High-efficiency desalination battery material, preparation method and application thereof

Abstract

The application provides a preparation method of a high-efficiency desalination battery material, which comprises the following steps: dissolving Na salt and non-ionic surfactant in an ethanol solution to obtain solution A; under the condition of magnetic stirring, Mn salt is added into the solution A to form solution B; then Na4Fe(CN)6 is added into the solution B for mixing, acid is added drop by drop to obtain a clear solution; the clear solution is subjected to hydrothermal reaction, and the precursor product is obtained through centrifugal washing and drying; the precursor product is dissolved in deionized water, Ni salt is added for coating reaction under the condition of room temperature, and the FeMnPBA@Ni electrode material is obtained through centrifugal washing and drying. 2+ The application effectively solves the problem of Mn dissolution in the cycle process of the high-capacity manganese-containing prussian blue battery material, and combines vitamin B 12 The desalination battery composed of the electrode material has excellent desalination performance.

Description

Technical Field

[0001] This invention belongs to the field of battery materials technology, and in particular relates to a high-efficiency desalination battery material, its preparation method and its application. Background Technology

[0002] Developing sustainable new water supply technologies to convert abundant seawater and brackish water into freshwater is a key approach to addressing the global water crisis. Traditional seawater desalination technologies are mainly divided into two categories: thermal methods and membrane methods, both of which are mature and widely used. Thermal methods, also known as distillation, separate water and salt by controlling temperature and pressure and utilizing seawater vaporization. Membrane methods rely on semi-permeable membranes to achieve selective permeation of water molecules and retention of salt under external pressure, and mainly include reverse osmosis, electrodialysis, microfiltration, ultrafiltration, and nanofiltration. However, both types of technologies generally suffer from problems such as complex pretreatment, high operation and maintenance costs, susceptibility to pollution, and high energy consumption, which limit their large-scale application. To overcome the bottlenecks of traditional technologies, new energy-saving and environmentally friendly desalination technologies have attracted widespread attention. Among them, capacitive deionization (CDI) technology, with its advantages of simple operation, low operating voltage, low energy consumption, and environmental friendliness, has become one of the most promising electrochemical desalination technologies.

[0003] CDI, also known as electro-adsorption, is a highly efficient water treatment technology for removing charged ions from aqueous solutions. Its core consists of a pair of porous carbon electrodes. When a DC voltage below 2 V is applied, anions and cations in the solution migrate to the positive and negative electrodes, respectively, and are adsorbed, achieving desalination. After the voltage is removed, the ions are desorbed and released, and the electrodes are regenerated. Unlike traditional technologies that require extracting large amounts of water from brine, CDI directly removes salt ions from the water, resulting in lower energy consumption and higher desalination efficiency in low-salinity water treatment. Furthermore, the CDI electrode regeneration process releases and recovers some energy, further improving energy utilization and demonstrating significant technological advantages.

[0004] Prussian blue and its analogues (PBA), with the general formula M x N y [Fe(CN)6] is a class of metal-organic framework materials with simple structures, which can be divided into single-electron transfer type and two-electron transfer type according to the electron transfer type. Among them, the two-electron transfer type PBA (such as Mn[Fe(CN)6], Fe[Fe(CN)6], etc.) has a theoretical specific capacity of up to 170 mAh g. -1 This is significantly higher than that of single-electron transfer materials. These materials possess three-dimensional open ion channels, fast ion transport rates, and dual redox active centers. Their energy storage behavior can be optimized by controlling the metal composition. Furthermore, they have low raw material costs, making them suitable for large-scale applications. Their operating voltage range is also highly compatible with CDI systems, making them highly promising CDI electrode materials.

[0005] Despite their significant advantages, Prussian blue analogues still face numerous bottlenecks in practical applications. PBA crystals prepared by conventional coprecipitation methods are large, prone to aggregation, and have low crystallinity, resulting in long ion transport paths, insufficient utilization of active sites, and actual capacity far below theoretical values, along with poor cycle stability. Furthermore, when matched with low-capacity activated carbon electrodes, they cannot achieve efficient capacitive deionization performance, and the problems of low capacity and poor long-term cycle stability persist. Therefore, improving the structural stability of Prussian blue materials and their desalination performance in capacitive deionization has become a critical issue that urgently needs to be addressed. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide a high-efficiency desalted battery material, its preparation method, and its application. The preparation method provided by this invention involves dissolving Na and Mn salts in an ethanol solution, controlling the growth environment of the electrode material, and regulating the hydrothermal reaction and Ni salt coating reaction to obtain a Prussian blue electrode material with suitable capacity, improved structural stability, and maintained capacity after long cycling. This material is then combined with vitamin B... 12 Electrode materials are assembled into an asymmetric desalination battery to achieve excellent desalination performance.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a high-efficiency desalination battery material, comprising the following steps: S1: Dissolve the sodium salt and nonionic surfactant in an ethanol solution to obtain solution A; Under magnetic stirring, Mn salt was added to solution A to form solution B; then Na4Fe(CN)6 was added to solution B and mixed, and acid was added dropwise to obtain a clear solution; The clear solution was subjected to a hydrothermal reaction, followed by centrifugation, washing, and drying to obtain the precursor product. S2: Dissolve the above precursor product in deionized water, add Ni salt at room temperature for coating reaction, and obtain FeMnPBA@Ni electrode material by centrifugation, washing and drying. S3: Vitamin B 12 Dissolved in deionized water, then nano-carbon spheres were added and composited under oil bath conditions. After vacuum drying, vitamin B was obtained. 12 Electrode materials.

