Sodium ion battery positive electrode material precursor, preparation method thereof, sodium ion battery positive electrode material, sodium ion battery and electrical device

Abstract

The present invention provides a sodium ion battery positive electrode material precursor, a method for preparing the same, a sodium ion battery positive electrode material, a sodium ion battery and an electric device, which are in the field of batteries. The sodium ion battery positive electrode material precursor has the general formula Ni x Mn y Fe 1-x-y (OH)2, where x satisfies 0.15≦x≦0.35 and y satisfies 0.2≦y≦0.5, the content of S element in the sodium ion battery positive electrode material precursor is 4000 ppm or less, and the mass ratio of Na / S is 1.5 or less. According to the sodium ion battery positive electrode material precursor of the present application, the prepared positive electrode material has good element uniformity, few structural defects, controllable particle size, good sphericity, high energy density, and retains a trace amount of sulfur impurity content, so that when the sulfur content is at the same level, the lower the ratio of sodium to sulfur, the better the battery capacity, initial coulombic efficiency and cycle performance.

Description

[Technical field]

[0001] The present application relates to the field of batteries, and in particular to a sodium ion battery positive electrode material precursor, a preparation method thereof, a sodium ion battery positive electrode material, a sodium ion battery and an electric device. CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority based on a Chinese application filed with the State Intellectual Property Office of the People's Republic of China on September 28, 2022, bearing application number 202211188250.3 and entitled "Sodium ion battery positive electrode material precursor, preparation method thereof, sodium ion battery positive electrode material, sodium ion battery and electrical device", the entire contents of which are incorporated herein by reference. [Background technology]

[0003] The problem of scarcity of lithium resources and high cost limits the application of lithium-ion batteries in the field of large-scale energy storage. Sodium-ion batteries, which are abundant in resources and relatively low in cost, are expected to replace lithium-ion batteries in this field, and the positive electrode material is a crucial factor that limits the development of sodium-ion batteries. Layered transition metal oxides are sodium-ion battery positive electrode materials with relatively high capacity and relatively good stability, and their composition and working principle are similar to those of lithium-ion batteries, so they have attracted the attention of researchers. However, the commercialization of such materials is still hindered by problems such as low energy density and relatively short cycle life.

[0004] How to solve the above problems of the sodium ion battery and synthesize a positive electrode material with higher energy density, higher capacity and longer cycle life has become a challenge in the art. Summary of the Invention

[0005] An object of the present application is to provide a sodium ion battery positive electrode material precursor, a preparation method thereof, a sodium ion battery positive electrode material, a sodium ion battery, and an electrical device, which can solve the above problems. To achieve the above objectives, the present application adopts the following technical solutions:

[0006] The sodium ion battery positive electrode material precursor has the general formula Ni x Mn y Fe 1-x-y (OH) 2 where x satisfies 0.15≦x≦0.35, y satisfies 0.2≦y≦0.5, and the content of S element in the sodium ion battery positive electrode material precursor is 4000 ppm or less. Optionally, the precursor further contains Na, and the mass ratio of Na / S is 1.5 or less.

[0007] Optionally, the sodium ion battery positive electrode material precursor has: A. a content of S element in the sodium ion battery positive electrode material precursor is 800 to 3700 ppm, and a mass ratio of Na / S is 1.18 or less, and optionally a content of S element in the sodium ion battery positive electrode material precursor is 1700 to 2800 ppm, and a mass ratio of Na / S is 0.45 or less; B. a D50 of the sodium ion battery positive electrode material precursor is 3 to 14 μm, and preferably 5 to 10 μm; C. a specific surface area of ​​the sodium ion battery positive electrode material precursor is 6 to 11 m 2 / g, preferably 6 to 8m 2 / g, and D. The tap density of the sodium ion battery positive electrode material precursor is 1.7 g / cm 3 or more, preferably 1.9 to 2.3 g / cm 3 and E. the sodium ion battery positive electrode material precursor has a spherical or nearly spherical shape.

[0008] The present application further provides a method for preparing a sodium-ion battery positive electrode material precursor, the method includes the steps of: mixing raw materials including a nickel source, a manganese source, a ferrous iron source, and water to obtain a mixed salt solution, mixing materials including water, a part of a complexing agent, and a part of a precipitating agent to obtain a base solution, adding the remaining complexing agent, the remaining precipitating agent, and the mixed salt solution to the base solution to carry out a co-precipitation reaction, obtaining a solid material by solid-liquid separation, and then carrying out alkali washing, water washing, and drying to obtain a sodium-ion battery positive electrode material precursor, where at least one of the nickel source, the manganese source, and the ferrous iron source includes a sulfate salt.

