A sodium-ion battery p2 type nickel-manganese-based layered oxide positive electrode material and a preparation method thereof

Abstract

This invention provides a P2-type nickel-manganese base-based oxide cathode material for sodium-ion batteries and its preparation method. It relates to the field of sodium-ion battery material preparation and is prepared via a simple solid-state method, suppressing the formation of Na+. + This cathode material improves cycle stability based on a vacancy-ordered structure using Ti. 4+ Doping stabilizes the material structure and suppresses the deterioration of cycle performance caused by undesirable phase transitions under high pressure. Its chemical formula is Na. 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.67‑x Ti x O2 (0≤x≤0.2), the preparation method of this invention is simple, the prepared material has good cycle performance, and it has a good application prospect in the cathode material of sodium-ion batteries.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a P2-type sodium ion battery nickel-manganese-based layered oxide positive electrode material and a preparation method thereof BACKGROUND

[0002] Energy, as the lifeline of the economy, has always been a topic that never fades away. Human beings have completed the industrial revolution of society through the use of disposable fossil energy such as coal and oil. However, with the rapid increase in global population, problems such as climate warming and energy crisis have emerged one after another. Today, renewable energy such as solar energy, geothermal energy, wind energy and tidal energy has been developed vigorously. These energies cannot be directly integrated into the power grid and need to be stored in scale by energy storage technology. At the same time, with the rapid development of electric vehicles, lithium ion batteries have been widely used in these fields. However, the global distribution of lithium resources is uneven and the content in the earth's crust is not high, so it is urgent to find a substitute for lithium ion batteries.

[0003] Sodium resources are extremely abundant and also belong to alkali metal elements; compared with lithium ion batteries, there is a great cost advantage. Sodium ion batteries and lithium ion batteries have the same working principle, so they can be produced using existing equipment and have great application prospects. The radius of sodium ion is greater than the radius of lithium ion Therefore, the rate performance and cycle performance are relatively poor. Sodium ion batteries are roughly divided into layered oxides, polyanions and prussian blue. Among them, layered oxides have high reversible capacity and good conductivity and become the most promising application material. Mg 2+ , Cu 2+ doped Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.67 O2 can inhibit the Na + / vacancy ordered structure, make the charge-discharge curve more smooth, allow more Na + to be retained in the space position of the triangular prism, stabilize the material structure, thereby effectively inhibiting P2-O2 phase transition and improving the performance of the battery. However, the cycle performance of the material is expected to be further improved, and therefore a Ti 4+ doped Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.67-x Ti x O2 (0≤x≤0.2) is designed to improve the capacity retention rate and cycle stability. SUMMARY

[0004] The present application aims to solve at least one of the above technical problems by a method for doping a transition metal layer with a hetero element, and provides a sodium ion battery cathode material with high performance, high specific capacity and high capacity retention rate.

[0005] The present application first provides a sodium ion battery P2 type nickel-manganese-based layered oxide cathode material and a preparation method thereof, characterized in that the cathode material is a layered oxide material prepared by adding Ti to a transition metal layer of Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.67 O2. 4+ The chemical formula of the cathode material is Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.67-x Ti x O2 (0≤x≤0.2).

[0006] The present application also provides a preparation method of the above-mentioned sodium ion battery cathode material, which is prepared by a solid-phase sintering method and includes the following steps:

[0007] (1) A sodium source compound, a manganese source compound, a nickel source compound, a titanium source compound, a magnesium source compound and a copper source compound are weighed according to stoichiometric ratios, and then fully hand-ground and ball-milled after adding a dispersing agent, and then high-temperature dried to obtain a precursor;

[0008] (2) The precursor powder in step (1) is high-temperature calcined and cooled in the furnace to obtain a layered oxide material.