[0008] Preferably, the Na salt in S1 includes one or more of Na2NO3, NaCl, and Na2CO3.

[0009] Preferably, the nonionic surfactant in S1 includes one or more of polyvinylpyrrolidone, sucrose ester, and alkylolamide.

[0010] Preferably, the hydrothermal reaction temperature in S1 is 70~90℃, and the hydrothermal reaction time is 4~10 h.

[0011] Preferably, the mass ratio of Ni salt to precursor product in S2 is 4~0.5:1, and the amount of Ni salt used is 0.125~1 g; The Ni salt includes one or more of NiCl2, NiSO4, and Ni(NO3)2.

[0012] Preferably, the coating reaction in S2 is carried out under stirring at room temperature, wherein the room temperature is 20~25℃ and the stirring rate is 300rpm~600rpm.

[0013] Preferably, the S3 contains nanocarbon spheres and vitamin B. 12 The mass ratio is 4~1:1.

[0014] Preferably, the temperature of the oil bath in S3 is 70~90℃, and the oil bath time is 4~10 h.

[0015] This invention also provides desalted battery materials prepared by the above method, including FeMnPBA@Ni electrode materials and vitamin B. 12 The electrode material, FeMnPBA@Ni, is a core-shell structured Prussian blue material with a cubic structure and a particle size of 200nm~300nm.

[0016] This invention also provides a desalination battery, comprising FeMnPBA@Ni electrode material and vitamin B. 12 Electrode material, current collector titanium plate, rubber gasket, insulating components, peristaltic pump and conductivity meter, the FeMnPBA@Ni electrode material and vitamin B 12 The electrode material was prepared according to the method described above.

[0017] Beneficial effects: This invention provides a method for preparing a high-efficiency desalted battery material. By adding Ni salt, the shell thickness of the battery material is controlled, resulting in a core-shell structure with a uniform shell and ion-sieving properties. The addition of Ni salt also suppresses Mn oxidation during long-cycle operation. 2+ The dissolution of ions disrupts cycle stability, but significantly improves electrochemical performance; this invention controls the interaction with vitamin B by adding carbon nanospheres. 12 The composite process, with appropriately sized nanocarbon spheres, can effectively prevent vitamin B. 12 During cycling, Co ions dissolve and improve the cycle stability of the desalted battery.

[0018] Experimental results show that the preparation method provided by this invention can obtain core-shell structured battery materials with good crystallinity, cubic structure, uniform morphology, and small particle size; among them, the core-shell structured FeMnPBA@Ni battery material has a high performance at 1 A·g -1 At current density, the capacity retention rate reaches over 81% after 1000 cycles; combined with vitamin B... 12 The electrode materials form a desalination battery. An asymmetric hybrid capacitor deionization battery assembled using these desalination battery materials achieves a desalination capacity of 81.28 mg·g⁻¹ at a working voltage of 1.4 V. -1 . Attached Figure Description

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Figure 1 This is a scanning electron microscope image of FeMnPBA@0.5gNi prepared in Example 2 of the present invention; Figure 2 This is a capacitance diagram of FeMnPBA@0.5gNi prepared in Example 2 of this invention under optimal constant voltage conditions for deionization. Figure 3 The electrode materials prepared in Examples 1-3 and Comparative Examples 1-2 of this invention are measured at 1 A g. -1 Comparison chart of cycle performance; Figure 4 This is a comparison chart of the desalination performance of the asymmetric batteries assembled in Examples 1-3 of this invention under a constant voltage of 1.4 V. Detailed Implementation

[0021] This invention provides a method for preparing a high-efficiency desalination battery material, comprising the following steps: S1: Dissolve the sodium salt and nonionic surfactant in an ethanol solution to obtain solution A; Under magnetic stirring, Mn salt was added to solution A to form solution B; then Na4Fe(CN)6 was added to solution B and mixed, and acid was added dropwise to obtain a clear solution; The clear solution was subjected to a hydrothermal reaction, followed by centrifugation, washing, and drying to obtain the precursor product. S2: Dissolve the above precursor product in deionized water, add Ni salt at room temperature for coating reaction, and obtain FeMnPBA@Ni electrode material by centrifugation, washing and drying. S3: Vitamin B 12 Dissolved in deionized water, then nano-carbon spheres were added and composited under oil bath conditions. After vacuum drying, vitamin B was obtained. 12 Electrode materials.

[0022] In this invention, Na salt and nonionic surfactant are first dissolved in an ethanol solution to obtain solution A; under magnetic stirring, Mn salt is added to solution A to form solution B; then Na4Fe(CN)6 is added to solution B and mixed, and acid is added dropwise to obtain a clear solution; the clear solution is subjected to a hydrothermal reaction, and the precursor product is obtained by centrifugation, washing, and drying.

