CN116062807A - High-entropy doped manganese-based layered oxide, preparation method thereof, sodium ion battery positive electrode material and battery - Google Patents

High-entropy doped manganese-based layered oxide, preparation method thereof, sodium ion battery positive electrode material and battery Download PDF

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CN116062807A
CN116062807A CN202310267446.XA CN202310267446A CN116062807A CN 116062807 A CN116062807 A CN 116062807A CN 202310267446 A CN202310267446 A CN 202310267446A CN 116062807 A CN116062807 A CN 116062807A
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杨树斌
王梓铭
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Beihang University
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Abstract

The invention discloses a high-entropy doped manganese-based layered oxide, a preparation method thereof, a sodium ion battery anode material and a battery, wherein the chemical formula of the high-entropy doped manganese-based layered oxide is expressed as follows: na (Na) x Mn y M z O 2 Wherein Na represents a sodium element, mn represents a manganese element, M represents a doping element selected from five or more metal elements different from sodium and manganese in the third to fifth periods of the periodic table, x is more than or equal to 0.6 and less than or equal to 1,0.8 and y is more than or equal to 1, z is more than or equal to 0 and less than or equal to 0.2, and y+z=1. The invention realizes high entropy doping of more than five metal elements with low content to obtain a novel high entropy doped manganese-based layered oxide which is used asThe positive electrode material of the sodium ion battery shows electrochemical characteristics of excellent rate performance and cycle stability.

Description

High-entropy doped manganese-based layered oxide, preparation method thereof, sodium ion battery positive electrode material and battery
Technical Field
The invention belongs to the field of sodium ion batteries, and particularly relates to a high-entropy doped manganese-based layered oxide, a preparation method thereof, a sodium ion battery anode material and a battery.
Background
Along with the continuous expansion of new energy automobile markets and the continuous promotion of electric power industry scales such as wind power, photoelectricity and the like, the demand for large-scale energy storage devices is also continuously increased, and the lithium ion battery becomes a first choice widely applied in various fields due to excellent electrochemical performance and mature preparation technology. However, due to the shortage of lithium resources and local abundance, lithium resources are in shortage in many countries, the price is rapidly increased, and the application of the lithium ion battery in the field of large-scale energy storage is severely limited.
The sodium ion battery is very rich in raw material reserves, low in cost and better in safety performance, is very suitable for a large-scale energy storage device, becomes a candidate for replacing the lithium ion battery, and causes wide research of researchers at home and abroad. However, the low capacity of the positive electrode material of the sodium ion battery, poor cycle performance and low energy density become main reasons for limiting the wide application of the sodium ion battery. Therefore, developing a positive electrode material of a sodium ion battery with low cost, high capacity, high energy density and good cycling stability is of great importance for realizing the wide application of the sodium ion battery.
In the positive electrode material of the sodium ion battery, the layered oxide becomes the positive electrode material of the sodium ion battery which is most likely to go to practical application due to the higher specific capacity and the structure similar to that of the positive electrode material of the lithium ion battery. In order to optimize the cycling stability of the layered oxide cathode material, researchers have mainly adopted strategies of element doping and substitution. For example Prakash et al (chem. Mater.2012, 24, 1846-1853) prepared NaNi by Co element doping 1/3 Mn 1/3 Co 1/3 O 2 Although the cycling stability of the positive electrode material is improved to a certain extent, the multiplying power performance of the positive electrode material is poor, and the positive electrode material is difficult to adapt to the requirement of quick charge; yan et al (Journal of Advanced ceramics.2022,11, 158-171) prepared a mid-entropy layered oxide Na 2/3 Ni 1/3 Mn 1/3 Fe 1/4 Al 1/12 O 2 The electrode material has a higher ratioHigh capacity and good rate capability, but cycle stability is still to be improved; CN112467119a discloses a high entropy layered oxide positive electrode material Na (Fe) for sodium ion battery (1-x)/5 Co (1-x)/5 Ni (1-x)/5 Sn (1-x)/5 Ti (1-x)/5 )Li x O 2 Because various elements are added in equal proportion, the positive electrode material has good cycling stability, but has extremely low capacity and cannot meet the practical application;
although the cycle performance of the layered oxide cathode material can be improved through doping and replacement of single or few elements, the cycle stability and specific discharge capacity of the sodium ion battery cathode material prepared by the scheme still cannot meet the requirements of practical application, and the preparation method of the layered oxide cathode material needs to be further optimized.
