A water-soluble high-nuclear rare earth tungsten polyacid cluster compound and its preparation method and application

Abstract

The present invention discloses a water-soluble high-nuclear rare earth tungsten polyacid cluster compound and its preparation method and application. The molecular formula of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound is: [H2N(CH3)2]9H 5.5 Na8[Nd9(OH)6(H2O)6(NO3)(XO4)(A‑α‑SiW9O 34 )(A‑α‑SiW 10 O 37 )3]·50H2O, wherein X=0.25Si+0.75W; A-α represents the configuration of the metal-oxygen cluster; the water-soluble high-nuclear rare earth tungsten polyacid cluster crystallizes in the triclinic system, the space group is P-1, and the crystal structure is a three-shell structure with C3 symmetry, the innermost layer is a planar triangular NO3 ‑ Anion; Shell 2 consists of two parts, one of which is a cup-shaped nine-nuclear {Nd9O 37 (OH)6(H2O)6} cluster, and the other part is a XO4 tetrahedron with disordered Si and W distribution. The XO4 tetrahedron and three NdO6(OH)(H2O) form a cage-like {Nd9O 33 (OH)6(H2O)6(XO4)} cluster; Shell 3 is composed of a {A‑α‑SiW9O 34}tungsten polyoxide clusters and three {A‑α‑SiW 10 O 37}It is composed of tungsten polyacid clusters.

Description

Technical Field

[0001] The invention belongs to the technical field of crystal materials and electrolyte additives, and particularly relates to a water-soluble high-nuclear rare earth tungsten polyacid cluster compound, a preparation method and an application thereof. Background Art

[0002] In the energy field, the development and application of lithium-ion batteries are restricted due to the limited availability of lithium resources and safety issues caused by the use of flammable organic electrolytes. Aqueous zinc-ion batteries (AZIBs) are a promising alternative with low cost, high safety, a theoretical specific capacity of 820 mAh / g and Zn 2+ Although Zn / Zn has the advantages of low reoxidation potential (-0.76 V vs. SHE), its practical application faces problems such as Zn dendrite growth, corrosion and hydrogen evolution reaction (HER).

[0003] Therefore, researchers are committed to developing strategies to improve the performance of zinc anodes, including membrane modification, artificial protective layer construction and electrolyte regulation. Among them, the addition of additives to the electrolyte is considered to be an effective strategy to regulate and stabilize the zinc anode. The functions of electrolyte additives can be divided into two categories: the first category involves shielding the tip effect to inhibit dendrite growth; the second category aims to inhibit side reactions such as HER. At present, single-functional electrolyte additives have made some progress in improving the performance of AZIBs. In comparison, the development of bifunctional electrolyte additives has been relatively slow. In addition, due to the consumption of additives during the cycle, their stability will be insufficient. There is an urgent need to develop stable and efficient bifunctional electrolyte additives.

[0004] Polyoxometalates (POMs) are a class of polyoxyanions composed of early transition metals (W, Mo, V, Nb, Ta) and oxygen atoms. POMs have diverse structures and excellent chemical properties, and are widely used in catalysis, medicine, batteries and other fields. In particular, they can accommodate a large number of electrons and ions in redox reactions while maintaining structural stability. Fascinatingly, this property makes POMs a potential class of highly efficient electrolyte additives for AZIBs. However, research in this area is quite limited and urgently needs to be expanded, especially the study of POMs as dual-functional electrolyte additives. Summary of the Invention

[0005] To solve the above problems, the present invention proposes a water-soluble high-nuclear rare earth tungsten polyacid cluster compound, its preparation method and application. The preparation method of the invention is simple, and the prepared water-soluble high-nuclear rare earth tungsten polyacid cluster compound exhibits excellent electrolyte modification performance in aqueous zinc ion batteries, greatly improving the battery life and having good stability.

[0006] The present invention adopts the following technical solutions:

[0007] A water-soluble high-nuclear rare earth tungsten polyacid cluster compound, wherein the molecular formula of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound is:

[0008] [H2N(CH3)2]9H 5.5 Na8[Nd9(OH)6(H2O)6(NO3)(XO4)(A-α-SiW9O 34 )(A-α-SiW 10 O 37 )3]·50H2O, wherein X=0.25Si+0.75W; A-α represents the configuration of the metal-oxygen cluster; the water-soluble high-nuclear rare earth tungsten polyacid cluster crystallizes in the triclinic system, the space group is P-1, and the crystal structure is a three-shell structure with C3 symmetry, the innermost layer is a planar triangular NO3 - Anion; Shell 2 consists of two parts, one of which is a cup-shaped nine-nuclear {Nd9O 37 (OH)6(H2O)6} cluster, and the other part is a Si and W disorderly distributed XO4 tetrahedron, which forms a cage-like {Nd9O 33 (OH)6(H2O)6(XO4)} cluster; Shell 3 is composed of a {A-α-SiW9O 34}Tungsten polyoxide clusters and three {A-α-SiW 10 O 37}It is composed of tungsten polyacid clusters.