[0023] In this invention, the Na salt includes one or more of Na2NO3, NaCl, and Na2CO3.

[0024] In this invention, the nonionic surfactant includes one or more of polyvinylpyrrolidone, sucrose ester, and alkylolamide.

[0025] In this invention, the ethanol solution is prepared by mixing ethanol and deionized water, and the volume ratio of deionized water to ethanol in the ethanol solution is 4~1:1.

[0026] In this invention, the stirring speed of the magnetic stirrer is 100 rpm to 1500 rpm, the stirring time is 5 min to 180 min, and the stirring temperature is 10℃ to 80℃.

[0027] In this invention, the Mn salt includes one or more of MnCl2, MnSO4 and Mn(NO3)2.

[0028] In this invention, Na salt and Mn salt are dissolved in an ethanol solution. Compared with deionized water, the hydroxyl groups in the ethanol solution adsorb onto the surface of some Prussian blue crystals, coordinate with the metal ions in the Prussian blue crystal structure, inhibit the growth of crystal nuclei, and form a Prussian blue precursor with uniform morphology and small particles.

[0029] In this invention, the acid includes hydrochloric acid and / or sulfuric acid, and the concentration of the hydrochloric acid or sulfuric acid is as conventional as that in the art; the dripping rate of the acid is preferably 0.1 mL / min to 0.2 mL / min. In this invention, the acid is added dropwise, and under acidic conditions, the Fe in Na4Fe(CN)6... 2+ It can release slowly and steadily drive crystal nucleation and growth, slowing down the nucleation rate of Prussian blue, forming Prussian blue with lower bound water and fewer vacancies, avoiding the problem of water molecules interfering with ion transport and structural stability, and improving cycle stability; the dripping rate provided by this invention can ensure rapid dispersion of acid, maintain overall pH stability, and help control the nucleation rate and crystal integrity, ultimately obtaining Prussian blue material with stable structure and excellent ion conductivity.

[0030] In this invention, the hydrothermal reaction temperature is 70-90℃, and the hydrothermal reaction time is 4-10 h. This invention controls the grain size of Prussian blue by adjusting the hydrothermal reaction time during the reaction process. By controlling the hydrothermal reaction time to 4-10 h, Prussian blue with controllable grain size is formed, resulting in Prussian blue with suitable grain size. This increases active sites, reduces ion transport distance, and improves electrochemical performance. If the hydrothermal time is too short, Prussian blue will not nucleate; if the hydrothermal time is too long, the particle size of Prussian blue will be inconsistent, changing from nanometer-scale to micrometer-scale.

[0031] In this invention, the centrifugal washing is preferably performed by centrifuging a mixed solution of deionized water and ethanol 3 to 5 times; in this invention, the drying temperature is 70 to 90°C, preferably 80°C, the drying is carried out under vacuum negative pressure, and the drying time is 10 to 15 hours.

[0032] After obtaining the precursor product, the present invention dissolves the above-mentioned precursor product in deionized water, adds Ni salt at room temperature for coating reaction, and obtains FeMnPBA@Ni electrode material by centrifugation, washing and drying.

[0033] This invention controls the shell thickness of Prussian blue by adjusting the amount of Ni salt added during the reaction process. By controlling the amount of Ni salt to 0.125~1 g, a core-shell structured Prussian blue material with a uniform shell and ion-sieving properties is formed, suppressing Mn production during long-term cycling. 2+ Ion dissolution disrupts cycle stability and improves electrochemical performance; adding too little Ni salt will prevent Prussian blue from being fully coated; adding too much Ni salt will result in an overly thick shell, which will prevent ions from properly intercalating and deintercalating during cycling.

[0034] In this invention, the mass ratio of Ni salt to precursor product is 4~0.5:1, and the amount of Ni salt used is preferably 0.125~1 g; in this invention, the Ni salt includes one or more of NiCl2, NiSO4 and Ni(NO3)2.

[0035] In this invention, the Ni salt is added by dropwise addition of a solution, and the addition rate of the Ni salt is controlled at 1~5 mg / min.

[0036] In this invention, the coating reaction is carried out under stirring at room temperature, wherein the room temperature is 20°C to 25°C, and the stirring speed is preferably 300 rpm to 600 rpm. The room temperature condition is chosen in this invention considering Ni... 2+ The diffusion rate is relatively low, and the surface reaction rate is relatively faster than the internal diffusion rate, therefore Ni 2+First, ions are enriched on the surface and preferentially form a shell, creating a core-shell structure. Increased temperature or high-temperature environments accelerate ion diffusion and exchange, potentially leading to Ni... 2+ It completely permeates the entire particle to form a solid solution, rather than a core-shell structure.

[0037] In this invention, the centrifugal washing is preferably performed by centrifuging a mixed solution of deionized water and ethanol 3 to 5 times; in this invention, the drying temperature is 70 to 90°C, preferably 80°C, the drying is carried out under vacuum negative pressure, and the drying time is 10 to 15 hours.