Disclosure of Invention
Aiming at the technical problem of poor cycling stability of the positive electrode material of the sodium ion battery, the invention provides a method for preparing a lithium ion battery by using more than five low-content metal elements in Na x MnO 2 The technical scheme of high entropy doping is formed in the crystal lattice, a novel high entropy doped manganese-based layered oxide is obtained, and the high entropy doped manganese-based layered oxide is used for a sodium ion battery positive electrode material, and the result shows that Na can be improved through high entropy doping x MnO 2 The stability of the crystal lattice, as a positive electrode material of a sodium ion battery, shows excellent cycle stability and rate characteristics.
The first aspect of the present invention provides a cathode material for a sodium ion battery, namely a high entropy doped manganese-based layered oxide, wherein the chemical formula of the high entropy doped manganese-based layered oxide is as follows: na (Na) x Mn y M z O 2 Wherein Na represents a sodium element, mn represents a manganese element, and M represents a doping element selected from five or more metal elements other than sodium (Na) and manganese (Mn) in the third to fifth periods of the periodic table; x is more than or equal to 0.6 and less than or equal to 1,0.8, y is more than or equal to 1, z is more than or equal to 0 and less than or equal to 0.2, and y+z=1.
In some embodiments, the doping element (M) is selected from five or more elements of iron (Fe), nickel (Ni), cobalt (Co), copper (Cu), titanium (Ti), magnesium (Mg), zinc (Zn), calcium (Ca), vanadium (V), chromium (Cr), zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), tin (Sn), antimony (Sb), aluminum (Al). The doping element in the invention is selected from metal elements including transition metal elements.
In some embodiments, the doping element (M) includes: at least 1 to 3 kinds of metal elements selected from the fifth period, and at least 2 to 4 kinds of metal elements selected from the third period and/or the fourth period;
in some embodiments, the metal element of the fifth period is selected from zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), tin (Sn), antimony (Sb); the metal element in the third period is selected from magnesium (Mg) and aluminum (Al); the metal element of the fourth period is selected from calcium (Ca), titanium (Ti), vanadium (V), chromium (Cr), nickel (Ni), iron (Fe), cobalt (Co), copper (Cu), and zinc (Zn).
In some embodiments, the high entropy doped manganese-based layered oxide has five or six species of doping elements, represented by the formula: na (Na) x Mn y (M 1a M 2b M 3c M 4d M 5e M 6f )O 2 ，M 1 、M 2 、M 3 、M 4 、M 5 、M 6 Representing different doping elements, wherein a is more than 0 and less than or equal to 0.05, b is more than 0 and less than or equal to 0.05, c is more than 0 and less than or equal to 0.05, d is more than 0 and less than or equal to 0.05, e is more than 0 and less than or equal to 0.05, and f is more than or equal to 0 and less than or equal to 0.05.
In some embodiments, 0 < a.ltoreq. 0.04,0 < b.ltoreq. 0.04,0 < c.ltoreq. 0.04,0 < d.ltoreq. 0.04,0 < e.ltoreq. 0.04,0.ltoreq.f.ltoreq.0.04 in the above formula.
In some embodiments, 0 < a.ltoreq. 0.03,0 < b.ltoreq. 0.03,0 < c.ltoreq. 0.03,0 < d.ltoreq. 0.03,0 < e.ltoreq. 0.03,0.ltoreq.f.ltoreq.0.03 in the above formula.