[0009] Preferably, the unit cell parameters of the water-soluble high-nuclear rare earth tungsten polyacid cluster are: α=103.0350(10)°, β=106.7890(10)°, γ=97.0860(10)°, The calculated density is 3.347 g / cm 3 .

[0010] A method for preparing a water-soluble high-nuclear rare earth tungsten polyacid cluster compound, the specific preparation process is: weighing the precursor Na 10 [A-α-SiW9O 34]·18H2O, neodymium nitrate hexahydrate, nickel hydroxide, and dimethylamine hydrochloride are dissolved in water, and the pH of the mixed solution is adjusted to 10 with sodium hydroxide. After sufficient stirring, the mixture is transferred into a polytetrafluoroethylene reactor and placed in an oven for hydrothermal reaction. The solution after the hydrothermal reaction is filtered, and the filtrate is slowly evaporated at room temperature for one week. The product obtained after the volatilization is collected and washed to obtain purple block crystals, that is, a water-soluble high-nuclear rare earth tungsten polyacid cluster compound is obtained; the precursor Na 10 [A-α-SiW9O 34 ]·The molar ratio of 18H2O, neodymium nitrate hexahydrate, nickel hydroxide, dimethylamine hydrochloride and water is 0.095:0.19:0.32:0.93:222.22; the temperature of the hydrothermal reaction is 140°C, and the reaction time is 5 days.

[0011] The invention discloses an application of a water-soluble high-nuclear rare earth tungsten polyacid cluster compound, wherein the water-soluble high-nuclear rare earth tungsten polyacid cluster compound is used as an electrolyte additive in the field of aqueous zinc ion batteries; when the water-soluble high-nuclear rare earth tungsten polyacid cluster compound is dissolved in a ZnSO4 solution, the cluster anions of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound and the Zn 2+ The interactions between them induce in-situ connections between clusters to generate a new two-dimensional cellular base layer of infinitely extended clusters.

[0012] After adopting the above technical solution, the present invention has the following advantages compared with the background technology: the preparation method of the present invention is simple, and a high-yield pure water-soluble high-nuclear rare earth tungsten polyacid cluster can be obtained by a hydrothermal synthesis method combined with a volatilization method. The water-soluble high-nuclear rare earth tungsten polyacid cluster is a novel high-nuclear rare earth tungsten polyacid cluster formed by substitution of a nine-nuclear neodymium cluster. The prepared water-soluble high-nuclear rare earth tungsten polyacid cluster exhibits a relatively excellent electrolyte additive effect in aqueous zinc ion batteries, can form a protective layer on the zinc anode, effectively inhibit the side reaction on the zinc anode, and inhibit the growth of zinc dendrites, promoting the Zn 2+ The uniform deposition of ions on the anode surface greatly improves the service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a crystal photograph of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound, the product of Example 1 of the present invention;

[0014] Figure 2 This is a structural diagram of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound, the product of Example 1 of the present invention;

[0015] Figure 3 This is the X-ray powder diffraction (XRD) pattern of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound, the product of Example 1 of the present invention;

[0016] Figure 4The liquid UV-vis graphs of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound, the product of Example 1 of the present invention, in aqueous solution and ZnSO4 solution respectively;

[0017] Figure 5 This is a structural diagram of the in-situ conversion of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound, the product of Example 1 of the present invention, into a new 2D honeycomb infinitely expanding cluster base layer in a ZnSO4 solution;

[0018] Figure 6 This is the XRD pattern of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound, the product of Example 1 of the present invention, which is in situ converted into a new 2D honeycomb infinitely extended cluster base layer in a ZnSO4 solution;

[0019] Figure 7 This is a time-resolved liquid UV-vis image of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound, the product of Example 1 of the present invention, in a ZnSO4 solution;