[0038] This invention will use vitamin B 12 Dissolved in deionized water, then nano-carbon spheres were added and composited under oil bath conditions. After vacuum drying, vitamin B was obtained. 12 Electrode materials. This invention chooses oil bath composite treatment because oil bath treatment can reduce solution viscosity, enhance molecular motion, and promote vitamin B... 12 The carbon nanospheres are uniformly dispersed and anchored on the surface to prevent aggregation. Furthermore, thanks to their highly conductive porous framework and oxygen-containing surface groups, the carbon nanospheres uniformly load vitamin B through hydrogen bonding, electrostatics, and weak coordination. 12 Vitamin B 12 The nanocarbon spheres provide N / Co active sites, strong hydrophilicity, and pseudocapacitance, synergistically enhancing the electrode desalination capacity, rate, and cycling stability. In this invention, the nanocarbon spheres and vitamin B... 12 The mass ratio is 4~1:1.

[0039] In this invention, the oil bath temperature is 70~90℃, and the oil bath time is 4~10 h. In this invention, if the oil bath temperature is too low, the load will be uneven; if it is too high, the structure will be damaged; if the oil bath time is insufficient, the reaction will be incomplete; if it is too long, the channels will be blocked, all of which will weaken the desalination performance.

[0040] In this invention, the drying temperature is 70~90℃, preferably 80℃, the drying is carried out under vacuum negative pressure, and the drying time is 10~15 h.

[0041] This invention also provides a desalination battery material prepared by the above method, comprising FeMnPBA@Ni electrode material and vitamin B. 12 In this invention, the FeMnPBA@Ni electrode material is a core-shell structured Prussian blue material with a cubic structure and a particle size of 200nm~300nm.

[0042] This invention also provides a desalination battery, comprising FeMnPBA@Ni electrode material and vitamin B. 12Electrode material, current collector titanium plate, rubber gasket, insulating components, peristaltic pump, and conductivity meter; in this invention, the FeMnPBA@Ni electrode material and vitamin B... 12 The electrode material was prepared using the method described above; This invention provides a method for preparing desalinated battery materials, which can obtain core-shell Prussian blue materials with good crystallinity, cubic structure, uniform morphology, and small particle size, suitable for deionized capacitor batteries. The core-shell Prussian blue battery material (FeMnPBA@Ni) exhibits a high crystallinity of 1 A·g⁻¹. -1 At current density, the capacity retention rate reaches over 81% after 1000 cycles; combined with vitamin B... 12 The electrode materials used to construct the desalination battery, and the assembled asymmetric hybrid capacitor deionization battery, achieved a desalination capacity of 81.28 mg·g at an operating voltage of 1.4 V. -1 .

[0043] The following detailed description of the aqueous zinc-ion battery preparation method and its application provided by the present invention, with reference to specific embodiments, should not be construed as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] Preparation of core-shell Prussian blue (FeMnPBA@Ni) and vitamin B 12 Desalination electrode material: First, dissolve 1 g NaCl in a mixed solution of 80 mL deionized water and 20 mL ethanol. Then, under magnetic stirring, add 7.55 mg MnCl2·4H2O, 0.36 g Na4Fe(CN)6 and 1 g polyvinylpyrrolidone (K30) to the sodium chloride solution. After the solution is mixed evenly, add 2.0 mL hydrochloric acid (37%) (solution pH=0.5) dropwise. After stirring vigorously for 1 h, a clear solution is obtained.

[0046] The clarified solution was transferred to a 100 mL hydrothermal reactor and hydrothermally reacted at 80 °C for 10 h. After the reaction was completed, the precipitate was obtained and washed 3-5 times with deionized water and ethanol by centrifugation at 10000 r / min for 4 min. Then, the product was vacuum dried at 80 °C for 12 h to obtain the precursor product.

[0047] The above precursor product was dissolved in deionized water, and 0.125 g NiCl2·6H2O was added dropwise under stirring at room temperature for 6 h. After the reaction was completed, a precipitate was obtained, which was washed 3-5 times with deionized water and ethanol by centrifugation at 10000 r / min for 4 min. Then, it was vacuum dried at 80℃ for 12 h to obtain FeMnPBA@0.125gNi electrode material.

[0048] 30 mg of vitamin B 12 Dissolved in deionized water, then 60 mg of carbon nanospheres were added and composited in an oil bath at 80 °C, followed by evaporation of water and vacuum drying at 80 °C for 12 h to obtain B. 12 Electrode materials.

[0049] The prepared FeMnPBA@0.125gNi electrode material was ground and mixed with Ketjen Black and polytetrafluoroethylene emulsion at a mass ratio of 7:2:1 to prepare a slurry. The slurry was then uniformly pressed onto a titanium mesh and vacuum dried in a vacuum drying oven at 120℃ for 5 h using 1 mol L⁻¹. -1 NaCl solution was used as the electrolyte, and Prussian blue electrode material (Prussian blue loading: 2 mg cm⁻¹) was used. -1 A complete battery testing system is constructed using an Ag / AgCl electrode as the reference electrode, with excess activated carbon as the counter electrode and Ag / AgCl electrode as the reference electrode.