[0009] Optionally, the method for preparing a sodium ion battery cathode material precursor includes: a. the nickel source includes one or more of nickel sulfate, nickel nitrate, and nickel acetate; the manganese source includes one or more of manganese sulfate, manganese nitrate, and manganese acetate; and the ferrous source includes one or more of ferrous sulfate, ferrous nitrate, and ferrous chloride; b. the concentration of the mixed salt solution is 1.0-2.2 mol / L; c. the precipitating agent includes at least one of sodium hydroxide and potassium hydroxide, and the complexing agent includes one or more of ammonium bicarbonate, ammonium carbonate, and aqueous ammonia; d. the complexing agent is used in the form of an aqueous solution and has a concentration of 0.3-8 mol / L, and optionally has a concentration of 0.3-2.0 mol / L; e. the temperature of the water used in preparing the base solution is 40-60° C., and the temperature of the prepared base solution is raised to 40-60° C., and the pH of the base solution is adjusted to 1. f. The flow rate of the mixed salt solution added to the base solution is 2% / h-8% / h of the available volume of the reaction vessel, the flow rate of the precipitant added to the base solution is 0.08% / h-0.32% / h of the available volume of the reaction vessel, and the flow rate of the complexing agent added to the base solution is 0.04% / h-0.16% / h of the available volume of the reaction vessel, g. The coprecipitation reaction is carried out under stirring conditions, and the stirring speed is 300-1000 r / min, h. The coprecipitation reaction is carried out under stirring conditions. The washing is stopped when the D50 of the sodium ion battery positive electrode material precursor becomes 3 to 14 μm; i. the end point of the water washing (i.e., the criterion for stopping the water washing) is when the electrical conductivity of the washing liquid (i.e., the mother liquid obtained by filtration after washing) becomes less than 50 μS / cm; the drying is performed at a temperature of 120 to 180° C. for a time of 10 to 16 hours; and the drying is stopped when the moisture content of the material becomes 0.6 wt % or less. Optionally, the flow rates at which the remaining complexing agent, the remaining precipitating agent, and the mixed salt solution are added to the base solution are controlled in stages.

[0010] Optionally, the stepwise control includes a first step and a second step, and in the first step, a first flow rate of adding the mixed salt solution to the base solution is 2% / h to 4% / h of the available volume of the reaction vessel, a first flow rate of adding the precipitant to the base solution is 0.08% / h to 0.16% / h of the available volume of the reaction vessel, and a first flow rate of adding the complexing agent to the base solution is 0.04% / h to 0.20% / h of the available volume of the reaction vessel until a first precipitate having a D50 of 3 to 5 μm is obtained. h~0.08% / h, in a second step, a second flow rate for adding the mixed salt solution to the base solution is 4% / h~8% / h of the available volume of the reaction kettle, a second flow rate for adding the precipitant to the base solution is 0.16~0.32% / h of the available volume of the reaction kettle, and a second flow rate for adding the complexing agent to the base solution is 0.08~0.16% / h of the available volume of the reaction kettle until the D50 of the sodium ion battery positive electrode material precursor is 6~14 μm. The usable volume of the reaction kettle is the remaining volume of the reaction kettle after adding the base solution without splashing when stirring.

[0011] The first flow rate and the second flow rate of each of the above solutions are adjusted according to the D50 of the target material. The present application further provides a sodium-ion battery cathode material, the sodium-ion battery cathode material being prepared by reacting a sodium-ion battery cathode material precursor with a sodium source, Optionally, a molar ratio of the sum of nickel, manganese, and iron in the sodium-ion battery cathode material precursor to sodium in the sodium source is 1:(1.02 to 1.07); Optionally, the reaction is calcined by programmed heating; The temperature is raised to 780-880°C at a rate of 2-4°C / min, and firing is carried out for 10-20 hours.

[0012] The present application further provides a sodium-ion battery, the raw material of which includes a sodium-ion battery positive electrode material. The present application further provides an electrical device comprising a sodium ion battery. Compared with the prior art, the present application has at least the following beneficial effects:

[0013] The sodium ion battery positive electrode material precursor according to the present application is based on nickel manganese iron hydroxide, and the sulfur element content and the mass ratio of sodium to sulfur are optimized to improve the material performance. As long as a trace amount of sulfur impurities is maintained, the lower the ratio of sodium to sulfur is, under the same level of sulfur content, the better the battery capacity, initial coulombic efficiency and cycle performance are. At 2 to 4.2 V, the initial discharge capacity at 0.1 C is more than 165 mAh / g, the discharge capacity at 1 C is more than 154 mAh / g, the capacity retention rate after 50 cycles under 1 C condition is more than 78%, and the charge and discharge speed is fast under the condition of high cycle efficiency.

[0014] Specifically, when a certain amount of non-sodium sulfate is present on the surface of the particles in the sodium ion battery positive electrode material precursor, it can suppress the lattice cracks that occur during the charge and discharge process of the material, and when dissolved in the electrolyte, it can contribute to the diffusion of metal cations and reduce the DCR (direct current resistance). When the sulfur content is increased, the battery capacity can be improved, and the cycle performance and rate performance can be improved. However, if the content of sulfate ions is too high, the defects in the positive electrode material will increase, so the crystallinity will decrease, and sodium sulfate cannot improve the performance in terms of capacity. Therefore, the higher the sulfur content, the lower the initial charge and discharge capacity, and the damage of the equipment due to the volatilization of sulfate during the sintering process may occur. In addition, the high sodium content in the precursor (sodium sulfate or sodium hydroxide) will reduce the crystallinity of the precursor, which is unfavorable to the battery performance. Therefore, when the sulfur content is at the same level, the lower the ratio of sodium to sulfur, the better the battery capacity, initial coulombic efficiency and cycle performance, and the lower the cost.

