes such as Fenton oxidation, strong alkali complex breaking, and chemical precipitation, which have obvious drawbacks: First, they are highly polluting, energy-intensive, and costly. Strong oxidation and strong alkali conditions consume a lot of energy and have high reagent costs, and are prone to generating nickel-containing sludge and secondary pollution. Second, they have low resource utilization and poor added value. The EDTA complexing agent is completely oxidized and degraded, and only low-priced nickel salts are recovered, resulting in a complete waste of EDTA resources and extremely low economic benefits. Third, there is great pressure to comply with regulations, and the cost of hazardous waste disposal is increasing year by year, placing a heavy environmental burden on enterprises.

[0003] Perovskite solar cells, as a new generation of high-efficiency photovoltaic technology, have achieved a photoelectric conversion efficiency exceeding 26% in the laboratory, possessing advantages such as low cost, high efficiency, and solution-processability, and have broad prospects for industrialization. However, they still face three major bottlenecks: First, the high density of bulk and interface defects makes it easy to generate defects such as vacancies, interstitial atoms, and grain boundaries during the preparation process, which become non-radiative recombination centers for charge carriers; second, severe ion migration and poor stability occur easily under light and humid heat environments, accelerating thin film degradation and resulting in short device lifespan; third, the performance of existing passivation additives is insufficient. Organic ammonium salts, polymers, and noble metal complexes have problems such as high cost, poor thermal stability, environmental unfriendliness, and limited passivation effect, making it difficult to achieve a balance between low cost, high efficiency, and high stability.

[0004] Studies have shown that metal-EDTA chelates can passivate uncoordinated Pb in perovskites through strong coordination. 2+ Defects can be addressed by simultaneously regulating precursor colloidal behavior, optimizing crystal growth, and improving film quality. However, current technologies have not yet fully utilized intact Ni (EDTA) in nickel plating wastewater. 2- The direct recycling and high-value application of perovskite solar cells has long been separated from the industrial hazardous waste treatment and photovoltaic high-performance needs, resulting in a serious undervaluation of resources.

[0005] In summary, there is an urgent need to develop a clean, low-energy-consumption, and scalable nickel plating waste liquid Ni(EDTA) solution that does not require complex breaking. 2- The technology utilizes recycling techniques and directly applies the recycled products to passivate defects in perovskite solar cells, achieving a triple breakthrough in the harmless treatment of industrial hazardous waste, the high-value utilization of resources, and a leapfrog improvement in photovoltaic performance. Summary of the Invention

[0006] To address the aforementioned issues, this invention aims to overcome the industry pain points of existing nickel plating wastewater treatment technologies, which suffer from heavy pollution, low resource utilization, and low added value; high cost, poor stability, and limited performance of perovskite battery additives; and the disconnect between the two technological fields, which prevent them from synergistically empowering each other. The invention provides a Na2[Ni(EDTA)] additive based on nickel plating wastewater, its preparation method, and its application in the active layer of perovskite batteries.

[0007] The technical content of this invention is as follows: This invention provides a method for preparing NaNa2[Ni(EDTA)] additive based on nickel plating waste liquid, comprising the following steps: 1) Pretreatment of nickel plating waste liquid Get Ni(EDTA) 2- For electroless nickel plating wastewater containing EDTA-Ni complex, suspended impurities are removed by filtration with a filter cloth; the pH of the wastewater is adjusted to 4.0-6.0 with dilute hydrochloric acid or dilute sodium hydroxide to stabilize Ni(EDTA). 2- To avoid damaging the complex, add 0.05% to 0.2% of an antioxidant by weight of the waste liquid, stir well, and let stand for 15 to 30 minutes to obtain the pretreated waste liquid.

