High-entropy configuration sodium ion battery O3 type layered positive electrode material and preparation method and application thereof

Abstract

The invention discloses an O3 type layered positive electrode material of a high-entropy configuration sodium ion battery. The molecular formula of the O3 type layered positive electrode material is Na < 0.85 > Li < 0.1 > Al < 0.02 > Sn < 0.08 > Cu < 0.1 > Ti < 0.1 > Ni < 0.3 > Mn < 0.3 > O < 2 >; the method comprises the following steps: ball-milling and mixing a sodium source and metal sources to obtain a precursor; then tabletting the precursor to obtain a sheet material; and finally calcining the sheet material to obtain the product. According to the high-entropy configuration sodium ion battery O3 type layered positive electrode material, high-voltage (4.3 V) stability and air stability of the sodium ion battery O3 type layered positive electrode material can be achieved, and high-load application of the sodium ion battery O3 type layered positive electrode material is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of sodium ion battery positive electrode materials, and in particular relates to a high entropy configuration sodium ion battery O3 type layered positive electrode material and a preparation method and application thereof. Background Art

[0002] As one of the most promising cathode materials for sodium-ion batteries, O3-type layered cathode materials have higher theoretical specific capacity and faster sodium ion diffusion rate. However, traditional O3 layered cathode materials will undergo irreversible phase transitions under high voltage, leading to structural collapse and continuous structural damage, resulting in rapid capacity decay. In addition, its active sodium ions will react with moisture and carbon dioxide in the air to produce alkaline compounds as byproducts, resulting in reduced capacity and reduced conductivity. High voltage instability prevents the capacity advantage of O3-type layered cathode materials from being highlighted, while air instability greatly limits their large-scale application. In order to achieve large-scale application of high-voltage O3-type layered cathode materials, how to stabilize high voltage and air stability are very critical links.

[0003] High-load applications are conducive to improving the energy density of sodium-ion full batteries and promoting the practical application of high-entropy layered materials. However, under high-load applications, the structural changes and structural stability inside the material are of great significance. Therefore, how to achieve the coordinated optimization of high voltage and air stability of O3-type layered cathode materials, as well as high-load applications, is a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the problems existing in the existing O3 type layered positive electrode materials, the purpose of the present invention is to provide a high entropy configuration sodium ion battery O3 type layered positive electrode material and a preparation method thereof, and a sodium ion battery, which can achieve the high voltage (4.3V) stability and air stability of the sodium ion battery O3 type layered positive electrode material and realize its high load application.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] A high entropy sodium ion battery O3-type layered cathode material, whose molecular formula is Na 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 .

[0007] The present invention also provides a method for preparing the above-mentioned high entropy configuration sodium ion battery O3 type layered positive electrode material, firstly, a sodium source and various metal sources are ball-milled and mixed according to the molecular formula to obtain a precursor; then the precursor is pressed into sheets to obtain flakes; finally, the flakes are calcined to obtain the high entropy configuration sodium ion battery O3 type layered positive electrode material.

[0008] Furthermore, the thickness of the sheet is 2-5 mm.

[0009] Furthermore, the calcination temperature is 850-950°C and the calcination time is 12-24h.

[0010] The present invention also provides a sodium ion battery, wherein the positive electrode of the sodium ion battery comprises the above-mentioned high entropy configuration sodium ion battery O3 type layered positive electrode material.

[0011] The present invention selects a specific combination of metal elements (Li, Al, Sn, Cu, Ti) and a specific atomic ratio for doping to construct high entropy, thereby improving the regulatory effect of the high entropy effect on the stability of the transition metal layer, enhancing the stability of the transition metal layer skeleton, inhibiting the excessive contraction of the transition metal-oxygen bond, stabilizing the interlayer oxygen charge, and realizing the reversible phase transition P3-OP2-P3 at a high voltage (4.3V). At the same time, the transition metal interlayer spacing is regulated, the Na-O bond strength is enhanced, and the erosion of active sodium by water molecules in the air is inhibited, so that the material has good air stability and can withstand high cathode loads (≥8mg cm -2 ) under the condition of stable cycling of sodium-ion full battery.

[0012] The beneficial effects of the present invention are:

[0013] 1. The present invention selects a specific combination of metal elements (Li, Al, Sn, Cu, Ti) and a specific atomic ratio for doping to construct high entropy, which improves the regulatory effect of the high entropy effect on the stability of the transition metal layer, and can achieve high voltage (4.3V) stability and air stability of the O3-type layered positive electrode material for sodium ion batteries, and realize its high-load application.