[0015] The positive electrode material precursor prepared by the method for preparing a sodium ion battery positive electrode material precursor according to the present application has good element uniformity, few structural defects, controllable particle size, good sphericity, low sodium content, and moderate sulfur content. The sodium ion battery positive electrode material, the sodium ion battery, and the electrical device according to the present application have excellent electrical properties. [Brief description of the drawings]

[0016] In order to more clearly describe the technical solutions of the embodiments of the present application, the drawings used in the embodiments are briefly described below. The drawings described are only for illustrating some embodiments of the present application, and are not intended to limit the scope of the present application. [Figure 1] 1 is a scanning electron microscope photograph of the precursor obtained in Example 1. [Diagram 2] 1 is an XRD pattern of the precursor obtained in Example 1. [Diagram 3] 4 is a graph showing the change in discharge capacity versus sulfur content in some examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The sodium ion battery positive electrode material precursor has the general formula Ni x Mn y Fe 1-x-y (OH) 2 where x satisfies 0.15≦x≦0.35 and y satisfies 0.2≦y≦0.5. The content of S element in the sodium ion battery positive electrode material precursor is 4000 ppm or less. Optionally, the precursor further contains Na, and the mass ratio of Na / S is 1.5 or less.

[0018] Optionally, x is 0.15, 0.20, 0.25, 0.30, 0.35 or any other value in the range of 0.15 to 0.35, and y is 0.2, 0.3, 0.4, 0.5 or any other value in the range of 0.2 to 0.5. In an alternative embodiment, the sodium ion battery cathode material precursor meets at least one of the following conditions:

[0019] A. The content of S element in the sodium ion battery positive electrode material precursor is 800-3700 ppm, and the mass ratio of Na / S is 1.18 or less, and optionally, the content of S element in the sodium ion battery positive electrode material precursor is 1700-2800 ppm, and the mass ratio of Na / S is 0.45 or less.

[0020] Optionally, the content of S element in the sodium ion battery positive electrode material precursor is 800 ppm, 900 ppm, 1000 ppm, 1100 ppm, 1200 ppm, 1300 ppm, 1400 ppm, 1500 ppm, 1600 ppm, 1700 ppm, 1800 ppm, 1900 ppm, 2000 ppm, 2100 ppm, 2200 ppm, 2300 ppm, 2400 ppm, 2500 ppm, 2600 ppm, 2700 ppm, 2800 ppm, 2900 ppm, 3000 ppm, 3100 ppm, 3200 ppm, 3300 ppm, 3400 ppm, 3500 ppm, 3600 ppm, 3700 ppm, 3800 ppm, 3900 ppm, 4000 ppm, 4100 ppm, 4200 ppm, 4300 ppm, 4400 ppm, 4500 ppm, 4600 ppm, 4700 ppm, 4800 ppm, 4900 ppm, 5000 ppm, 5100 ppm, 5200 ppm, 5300 ppm, 5400 ppm, 5500 ppm, 5600 ppm, 5700 ppm, 5800 ppm, 5900 ppm, 6000 ppm, 6100 ppm, 6200 ppm, 6300 ppm, 6400 ppm, 6500 ppm, 6600 ppm, 6700 ppm, 6800 ppm, 6900 ppm, 7000 ppm, 7100 ppm, 7200 ppm, 7300 ppm, 7400 ppm, 7500 ppm, 7600 ppm, 7700 ppm, 78 200 ppm, 3300 ppm, 3400 ppm, 3500 ppm, 3600 ppm, 3700 ppm or any other value in the range of 800 to 3700 ppm, and the mass ratio of Na / S is 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.18 or any other value in the range of less than or equal to 1.18. B. The D50 of the sodium ion battery positive electrode material precursor is 3 to 14 μm, and preferably 5 to 10 μm.

[0021] Optionally, the D50 of the sodium ion battery cathode material precursor is 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or any other value in the range of 3 to 14 μm. C. The specific surface area of ​​the sodium ion battery positive electrode material precursor is 6 to 11 m 2 / g, preferably 6 to 8m 2 / g.

[0022] Optionally, the specific surface area of ​​the sodium ion battery cathode material precursor is 6 m2 / g, 7m 2 / g, 8m 2 / g, 9m 2 / g, 10m 2 / g, 11m 2 / g or 6~11m 2 / g and any other value within the range. D. The tap density of the sodium ion battery positive electrode material precursor is 1.7 g / cm 3 or more, preferably 1.9 to 2.3 g / cm 3 It is.

[0023] Optionally, the tap density of the sodium ion battery cathode material precursor is 1.7 g / cm 3 , 1.8g / cm 3 , 1.9g / cm 3 , 2.0g / cm 3 , 2.1g / cm 3 , 2.2g / cm 3 , 2.3g / cm 3 or 1.9~2.3g / cm 3 and any other value in the range. E. The sodium ion battery cathode material precursor exhibits a spherical or nearly spherical shape. The present application further provides a method for preparing a sodium ion battery positive electrode material precursor.

[0024] Raw materials including a nickel source, a manganese source, a ferrous source, and water are mixed to obtain a mixed salt solution, and materials including water, a portion of a complexing agent, and a portion of a precipitating agent are mixed to obtain a base solution.