[0008] Among them, Ni(EDTA) 2- Concentration ranges from 5 to 500 g / L; The antioxidants include one or more of sodium sulfite and sodium metabisulfite; 2) Complexation and purification Add sodium ion regulator to the pretreated waste liquid, control the reaction temperature at 25~50℃, and stir the reaction for 0.5~2 hours to reduce the Ni(EDTA) concentration in the waste liquid. 2- with Na + Directional complexation was performed to generate the target product, nickel plating waste liquid-based EDTA-Na2Ni; subsequently, a crude Na2[Ni(EDTA)] solution was obtained by combined ultrafiltration and nanofiltration. The sodium ion regulator includes one or more of sodium carbonate, sodium hydroxide, and sodium sulfate, and the amount added is Ni(EDTA). 2- 2.0 to 2.5 times the molar amount; The ultrafiltration membrane has a pore size of 0.01~0.1 μm, removing fine suspended particles and large molecular organic impurities; the nanofiltration membrane has a molecular weight cutoff of 100~300 Da, retaining nickel plating waste liquid-based EDTA-Na2Ni complex, and removing trace anionic impurities such as phosphate and sulfate. 3) Low-temperature refining and purification The crude EDTA-Na2Ni solution was concentrated by vacuum distillation at a vacuum of 0.06-0.09 MPa and a temperature of 50-70℃ to 1 / 3-1 / 5 of its original volume. The concentrate was then crystallized at a controlled cooling temperature of 0-10℃ for 2-8 hours. The crystals were then filtered to obtain crude Na2[Ni(EDTA)] crystals based on nickel plating waste liquid. These crystals were washed 2-3 times with anhydrous ethanol or deionized water. The washed crystals were then placed in a vacuum drying oven and dried at 60-80℃ for 4-12 hours to obtain high-quality Na2[Ni(EDTA)] based on nickel plating waste liquid with a purity ≥98.5%.

[0009] This invention also provides the Na2[Ni(EDTA)] additive prepared based on nickel plating waste liquid, which has a purity of ≥98.5% and a particle size of 10~100 nm. It exhibits excellent dispersibility in organic solvents such as N,N-dimethylformamide, dimethyl sulfoxide, and ethanol, and can remain stable for more than 72 hours without precipitation. It also possesses the triple functions of defect passivation, energy level regulation, and colloidal stabilization, making it suitable for various perovskite battery structures, including both positive and reverse orientations.

[0010] The present invention also provides an application of the above-mentioned Na2[Ni(EDTA)] additive in the preparation of a battery, which is applied to the preparation of the active layer of the battery, the battery including a perovskite solar cell; The preparation and application of the active layer of perovskite solar cells include the following steps: a) Precursor preparation: Add nickel plating waste liquid-based Na2[Ni(EDTA)] to 1 mL of perovskite precursor solution, stir for 6 hours until completely dissolved, and control the concentration of Na2[Ni(EDTA)] in the active layer system to be 0~100 mg / mL, preferably 0~50 mg / mL; b) Film formation and heat treatment: The doped precursor solution is formed into a film by spin coating, inkjet printing or printing process, with a spin coating speed of 3000~6000 rpm; heat treatment is carried out at 80~120℃ to form a high-quality perovskite active layer with a thickness of 10~1000 nm. c) Device assembly: Adapt to ITO / SAM / perovskite:Na2[Ni(EDTA)] / PCBM / BCP / Ag and other upright or inverted device structures, and perform photovoltaic performance testing after packaging.

[0011] The beneficial effects of this invention are as follows: This invention relates to a Na2[Ni(EDTA)] additive based on nickel plating wastewater. Through pretreatment of the nickel plating wastewater, directional complexation control, membrane-based fractional purification, and low-temperature refining, it eliminates the need for complex breaking and strong oxidizing / alkaline conditions. Energy consumption is reduced by more than 50% compared to traditional methods, and treatment costs are reduced by more than 40%. It completely avoids the risks of nickel-containing sludge and secondary pollution, achieving 100% synergistic recovery of EDTA and nickel resources. This invention directly utilizes Ni(EDTA)-containing... 2- This method extracts Na2[Ni(EDTA)] additives with a purity of ≥98.5% from nickel plating wastewater, achieving near-zero raw material costs and reducing costs by over 60% compared to traditional synthesis routes. This breaks the low-value-added predicament of only extracting low-priced nickel salts from wastewater, realizing the value-added transformation of hazardous waste into high-value photovoltaic materials. The entire extraction process requires no complex equipment, operates under mild conditions, and is easy to scale up industrially. Furthermore, the additive application is fully compatible with existing perovskite battery fabrication processes, requiring no production line modifications. It is adaptable to various device structures and components, resulting in low industrialization barriers and strong practicality.