[0020] Figure 8 The water-soluble high-nuclear rare earth tungsten polyacid cluster compound of Example 1 of the present invention is subjected to different addition amounts at 1 mA cm -2 、1mAh cm -2 Long-term cycling performance diagram of Zn||Zn symmetric battery;

[0021] Figure 9 The water-soluble high-nuclear rare earth tungsten polyacid cluster compound of Example 1 of the present invention is subjected to different addition amounts at 5 mA cm -2 、1mAh cm -2 Long-term cycling performance of Zn||Zn symmetric battery at high current density;

[0022] Figure 10 This is a time-voltage-rate performance diagram of the product of Example 1 of the present invention using ZSPE-2 and ZSPE-0 electrolytes;

[0023] Figure 11 The XRD patterns of the zinc foil using ZSPE-2 and ZSPE-0 electrolytes and the XRD pattern of the zinc foil converted into a new 2D honeycomb infinitely extended cluster base layer are shown in Example 1 of the present invention;

[0024] Figure 12 UV-vis graphs of zinc foil and bare zinc using ZSPE-2 and ZSPE-0 electrolytes as the product of Example 1 of the present invention;

[0025] Figure 13 The Tafel plots for the product of Example 1 of the present invention using ZSPE-2 and ZSPE-0 electrolytes;

[0026] Figure 14 The polarization curves of the zinc electrode when the product of Example 1 of the present invention is prepared using ZSPE-2 and ZSPE-0 electrolytes;

[0027] Figure 15 The product of Example 1 of the present invention is prepared by using ZSPE-2 and ZSPE-0 electrolytes at 1 mA cm -2 、1mAh cm -2 XRD patterns of zinc foil and bare zinc after cycling at different current densities;

[0028] Figure 16 This is a dendrite growth diagram of zinc foil using ZSPE-2 electrolyte as the product of Example 1 of the present invention, observed under an in-situ metallographic microscope;

[0029] Figure 17 This is a dendrite growth diagram of zinc foil using ZSPE-0 electrolyte as the product of Example 1 of the present invention, observed under an in-situ metallographic microscope;

[0030] Figure 18 This is a characterization diagram of the product of Example 1 of the present invention measured by chronoamperometry using ZSPE-2 and ZSPE-0 electrolytes;

[0031] Figure 19 This is an SEM image of the zinc anode surface of the product of Example 1 of the present invention after 100 cycles of ZSPE-2 and ZSPE-0 electrolytes;

[0032] Figure 20 This is the nucleation overpotential diagram of the product of Example 1 of the present invention using ZSPE-2 and ZSPE-0 electrolytes;

[0033] Figure 21 The Zn content of the product of Example 1 of the present invention is as follows: when the rare high-nuclear rare earth tungsten polyacid cluster compound with solubility and water stability is used as the electrolyte 2+ Ion transfer number diagram;

[0034] Figure 22 The Arrhenius curve and activation energy diagram of the product of Example 1 of the present invention using ZSPE-2 and ZSPE-0 electrolytes. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] See also Figures 1 to 22 .

[0037] Example 1

[0038] [H2N(CH3)2]9H 5.5Na8[Nd9(OH)6(H2O)6(NO3)(XO4)(A-α-SiW9O 34 )(A-α-SiW 10 O 37 )3]·50H2O (abbreviated as [H2N(CH3)2]9H 5.5 Na8[1a], X=0.25Si+0.75W) water-soluble high-nuclearity rare earth tungsten polyacid clusters

[0039] According to the molar ratio of 0.095:0.19:0.32:0.93, the precursor Na 10 [A-α-SiW9O 34 ]·18H2O, neodymium nitrate hexahydrate, nickel hydroxide, and dimethylamine hydrochloride were added to 4 mL of water and uniformly mixed. The pH of the mixed solution was then adjusted to 10 with sodium hydroxide. After stirring for 1.5 hours, the resulting mixture was placed in a 23 mL polytetrafluoroethylene reactor and placed in an oven for hydrothermal reaction. The reaction was carried out at 140°C for 5 days and then cooled to room temperature. The reaction solution was filtered, and the filtrate was slowly evaporated at room temperature for one week. The product obtained after the volatilization was collected and washed to obtain a water-soluble high-nuclear rare earth tungsten polyacid cluster compound, that is, the product of Example 1 was [H2N(CH3)2]9H 5.5 Na8[Nd9(OH)6(H2O)6(NO3)(XO4)(A-α-SiW9O 34 )(A-α-SiW 10 O 37 )3]·50H2O (X=0.25Si+0.75W).