[0025] The remaining complexing agent, the remaining precipitating agent, and the mixed salt solution are added to the base solution to carry out a coprecipitation reaction, and a solid substance is obtained by solid-liquid separation. The solid substance is then washed with an alkali, washed with water, and dried to obtain a sodium ion battery positive electrode material precursor. At least one of the nickel source, the manganese source and the ferrous source comprises a sulfate salt. In an alternative embodiment, the method for preparing a sodium-ion battery positive electrode material precursor satisfies at least one of the following conditions:

[0026] a. the nickel source includes one or more of nickel sulfate, nickel nitrate, and nickel acetate; the manganese source includes one or more of manganese sulfate, manganese nitrate, and manganese acetate; and the ferrous source includes one or more of ferrous sulfate, ferrous nitrate, and ferrous chloride. b. The concentration of the mixed salt solution is 1.0 to 2.2 mol / L.

[0027] Optionally, the concentration of the mixed salt solution is 1.0 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2.0 mol / L, 2.1 mol / L, 2.2 mol / L or any other value in the range of 1.0-2.2 mol / L.

[0028] c. The precipitating agent includes at least one of sodium hydroxide and potassium hydroxide, and the complexing agent includes one or more of ammonium bicarbonate, ammonium carbonate, and aqueous ammonia. d. The complexing agent is used in the form of an aqueous solution, with a concentration of 0.3-8 mol / L, optionally with a concentration of 0.3-2.0 mol / L.

[0029] Optionally, the concentration of the aqueous complexing agent solution is 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2.0 mol / L, 3.0 mol / L, 4.0 mol / L, 5.0 mol / L, 6.0 mol / L, 7.0 mol / L, 8.0 mol / L or any other value in the range of 0.3 to 8.0 mol / L.

[0030] e. The temperature of the water used to prepare the base solution is set to 40-60°C, and the temperature of the prepared base solution is raised to 40-60°C by heating, and the pH of the base solution is set to 10-12.

[0031] Optionally, the temperature of the water is 40° C., 50° C., 60° C. or any other value in the range of 40-60° C., and the pH of the base solution is 10.0, 10.5, 11.0, 11.5, 12.0 or any other value in the range of 10-12.

[0032] f. The flow rate of the mixed salt solution is added to the base solution is 2% / h~8% / h of the available volume of the reaction kettle, the flow rate of the precipitating agent is added to the base solution is 0.08% / h~0.32% / h, and the flow rate of the complexing agent is added to the base solution is 0.04% / h~0.16% / h.

[0033] Optionally, the flow rate of the mixed salt solution added to the base solution is 2% / h, 3% / h, 4% / h, 5% / h, 6% / h, 7% / h, 8% / h, or any other value in the range of 2-8% / h of the available volume of the reaction vessel, and the flow rate of the precipitant added to the base solution is 0.08% / h, 0.10% / h, 0.15% / h, 0.20% / h, 0.25% / h, 0.30% / h, 0.32% / h, or 0.08% / h to 0.5% / h of the available volume of the reaction vessel. 0.04% / h, 0.05% / h, 0.06% / h, 0.07% / h, 0.08% / h, 0.09% / h, 0.10% / h, 0.11% / h, 0.12% / h, 0.13% / h, 0.14% / h, 0.15% / h, 0.16% / h or any other value in the range of 0.04% / h to 0.16% / h of the available volume of the reaction kettle. g. The coprecipitation reaction is carried out under stirring conditions, and the stirring speed is 300-1000 r / min.

[0034] Optionally, the stirring speed is 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min, 800 r / min, 900 r / min, 1000 r / min or any other value in the range of 300-1000 r / min. h. The co-precipitation reaction is stopped when the D50 of the sodium ion battery positive electrode material precursor is 3-14 μm.

[0035] Optionally, the D50 of the product upon stopping the co-precipitation reaction is 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or any other value within the range of 3 to 14 μm.

[0036] i. The end point of the water washing (i.e., the criterion for stopping the water washing) is when the conductivity of the washing liquid (i.e., the mother liquor obtained by filtration after washing) becomes less than 50 μS / cm, and the drying is performed at a temperature of 120-180°C for a time of 10-16 hours, and the drying is stopped when the moisture content of the material becomes 0.6 wt% or less.

[0037] Optionally, the conductivity of the cleaning solution at the time when the water washing is stopped is 10 μS / cm, 20 μS / cm, 30 μS / cm, 40 μS / cm, 49 μS / cm or any other value in the range of less than 50 μS / cm, the drying is at a temperature of 120° C., 130° C., 140° C., 150° C., 160° C., 170° C., 180° C. or any other value in the range of 120-180° C., and the drying time is 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h or any other value in the range of 10-16 h, and the moisture content of the material at the time when the drying is stopped is 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, or 0.6 wt% or less. In one alternative embodiment, the flow rates at which the remaining complexing agent, remaining precipitating agent and mixed salt solution are added to the base solution are controlled in stages. In one alternative embodiment, the stepwise controlling includes a first step and a second step.

[0038] In the first stage, a first flow rate for adding the mixed salt solution to the base solution is 2% / h-4% / h of the available volume of the reaction vessel, a first flow rate for adding the precipitant to the base solution is 0.08% / h-0.16% / h of the available volume of the reaction vessel, and a first flow rate for adding the complexing agent to the base solution is 0.04% / h-0.08% / h of the available volume of the reaction vessel, until a first precipitate having a D50 of 3-5 μm is obtained.