In some embodiments, 0 < a.ltoreq. 0.02,0 < b.ltoreq. 0.02,0 < c.ltoreq. 0.02,0 < d.ltoreq. 0.02,0 < e.ltoreq. 0.02,0.ltoreq.f.ltoreq.0.02 in the above formula.
In some embodiments, at least 4 of a, b, c, d, e, f have a value of 0.02 or less and greater than 0 in the above formulas.
In some embodiments, the doping element (M) is selected from iron (Fe), nickel (Ni), copper (Cu), titanium (Ti), magnesium (Mg), zinc (Zn), antimony (Sb), tin (Sn), zirconium (Zr), aluminum (Al), niobium (Nb) elements.
In some embodiments, the high entropy doped layered oxide described above is a P2/O '3 bi-phase, or O'3 phase.
In some embodiments, the XRD diffraction pattern of the above-described high entropy doped layered manganese-based oxide comprises P2 phase diffraction peaks (002) (004) (100) (102); and/or, the O'3 phase diffraction peak (001) (002) (200) (-111) (-202) (111).
The second aspect of the present invention provides a method for preparing the above-mentioned high entropy doped manganese-based layered oxide, comprising the steps of: weighing sodium salt and manganese oxide with corresponding molar ratios and oxide of the doping elements according to the chemical formula of the high-entropy doping manganese-based layered oxide, and carrying out mixing treatment to obtain mixed powder; pressing the mixed powder to obtain a pressed block; and sintering the block.
In some embodiments, the sodium salt is selected from sodium carbonate (Na 2 CO 3 ) Sodium bicarbonate (NaHCO) 3 ) Sodium acetate (CH) 3 COONa), sodium oxalate (Na 2 C 2 O 4 ) Sodium citrate (C) 6 H 5 Na 3 O 7 ) Sodium nitrate (NaNO) 3 ) One or more of sodium hydroxide (NaOH).
In some embodiments, the mixing process comprises ball milling, wherein the ball mass ratio is (5-20): 1, the ball milling speed is 300 to 600r/min, and the ball milling time is 3 to 24 hours.
In some embodiments, the above-mentioned pressing process, the step more specifically includes loading the mixed powder into a mold, and press-molding under a pressure of 5 to 30Mpa.
In some embodiments, in the above sintering process, the sintering temperature is between 500 and 1100 ℃, the temperature rising rate is between 3 and 20 ℃/min, and the sintering time is between 1 and 24 hours.
The third aspect of the present invention provides a positive electrode material for a sodium ion battery, comprising: the high-entropy doped manganese-based layered oxide or the high-entropy doped manganese-based layered oxide obtained by the preparation method.
According to a fourth aspect of the invention, there is provided an electrode sheet comprising the above-described high entropy doped manganese-based layered oxide, or the above-described high entropy doped manganese-based layered oxide obtained by the above-described production method.
In a fifth aspect, the present invention provides a sodium ion battery comprising the above-described sodium ion battery cathode material.
The sixth aspect of the invention provides an electric device comprising the sodium ion battery. The electric devices comprise electric automobiles, electric bicycles, energy storage power stations, electronic appliances and the like.
Compared with the prior art, the manganese-based layered oxide anode material Na x MnO 2 The high-entropy doping is realized by using more than five metal elements with low content as a matrix, so that a novel high-entropy doped manganese-based layered oxide is obtained, wherein each doping element can form a combined lattice by sharing the same atomic site, a certain degree of lattice distortion is caused, the mixed entropy of the material is increased by disordered arrangement of each doping element, and the structural stability of the material is improved. The high-entropy doped manganese-based layered oxide is used as a positive electrode material of a sodium ion battery, and the result shows that the high-entropy doped manganese-based layered oxide has electrochemical characteristics of excellent rate performance and cycle stability.
