Zn 3 V 4-x M x (PO 4 ) 6 Application as positive electrode active material for zinc ion batteries

Abstract

The present invention relates to a Zn3V 4‑x M x Application of (PO4)6 (M is one or more of Ti, Cr, Mn, Fe, Co, Ni, Al, Ga, Ge; 4≥x≥0) as positive electrode active material for zinc ion batteries. 4‑x M x (PO4)6 compound is used as an active material in the positive electrode of zinc ion battery. It has good zinc ion battery charge and discharge performance, good cycle stability, and suitable operating voltage, and can be used as a zinc ion battery positive electrode material.

Description

Technical Field

[0001] The present invention relates to a Zn3V 4-x M x A zinc ion battery positive electrode material of (PO4)6 (M is one or more of Ti, Cr, Mn, Fe, Co, Ni, Al, Ga, Ge; 4≥x≥0), a preparation method, and the application of zinc ion batteries made using the material. Background Art

[0002] In recent years, with the increasingly serious environmental pollution and resource shortage caused by the burning of fossil energy, the society's demand for clean energy is also increasing, so it is particularly important to develop effective energy storage equipment. Lithium-ion batteries are a highly efficient and environmentally friendly new energy storage device that can serve as an ideal power source for various electronic devices. However, due to problems such as the shortage of lithium resources, scientists have been working hard to find alternatives. Aqueous zinc-ion batteries, as a low-cost, safe and environmentally friendly emerging energy storage system, have broad development prospects.

[0003] At present, the cathode materials used in zinc-ion batteries mainly include manganese dioxide, Prussian blue homologues, and vanadium oxides and their salts. However, these materials still have many problems: poor cycle stability and difficulty in preparation, which seriously limit the practical application of these materials. Therefore, exploring new cathode materials for zinc-ion batteries is a hot spot and difficulty in zinc-ion battery research. Among various cathode materials, polyanion materials have received widespread attention due to their stable structural framework. Summary of the invention

[0004] In view of the above-mentioned technical problems, the present invention aims to provide a Zn3V 4-x M x (PO4)6 (M is one or more of Ti, Cr, Mn, Fe, Co, Ni, Al, Ga, Ge; 4≥x≥0) is used as a positive electrode material in zinc ion batteries;

[0005] The specific technical solutions are as follows:

[0006] A Zn3V 4-x M x Application of (PO4)6 as positive electrode active material for zinc ion batteries, the Zn3V 4-x M x (PO4)6 compounds are used as active materials in the positive electrode of zinc-ion batteries.

[0007] Specifically, a Zn3V 4-x M x Application of (PO4)6 as positive electrode active material for zinc ion batteries, and the Zn3V 4-x M xM in (PO4)6 is one or more of Ti, Cr, Mn, Fe, Co, Ni, Al, Ga, Ge; 4≥x≥0).

[0008] The positive electrode active material of the zinc ion battery is Zn3V 4-x M x (PO4)6 material.

[0009] The Zn3V provided by the present invention 4-x M x (PO4)6 zinc ion battery positive electrode material, prepared by hydrothermal method Zn3V 4-x M x (PO4)6, the steps are as follows:

[0010] 1) Ingredients: Add the Zn-containing compound, the V-containing compound and the P-containing compound into deionized water at 80° C. in a molar ratio of Zn:V:M:P:oxalic acid:carbon source precursor of 3:(4-x):x:6:6:6 and stir until a uniform blue solution is formed;

[0011] 2) Transfer the stirred solution to a polytetrafluoroethylene liner, react at 180°C for 48 hours, and then cool to room temperature;

[0012] 3) Material synthesis: The hydrothermal product was heated from room temperature to 800°C at a rate of 3-5°C / min; kept warm for 8 hours; after the reaction was complete, it was cooled to room temperature at a rate of 1-50°C / h to obtain Zn3V 4-x M x (PO4)6 material;

[0013] The Zn-containing compound is one or more of Zn oxide, Zn acetate, Zn halide, Zn carbonate, Zn sulfate, Zn phosphate, Zn nitrate or Zn oxalate;

[0014] The V-containing compound is one or more of V oxide, ammonium metavanadate, V sulfate, V nitrate, V halide, V oxalate or V phosphate;

[0015] The M-containing compound is one or more of an oxide of M, a nitrate of M, an acetate of M, a halide of M, a carbonate of M, a sulfate of M, a phosphate of M, and an oxalate of M;

[0016] The P-containing compound is one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and phosphorus pentoxide;

[0017] The carbon source precursor is one or more of sucrose, polyvinyl alcohol, polyethylene glycol, citric acid, glucose and activated carbon.