[0012] The Na2[Ni(EDTA)] additive prepared in this invention, with its unique chelating structure, possesses a triple function of defect passivation, energy level modulation, and colloidal stabilization in the active layer of perovskite solar cells. It can efficiently passivate bulk and interface defects, suppress non-radiative recombination of charge carriers and ion migration, and optimize charge transport performance. The device performance achieves a significant leap forward: the highest photoelectric conversion efficiency reaches 27.05%, an improvement of 14.23% compared to the group without additives, and the key parameter V... oc =1.194 V, J sc With an efficiency of 26.24 mA / cm² and an efficiency factor (FF) of 86.35%, this invention achieves international leading levels. In terms of stability, after 1000 hours of continuous operation at maximum power point, the efficiency retention rate is ≥90%, and after 500 hours of high-temperature aging at 85℃, the efficiency retention rate is ≥88%, effectively addressing the industry pain point of the trade-off between high efficiency and stability in perovskite solar cells. This invention achieves cross-domain synergy between the harmless treatment of industrial hazardous waste, high-value utilization of resources, and photovoltaic performance upgrades. It breaks down the technical barriers between industrial environmental protection and new energy photovoltaics, pioneering a new green circular model of "hazardous waste treatment → high-value material preparation → photovoltaic performance upgrades." The process is simple and easily scalable. While promoting the green transformation of the nickel plating industry, it also helps achieve carbon peaking and carbon neutrality goals, resulting in significant environmental, economic, and social benefits, and promoting the coordinated and sustainable development of the photovoltaic and environmental protection industries. Attached Figure Description

[0013] Figure 1 Scanning electron microscope (SEM) image and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) image of Na2[Ni(EDTA)] prepared in Example 1 of this invention.

[0014] Figure 2The Fourier transform infrared (FT-IR) spectrum of the nickel plating waste liquid-based Na2[Ni(EDTA)], perovskite (PbI2) and blended powder prepared in Example 1 of this invention is shown below. Figure 3 The photoluminescence (PL) spectra of the top and bottom interfaces of the nickel plating waste liquid-based Na2[Ni(EDTA)] modified perovskite film prepared in Example 2 of this invention are shown. Figure 4 These are scanning electron microscope (SEM) images of the pure perovskite film (Control) and the perovskite film modified with nickel plating waste liquid based on Na2[Ni(EDTA)] of the present invention. Figure 5 The graphs show the current density-voltage (JV) curves of perovskite solar cells with and without nickel plating waste liquid-based Na2[Ni(EDTA)] and with 1.5 mg / mL nickel plating waste liquid-based Na2[Ni(EDTA)].

[0015] Figure 6 The graph shows the stability test curves of the perovskite solar cells of the present invention with and without the addition of nickel plating waste liquid-based Na2[Ni(EDTA)] and with the addition of 1.5 mg / mL nickel plating waste liquid-based Na2[Ni(EDTA)]. Detailed Implementation

[0016] The present invention will be further described in detail below through specific implementation examples and accompanying drawings. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope of the appended claims.

[0017] Unless otherwise specified, all raw materials and reagents used in this invention are from the conventional market.

[0018] Example 1 Preparation of Na2[Ni(EDTA)] additive based on nickel plating waste liquid 1) Pretreatment of nickel plating waste liquid Take 1000 mL of electroless nickel plating waste liquid, containing Ni(EDTA). 2- The concentration was 20 g / L. Suspended impurities were removed by filtration with a filter cloth. The pH was adjusted to 5.0 with dilute hydrochloric acid, and 0.1 g of sodium sulfite (0.1% of the waste liquid mass) was added. After stirring evenly, the mixture was allowed to stand for 20 minutes to obtain the pretreated waste liquid. 2) Complexation and purification Sodium carbonate (Ni(EDTA)) is added to the pretreated waste liquid. 2-(2.2 times the molar amount), stir the reaction at 35℃ for 1 hour; filter sequentially using a 0.05 μm ultrafiltration membrane and a 200 Da nanofiltration membrane to obtain a crude Na2[Ni(EDTA)] solution; 3) Low-temperature refining and purification The crude EDTA-Na2Ni solution was transferred to a vacuum distillation apparatus and concentrated under vacuum conditions of 0.08 MPa and 60°C to 1 / 4 of its original volume. The concentrate was then transferred to a crystallization vessel and cooled at 5°C for 4 hours to crystallize. The resulting crude crystalline product, Na2[Ni(EDTA)] based on nickel plating waste liquid, was obtained by filtration and washed three times with anhydrous ethanol. The washed crystals were then placed in a vacuum drying oven and dried under vacuum at 60°C for 8 hours to obtain a high-purity nickel plating waste liquid-based EDTA-Na2Ni product with 99.7% purity. The recovery rate, calculated using Ni as the standard, was 48.9%.