[0009] Further, the sodium source in step (1) is selected from one or more of sodium carbonate, sodium nitrate, sodium acetate, sodium oxalate and sodium hydroxide;

[0010] The manganese source is selected from one or more of manganese dioxide, dimanganese trioxide, manganese nitrate, manganese oxalate and manganese sulfate;

[0011] The nickel source is selected from one or more of nickel sulfate, nickel oxalate, nickel carbonate, nickel oxide and nickel acetate;

[0012] The titanium source is selected from one or more of titanium oxide, titanium acetate, titanium nitrate and titanium sulfate;

[0013] The magnesium source is selected from one or more of magnesium oxide, magnesium sulfate, magnesium carbonate, magnesium chloride, magnesium hydroxide, magnesium silicate and magnesium acetate;

[0014] The copper source is selected from one or more of copper nitrate, copper oxide, nano-copper oxide, cuprous oxide and cuprous acetate.

[0015] Further, the dispersant in step (1) is acetone or anhydrous ethanol.

[0016] Further, in the step (2), the calcination temperature is 850-1150℃, the heating rate is 1-10℃ / min, the calcination time is 8-24h, the calcination atmosphere includes but is not limited to air atmosphere, argon atmosphere, oxygen atmosphere, helium atmosphere, nitrogen atmosphere, and the sampling temperature after furnace cooling is 100-800℃.

[0017] The application also provides a preparation method of a P2 type nickel-manganese-based layered oxide positive electrode sheet of a sodium ion battery.

[0018] (1) The active positive electrode material, the conductive additive and the binder are uniformly ground according to the mass ratio of 8:1:1, 7:2:1 or 75:15:10;

[0019] (2) The NMP solution is added to the powder in step (1), and the ratio of the active material is 1 / 1-1.5 (g / ml), and the slurry is prepared by stirring on a magnetic stirrer for 0.5-8h;

[0020] (3) The slurry is uniformly coated on an aluminum foil by a coater, and the thickness is 50-400μm;

[0021] (4) The positive electrode sheet is dried in a vacuum drying oven at 80-120℃ for 5-12h;

[0022] The application improves the cycle stability, rate performance and capacity retention rate of the positive electrode material.

[0023] The beneficial effects of the application are as follows:

[0024] (1) The Mn 3+ The resulting Jahn-Teller effect has been considered as one of the important reasons for the performance reduction of the sodium ion battery, and the hetero-element doping can reduce the proportion of Mn 3+ , thereby weakening the influence of the Jahn-Teller effect. The titanium element is an electrochemically inactive element, which can stabilize the P2 plate structure and inhibit the P2-O2 undesirable phase change, so that the Mg 2+ , Cu 2+ co-doping can improve the cycle stability of the P2 type material with Na + / vacancy ordered structure, improve the capacity retention rate and further improve the rate performance.

[0025] (2) The application provides a high-performance sodium ion battery layered oxide material, which is low in manufacturing cost and has widely distributed raw materials.

[0026] (3) The material provided by the application is prepared by a solid-phase sintering method, which is easy to operate, green and convenient, and is conducive to industrial large-scale production and manufacturing. Attached Figure Description

[0027] Figure 1 The X-ray diffraction (XRD) pattern of the sodium-ion battery cathode material obtained in Example 3 of this invention;

[0028] Figure 2 The XRD pattern of the sodium-ion battery cathode material obtained in Example 3 of this invention is shown.

[0029] Figure 3 This is a scanning electron microscope (SEM) morphology image of the sodium-ion battery cathode material obtained in Example 3 of the present invention;

[0030] Figure 4 This is a comparison chart of the cycle performance of the sodium-ion battery cathode materials obtained in Example 3 and Comparative Example 1 of the present invention;

[0031] Figure 5 This is a comparison chart of the rate performance of the sodium-ion battery cathode materials obtained in Example 3 and Comparative Example 1 of the present invention. Specific implementation methods

[0032] The present invention will now be described in detail with reference to the embodiments. The described embodiments are only some embodiments of the present invention, and not all embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0033] Comparative Example 1:

[0034] This comparative example provides a method for preparing a sodium-ion battery cathode material and its electrode sheet, with the chemical formula Na. 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.67 O2, including:

[0035] Step 1: Preparation of cathode materials via solid-state method

[0036] (1) Thoroughly mix the sodium source, manganese source, nickel source, copper source, and magnesium source;

[0037] (2) After drying the above mixture in a drying oven, transfer it to an alumina crucible;

[0038] (3) Place the corundum crucible into a tube furnace and sinter it in an air atmosphere to obtain the battery cathode material.