[0018] Preparation of Zn3V by sol-gel method 4-x M x (PO4)6 zinc ion battery positive electrode material, the steps are as follows:

[0019] 1) Ingredients: Add Zn-containing compound, V-containing compound, M-containing compound and P-containing compound into deionized water at 80°C in a molar ratio of Zn:V:M:P:oxalic acid:carbon source precursor of 3:(4-x):x:6:6:6, and stir until a uniform blue solution is formed (M is one or more of Ti, Cr, Mn, Fe, Co, Ni, Al, Ga, Ge; 4≥x≥0), and continue stirring until a sol is formed;

[0020] 2) drying the sol at 100°C, grinding it into powder and pre-treating it;

[0021] The pretreatment is heating from room temperature to 350° C. for more than 4 hours, and then cooling to room temperature;

[0022] 3) Material synthesis: The material pretreated in step 2) was heated to 800°C at a rate of 3-5°C; kept warm for 8 hours; after the reaction was sufficient, cooled to room temperature at a rate of 1-50°C / h to obtain Zn3V 4-x M x (PO4)6 material;

[0023] The Zn-containing compound is one or more of Zn oxide, Zn acetate, Zn halide, Zn carbonate, Zn sulfate, Zn phosphate, Zn nitrate or Zn oxalate;

[0024] The V-containing compound is one or more of V oxide, ammonium metavanadate, V sulfate, V nitrate, V halide, V oxalate or V phosphate;

[0025] The M-containing compound is one or more of an oxide of M, a nitrate of M, an acetate of M, a halide of M, a carbonate of M, a sulfate of M, a phosphate of M, and an oxalate of M;

[0026] The P-containing compound is one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, and phosphorus pentoxide;

[0027] The carbon source precursor is one or more of sucrose, polyvinyl alcohol, polyethylene glycol, citric acid, glucose and activated carbon.

[0028] Beneficial Effects

[0029] Zn3V of the present invention 4-x M x (PO4)6 is synthesized for the first time. 4-xM x (PO4)6 as a positive electrode active material for zinc ion batteries has high specific capacity, rate performance and cycle stability. 4-x M x (PO4)6 zinc-ion battery positive electrode material has a high specific capacity of 180 mAh / g, an operating voltage between 0.1-1.9 V, and still has a specific capacity of 120 mAh / g at a rate of 30 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention Zn3V 4-x M x SEM image of (PO4)6 zinc-ion battery positive electrode material.

[0031] Figure 2 The Zn3V 4-x M x X-ray diffraction pattern of polycrystalline powder of (PO4)6.

[0032] Figure 3 The Zn3V 4-x M x Crystal structure of (PO4)6 zinc.

[0033] Figure 4 The Zn3V 4-x M x The charge and discharge curves of (PO4)6 zinc cathode material at 2C rate and 0.1-1.9V.

[0034] Figure 5 The Zn3V 4-x M x Rate performance curve of (PO4)6 zinc cathode material. DETAILED DESCRIPTION

[0035] Example 1 Hydrothermal preparation of Zn3V4(PO4)6 positive electrode material

[0036] Dissolve 6mmolH2C2O4∙2H2O in 35mL deionized water, then add 4mmolNH4VO3, stir in a constant temperature water bath at 70-80℃ until the solution turns blue, then add 6mmolNH4H2PO4, 3mmol(CH3COO)2Zn∙2H2O, and 6mmolcitric acid and continue stirring for 30min to form a uniform solution. Transfer the solution to a polytetrafluoroethylene liner, tighten the reactor shell, and place it in an oven at 180℃ for 48 hours. Dry the resulting hydrothermal product at 100℃ for 6 hours, grind it into powder and place it in a porcelain boat, place the porcelain boat in a tube furnace, and heat the furnace to 350℃ at a rate of 3℃ / min in a N2 atmosphere, keep it warm for 4 hours, and finally cool it to room temperature at a rate of 20℃ / min. The pre-fired material is taken out, ground into powder, and then transferred to a porcelain boat again. The porcelain boat is placed in a tube furnace. The furnace is heated to 800°C at a rate of 3°C / min in a N2 atmosphere, kept warm for 8 hours, and finally cooled to room temperature at a rate of 20°C / min. The obtained product is taken out and ground into powder to obtain a Zn3V4(PO4)6 compound.