[0019] Example 2 Preparation of Na2[Ni(EDTA)] additive based on nickel plating waste liquid 1) Pretreatment of nickel plating waste liquid Take 1000 mL of electroless nickel plating waste liquid, containing Ni(EDTA). 2- The concentration was 10 g / L. Suspended impurities were removed by filtration with a filter cloth. The pH was adjusted to 4.5 with dilute sodium hydroxide, and 0.08 g of sodium metabisulfite (0.08% of the waste liquid mass) was added. The mixture was allowed to stand for 15 minutes to obtain the pretreated waste liquid. 2) Complexation and purification Sodium hydroxide (Ni(EDTA)) is added to the pretreated waste liquid. 2- (2.0 times the molar amount), stirred at 25℃ for 1.5 hours; then filtered sequentially using a 0.01 μm ultrafiltration membrane and a 100 Da nanofiltration membrane to obtain a crude Na2[Ni(EDTA)] solution; 3) Low-temperature refining and purification The crude Na₂[Ni(EDTA)] solution was transferred to a vacuum distillation apparatus and concentrated under vacuum conditions of 0.06 MPa and 50°C to one-third of its original volume. The concentrate was then transferred to a crystallization vessel and cooled at 0°C for 1 hour to crystallize. The resulting crude Na₂[Ni(EDTA)] crystals, based on nickel plating waste liquid, were obtained by filtration and washed twice with deionized water. The washed crystals were then placed in a vacuum drying oven and dried at 70°C for 6 hours to obtain a high-purity (99.0%) refined Na₂[Ni(EDTA)] based on nickel plating waste liquid. The recovery rate, calculated using Ni as the standard, was 45.6%.

[0020] Example 3 Preparation of Na2[Ni(EDTA)] additive based on nickel plating waste liquid 1) Pretreatment of nickel plating waste liquid Take 1000 mL of electroless nickel plating waste liquid, containing Ni(EDTA). 2- The concentration was 40 g / L. Suspended impurities were removed by filtration with a filter cloth. The pH was adjusted to 5.5 with dilute hydrochloric acid. 0.2 g of a mixed antioxidant of sodium sulfite and sodium metabisulfite (mass ratio 1:1) was added and allowed to stand for 30 minutes to obtain the pretreated waste liquid. 2) Complexation and purification Add a mixed sodium sulfate and sodium carbonate sodium ion regulator (mass ratio 1:2, Ni(EDTA)) to the pretreated waste liquid. 2- (2.5 times the molar amount), stirred at 50℃ for 0.5 hours; then filtered sequentially using a 0.1 μm ultrafiltration membrane and a 300 Da nanofiltration membrane to obtain a crude Na2[Ni(EDTA)] solution; 3) Low-temperature refining and purification The crude Na₂[Ni(EDTA)] solution was transferred to a vacuum distillation apparatus and concentrated under vacuum conditions of 0.09 MPa and 70°C to 1 / 5 of its original volume. The concentrate was then transferred to a crystallization vessel and cooled at 10°C for 6 hours to crystallize. The resulting crude Na₂[Ni(EDTA)] crystals, based on nickel plating waste liquid, were obtained by filtration and washed three times with anhydrous ethanol. The washed crystals were then placed in a vacuum drying oven and dried at 80°C for 4 hours to obtain a high-purity Na₂[Ni(EDTA)] product with 99.2% purity. The recovery rate, calculated using Ni as the standard, was 44.4%.

[0021] Comparative Example 1 Nickel salts prepared using traditional complex-breaking processes Using the same electroless nickel plating waste liquid as in Example 1, Fenton oxidation was used to break the complex and adjust the pH to precipitate nickel hydroxide. EDTA was not recovered. The treatment cost was 45% higher than that of the present invention, the nickel recovery rate was 12% lower, a large amount of nickel-containing sludge was generated, and secondary pollution was serious.

[0022] Example 4 Preparation of perovskite solar cells based on nickel plating waste liquid and Na2[Ni(EDTA)] modification Device structure: ITO / SAM / Cs 0.05 MA 0.1 FA 0.85 PbI4:Na2[Ni(EDTA)] / PCBM / BCP / Ag; ITO substrate cleaning: ultrasonic cleaning with detergent, deionized water, acetone, and isopropanol in sequence, followed by UV-ozone treatment for 20 minutes; Hole transport layer: 0.75 mg / mL SAM ethanol solution, spin-coated at 4000 rpm for 30 seconds, annealed at 100℃ for 10 minutes; Preparation of active layer: 1.67 M Cs was prepared. 0.05 MA0.1 FA 0.85 PbI3 precursor solution (DMF:DMSO=745:155); add 0.5 mg / mL nickel plating waste liquid-based Na2[Ni(EDTA)], stir for 6 hours; spin coat at 1000 rpm for 10 seconds, spin coat at 5000 rpm for 35 seconds, add chlorobenzene antisolvent dropwise; anneal at 120℃ for 10 minutes; Surface passivation layer: 1 mg / mL PEABr / FAI isopropanol solution, spin-coated at 4000 rpm for 30 seconds, annealed at 100℃ for 5 minutes; Electron transport layer: 20 mg / mL PCBM chlorobenzene solution, spin-coated at 1500 rpm for 30 seconds; Buffer layer: 0.5 mg / mL BCP isopropanol solution, spin-coated at 4000 rpm for 30 seconds; Metal electrode: 100 nm Ag electrode deposited by vacuum evaporation, encapsulated with epoxy resin.