[0039] In some preferred embodiments, in the raw material of (1), sodium carbonate 1.8286 g (3% excess, to compensate for sodium loss at high temperature), nickel oxide 0.6722 g, magnesium oxide 0.2015 g, copper oxide 0.1989 g, and manganese sesquioxide 2.6443 g are weighed according to the stoichiometric ratio of 0.67:0.18:0.1:0.05:0.67, ground for 30 min, and then placed in a ball mill tank and added with anhydrous ethanol as a dispersant, and then ball-milled at 300 r / min for 5 h.

[0040] In some preferred embodiments, in (2), the drying temperature is 100°C, and the drying time is 5 h.

[0041] In some preferred embodiments, in (3), the heating rate is 10°C / min, the temperature is kept at 900°C for 15 h, and then the battery anode material is obtained by cooling to 300°C.

[0042] Step 2: Preparation of Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.67 O2 anode tab

[0043] (1) The prepared anode material, Super P, and polyvinylidene fluoride are mixed in a mass ratio of 8:1:1, ground by hand until uniform, and then added with N-methyl pyrrolidone. The mixed powder is placed in a magnetic stirrer at room temperature and stirred for 40 min. The slurry is coated on an aluminum foil with a thickness of 100 μm, and then placed in a vacuum drying oven at 80°C for 12 h to obtain an anode tab.

[0044] (2) A 2032 button cell is assembled with metallic sodium as the anode, and the entire assembly process is carried out in an argon-filled glove box. The assembly sequence is as follows: negative electrode shell, metallic sodium, glass fiber separator (GF / D), electrolyte (1M NaClO4 in EC:DC = 1:1 vol%), anode tab (14 mm), gasket, spring, and positive electrode shell. The charge-discharge cycle test is carried out in a Wuhan Laner battery test system at a current density of 1C (1C = 178 mAh g -1 ) and a voltage range of 2-4.3V. After 200 cycles, the capacity retention rate is 88%.

[0045] Example 1:

[0046] The present embodiment provides a preparation method of a sodium-ion battery anode material and an anode tab thereof, with a chemical formula of Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.65 Ti 0.02 O2, which comprises:

[0047] Step 1: preparing the positive electrode material by a solid phase method

[0048] (1) fully mix a sodium source, a manganese source, a nickel source, a copper source, a magnesium source, and a titanium source;

[0049] (2) place the mixture into a drying oven to dry and then move it into a corundum crucible;

[0050] (3) place the corundum crucible into a tube furnace, sinter in an air atmosphere, and obtain a battery positive electrode material.

[0051] In some preferred embodiments, in the raw material in (1), sodium carbonate 1.8286 g (over 3%, to compensate for sodium loss at high temperature), nickel oxide 0.6722 g, magnesium oxide 0.2015 g, copper oxide 0.1989 g, manganese sesquioxide 2.5654 g, and titanium oxide 0.0799 g are weighed according to the stoichiometric ratio of 0.67:0.18:0.1:0.05:0.65:0.02, hand ground for 30 min, placed into a ball mill jar, add anhydrous ethanol as a dispersant, and ball mill at 300 r / min for 5 h.

[0052] In some preferred embodiments, in (2), the drying temperature is 100°C, and the drying time is 5 h.

[0053] In some preferred embodiments, in (3), the heating rate is 10°C / min, the temperature is kept at 900°C for 15 h, and the battery positive electrode material is obtained by cooling to 300°C and taking out.