[0040] Example 2

[0041] Detection of the water-soluble high-nuclear rare earth tungsten polyacid cluster obtained in Example 1

[0042] Take a crystal photo of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound of Example 1, as shown in FIG. Figure 1 shown.

[0043] The water-soluble high-nuclear rare earth tungsten polyacid cluster compound of Example 1 was characterized by X-ray single crystal diffraction. Figure 2 As shown. The crystal belongs to the P-1 space group, and its unit cell parameters are: α=103.0350(10)°, β=106.7890(10)°, γ=97.0860(10)°,

[0044] The sample structure of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound of Example 1 was analyzed by SHELX-2018 / 3. The crystallographic parameters of the compound are shown in Table 1.

[0045] Table 1: Crystallographic parameters of water-soluble high-nuclear rare earth tungsten polyacid clusters

[0046]

[0047] a R1=Σ||Fo|-|Fc|| / Σ|Fo|, b wR2=[Σw(Fo 2 -Fc 2 ) 2 / w(Fo) 2 ] 1 / 2 ,w=1 / [σ 2 (Fo 2 )+(0.1035P) 2 +

[0048] 2714.6177P],where P=(Fo 2 +2Fc 2 ) / 3.

[0049] The X-ray powder diffraction (XRD) analysis of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound of Example 1 shows that Figure 3 shown.

[0050] Example 1 The product of water-soluble high-nuclear rare earth tungsten polyacid clusters in aqueous solution and ZnSO4 solution were respectively subjected to liquid UV-vis, such as Figure 4 shown.

[0051] Example 1 Product Water-soluble high-nuclear rare earth tungsten polyacid cluster compound is in situ converted into a new 2D honeycomb infinitely extended cluster base structure in ZnSO4 solution, as shown in FIG. Figure 5 shown.

[0052] Example 1 The product water-soluble high-nuclear rare earth tungsten polyacid cluster compound is in situ converted into a new 2D honeycomb infinitely extended cluster base layer in ZnSO4 solution. Figure 6 shown.

[0053] The time-resolved liquid UV-vis image of the product of Example 1, a water-soluble high-nuclear rare earth tungsten polyacid cluster compound, in a ZnSO4 solution, is as follows: Figure 7 The interesting structural transformation characteristics of the product of Example 1 in ZnSO4 solution and the structural stability of the transformed structure in ZnSO4 solution make the product of Example 1 a potential new and excellent additive for ZnSO4 electrolyte in AZIBs.

[0054] A series of electrolytes were prepared by mixing 1 mL of 1.0 M ZnSO4 solution with 0, 10, 20, and 30 mg of the product of Example 1, labeled as ZSPE-0, ZSPE-1, ZSPE-2, and ZSPE-3, respectively. Figure 8 As shown, at 1 mA cm -2 and 1mAh cm -2 Under these conditions, the ZSPE-0 cell exhibited increasing hysteresis accompanied by significant voltage fluctuations within 128 h (from 50 mV to 100 mV). In sharp contrast, the ZSPE-2 cell exhibited a much more stable voltage profile over more than 2000 h (from only 74 mV to 71 mV), a stability duration several dozen times longer than that of the ZSPE-0 cell. -2 At a high current density of , the ZSPE-2 battery can maintain a cycle time of more than 580 hours (e.g. Figure 9 As shown in Figure 2), it is more than 20 times longer than the battery with ZSPE-0 (27 hours). In addition, rate performance is an important criterion for evaluating battery performance. Figure 10 As shown, even at 10mA cm -2 At a high current density, the hysteresis voltage of the ZSPE-2 battery is 214 mV, which is 136 mV lower than that of the ZSPE-0 battery, indicating that the ZSPE-2 battery exhibits the fastest reaction kinetics.

[0055] In order to study the key role of the product of Example 1 in the zinc stripping / plating process, the product crystallized from the electrolyte ZSPE-2 after 200h of battery cycling was first characterized using X-ray single crystal diffraction. The results show that the product of Example 1 was in situ converted into a new 2D honeycomb infinitely extended cluster-based structure in the ZnSO4 solution, indicating that the new 2D honeycomb infinitely extended cluster-based structure formed by the reaction of the product of Example 1 with the ZnSO4 electrolyte maintained structural stability during the entire battery cycle. Subsequently, the zinc electrode after charge and discharge cycles was characterized using XRD and UV-vis. The results show that the zinc electrode cycled in ZSPE-2 exhibits XRD signals corresponding to the new 2D honeycomb infinitely extended cluster-based structure (such as Figure 11 UV-visible spectra show that the O→W charge transfer of the new 2D honeycomb infinitely extended cluster-based structure has a characteristic peak at about 260nm (as shown in Figure 2). Figure 12 The new 2D honeycomb infinitely extended cluster-based structure was further confirmed. These findings indicate that the new 2D honeycomb infinitely extended cluster-based structure not only exists stably in the electrolyte but also deposits on the surface of the zinc electrode to form a protective layer.