[0014] 2. The high entropy configuration sodium ion battery O3 type layered positive electrode material of the present invention has a -1 The capacity retention rate can reach more than 70% after 1000 cycles at the current density. The material has strong air stability. After being exposed to air for 15 days, its capacity retention rate relative to the newly synthesized material is more than 90%. At the same time, the high-load soft-pack full battery shows good stability at 100mAg -1 The capacity retention rate can reach more than 76% after 100 cycles at the current density, and it has excellent high voltage, air stability and high load performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The Na obtained in Comparative Example 1 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 (NFM), Na prepared in Example 1 0.85 Li 0.1 Al 0.0 2 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 (HEO), Na prepared in Comparative Example 2 0.85 Li 0.05 Al 0.05 Sn 0.05 Cu 0.1 Ti 0.15 Ni 0.3 Mn 0. 3 O 2 , Na prepared in Example 3 0.85 Li 0.07 Al 0.03 Sn 0.05 Cu 0.15 Ti 0.1 Ni 0.3 Mn 0.3 O 2 and Na obtained in Comparative Example 4 0.85 Li 0. 1 Al 0.02 Sn 0.03 Cu 0.1 Ti 0.15 Ni 0.3 Mn 0.3 O 2 XRD spectrum of O3-type layered oxide positive electrode material for sodium-ion battery.

[0016] Figure 2 The Na obtained in Comparative Example 1 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 (NFM) and Na prepared in Example 1 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2(HEO) SEM image of O3-type layered oxide positive electrode material for sodium-ion battery.

[0017] Figure 3 The Na obtained in Comparative Example 1 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 (NFM) and Na prepared in Example 1 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 (HEO) O3-type layered oxide cathode materials for sodium-ion batteries at 10 mAg -1 Charge and discharge curves at different rates (a) and CV curves at a scan rate of 0.1 mV / s (b).

[0018] Figure 4 The Na obtained in Comparative Example 1 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 (NFM) In situ XRD pattern of O3-type layered oxide cathode material for sodium-ion battery during a charge-discharge cycle.

[0019] Figure 5 The Na obtained in Example 1 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 In situ XRD pattern of (HEO) O3-type layered oxide cathode material for sodium-ion battery during a charge-discharge cycle.

[0020] Figure 6 The Na obtained in Comparative Example 1 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 (NFM) and Na prepared in Example 1 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn0.3 O 2 (HEO) O3-type layered oxide cathode material for sodium-ion batteries at 50 mAg -1 Cycling performance diagram at different current densities.

[0021] Figure 7 The Na obtained in Comparative Example 1 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 (NFM) and Na prepared in Example 1 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 (HEO) O3-type layered oxide cathode materials for sodium-ion batteries at 1Ag -1 Cycling performance diagram at different current densities.

[0022] Figure 8 The Na obtained in Comparative Example 1 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 (NFM) and Na prepared in Example 1 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 (HEO) XRD patterns of the initial material of O3-type layered oxide positive electrode material for sodium-ion batteries and after exposure to air for 5, 10, and 15 days and soaking in water for 2 hours (the order of the curves is from bottom to top).

[0023] Fig. 9 The Na obtained in Comparative Example 1 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 (NFM) and Na prepared in Example 1 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2(HEO) sodium-ion battery O3-type layered oxide positive electrode material initial material and the first cycle charge and discharge curves after exposure to air for 15 days.

[0024] Fig.10 The Na obtained in Example 1 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 (HEO) sodium ion battery O3-type layered oxide cathode material matched with hard carbon anode soft pack full cell at 10mAg -1 The charge and discharge curves at current density and the actual picture of the soft-pack battery.

[0025] Fig.11 The Na obtained in Example 1 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 (HEO) sodium ion battery O3-type layered oxide cathode material matched with hard carbon anode soft pack full cell at 100mAg -1 Cycling performance diagram at current density of . DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific implementation modes of the present invention are further described below.