[0054] Step 2: preparing Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.65 Ti 0.02 O2 positive electrode tab, and the preparation process is the same as that in Comparative Example 1. The charge-discharge cycle test is performed in a Wuhan LanDian battery test system, the current density is 1C (1C = 178 mAh g -1 ), the voltage interval is 2-4.3V, and the capacity retention rate is 89% after 200 cycles.

[0055] Example 2:

[0056] The present embodiment provides a preparation method of a sodium ion battery positive electrode material and a tab thereof, and the chemical formula is Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.63 Ti 0.04 O2, which comprises:

[0057] Step 1: preparing the positive electrode material by a solid phase method

[0058] (1) Mix the sodium source, manganese source, nickel source, copper source, magnesium source, and titanium source thoroughly;

[0059] (2) Place the mixture into a drying oven and dry, then move it into a corundum crucible;

[0060] (3) Place the corundum crucible into a tube furnace and sinter in an air atmosphere to obtain a battery positive electrode material.

[0061] In some preferred embodiments, in the raw materials in (1), sodium carbonate 1.8286 g (over 3%, to compensate for sodium loss at high temperature), nickel oxide 0.6722 g, magnesium oxide 0.2015 g, copper oxide 0.1989 g, manganese sesquioxide 2.4865 g, and titanium oxide 0.1597 g are weighed according to the stoichiometric ratio of 0.67:0.18:0.1:0.05:0.63:0.04, ground for 30 min, placed into a ball mill jar, and added with anhydrous ethanol as a dispersant, and ball milled at 300 r / min for 5 h.

[0062] In some preferred embodiments, in (2), the drying temperature is 100°C, and the drying time is 5 h.

[0063] In some preferred embodiments, in (3), the heating rate is 10°C / min, the temperature is kept at 900°C for 15 h, and the battery positive electrode material is obtained by cooling to 300°C and taking out.

[0064] Step 2: Preparation of Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.63 Ti 0.04 O2 positive electrode tab, and the preparation process is the same as that of Comparative Example 1. The charge-discharge cycle test is performed in a Wuhan LanDian battery test system, the current density is 1C (1C = 178 mAh g -1 ), the voltage interval is 2-4.3V, and the capacity retention rate is 91% after 200 cycles.

[0065] Example 3:

[0066] The present embodiment provides a preparation method of a sodium ion battery positive electrode material and a tab thereof, with a chemical formula of Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.57 Ti 0.1 O2, comprising:

[0067] Step 1: Preparation of a positive electrode material by a solid phase method

[0068] (1) Mix the sodium source, manganese source, nickel source, copper source, magnesium source, and titanium source thoroughly;

[0069] (2) Put the mixture into a drying oven and dry, then move it into a corundum crucible;

[0070] (3) Put the corundum crucible into a tube furnace and sinter in an air atmosphere to obtain the battery positive electrode material.

[0071] In some preferred embodiments, in the raw material of (1), sodium carbonate 1.8286 g (over 3%, to compensate for sodium loss at high temperature), nickel oxide 0.6722 g, magnesium oxide 0.2015 g, copper oxide 0.1989 g, manganese sesquioxide 2.2496 g, and titanium oxide 0.3994 g are weighed according to the stoichiometric ratio of 0.67:0.18:0.1:0.05:0.57:0.1, ground for 30 min, put into a ball mill jar, add anhydrous ethanol as a dispersant, and ball mill at 300 r / min for 5 h.

[0072] In some preferred embodiments, in (2), the drying temperature is 100°C and the drying time is 5 h.

[0073] In some preferred embodiments, in (3), the heating rate is 10°C / min, the temperature is kept at 900°C for 15 h, and the battery positive electrode material is obtained by cooling to 300°C and taking out.