[0023] Example 5 Same as Example 4, except that the concentration of nickel plating waste liquid-based Na2[Ni(EDTA)] added in the preparation of the active layer is 1.5 mg / mL.

[0024] Example 6 Same as Example 4, except that the concentration of nickel plating waste liquid-based Na2[Ni(EDTA)] added in the preparation of the active layer is 5 mg / mL.

[0025] Example 7 Same as Example 4, except that the concentration of nickel plating waste liquid-based Na2[Ni(EDTA)] added in the preparation of the active layer is 10 mg / mL.

[0026] Example 8 Same as Example 4, except that the concentration of nickel plating waste liquid-based Na2[Ni(EDTA)] added in the preparation of the active layer is 20 mg / mL.

[0027] Comparative Example 2 Perovskite solar cells without added nickel plating waste liquid-based Na2[Ni(EDTA)] The preparation process is the same as in Application Example 4, except that nickel plating waste liquid-based Na2[Ni(EDTA)] is not added to the precursor solution.

[0028] Comparative Example 3 Perovskite solar cells with added phenylethylamine iodine The preparation process is the same as in Application Example 4, except that 1.5 mg / mL phenethylamine iodine is added to the precursor solution.

[0029] The Na2[Ni(EDTA)] prepared in Example 1 of this invention was tested as follows: 1. SEM and SEM-EDS analysis: such as Figure 1 As shown, Na2[Ni(EDTA)] has a wrinkled structure, which means that it has a large specific surface area, which is beneficial to increasing the number of active sites. The EDS diagram shows that the distribution of C and O elements is highly dense and uniform; Na and Ni elements are locally enriched in a point-like manner, indicating that Na2[Ni(EDTA)] has been successfully complexed.

[0030] 2. FT-IR analysis: such as Figure 2 As shown, the nickel plating waste liquid-based Na2[Ni(EDTA)] at 1508.59 cm⁻¹ -1 (C=O stretching vibration), 1396.13 cm -1 A characteristic peak appears at the (NH bending vibration) location; after blending with perovskite, the C=O peak shifts to 1605.63 cm⁻¹. -1 The NH peak shifted to 1397.89 cm⁻¹. -1 This confirms that N and O atoms in nickel plating waste liquid-based Na2[Ni(EDTA)] are related to Pb. 2+ Strong coordination occurs, resulting in significant defect passivation.

[0031] 3. PL spectral analysis: such as Figure 3 As shown, the fluorescence intensity at the top and bottom interfaces of the nickel plating waste liquid-based Na2[Ni(EDTA)] modified film is significantly higher than that of the pure perovskite film, indicating that the additive effectively passivates bulk phase and interface defects, inhibits non-radiative recombination, and improves the carrier radiative recombination efficiency.

[0032] 4. SEM analysis: such as Figure 4 As shown, pure perovskite films have loose grains, many pores, and long grain boundaries; while perovskite films modified with nickel plating waste liquid-based Na2[Ni(EDTA)] have dense and uniform grains, fewer pores, and shorter grain boundaries, resulting in a significant reduction in bulk defect density and a significant improvement in film quality.

[0033] 5. JV curve and performance parameters: such as Figure 5 As shown in Table 1, the battery performance was significantly improved after adding nickel plating waste liquid-based Na2[Ni(EDTA)]. Among them, Example 5 (1.5 mg / mL) had the best performance, with a PCE of 27.05%, which was 14.23% higher than the group without the addition.