[0037] like Figure 1 As shown, it is a black powder. Figure 2 Its crystal structure is shown in Figure 3 As shown. Figure 3 As can be seen in the figure, it is composed of two octahedrons V2O 10 The three-dimensional framework network structure composed of ZnO6 octahedron and ZnO5 triangular bipyramid can promote the 2+ transmission.

[0038] Example 2 Zn3V 3.5 Cr 0.5 Sol-gel preparation of (PO4)6 cathode materials

[0039] Dissolve 6mmolH2C2O4∙2H2O in 35mL deionized water, then add 3.5mmolNH4VO3, 0.5mmolCr(NO3)3 and stir in a constant temperature water bath at 70-80℃ until the solution turns blue, then add 6mmolNH4H2PO4, 3mmol(CH3COO)2Zn∙2H2O, 6mmolsucrose, and continue stirring to form a green sol. Place the sol in a 100℃ oven for about 10 hours to obtain a comprehensive precursor, grind the precursor into powder and place it in a porcelain boat, put the porcelain boat into a tube furnace, raise the furnace to 350℃ at a heating rate of 3℃ / min in a N2 atmosphere, keep it warm for 4 hours, and finally cool it to room temperature at a rate of 20℃ / min. The pre-fired material was taken out and ground into powder, and then placed in a porcelain boat again. The porcelain boat was placed in a tube furnace, and the furnace was heated to 800°C at a rate of 3°C / min in a N2 atmosphere, and kept warm for 8 hours, and finally cooled to room temperature at a rate of 20°C / min. The obtained product was taken out and ground into powder to obtain Zn3V 3.5 Cr 0.5 (PO4)6 compounds.

[0040] The materials obtained in Examples 1 and 2 were used as active materials, and were rolled into thin films according to the mass ratio of active material, conductive carbon black and binder of 7:2:1. After drying at 100°C in vacuum, they were cut into electrode sheets with a diameter of 14 mm using a slicer. The mass of the active material was weighed and calculated, and then pressed onto a stainless steel mesh. At the same time, a zinc sheet was used as the negative electrode, a double-layer non-woven fabric was used as a diaphragm, and a 2mol / L ZnSO4 solution was used as the electrolyte. The pressed stainless steel electrode sheet was immersed in a 2mol / L ZnSO4 electrolyte and purged with N2 for 30 minutes, and then assembled into a button cell. The assembled battery was then subjected to electrochemical testing, and tested under constant current conditions of 0.1-1.9V. The test results showed that Zn3V4(PO4)6 and Zn3V 3.5 Cr 0.5 The electrochemical performance of (PO4)6 has been significantly improved. Among them, the discharge capacity of Zn3V4(PO4)6 reached 168mAhg -1 , 117 mAhg at 30 times -1 The specific capacity of Figure 4 and 5 As shown, we can see that Zn3V 3.5 Cr 0.5 (PO4)6 has a good discharge specific capacity of 180 mAhg -1 , and has good rate performance, still 120 mAhg at a rate of 30 -1 Specific capacity.

[0041] The Zn3V 4-x Mx (PO4)6 compound is used as an active material in the positive electrode of zinc ion battery. It has good zinc ion battery charge and discharge performance, good cycle stability, and suitable operating voltage. It can be used as a positive electrode material for zinc ion batteries.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Zn3V 3.5 Cr 0.5 The application of (PO4)6 as a positive electrode active material for zinc ion batteries is characterized by: The Zn3V 3.5 Cr 0.5 (PO4) 6， The preparation was carried out according to the following method, the steps are as follows: 6mmolH2C2O4·2H2O was dissolved in 35mL deionized water, and then 3.5mmolNH4VO3 and 0.5mmolCr(NO3)3 were added and stirred in a constant temperature water bath at 70-80℃ until the solution turned blue. Then 6mmolNH4H2PO4, 3mmol(CH3COO)2Zn·2H2O and 6mmolsucrose were added and stirred continuously to form a green sol. The sol was placed in an oven at 100℃ for 10 hours to obtain a comprehensive precursor. The pre-fired material was taken out and ground into powder and placed in a porcelain boat again, which was placed in a tube furnace. The furnace was heated to 350°C at a heating rate of 3°C / min in a N2 atmosphere, kept warm for 4 hours, and finally cooled to room temperature at a rate of 20°C / min. The pre-fired material was taken out and ground into powder and placed in a porcelain boat again, which was placed in a tube furnace. The furnace was heated to 800°C at a heating rate of 3°C / min in a N2 atmosphere, kept warm for 8 hours, and finally cooled to room temperature at a rate of 20°C / min. The obtained product was taken out and ground into powder to obtain Zn3V 3.5 Cr 0.5 (PO4)6.

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