[0039] Optionally, the first flow rate at which the mixed salt solution is added to the base solution is 2% / h, 3% / h, 4% / h or any other value in the range of 2% / h to 4% / h of the available volume of the reaction kettle, and the first flow rate at which the precipitating agent is added to the base solution is 0.08% / h, 0.09% / h, 0.10% / h, 0.11% / h, 0.12% / h, 0.13% / h, 0. and the first flow rate at which the complexing agent is added to the base solution is 0.04% / h, 0.05% / h, 0.06% / h, 0.07% / h, 0.08% / h, or any other value within the range of 0.04% / h to 0.08% / h of the available volume of the precipitant kettle.

[0040] In the second stage, the second flow rate of adding the mixed salt solution to the base solution is 4% / h-8% / h of the available volume of the reaction kettle, the second flow rate of adding the precipitant to the base solution is 0.16% / h-0.32% / h of the available volume of the reaction kettle, and the second flow rate of adding the complexing agent to the base solution is 0.08% / h-0.16% / h of the available volume of the reaction kettle, until the D50 of the sodium ion battery positive electrode material precursor is 6-14 μm.

[0041] Optionally, the second flow rate at which the mixed salt solution is added to the base solution is 4% / h, 5% / h, 6% / h, 7% / h, 8% / h, or any other value in the range of 4% / h to 8% / h of the available volume of the reaction kettle, and the second flow rate at which the precipitant is added to the base solution is 0.16% / h, 0.18% / h, 0.20% / h, 0.22% / h, 0.24% / h, 0.26% / h, 0.28% / h, 0.30% of the available volume of the reaction kettle. / h, 0.32% / h or any other value in the range of 0.16% / h to 0.32% / h, and the second flow rate at which complexing agent is added to the base solution is 0.08% / h, 0.09% / h, 0.10% / h, 0.11% / h, 0.12% / h, 0.13% / h, 0.14% / h, 0.15% / h, 0.16% / h or any other value in the range of 0.08% / h to 0.16% / h of the available volume of the reaction kettle. A stepwise control of the mixed salt flow rate contributes to maintaining some sulfur content in the precursor structure and to obtaining the desired sulfur content in the washing step.

[0042] The present application further provides a sodium-ion battery cathode material, the sodium-ion battery cathode material being prepared by reacting a sodium-ion battery cathode material precursor with a sodium source.

[0043] In one alternative embodiment, the molar ratio of the sum of nickel, manganese, and iron in the sodium ion battery positive electrode material precursor to sodium in the sodium source is 1:(1.02 to 1.07). In one alternative embodiment, the reaction is baked using a programmed temperature ramp. The temperature is raised to 780-880°C at a rate of 2-4°C / min, and firing is carried out for 10-20 hours.

[0044] Optionally, the molar ratio of the sum of nickel, manganese and iron in the sodium ion battery cathode material precursor to sodium in the sodium source is 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07 or any other value in the range of 1:(1.02-1.07), the heating rate is 2°C / min, 3°C / min, 4°C / min or any other value in the range of 2-4°C / min, the temperature at the end of the heating is 780°C, 800°C, 820°C, 840°C, 860°C, 880°C or any other value in the range of 780-880°C, and the firing time is 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours or any other value in the range of 10-20 hours. The present application further provides a sodium ion battery. The raw materials of the sodium ion battery include a sodium ion battery positive electrode material. The present application further provides an electrical device comprising a sodium ion battery. The electric device here may be an electric vehicle, a mobile battery, a mobile phone, or the like.

[0045] The present application will be described in detail below with specific examples. Those skilled in the art will understand that the following examples are merely for the purpose of illustrating the present application, and are not intended to limit the scope of the present application. In the examples, the specific conditions are not specified, and may be performed under conventional conditions or conditions recommended by the manufacturer. For reagents or equipment used that are not specified by manufacturer, conventional products available on the market may be used. Example 1 This example provides a sodium ion battery positive electrode material precursor, the preparation method of the sodium ion battery positive electrode material precursor is as follows:

[0046] Nickel sulfate, manganese sulfate, and ferrous sulfate (molar ratio 1:1:1) were prepared into a 2 mol / L mixed salt solution, and this was added to a reaction kettle equipped with a stirrer and mixed with 50°C deionized water, 10 mol / L sodium hydroxide solution, and 8 mol / L ammonia water to prepare a base solution with a pH of 11.5. The temperature of the reactor is raised to 50°C, and at a stirring speed of 600r / min, ammonia water, sodium hydroxide solution and mixed salt solution are slowly added, the first flow rate of the mixed salt solution added to the base solution is 2% / h of the available volume of the reactor, the first flow rate of the sodium hydroxide solution added to the base solution is 0.08% / h of the available volume of the reactor, the first flow rate of the ammonia water added to the base solution is 0.04% / h of the available volume of the reactor, and the first flow rate of the ammonia water added to the base solution is 0.04% / h of the available volume of the reactor, until a first precipitate with D50 of 3.0μm is obtained, and then the second flow rate of the mixed salt solution is increased to 4% / h of the available volume of the reactor, and the second flow rates of the ammonia water solution and the sodium hydroxide solution are synchronously adjusted to 0.12% / h and 0.20% / h of the available volume of the reactor, respectively, until the sodium ion battery positive electrode material precursor has D50 of 10.0μm.