[0056] The experiment showed that after adding 20 mg of the product of Example 1 to 1 mL of 1.0 M ZnSO4 electrolyte, the pH value of the electrolyte increased from 4.9 to 5.9. During the charge and discharge cycle of AZIBs, side reactions such as HER will inevitably occur on the zinc foil in the ZnSO4 electrolyte, leading to corrosion of the zinc sheet. Increasing the pH value of the weakly acidic ZnSO4 electrolyte can inhibit HER. To this end, Tafel and polarization curve tests were carried out to examine the effect of the formation of a new 2D honeycomb infinitely extended cluster-based structure on the corrosion of the zinc electrode. The Tafel curve test showed that the corrosion current density (j c ) is 0.828 mA cm -2 , which is much lower than the corrosion current density in ZSPE-0 (1.206 mA cm -2 )(like Figure 13 Polarization curve (as shown). Figure 14 The results (shown in Figure 2) show that the hydrogen evolution current density of the zinc electrode in ZSPE-2 is significantly lower than that in ZSPE-0. These results indicate that the formation of a stable 2D honeycomb infinitely extended cluster-based structure and the subsequent increase in electrolyte pH can effectively suppress the corrosion of HER and the generation of byproducts, thereby positively affecting the battery life.

[0057] Afterwards, various characterization methods were used to explore the role of the protective layer on the zinc electrode. -2 After 100 cycles (200 hours) of current density, the zinc foil was subjected to XRD test (e.g. Figure 15 As shown). It can be seen that (002) Zn The crystal face has the lowest surface energy, which is conducive to the formation of crystal nuclei. According to the Wulff structure principle, it grows into a metal crystal with a thermodynamic equilibrium structure (101). Zn The crystal face is mainly conducive to the formation of dendrites. Therefore, the XRD peak intensity ratio (I 002 / I 101 ) can be used to evaluate the proportion of zinc dendrites. The ratio of ZSPE-2 is 1.1, which is higher than that of bare zinc (0.49) and ZSPE-0 (0.46), indicating that the protective layer can induce dendrite-free zinc deposition.

[0058] Then, in situ optical microscopy was used to monitor the Zn 2+ At 5 mA cm -2 The case of sedimentation for 30 minutes. Figure 16 As shown in Figure 2, the zinc anode morphology of ZSPE-2 remained flat and smooth after 30 minutes, with uniform zinc deposition and no dendrite growth. In sharp contrast, obvious zinc dendrites appeared on the surface of the zinc anode of ZSPE-0 after only 10 minutes of deposition (e.g. Figure 17 shown).

[0059] Then, chronoamperometric tests were performed to estimate the Zn 2+ Ion diffusion processes, such as Figure 18 As shown. The ZSPE-0 cell exhibited a two-dimensional (2D) diffusion process that lasted up to 300 seconds. In contrast, the ZSPE-2 cell exhibited a stable three-dimensional (3D) diffusion process after a short 2D diffusion process lasting 10 seconds. Consistent 3D diffusion was observed in the ZSPE-2 cell, which means that the nucleation process on the zinc anode was uniform. To confirm the uniform zinc deposition, the morphological evolution of the zinc anode after 100 cycles at different current densities was evaluated by scanning electron microscopy (SEM) images (as shown in Figure 2). Figure 19 As shown, ZSPE-2 is Figure 19 In the above figure, ZSPE-0 is Figure 19 (bottom image in the figure). The Zn foil surface in ZSPE-2 is dense and uniform with no protrusions, while the Zn foil surface in ZSPE-0 is irregular and exhibits dendritic growth. These results suggest that the protective layer can guide uniform Zn deposition and reduce irregularities and dendritic growth.