[0050] Assemble a desalination battery: using FeMnPBA@0.125gNi electrodes (3×3 cm) 2 The active material weighs approximately 20 mg. According to the active substance sample, Ketjen Black and polytetrafluoroethylene emulsion are ground and mixed evenly at a mass ratio of 7:2:1 to prepare a slurry. The prepared slurry is then evenly pressed onto a titanium mesh, along with vitamin B. 12 Electrode (4×4 cm) 2 The active material weighs approximately 30 mg. According to the active material sample, Ketjen Black and CMC and SBR mixed emulsion are ground and mixed evenly at a mass ratio of 90:5:5 to prepare a slurry. The prepared slurry is then evenly pressed onto a titanium mesh, a current collector titanium plate, a rubber gasket, an insulating component, a peristaltic pump, and a conductivity meter.

[0051] During the constant pressure operation, the FeMnPBA@0.125gNi electrode was used as the working electrode, and 1000 ppm NaCl solution (45 mL) was circulated at a rate of 35 mL / min, with the NaCl concentration continuously monitored by a conductivity meter.

[0052] In this embodiment, FeMnPBA@0.125gNi was prepared as the electrode material at 1 A g. -1 Cyclic performance such as Figure 3 As shown, when the current density is 1 A g -1 At that time, the capacity of FeMnPBA@0.125gNi was 91.6 mAh g. -1 After 1000 cycles, the capacity retention rate was 69.7%. Figure 4 As shown, the FeMnPBA@0.125gNi electrode was used with vitamin B.12 The electrodes were assembled into a desalination battery, and at an operating voltage of 1.4 V, the desalination capacity was 34.34 mg g. -1 .

[0053] Example 2

[0054] Preparation of core-shell Prussian blue (FeMnPBA@Ni) and vitamin B 12 Desalination electrode material: First, dissolve 1 g NaCl in a mixed solution of 80 mL deionized water and 20 mL ethanol. Then, under magnetic stirring, add 7.55 mg MnCl2·4H2O, 0.36 g Na4Fe(CN)6 and 1 g polyvinylpyrrolidone (K30) to the sodium chloride solution. After the solution is mixed evenly, add 2.0 mL hydrochloric acid (37%) (solution pH=0.5) dropwise. After stirring vigorously for 1 h, a clear solution is obtained.

[0055] The clarified solution was transferred to a 100 mL hydrothermal reactor and hydrothermally reacted at 80 °C for 4 h. After the reaction was completed, the precipitate was obtained and washed 3-5 times with deionized water and ethanol by centrifugation at 10000 r / min for 4 min. Then, the product was vacuum dried at 80 °C for 12 h to obtain the precursor product.

[0056] The above precursor product was dissolved in deionized water, and 0.5 g of NiCl2·6H2O was added dropwise under stirring at room temperature for 6 h. After the reaction was completed, a precipitate was obtained, which was washed 3-5 times with deionized water and ethanol by centrifugation at 10000 r / min for 4 min. Then, it was vacuum dried at 80℃ for 12 h to obtain FeMnPBA@0.5gNi electrode material.

[0057] 30 mg of vitamin B 12 Dissolved in deionized water, then 90 mg of carbon nanospheres were added and compounded in an oil bath at 80 °C. The water was then evaporated, and finally dried under vacuum at 80 °C for 12 h to obtain vitamin B. 12 Electrode materials.

[0058] The prepared FeMnPBA@0.5gNi electrode material was ground and mixed with Ketjen Black and polytetrafluoroethylene emulsion at a mass ratio of 7:2:1 to prepare a slurry. The slurry was then uniformly pressed onto a stainless steel current collector and vacuum dried in a vacuum drying oven at 120℃ for 5 h. A 1 mol L⁻¹ solution was then used. -1 NaCl solution was used as the electrolyte, and Prussian blue electrode material (Prussian blue loading: 2 mg cm⁻¹) was used. -1A complete battery testing system is constructed using an Ag / AgCl electrode as the reference electrode, with excess activated carbon as the counter electrode and Ag / AgCl electrode as the reference electrode.

[0059] Assemble a desalination battery: using FeMnPBA@0.5gNi electrodes (3×3 cm) 2 The active material weighs approximately 20 mg. According to the active material sample, Ketjen Black and polytetrafluoroethylene emulsion were ground and mixed evenly at a mass ratio of 7:2:1 to prepare a slurry. The prepared slurry was then evenly pressed onto a titanium mesh and a vitamin B12 electrode (4×4 cm). 2 The active material weighs approximately 30 mg. According to the active material sample, Ketjen Black and CMC and SBR mixed emulsion are ground and mixed evenly at a mass ratio of 90:5:5 to prepare a slurry. The prepared slurry is then evenly pressed onto a titanium mesh, a current collector titanium plate, a rubber gasket, an insulating component, a peristaltic pump, and a conductivity meter.

[0060] During the constant pressure operation, the FeMnPBA@0.5gNi electrode was used as the working electrode, and 1000 ppm NaCl solution (45 mL) was circulated at a rate of 35 mL / min, with the NaCl concentration continuously monitored by a conductivity meter.