[0074] Step 2: Preparation of Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.57 Ti 0.1 O2 positive electrode tab, the preparation process is the same as that of Comparative Example 1. The charge-discharge cycle test is carried out in a Wuhan LanDian battery test system.

[0075] Figure 1 The XRD pattern of the target product obtained in Example 3 is shown in the figure. As can be seen from the figure, the material is a typical P2 structure (space group P63 / mmc) and does not contain any impurity phase.

[0076] Figure 2 The XRD pattern of Example 3 is refined (Rietveld method, using GSAS-II software). As can be seen from the figure, when using a standard crystal with P63 / mmc space group as a reference, all the reflection peaks in the XRD pattern match the standard spectrum Figure 1 without impurity peaks and with high intensity of diffraction peaks, indicating that the material has good crystallinity (R wp / %=11.9,Gof=1.8).

[0077] Figure 3SEM images of the target product obtained in Example 3 show the material clearly exhibits a platelet-like structure, and the particle size is in the range of 2-5 μm.

[0078] Figure 4 The cycle stability curves of Example 3 and Comparative Example 1 at 1C (1C = 173 mAh g -1 ) current density, cycled 200 times in the voltage range of 2-4.3 V. The capacity retention of Comparative Example 1 after 200 cycles is 88%, and the capacity retention of Example 3 after 200 cycles is 93%.

[0079] Figure 5 The rate plots of Example 3 and Comparative Example 1 at 0.1C, 0.2C, 0.5C, 1C, 2C, 5C, 0.2C and 0.1C current density, in the voltage range of 2-4.3 V are shown. As can be seen from the figure, the capacity of Example 3 is higher than that of Comparative Example 1 at all current densities, even at 5C high current, the discharge specific capacity is 78 mAh g -1 , compared with Comparative Example 1, Example 3 still maintains a higher capacity retention, and the discharge specific capacity returns to 93 mAh g -1 when returning to 0.2C. Therefore, the titanium element stabilizes the structure of the material and improves the rate performance of the battery.

[0080] Example 4:

[0081] The present embodiment provides a sodium ion battery positive electrode material and a preparation method of a positive electrode sheet thereof, with a chemical formula of Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.55 Ti 0.12 O2, comprising:

[0082] Step 1: preparing the positive electrode material by a solid phase method

[0083] (1) fully mixing a sodium source, a manganese source, a nickel source, a copper source, a magnesium source, and a titanium source;

[0084] (2) placing the mixture into a drying oven for drying and then moving into a corundum crucible;

[0085] (3) placing the corundum crucible into a tube furnace, sintering in an air atmosphere, and obtaining the battery positive electrode material.

[0086] In some preferred embodiments, in the raw material of (1), sodium carbonate 1.8286 g (3% excess, to compensate for sodium loss at high temperature), nickel oxide 0.6722 g, magnesium oxide 0.2015 g, copper oxide 0.1989 g, manganese sesquioxide 2.1707 g, and titanium oxide 0.4792 g are weighed according to the stoichiometric ratio of 0.67:0.18:0.1:0.05:0.55:0.12, ground for 30 min, and then placed in a ball mill tank and added with anhydrous ethanol as a dispersant, and ball-milled at 300 r / min for 5 h.

[0087] In some preferred embodiments, in (2), the drying temperature is 100°C, and the drying time is 5 h.

[0088] In some preferred embodiments, in (3), the heating rate is 10°C / min, the temperature is kept at 900°C for 15 h, and the sample is taken out after cooling to 300°C to obtain the battery cathode material.

[0089] Step 2: Preparation of Na 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.55 Ti 0.12 O2 cathode sheet, and the preparation process is the same as that of Comparative Example 1. The charge-discharge cycle test is performed in a Wuhan LanDian battery test system, the current density is 1C (1C = 178 mAh g -1 ), the voltage interval is 2-4.3V, and the capacity retention rate is 90% after 200 cycles.

[0090] The above description is only preferred embodiments of the present application, and the embodiments of the present application are not limited by the above examples. Improvements and modifications made without departing from the principles of the present application are included in the protection scope of the present application.