[0060] In addition to the above characterization methods, the deposition mechanism and process in AZIBs under different electrolytes were also studied. The study showed that a lower nucleation overpotential (ηn) can reduce the driving force of the zinc electrochemical deposition (EDZ) process, thereby promoting favorable zinc deposition kinetics as shown by the capacity-voltage curve (e.g. Figure 20 As shown in the figure, at a current density of 1 mA cm -2 When ηn is 0.05, the ηn of EDZ in the ZSPE-2 battery is 63 mV, which is lower than the ηn of the ZSPE-0 battery (76 mV), indicating that adding the product of Example 1 to the electrolyte may enhance the deposition behavior of zinc.

[0061] In addition, Zn 2+ The slow migration kinetics in AZIBs poses a challenge to the development of AZIBs and seriously affects their service life. 2+ The transfer number is 0.75, while the Zn 2+ The number of transfers is only 0.24 (e.g. Figure 21 As shown). It can be seen that adding the product of Example 1 to the electrolyte can effectively accelerate the 2+ migration, while hindering SO4 2- The Ea value of the ZSPE-2 cell is 63.9 kJ / mol (e.g. Figure 22 The Ea value of ZSPE-0 battery (69.6 kJ / mol) is lower than that of ZSPE-0 battery, indicating that adding the product of Example 1 to the electrolyte is beneficial to the Zn 2+ The transfer of EDZ improves the EDZ reaction kinetics.

[0062] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A water-soluble high-nuclear rare earth tungsten polyacid cluster compound, characterized in that: The molecular formula of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound is: [H2N(CH3)2]9H 5.5 Na8[Nd9(OH)6(H2O)6(NO3)(XO4)(A-α-SiW9O 34 )(A-α-SiW 10 O 37 )3]·50H2O, wherein X=0.25Si+0.75W; A-α represents the configuration of the metal-oxygen cluster; the water-soluble high-nuclear rare earth tungsten polyacid cluster crystallizes in the triclinic system, the space group is P-1, and the crystal structure is a three-shell structure with C3 symmetry, the innermost layer is a planar triangular NO 3- Anion; Shell 2 consists of two parts, one of which is a cup-shaped nine-nuclear {Nd9O 37 (OH)6(H2O)6} cluster, and the other part is a XO4 tetrahedron with disordered Si and W distribution. The XO4 tetrahedron and three NdO6(OH)(H2O) form a cage-like {Nd9O 33 (OH)6(H2O)6(XO4)} cluster; Shell 3 is composed of a {A-α-SiW9O 34 }Tungsten polyoxide clusters and three {A-α-SiW 10 O 37 }It is composed of tungsten polyacid clusters.

2. The water-soluble high-nuclear rare earth tungsten polyacid cluster compound according to claim 1, characterized in that: The unit cell parameters of the water-soluble high-nuclear rare earth tungsten polyacid cluster are: α=103.0350(10)°, β=106.7890(10)°, γ=97.0860(10)°, The calculated density is 3.347 g / cm 3 .

3. A method for preparing a water-soluble high-nuclear rare earth tungsten polyacid cluster compound according to any one of claims 1 to 2, characterized in that: The specific preparation process is as follows: weigh the precursor Na 10 [A-α-SiW9O 34 ]·18H2O, neodymium nitrate hexahydrate, nickel hydroxide, and dimethylamine hydrochloride are dissolved in water, and the pH of the mixed solution is adjusted to 10 with sodium hydroxide. After sufficient stirring, the mixture is transferred into a polytetrafluoroethylene reactor and placed in an oven for hydrothermal reaction. The solution after the hydrothermal reaction is filtered, and the filtrate is slowly evaporated at room temperature for one week. The product obtained after the volatilization is collected and washed to obtain purple block crystals, that is, a water-soluble high-nuclear rare earth tungsten polyacid cluster compound is obtained; the precursor Na 10 [A-α-SiW9O 34 ]·The molar ratio of 18H2O, neodymium nitrate hexahydrate, nickel hydroxide, dimethylamine hydrochloride and water is 0.095:0.19:0.32:0.93:222.22; the temperature of the hydrothermal reaction is 140°C, and the reaction time is 5 days.

4. A use of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound according to any one of claims 1 to 2, characterized in that: The water-soluble high-nuclear rare earth tungsten polyacid cluster compound is used as an electrolyte additive in the field of aqueous zinc ion batteries; When the water-soluble high-nuclear rare earth tungsten polyacid cluster compound is dissolved in a ZnSO4 solution, the cluster anions of the water-soluble high-nuclear rare earth tungsten polyacid cluster compound and the Zn 2+ The interactions between them induce in-situ connections between clusters to generate a new two-dimensional cellular base layer of infinitely extended clusters.

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