[0047] The sodium ion battery positive electrode material precursor precipitate was centrifuged and washed, and then alkaline washed several times using 0.5 mol / L sodium hydroxide solution, and then washed several times using deionized water at 70°C. When the electrical conductivity of the mother liquor obtained by filtration after washing was less than 50 μS / cm, the washing was completed, and so on.

[0048] After centrifugation and washing, the solid material was dispersed and placed in a blower oven for drying and dehydration at 120°C for 12 hours. When the moisture content of the material reached 0.4 wt%, the drying was stopped, and the material was then removed, sealed, and stored.

[0049] The resulting dried material was sieved, demagnetized, and other processes to determine that the molecular formula was Ni 0.33 Mn 0.33 Fe 0.34 (OH) 2 As a result, a sodium ion battery positive electrode material precursor was obtained.

[0050] FIG. 1 is a scanning electron microscope photograph of the obtained sodium ion battery positive electrode material precursor. As shown in FIG. 1, the prepared sodium ion battery positive electrode material precursor has a spherical structure with good sphericity and a relatively narrow particle size distribution. FIG. 2 is the XRD pattern of the obtained sodium ion battery positive electrode material precursor. As shown in the XRD of FIG. 2, the sodium ion battery positive electrode material precursor corresponds to an α-type hydroxide. This Example 1 further provides a sodium ion battery positive electrode material, the preparation method of the sodium ion battery positive electrode material is as follows:

[0051] The obtained precursor and sodium carbonate were mixed in an element molar ratio of (Ni+Mn+Fe):Na=1:1.05, then the mixture was heated to 830°C at a heating rate of 3°C / min in a muffle furnace and sintered for 15 hours, cooled and sieved, and then assembled into a battery, and the battery performance was evaluated at 2 to 4.2V. Examples 2 to 15 and Comparative Examples 1 to 3 The reaction steps were the same as in Example 1, and a nickel-iron-manganese ternary precipitate was obtained.

[0052] The above-mentioned sodium ion battery positive electrode material precursor precipitate is centrifuged and washed, and then alkaline washed multiple times using 0.5 mol / L sodium hydroxide solution, and then washed multiple times using deionized water at 70°C. By adjusting the number of washings, washing time, amount of alkaline solution for washing and amount of water used in the alkaline washing and water washing, the contents of Na impurities and S impurities are made to different levels, and the specific values ​​are shown in Table 1. The subsequent drying process, sintering to the cathode material and battery fabrication steps were the same as in Example 1. Examples 16 to 17 and Comparative Example 4

[0053] Nickel sulfate, manganese sulfate, and ferrous sulfate (molar ratio 2:4:4) were prepared into a 2 mol / L mixed salt solution, and the solution was mixed in a reaction kettle equipped with a stirrer with 40°C deionized water, 10 mol / L sodium hydroxide solution, and 8 mol / L ammonia water to prepare a base solution with a pH of 11.5. The temperature in the reactor is raised to 40°C, and at a stirring speed of 1000r / min, ammonia water, sodium hydroxide solution and mixed salt solution are slowly added, the first flow rate of adding mixed solution salt to base solution is 4% / h of the available volume of the reactor, the first flow rate of adding sodium hydroxide solution to base solution is 0.16% / h of the available volume of the reactor, the first flow rate of adding ammonia water to base solution is 0.08% / h of the available volume of the reactor, the first flow rate of adding 5.0μm of the first precipitate, and the second flow rate of the mixed salt solution is increased to 8% / h of the available volume of the reactor, and the second flow rates of the ammonia water solution and the sodium hydroxide solution are adjusted synchronously to 0.12% / h and 0.20% / h of the available volume of the reactor, respectively, and the addition of materials is stopped when the D50 of the sodium ion battery positive electrode material precursor is 8.0μm.

[0054] The above-mentioned sodium ion battery positive electrode material precursor precipitate is centrifuged and washed, and then alkaline washed multiple times using 0.5 mol / L sodium hydroxide solution, and then washed multiple times using deionized water at 70°C. By adjusting the number of washings, washing time, amount of alkaline solution for washing and amount of water used in the alkaline washing and water washing, the contents of Na impurities and S impurities are made to different levels, and the specific values ​​are shown in Table 1.

[0055] The subsequent drying process, sintering to the positive electrode material, and battery fabrication steps were the same as in Example 1. The molecular formula of the obtained sodium ion battery positive electrode material precursor was Ni 0.2 Mn 0.4 Fe 0.4 (OH) 2 It was.

[0056] Comparative Example 5 Nickel sulfate, manganese sulfate, and ferrous sulfate (molar ratio 2:4:4) were prepared into a 2 mol / L mixed salt solution, and 40°C deionized water, 10 mol / L sodium hydroxide solution, and 8 mol / L ammonia water were added to a reaction vessel equipped with a stirrer and mixed to prepare a base solution with a pH of 11.5. The temperature in the reaction vessel was raised to 40°C, and ammonia water, sodium hydroxide solution, and mixed salt solution were slowly added at a stirring speed of 1000 r / min, and the first flow rate for adding the mixed salt solution to the base solution was set to 8% / h of the available volume of the reaction vessel, the first flow rate for adding the sodium hydroxide solution to the base solution was set to 0.32% / h of the available volume of the reaction vessel, and the first flow rate for adding the ammonia water to the base solution was set to 0.16% / h of the available volume of the reaction vessel, and the addition of the materials was stopped when the D50 of the sodium ion battery positive electrode material precursor became 8.0 μm. The above precipitate was centrifuged and washed, and the washing method was the same as in Example 16. The contents of Na impurities and S impurities are shown in Table 1.