[0061] In this embodiment, FeMnPBA@0.5gNi was prepared as the electrode material at 1 A g. -1 Cyclic performance such as Figure 3 As shown, when the current density is 1 A g -1 At that time, the capacity of FeMnPBA@0.5gNi was 98.8 mAh g. -1 After 1000 cycles, the capacity retention rate was 80.9%, demonstrating excellent cycling stability. Figure 4 As shown, the FeMnPBA@0.5gNi electrode was used with vitamin B. 12 The electrodes were assembled into a desalination battery, which exhibited a desalination capacity of 81.28 mg g at an operating voltage of 1.4 V. -1 This achieves optimal desalination performance.

[0062] Example 3

[0063] Preparation of core-shell Prussian blue (FeMnPBA@Ni) and vitamin B 12 Desalination electrode material: First, dissolve 1 g NaCl in a mixed solution of 80 mL deionized water and 20 mL ethanol. Then, under magnetic stirring, add 7.55 mg MnCl2·4H2O, 0.36 g Na4Fe(CN)6 and 1 g polyvinylpyrrolidone (K30) to the sodium chloride solution. After the solution is mixed evenly, add 2.0 mL hydrochloric acid (37%) (solution pH=0.5) dropwise. After stirring vigorously for 1 h, a clear solution is obtained.

[0064] The clarified solution was transferred to a 100 mL hydrothermal reactor and hydrothermally reacted at 80 °C for 4 h. After the reaction was completed, the precipitate was obtained and washed 3-5 times with deionized water and ethanol by centrifugation at 10000 r / min for 4 min. Then, the product was vacuum dried at 80 °C for 12 h to obtain the precursor product.

[0065] The above precursor product was dissolved in deionized water, and 1 g of NiCl2·6H2O was added dropwise under stirring at room temperature for 6 h. After the reaction was completed, a precipitate was obtained, which was washed 3-5 times with deionized water and ethanol by centrifugation at 10000 r / min for 4 min. Then, it was vacuum dried at 80℃ for 12 h to obtain FeMnPBA@1gNi electrode material.

[0066] 30 mg of vitamin B 12 The product was dissolved in a deionized aqueous solution, and then 120 mg of carbon nanospheres were added. The mixture was then composited in an oil bath at 80°C and the water was evaporated. Finally, the product was vacuum dried at 80°C for 12 h to obtain the target product.

[0067] The prepared FeMnPBA@1gNi electrode material, Ketjen Black, and polytetrafluoroethylene emulsion were ground and mixed evenly at a mass ratio of 7:2:1 to prepare a slurry. The slurry was then uniformly pressed onto a stainless steel current collector and vacuum dried in a vacuum drying oven at 120℃ for 5 h. A 1 mol L⁻¹ solution was then used for further drying. -1 NaCl solution was used as the electrolyte, and Prussian blue electrode material (Prussian blue loading: 2 mg cm⁻¹) was used. -1 A complete battery testing system is constructed using an Ag / AgCl electrode as the reference electrode, with excess activated carbon as the counter electrode and Ag / AgCl electrode as the reference electrode.

[0068] Assemble a desalination battery: using FeMnPBA@1gNi electrodes (3×3 cm) 2 The active material weighs approximately 20 mg. According to the active substance sample, Ketjen Black and polytetrafluoroethylene emulsion are ground and mixed evenly at a mass ratio of 7:2:1 to prepare a slurry. The prepared slurry is then evenly pressed onto a titanium mesh, along with vitamin B. 12 Electrode (4×4 cm) 2The active material weighs approximately 30 mg. According to the active material sample, Ketjen Black and CMC and SBR mixed emulsion are ground and mixed evenly at a mass ratio of 90:5:5 to prepare a slurry. The prepared slurry is then evenly pressed onto a titanium mesh, a current collector titanium plate, a rubber gasket, an insulating component, a peristaltic pump, and a conductivity meter.

[0069] During the constant pressure operation, the FeMnPBA@1gNi electrode was used as the working electrode, in which 1000 ppm NaCl solution (45 mL) was circulated at a rate of 35 mL / min, and the NaCl concentration was continuously monitored by a conductivity meter.

[0070] The FeMnPBA@1gNi prepared in this embodiment was used as the electrode material in 1 A g -1 Cyclic performance such as Figure 3 As shown, when the current density is 1 A g -1 At that time, the capacity of FeMnPBA@1gNi was 91.6 mAh g. -1 After 1000 cycles, the capacity retention rate was 68.7%. Figure 4 As shown, the FeMnPBA@1gNi electrode was used with vitamin B. 12 The electrodes were assembled into a desalination battery, and at an operating voltage of 1.4 V, the desalination capacity was 51.89 mg g. -1 .

[0071] Comparative Example 1

[0072] Preparation of Prussian blue and vitamin B 12 Desalination electrode material: First, dissolve 1 g NaCl in 100 mL of deionized water. Then, under magnetic stirring, add 7.55 mg MnCl2·4H2O, 0.36 g Na4Fe(CN)6 and 1 g polyvinylpyrrolidone (K30) to the sodium chloride solution. After the solution is mixed evenly, add 2.0 mL of hydrochloric acid (37%) (solution pH=0.5) dropwise. Stir vigorously for 1 h to obtain a clear solution.

[0073] The clarified solution was transferred to a 100 mL hydrothermal reactor and hydrothermally reacted at 80 °C for 8 h. After the reaction was completed, the precipitate was obtained and washed 3-5 times with deionized water and ethanol by centrifugation at 10000 r / min for 4 min. Then, the product was dried under vacuum at 80 °C for 12 h to obtain the precursor product.