Drawings
FIG. 1 is a high entropy doped manganese-based layered oxide NaMn of the P2/O'3 bi-phase of example 1 of the present invention 0.89 (Ni 0.02 Fe 0.02 Cu 0.02 Sb 0.03 Zn 0.02 )O 2 Is a XRD spectrum of (C).
FIG. 2 is a schematic diagram of a P2/O'3 dual-phase high entropy doped manganese-based layered oxide NaMn according to example 1 of the present invention 0.89 (Ni 0.02 Fe 0.02 Cu 0.02 Sb 0.03 Zn 0.02 )O 2 SEM photograph (a) of (c) and profiles (b to h) of each element Na, mn, ni, fe, cu, sb and Zn therein.
FIG. 3 is a graph showing the first charge and discharge curves of the P2/O'3 bi-phase high entropy doped manganese-based layered oxide as a positive electrode material for sodium ion batteries in example 1 of the present invention.
FIG. 4 is a graph showing the results of the cycle performance test of the P2/O'3 bi-phase high entropy doped manganese-based layered oxide as a positive electrode material for sodium ion battery in example 1 of the present invention.
FIG. 5 is a graph showing the results of the rate performance test of the P2/O'3 dual-phase high-entropy doped manganese-based layered oxide as a positive electrode material for sodium ion battery in example 1 of the present invention.
Fig. 6 is a comparison of XRD patterns of the high entropy doped manganese-based layered oxide of example 1 of the present invention after 100 cycles as a positive electrode material with an initial state.
FIG. 7 is a high entropy doped manganese-based layered oxide NaMn of the P2/O'3 bi-phase of example 2 of the present invention 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 Is a XRD spectrum of (C).
FIG. 8 is a high entropy doped manganese-based layered oxide NaMn of the P2/O'3 bi-phase of example 2 of the present invention 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 SEM photograph (a) of (a) and elemental profiles of each element Na, mn, ni, fe, cu, sb and Zn (b to h).
FIG. 9 is a graph showing the first charge and discharge curves of the P2/O'3 bi-phase high entropy doped manganese-based layered oxide as a positive electrode material for sodium ion batteries in example 2 of the present invention.
FIG. 10 is a graph showing the results of the cycle performance test of the P2/O'3 bi-phase high entropy doped manganese-based layered oxide as a positive electrode material for sodium ion battery in example 2 of the present invention.
FIG. 11 is a graph showing the results of the rate performance test of the P2/O'3 dual-phase high-entropy doped manganese-based layered oxide as a positive electrode material for sodium ion battery in example 2 of the present invention.
FIG. 12 is a comparison of XRD patterns of the P2/O'3 dual-phase high-entropy doped manganese-based layered oxide of example 2 of the present invention after 100 cycles as a positive electrode material with an initial state.
FIG. 13 is an XRD spectrum of a P2/O'3 dual-phase high entropy doped manganese-based layered oxide according to example 3 of the present invention.
FIG. 14 is an SEM photograph of a P2/O'3 dual-phase high-entropy doped manganese-based layered oxide according to example 3 of the present invention.
Fig. 15 is a comparison of the cycling performance test of sodium ion batteries using different P2/O'3 bi-phase high entropy doped manganese-based layered oxides as positive electrode materials in example 3 of the present invention.
Detailed Description
The technical scheme of the invention is described below through specific examples. It is to be understood that the reference to one or more steps of the invention does not exclude the presence of other methods and steps before or after the combination of steps, or that other methods and steps may be interposed between the explicitly mentioned steps. It should also be understood that these examples are illustrative of the present invention and are not intended to limit the scope of the present invention. Unless otherwise indicated, the numbering of the method steps is for the purpose of identifying the method steps only and is not intended to limit the order of arrangement of the method steps or to limit the scope of the invention, which relative changes or modifications may be regarded as the scope of the invention which may be practiced without substantial technical content modification.