Claims

1. A sodium-ion battery P2 type nickel-manganese base layer oxide cathode material, characterized in that: The cathode material is made of Na. 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.67 Adding Ti to the transition metal layer of O2 4+ The chemical formula of the positive electrode material is Na. 0.67 Ni 0.18 Mg 0.1 Cu 0.05 Mn 0.67-x Ti x O2, 0≤x≤0.2, the sodium-ion battery cathode material is prepared by solid-state sintering, including the following steps: (1) The sodium source compound, manganese source compound, nickel source compound, titanium source compound, magnesium source compound and copper source compound were weighed according to the stoichiometric ratio, and then hand-milled thoroughly before adding the dispersant and ball-milling. The precursor was then dried at high temperature. (2) The precursor powder described in step (1) is calcined at high temperature and then cooled in the furnace to obtain a layered oxide material.

2. A method for preparing the sodium-ion battery cathode material as described in claim 1, characterized in that, The preparation is carried out by solid-state sintering, including the following steps: (1) The sodium source compound, manganese source compound, nickel source compound, titanium source compound, magnesium source compound and copper source compound were weighed according to the stoichiometric ratio, and then hand-milled thoroughly before adding the dispersant and ball-milling. The precursor was then dried at high temperature. (2) The precursor powder described in step (1) is calcined at high temperature and then cooled in the furnace to obtain a layered oxide material.

3. The preparation method according to claim 2, characterized in that: The sodium source mentioned in step (1) is selected from one or more of sodium carbonate, sodium nitrate, sodium acetate, sodium oxalate, and sodium hydroxide; The manganese source is selected from one or more of manganese dioxide, manganese trioxide, manganese nitrate, manganese oxalate, and manganese sulfate; The nickel source is selected from one or more of nickel sulfate, nickel oxalate, nickel carbonate, nickel oxide, and nickel acetate; The titanium source is selected from one or more of titanium oxide, titanium acetate, titanium nitrate, and titanium sulfate; The magnesium source is selected from one or more of magnesium oxide, magnesium sulfate, magnesium carbonate, magnesium chloride, magnesium hydroxide, magnesium silicate, and magnesium acetate; The copper source is selected from one or more of copper nitrate, copper oxide, nano copper oxide, cuprous oxide, and cuprous acetate.

4. The preparation method according to claim 2, characterized in that: The dispersant in step (1) is acetone or anhydrous ethanol.

5. The preparation method according to claim 2, characterized in that: In step (2), the calcination temperature is 850~1150℃, the heating rate is 1~10℃ / min, the calcination time is 8~24h, the calcination atmosphere is selected from air atmosphere, argon atmosphere, oxygen atmosphere, helium atmosphere or nitrogen atmosphere, and the sampling temperature during furnace cooling is 100~800℃.

6. A sodium-ion battery electrode comprising the positive electrode material of claim 1.

7. A method for preparing a sodium-ion battery electrode according to claim 6, characterized in that, The active positive electrode material, conductive additives, and binders are ground evenly at a mass ratio of 8:1:1, 7:2:1, or 75:15:

10. NMP is added, and the mass-volume ratio of the mixed powder to the binder is 1:1~1.5, g / ml. The mixture is then dried at room temperature to form a slurry. The slurry is then evenly coated onto aluminum foil to a thickness of 50-400μm. Finally, the slurry is dried in a vacuum drying oven at 80~120℃ for 5-12 hours.

8. The preparation method according to claim 7, characterized in that: The binder is one or more of polyvinylidene fluoride, polyacrylic acid, sodium carboxymethyl cellulose, and sodium alginate, and the conductive agent is one or more of Super P, carbon black, and Ketjen black.

9. A sodium-ion battery comprising the sodium-ion battery electrode of claim 6 or the sodium-ion battery electrode prepared according to claim 7.

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