[0074] 30 mg of vitamin B 12 The product was dissolved in a deionized aqueous solution, and then 60 mg of carbon nanospheres were added. The mixture was then composited in an oil bath at 80 °C and the water was evaporated. Finally, the product was vacuum dried at 80 °C for 12 h to obtain the target product.

[0075] In this comparative example, the precursor product FeMnPBA was not treated. At this time, the yield of the precursor FeMnPBA was low and the morphology was irregular, and a complete cubic phase structure was not formed.

[0076] The precursor product, Ketjen black, and polytetrafluoroethylene emulsion were ground and mixed evenly at a mass ratio of 7:2:1 to prepare a slurry. The slurry was then uniformly pressed onto a stainless steel current collector and vacuum dried in a vacuum drying oven at 120℃ for 5 h. A 1 mol L⁻¹ solution was used for further drying. -1 NaCl solution was used as the electrolyte, and Prussian blue electrode material (Prussian blue loading: 2 mg / cm³) was used. -1 A complete battery testing system is constructed using an Ag / AgCl electrode as the reference electrode, with excess activated carbon as the counter electrode and Ag / AgCl electrode as the reference electrode.

[0077] Assemble a desalination battery: using FeMnPBA electrodes (3×3 cm) 2 The active material weighs approximately 20 mg. According to the active substance sample, Ketjen Black and polytetrafluoroethylene emulsion are ground and mixed evenly at a mass ratio of 7:2:1 to prepare a slurry. The prepared slurry is then evenly pressed onto a titanium mesh, along with vitamin B. 12 Electrode (4×4 cm) 2 The active material weighs approximately 30 mg. According to the active material sample, Ketjen Black and CMC and SBR mixed emulsion are ground and mixed evenly at a mass ratio of 90:5:5 to prepare a slurry. The prepared slurry is then evenly pressed onto a titanium mesh, a current collector titanium plate, a rubber gasket, an insulating component, a peristaltic pump, and a conductivity meter.

[0078] During the constant pressure operation, the FeMnPBA electrode was used as the working electrode, in which 1000 ppm NaCl solution (45 mL) was circulated at a rate of 35 mL / min, and the NaCl concentration was continuously monitored by a conductivity meter.

[0079] The FeMnPBA prepared in this comparative example was used as an electrode material at 1 A g. -1 Cyclic performance such as Figure 3 As shown, when the current density is 1 A g -1 At that time, FeMnPBA had a low capacity and was used to form a desalination battery for desalination. Compared with materials that are composited with precursor products, its performance was not good.

[0080] Comparative Example 2

[0081] Preparation of core-shell Prussian blue (FeMnPBA@Ni) and vitamin B 12 Desalination electrode material: First, dissolve 1 g NaCl in 100 mL of deionized water. Then, under magnetic stirring, add 7.55 mg MnCl2·4H2O, 0.36 g Na4Fe(CN)6 and 1 g polyvinylpyrrolidone (K30) to the sodium chloride solution. After the solution is mixed evenly, add 2.0 mL of hydrochloric acid (37%) (solution pH=0.5) dropwise. Stir vigorously for 1 h to obtain a clear solution.

[0082] The clarified solution was transferred to a 100 mL hydrothermal reactor and hydrothermally reacted at 80 °C for 6 h. After the reaction was completed, the precipitate was obtained and washed 3-5 times with deionized water and ethanol by centrifugation at 10000 r / min for 4 min. Then, the product was vacuum dried at 80 °C for 12 h to obtain the precursor product.

[0083] The above precursor product was dissolved in deionized water, and 0.125 g of NiCl2·6H2O was added dropwise under stirring at room temperature for 6 h. After the reaction was completed, a precipitate was obtained, which was washed 3-5 times with deionized water and ethanol by centrifugation at 10000 r / min for 4 min. Then, it was vacuum dried at 80℃ for 12 h to obtain FeMnPBA@Ni electrode material. The yield of FeMnPBA@Ni was small and the morphology was irregular, and a complete core-shell structure was not formed.

[0084] 30 mg of vitamin B 12 Dissolved in deionized water, then 30 mg of carbon nanospheres were added and composited in an oil bath at 80°C. The water was then evaporated, followed by vacuum drying at 80°C for 12 h to obtain the target product, vitamin B1. 12 During the circulation process, the dissolution of Co causes a change in the color of the solution.

[0085] The prepared FeMnPBA@Ni electrode material, Ketjen black, and polytetrafluoroethylene emulsion were ground and mixed evenly at a mass ratio of 7:2:1 to prepare a slurry. The slurry was then uniformly pressed onto a stainless steel current collector and vacuum dried in a vacuum drying oven at 120℃ for 5 h. A 1 mol L⁻¹ solution was used for further drying. -1 NaCl solution was used as the electrolyte, and Prussian blue electrode material (Prussian blue loading: 2 mg cm⁻¹) was used. -1 A complete battery testing system is constructed using an Ag / AgCl electrode as the reference electrode, with excess activated carbon as the counter electrode and Ag / AgCl electrode as the reference electrode.