[0034] Table 1 Photovoltaic performance parameters of perovskite solar cells sample Dosage (mg / mL) <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm²)]]> FF(%) PCE (%) Comparative Example 1 0 1.138 25.50 81.50 23.68 Example 4 0.5 1.157 25.72 85.40 25.45 Example 5 1.5 1.194 26.24 86.35 27.05 Example 6 5.0 1.187 26.32 86.12 26.90 Example 7 10 1.180 26.42 86.62 26.80 Example 8 20 1.176 26.17 85.57 26.03 6. Stability testing: such as Figure 6As shown, Comparative Example 2 had an efficiency retention rate of 75.0% after 1000 hours of operation and 75.1% after 500 hours of aging at 85°C; Comparative Example 3 (phenylethylamine iodine) had a cost 3.2 times that of the present invention, a PCE of 23.0%, and a retention rate of 89.2% after 1000 hours; Example 5 had a retention rate of 90.6% after 1000 hours of operation and 91.2% after 500 hours of aging at 85°C, with stability far superior to the control group and a significant cost reduction.

Claims

1. A method for preparing Na2[Ni(EDTA)] additive based on nickel plating waste liquid, characterized in that, Includes the following steps: 1) Pretreatment of nickel plating waste liquid Get Ni(EDTA) 2- The chemical nickel plating waste liquid or electroplating nickel waste liquid is removed and precipitated to obtain pretreated waste liquid; 2) Complexation and purification Sodium ion regulator was added to the pretreated waste liquid, and the mixture was heated and stirred to generate the target product, nickel plating waste liquid base Na2[Ni(EDTA)]. The mixture was then filtered to obtain a crude Na2[Ni(EDTA)] solution. 3) Low-temperature refining and purification The crude EDTA-Na2Ni solution was subjected to vacuum distillation, and the resulting concentrate was cooled and crystallized. After filtration, crude Na2[Ni(EDTA)] crystals based on nickel plating waste liquid were obtained. The concentrate was washed and dried to obtain EDTA-Na2Ni with a purity ≥98.5%.

2. The method for preparing Na2[Ni(EDTA)] additive based on nickel plating waste liquid according to claim 1, characterized in that, In step 1), Ni(EDTA) 2- The concentration is 5~500 g / L.

3. The method for preparing Na2[Ni(EDTA)] additive based on nickel plating waste liquid according to claim 1, characterized in that, Step 1) The impurity removal and precipitation steps include: removing suspended impurities by filtration with filter cloth; adjusting the pH of the waste liquid to 4.0~6.0 with dilute hydrochloric acid or dilute sodium hydroxide; adding 0.05%~0.2% of antioxidant by mass of the waste liquid, stirring evenly and then letting it stand. The antioxidants include one or more of sodium sulfite and sodium metabisulfite.

4. The method for preparing Na2[Ni(EDTA)] additive based on nickel plating waste liquid according to claim 1, characterized in that, The sodium ion regulator includes one or more of sodium carbonate, sodium hydroxide, and sodium sulfate, and the amount added is Ni(EDTA). 2- 2.0 to 2.5 times the molar amount.

5. The method for preparing Na2[Ni(EDTA)] additive based on nickel plating waste liquid according to claim 1, characterized in that, Step 2) The heating temperature is 25~50℃, and the reaction is stirred for 0.5~2 hours.

6. The method for preparing Na2[Ni(EDTA)] additive based on nickel plating waste liquid according to claim 1, characterized in that, Step 2) The filtration is performed by using a combination of ultrafiltration and nanofiltration membranes for graded filtration.

7. The method for preparing Na2[Ni(EDTA)] additive based on nickel plating waste liquid according to claim 1, characterized in that, Step 3) The conditions for vacuum distillation are as follows: vacuum distillation and concentration are carried out under vacuum conditions of 0.06~0.09 MPa and 50~70℃, until the volume is reduced to 1 / 3~1 / 5 of the original volume.

8. A Na2[Ni(EDTA)] additive obtained by the preparation method according to any one of claims 1 to 7, characterized in that, Its purity is ≥98.5%, and its particle size is 10~100 nm.

9. The application of the Na2[Ni(EDTA)] additive of claim 8 in the preparation of a battery, characterized in that, It is used in the preparation of battery active layers.

10. The application according to claim 9, characterized in that, The battery includes a perovskite solar cell; The preparation and application of the active layer of perovskite solar cells include the following steps: a) Precursor preparation: Add Na2[Ni(EDTA)] additive to the perovskite precursor solution and stir until completely dissolved. Control the concentration of Na2[Ni(EDTA)] in the active layer system to be 0~100 mg / mL. b) Film formation and heat treatment: The doped precursor solution is formed into a film and then subjected to heat treatment to form a perovskite active layer; c) Assemble perovskite solar cells and perform photovoltaic performance testing after encapsulation.

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