[0027] Comparative Example 1: Na 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 (NFM) O3-type layered oxide cathode materials for sodium-ion batteries

[0028] The preparation steps are as follows:

[0029] (1) Using a simple high temperature solid phase reaction, 8.5 mmol Na 2 CO 3 , 2mmolFe 2 O 3 , 6mmolNiO, 10mmolMnO 2Put it into a zirconia ball mill and grind it with a YXQM-0.4L planetary ball mill at 500 rpm for 6 hours. After mixing evenly, take out the powder;

[0030] (2) The powder obtained in step (1) was placed in a tabletting mold to obtain a 2-5 mm thick tablet, which was placed in a muffle furnace and calcined at 900° C. for 12 hours and naturally cooled to room temperature to obtain Na 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 Positive electrode material.

[0031] Example 1: Na 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 (HEO) O3-type layered oxide cathode materials for sodium-ion batteries

[0032] The preparation method is as follows:

[0033] (1) Using a simple high temperature solid phase reaction, 8.5 mmol Na 2 CO 3 , 1mmolLi 2 CO 3 , 0.2mmolAl 2 O 3 , 1.6mmolSnO 2 , 2mmolCuO, 2mmolTiO 2 , 6mmolNiO, 6mmolMnO 2 Put it into a zirconia ball mill and grind it with a YXQM-0.4L planetary ball mill at 500 rpm for 6 hours. After mixing evenly, take out the powder;

[0034] (2) The powder obtained in step (1) was placed in a tabletting mold to obtain a 2-5 mm thick tablet, which was placed in a muffle furnace and calcined at 900° C. for 12 hours and naturally cooled to room temperature to obtain Na 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 Positive electrode material.

[0035] Comparative Example 2: Na 0.85 Li 0.05Al 0.05 Sn 0.05 Cu 0.1 Ti 0.15 Ni 0.3 Mn 0.3 O 2 O3-type layered oxide cathode materials for sodium-ion batteries

[0036] The preparation method is as follows:

[0037] (1) Using a simple high temperature solid phase reaction, 8.5 mmol Na 2 CO 3 , 0.5mmolLi 2 CO 3 , 0.5mmolAl 2 O 3 , 1mmolSnO 2 , 2mmolCuO, 3mmolTiO 2 , 6mmolNiO, 6mmolMnO 2 Put it into a zirconia ball mill and grind it with a YXQM-0.4L planetary ball mill at 500 rpm for 6 hours. After mixing evenly, take out the powder;

[0038] (2) The powder obtained in step (1) was placed in a tabletting mold to obtain a 2-5 mm thick tablet, which was placed in a muffle furnace and calcined at 900° C. for 12 hours and naturally cooled to room temperature to obtain Na 0.85 Li 0.05 Al 0.05 Sn 0.05 Cu 0.1 Ti 0.15 Ni 0.3 Mn 0.3 O 2 Positive electrode material.

[0039] Comparative Example 3: Na 0.85 Li 0.07 Al 0.03 Sn 0.05 Cu 0.15 Ti 0.1 Ni 0.3 Mn 0.3 O 2 O3-type layered oxide cathode materials for sodium-ion batteries

[0040] The preparation method is as follows:

[0041] (1) Using a simple high temperature solid phase reaction, 8.5 mmol Na 2 CO 3 , 0.7mmol Li 2 CO 3, 0.3mmolAl 2 O 3 , 1mmol SnO 2 , 3mmol CuO, 2mmol TiO 2 , 6mmol NiO, 6mmol MnO 2 Put it into a zirconia ball mill and grind it with a YXQM-0.4L planetary ball mill at 500 rpm for 6 hours. After mixing evenly, take out the powder;

[0042] (2) The powder obtained in step (1) was placed in a tabletting mold to obtain a 2-5 mm thick tablet, which was placed in a muffle furnace and calcined at 900° C. for 12 hours and naturally cooled to room temperature to obtain Na 0.85 Li 0.07 Al 0.03 Sn 0.05 Cu 0.15 Ti 0.1 Ni 0.3 Mn 0.3 O 2 Positive electrode material.