[0086] Assemble a desalination battery: using FeMnPBA@Ni electrodes (3×3 cm) 2The active material weighs approximately 20 mg. According to the active substance sample, Ketjen Black and polytetrafluoroethylene emulsion are ground and mixed evenly at a mass ratio of 7:2:1 to prepare a slurry. The prepared slurry is then evenly pressed onto a titanium mesh, along with vitamin B. 12 Electrode (4×4 cm) 2 The active material weighs approximately 30 mg. According to the active material sample, Ketjen Black and CMC and SBR mixed emulsion are ground and mixed evenly at a mass ratio of 90:5:5 to prepare a slurry. The prepared slurry is then evenly pressed onto a titanium mesh, a current collector titanium plate, a rubber gasket, an insulating component, a peristaltic pump, and a conductivity meter.

[0087] During the constant pressure operation, the FeMnPBA@Ni electrode was used as the working electrode, in which 1000 ppm NaCl solution (45 mL) was circulated at a rate of 35 mL / min, and the NaCl concentration was continuously monitored by a conductivity meter.

[0088] The FeMnPBA@Ni prepared in this comparative example was used as an electrode material at 1 A g. -1 Cyclic performance such as Figure 3 As shown, when the current density is 1 A g -1 At that time, the capacity of FeMnPBA@Ni was only 64.3 mAh g. -1 It is used to form a desalination battery for desalination, but the amount and rate of desalination are relatively low.

[0089] Example 2: Ethanol, as a co-solvent, can reduce solution polarity, alleviate ion aggregation, and result in more uniform raw material dispersion and a gradual and controllable nucleation rate. This is beneficial for forming Prussian blue nanocrystals with smaller and more uniform particle size. Simultaneously, the addition of ethanol may alter the Ni... 2+ The diffusion behavior of the sample promotes the complete encapsulation of the core-shell structure. However, Comparative Example 2 uses deionized water as the solvent, resulting in a highly polar solution with intense ion collisions and rapid, massive nucleation. This leads to defective crystal nuclei, the introduction of water of crystallization, and the formation of irregular particles, reducing the effective sites for electrode reactions and resulting in relatively poor uniformity of the core-shell structure. Furthermore, Comparative Example 2 has a longer hydrothermal time than Example 2, which further induces grain coarsening and agglomeration, exacerbates framework defects, and blocks pores, ultimately significantly weakening the material's structural stability and electrochemical desalination performance.

[0090] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-efficiency desalination battery material, comprising the following steps: S1: Dissolve the sodium salt and nonionic surfactant in an ethanol solution to obtain solution A; Under magnetic stirring, Mn salt was added to solution A to form solution B; then Na4Fe(CN)6 was added to solution B and mixed, and acid was added dropwise to obtain a clear solution; The clear solution was subjected to a hydrothermal reaction, followed by centrifugation, washing, and drying to obtain the precursor product. S2: Dissolve the above precursor product in deionized water, add Ni salt at room temperature for coating reaction, and obtain FeMnPBA@Ni electrode material by centrifugation, washing and drying. S3: Vitamin B 12 Dissolved in deionized water, then nano-carbon spheres were added and composited under oil bath conditions. After vacuum drying, vitamin B was obtained. 12 Electrode materials.

2. The preparation method according to claim 1, characterized in that, The Na salt in S1 includes one or more of Na2NO3, NaCl, and Na2CO3.

3. The preparation method according to claim 1, characterized in that, The nonionic surfactant in S1 includes one or more of polyvinylpyrrolidone, sucrose ester, and alkylolamide.

4. The preparation method according to claim 1, characterized in that, The hydrothermal reaction temperature in S1 is 70~90℃, and the hydrothermal reaction time is 4~10 h.

5. The preparation method according to claim 1, characterized in that, The mass ratio of Ni salt to precursor product in S2 is 4~0.5:1, and the amount of Ni salt used is 0.125~1 g; The Ni salt includes one or more of NiCl2, NiSO4, and Ni(NO3)2.

6. The preparation method according to claim 1, characterized in that, The coating reaction in S2 is carried out under stirring at room temperature, wherein the room temperature is 20~25℃ and the stirring rate is 300rpm~600rpm.

7. The preparation method according to claim 1, characterized in that, The S3 contains nanocarbon spheres and vitamin B. 12 The mass ratio is 4~1:

1.

8. The preparation method according to claim 1, characterized in that, The temperature of the oil bath in S3 is 70~90℃, and the oil bath time is 4~10 h.

9. The desalinated battery material prepared by the method according to any one of claims 1 to 8, characterized in that, Including FeMnPBA@Ni electrode materials and vitamin B 12 The electrode material, FeMnPBA@Ni, is a core-shell structured Prussian blue material with a cubic structure and a particle size of 200nm~300nm.

10. A desalination battery, comprising FeMnPBA@Ni electrode material and vitamin B... 12 Electrode material, current collector titanium plate, rubber gasket, insulating components, peristaltic pump and conductivity meter, the FeMnPBA@Ni electrode material and vitamin B 12 The electrode material is prepared by the method according to any one of claims 1 to 8.

Images