[0057] The subsequent drying, sintering to the positive electrode material and battery fabrication steps were the same as in Example 16. The molecular formula of the obtained sodium ion battery positive electrode material precursor was Ni 0.2 Mn0.4 Fe 0.4 (OH) 2 It was.

[0058] [Table 1] TIFF2025515867000003.tif127166

[0059] As can be seen from Examples 1-2, 3-5, 6-8, 9-12, and 13-15 in Table 1, when S≦4000 ppm and the sulfur content is at the same level, the lower the sodium to sulfur ratio, the better the performance of the material.

[0060] FIG. 3 is a graph showing the change in discharge capacity with respect to the sulfur content in some examples. As can be seen from FIG. 0.33 Mn 0.33 Fe 0.34 (OH) 2 For the same sodium content, the battery capacity and rate performance improved as the S content increased, but after the S content increased to a certain value, the battery capacity and rate performance decreased. Preferably, S is 800 to 3700 ppm, Na / S≦1.18, and in this case, the initial discharge capacity at 0.1C is 163 mAh / g or more, and the capacity retention rate after 50 cycles is 77.83% or more, and more preferably, S: 1700 to 2800 ppm, Na / S≦0.45, and in this case, the initial discharge capacity at 0.1C is 166 mAh / g or more, and the capacity retention rate after 50 cycles is 78.2%. As can be seen from Comparative Example 1, when S>4000 ppm, each performance significantly decreased. As can be seen from Comparative Examples 2 and 3, when Na / S>1.5, each performance also significantly decreased. Ni 0.2 Mn 0.4 Fe 0.4 (OH) 2 Examples 16 to 17 and Comparative Example 4 also have similar characteristics. Therefore, the presence of a trace amount of non-sodium sulfate in a specific range plays an important role in improving the performance of the material, and the lower the ratio of sodium to sulfur, the better the performance of the material.

[0061] Comparing Example 16 with Comparative Example 5, when the flow rate of the material added was set to be high throughout the entire process without changing the cleaning method and other conditions, the sulfur content of the precursor was reduced and the ratio of sodium to sulfur was higher, resulting in a decrease in performance. Therefore, by controlling the flow rate of the mixed salt stepwise, it is possible to maintain a certain amount of sulfur content in the precursor structure and more easily obtain a precursor material having the above-mentioned specific range of sulfur content and sodium to sulfur ratio.

[0062] The above embodiments are merely for illustrating the technical solution of the present application, and are not intended to limit it. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art may modify the technical solutions described in the above embodiments, and may make equivalent substitutions for some or all of the technical features therein. These modifications or substitutions do not cause the essence of the technical solution to depart from the scope of the technical solution of the embodiments of the present application.

[0063] In addition, some embodiments have some features included in other embodiments, but a combination of features of different embodiments will be another embodiment within the scope of the present application. For example, the embodiments to be protected in the scope of the claims may be arbitrarily combined. It should be understood that the information disclosed in the background section is intended to enhance the understanding of the background technology of the present application as a whole, and is not intended to acknowledge or imply in any way that the information is a prior art known to those skilled in the art. [Industrial Applicability]

[0064] The present application provides a sodium ion battery positive electrode material precursor, its preparation method, a sodium ion battery positive electrode material, a sodium ion battery and an electric device, and belongs to the field of batteries. The sodium ion battery positive electrode material precursor has the general formula Ni x Mn y Fe 1-x-y (OH) 2where x satisfies 0.15≦x≦0.35 and y satisfies 0.2≦y≦0.5. The sodium ion battery positive electrode material precursor has an S element content of 4000 ppm or less and an Na / S mass ratio of 1.5 or less. The sodium ion battery positive electrode material precursor according to the present application provides a positive electrode material with good element uniformity, few structural defects, controllable particle size, good sphericity, high energy density, and retains a trace amount of sulfur impurities, so that when the sulfur content is at the same level, the lower the ratio of sodium to sulfur, the better the battery capacity, initial coulombic efficiency, and cycle performance.

[0065] In addition, the sodium ion battery positive electrode material precursor, its preparation method, sodium ion battery positive electrode material, sodium ion battery, and electric device according to the present application are operable and can be used in various industrial applications. For example, the sodium ion battery positive electrode material precursor, its preparation method, sodium ion battery positive electrode material, sodium ion battery, and electric device according to the present application can be used in the field of batteries.

Claims

1. A sodium ion battery cathode material precursor, comprising: The sodium ion battery positive electrode material precursor has the general formula Ni ｘ Mn ｙ Fe １－ｘ－ｙ (OH) ２ where x satisfies 0.15≦x≦0.35 and y satisfies 0.2≦y≦0.5; The content of S element in the sodium ion battery positive electrode material precursor is 4000 ppm or less. A sodium ion battery positive electrode material precursor.

2. The sodium ion battery positive electrode material precursor further contains Na, and the mass ratio of Na / S is 1.5 or less. The sodium ion battery positive electrode material precursor according to claim 1.