[0043] Comparative Example 4: Na 0.85 Li 0.1 Al 0.02 Sn 0.03 Cu 0.1 Ti 0.15 Ni 0.3 Mn 0.3 O 2 O3-type layered oxide cathode materials for sodium-ion batteries

[0044] The preparation method is as follows:

[0045] (1) Using a simple high temperature solid phase reaction, 8.5 mmol Na 2 CO 3 , 1mmol Li 2 CO 3 , 0.2mmolAl 2 O 3 , 0.6mmol SnO 2 , 2mmol CuO, 3mmol TiO 2 , 6mmol NiO, 6mmol MnO 2 Put it into a zirconia ball mill and grind it with a YXQM-0.4L planetary ball mill at 500 rpm for 6 hours. After mixing evenly, take out the powder;

[0046] (2) The powder obtained in step (1) was placed in a tabletting mold to obtain a 2-5 mm thick tablet, which was placed in a muffle furnace and calcined at 900° C. for 12 hours and naturally cooled to room temperature to obtain Na0.85 Li 0.1 Al 0.02 Sn 0.03 Cu 0.1 Ti 0.15 Ni 0.3 Mn 0.3 O 2 Positive electrode material.

[0047] like Figure 1 As shown, the samples of Comparative Example 1 and Example 1 both have high crystallinity and similar diffraction peaks, and both can well index the pure phase of the O3 layered structure, indicating that the doped elements are successfully dissolved into the transition metal sites; while the samples of Comparative Examples 2-4 produce NiO impurities, the structural purity is reduced, and the Ni element is not completely dissolved into the transition metal sites, affecting the structural stability of the material.

[0048] like Figure 2 As shown, the particle sizes of both materials are between 1-4 μm and exhibit obvious lamellar characteristics.

[0049] like Figure 3 As shown, with Na 0.85 Fe 0.2 Ni 0.3 Mn 0.5 O 2 In comparison, Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O 2 There are fewer charge and discharge platforms, the curve is smoother, and the CV curve has only one pair of redox peaks, which indicates that it simplifies the structural evolution process of the O3-type layered positive electrode and inhibits the irreversible phase transition.

[0050] like Figure 4 and 5 As shown, the NFM positive electrode material undergoes a phase transition process of P3-P'3-XY-P'3-P3 in the high voltage region, where the 'X' and 'Y' phases are irreversible phases, which continue to cause structural damage during the cycle process, leading to rapid degradation of the material; while the HEO positive electrode material undergoes a reversible phase transition process of P3-OP2-P3 in the high voltage region, achieving high voltage stability of the material.

[0051] like Figure 6 and 7 As shown, at 50mAg -1 At the current density of 1Ag, the capacity retention rate of HEO after 100 cycles is 82.24%, while that of NFM after 100 cycles is only 48.80%. -1At a current density of , the capacity retention rate of HEO after 1000 cycles is 70.31%, while the capacity retention rate of NFM after 1000 cycles is only 22.45%. There is a significant difference in the cycle stability between the two.

[0052] like Figure 8 and 9 As shown, HEO inhibits the reaction of water and carbon dioxide in the air with the material to form hydrated alkaline compounds Na 2 CO 3 ·H 2 O, and after being immersed in water, it can still maintain a complete O3 structure. After being exposed to air for 15 days, HEO can still maintain a capacity retention rate of 90.11% relative to the initial material, indicating its excellent air stability.

[0053] like Fig.10 and 11 As shown, the soft pack full battery is at 10mAg -1 The capacity is about 60 mAh at a current density of 100 mAg -1 The capacity retention rate after 100 cycles at a current density of is 76.08%.

Claims

1. A high entropy sodium ion battery O3 type layered positive electrode material, characterized in that: The molecular formula of the high entropy configuration sodium ion battery O3 type layered positive electrode material is Na 0.85 Li 0.1 Al 0.02 Sn 0.08 Cu 0.1 Ti 0.1 Ni 0.3 Mn 0.3 O2.

2. The method for preparing the high entropy sodium ion battery O3 type layered positive electrode material according to claim 1, characterized in that: First, the sodium source and each metal source are ball-milled and mixed according to the molecular formula to obtain a precursor; then the precursor is pressed into sheets to obtain flakes; finally, the flakes are calcined to obtain a high-entropy configuration sodium-ion battery O3-type layered positive electrode material.

3. The preparation method according to claim 2, characterized in that: The thickness of the sheet is 2-5 mm.

4. The preparation method according to claim 2, characterized in that: The calcination temperature is 850-950° C. and the calcination time is 12-24 hours.

5. A sodium ion battery, characterized in that: The positive electrode of the sodium ion battery comprises the high entropy configuration sodium ion battery O3 type layered positive electrode material according to claim 1 or the high entropy configuration sodium ion battery O3 type layered positive electrode material prepared by the preparation method according to any one of claims 2-4.

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