3. A. The content of S element in the sodium ion battery positive electrode material precursor is 800 to 3700 ppm, and the mass ratio of Na / S is 1.18 or less, and optionally, the content of S element in the sodium ion battery positive electrode material precursor is 1700 to 2800 ppm, and the mass ratio of Na / S is 0.45 or less; B. The sodium ion battery positive electrode material precursor has a D50 of 3 to 14 μm, preferably 5 to 10 μm; C. The specific surface area of ​​the sodium ion battery positive electrode material precursor is 6 to 11 m ２ / g, preferably 6 to 8m ２ / g, D. The tap density of the sodium ion battery positive electrode material precursor is 1.7 g / cm ３ or more, preferably 1.9 to 2.3 g / cm ３ That is, E. The sodium ion battery positive electrode material precursor has a spherical or nearly spherical shape; Satisfy at least one of the conditions A to E The sodium ion battery positive electrode material precursor according to claim 2.

4. A method for preparing a sodium ion battery positive electrode material precursor according to any one of claims 1 to 3, comprising the steps of: Mixing raw materials including a nickel source, a manganese source, a ferrous source, and water to obtain a mixed salt solution, and mixing materials including water, a portion of a complexing agent, and a portion of a precipitating agent to obtain a base solution; adding the remaining complexing agent, the remaining precipitating agent, and the mixed salt solution to the base solution to carry out a co-precipitation reaction, and then performing solid-liquid separation to obtain a solid material, and then performing alkali washing, water washing, and drying to obtain the sodium ion battery positive electrode material precursor; At least one of the nickel source, the manganese source, and the ferrous iron source comprises a sulfate.

1. A method for preparing a sodium ion battery positive electrode material precursor, comprising:

5. a. the nickel source comprises one or more of nickel sulfate, nickel nitrate, nickel acetate, the manganese source comprises one or more of manganese sulfate, manganese nitrate, manganese acetate, and the ferrous source comprises one or more of ferrous sulfate, ferrous nitrate, ferrous chloride; b. The concentration of the mixed salt solution is 1.0 to 2.2 mol / L; c) the precipitating agent includes at least one of sodium hydroxide and potassium hydroxide, and the complexing agent includes one or more of ammonium bicarbonate, ammonium carbonate, and aqueous ammonia; d. the complexing agent is used in the form of an aqueous solution, with a concentration of 0.3-8 mol / L, optionally with a concentration of 0.3-2.0 mol / L; e. The temperature of the water used in preparing the base solution is 40 to 60° C., and the pH of the base solution is 10 to 12; f. The flow rate of the mixed salt solution is added to the base solution is 2% / h to 8% / h of the available volume of the reaction vessel, the flow rate of the precipitant is added to the base solution is 0.08% / h to 0.32% / h of the available volume of the reaction vessel, and the flow rate of the complexing agent is added to the base solution is 0.04% / h to 0.16% / h of the available volume of the reaction vessel; g. The coprecipitation reaction is carried out under stirring conditions, and the stirring speed is 300 to 1000 r / min; h. the co-precipitation reaction is stopped when the D50 of the sodium ion battery cathode material precursor is 3-14 μm; i. The criteria for stopping the water washing are that the electrical conductivity of the mother liquor obtained by filtration after washing is less than 50 μS / cm, the temperature of the drying is 120-180° C., the time is 10-16 h, and the drying is stopped when the moisture content of the material is 0.6 wt % or less; At least one of the conditions a to i is satisfied. A method for preparing the sodium ion battery positive electrode material precursor according to claim 4.

6. The flow rates of the remaining complexing agent, the remaining precipitating agent, and the mixed salt solution are added to the base solution in a stepwise manner. A method for preparing the sodium ion battery positive electrode material precursor according to claim 4 or 5.

7. The stepwise control includes a first stage and a second stage, In the first step, a first flow rate of adding the mixed salt solution to the base solution is 2% / h to 4% / h of the available volume of the reaction vessel, a first flow rate of adding the precipitant to the base solution is 0.08% / h to 0.16% / h of the available volume of the reaction vessel, and a first flow rate of adding the complexing agent to the base solution is 0.04% / h to 0.08% / h of the available volume of the reaction vessel, until a first precipitate having a D50 of 3 to 5 μm is obtained; In the second step, the second flow rate of the mixed salt solution added to the base solution is 4% / h to 8% / h of the available volume of the reaction vessel, the second flow rate of the precipitant added to the base solution is 0.16% / h to 0.32% / h of the available volume of the reaction vessel, and the second flow rate of the complexing agent added to the base solution is 0.08% / h to 0.16% / h of the available volume of the reaction vessel, until the D50 of the sodium ion battery positive electrode material precursor is 6 to 14 μm. A method for preparing the sodium ion battery positive electrode material precursor according to claim 6.

8. A sodium ion battery positive electrode material prepared by reacting the sodium ion battery positive electrode material precursor according to any one of claims 1 to 3 with a sodium source, Optionally, a molar ratio of the sum of nickel, manganese, and iron in the sodium-ion battery cathode material precursor to sodium in the sodium source is 1:(1.02-1.07); Optionally, the reaction is sintered by programmed heating, ramping the temperature to 780-880° C. at a rate of 2-4° C. / min and sintering for 10-20 hours. A sodium ion battery positive electrode material characterized by:

9. The raw material comprises the sodium ion battery positive electrode material according to claim 8. A sodium ion battery characterized by:

10. The sodium ion battery according to claim 9 is provided.

1. An electrical device comprising:

Images