The raw materials and instruments used in the examples are not particularly limited in their sources, and may be purchased on the market or prepared according to conventional methods well known to those skilled in the art.
The preparation method of the sodium ion battery positive plate disclosed by the invention comprises the following steps of: 1) Mixing a sodium ion battery anode material (high entropy doped manganese-based layered oxide in the invention), a conductive agent (Super P) and a binder (PVDF) according to a mass ratio of 7:2:1, grinding for 10min, adding a proper amount of N-methylpyrrolidone (NMP), grinding for 20min, and preparing to obtain mixed slurry; 2) Coating the obtained mixed slurry on an aluminum foil wafer with the diameter of 12mm, wherein the loading capacity is 1.5mg/cm 2 And then the coated electrode plate is put into a vacuum oven at 80 ℃ to be dried for 12 hours, and the positive electrode plate can be obtained.
The same method is adopted to replace the high entropy doped manganese-based layered oxide with other layered oxides, such as NaMnO 2 A small amount of doped layered oxide NaMn 0.8 Ni 0.2 O 2 、NaMn 0.89 Ni 0.04 Fe 0.04 Sb 0.03 O 2 、NaMn 0.8 Ni 0.07 Fe 0.07 Sb 0.06 O 2 And obtaining a reference positive plate.
The method for assembling the sodium ion battery comprises the following steps: the metal sodium sheet is used as a negative electrode, the prepared positive electrode sheet is used as a positive electrode, a CR2032 button cell is prepared in an argon glove box, a glass fiber diaphragm is adopted as a diaphragm, and NaClO with the concentration of 1M is adopted as electrolyte 4 Solution, solvent volume ratio 1:1 and dimethyl carbonate (DMC) and contains 2% by volume of fluoroethylene carbonate (FEC).
The charge and discharge performance test of the sodium ion battery is carried out on a Land BT2000 battery test system, the test temperature is room temperature, and the test voltage range is 2.0-4.0V.
Na in the high entropy doped layered oxide of the invention x Mn y M z O 2 The high-entropy doping is realized through more than five metal elements with low content, the selection of the types of the doping elements is a technical key point for forming the high-entropy doping, the sizes of doping metal atoms with different high entropies, and the selection of the metal elements with the atomic size in a staggered ratio is beneficial to forming a stable high-entropy doping lattice phase. Therefore, the doping element is preferably matched with the metal element of the third and/or fourth period and the metal element of the fifth period, so that a stable high-entropy doped layered oxide is obtained.
In some embodiments, the doping element M is selected from one to three of metallic elements zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), tin (Sn), antimony (Sb) in the fifth period of the periodic table; and/or the doping element M is selected from two to four of magnesium (Mg), aluminum (Al), calcium Ca, titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), copper (Cu) and zinc (Zn) in the third period and the fourth period of the periodic table.
Example 1
This example provides a high entropy doped manganese-based layered oxide NaMn 0.89 (Ni 0.02 Fe 0.02 Cu 0.02 Sb 0.03 Zn 0.02 )O 2 And a method for preparing the same. The preparation method comprises the following steps:
s01: doping manganese-based layers according to high entropyThe chemical formula of the oxide is that Na with corresponding molar ratio is weighed 2 CO 3 And MnO 2 Performing ball milling treatment on the oxide powder doped with the elements to obtain mixed powder; specifically, the molar ratio is 0.5:0.89:0.02:0.01:0.02:0.015:0.02, respectively weighing Na 2 CO 3 、MnO 2 、NiO、Fe 2 O 3 、CuO、Sb 2 O 5 And ZnO powder, and placing the ZnO powder into an agate tank according to the mass ratio of 10:1, adding agate balls, adding a proper amount of ethanol as a dispersing agent, finally placing a ball milling tank on a ball mill for ball milling for 4 hours, and placing the ball milling tank in a blast oven at 80 ℃ for drying for 10 hours after ball milling is completed to obtain mixed powder after ball milling;
s02: pressing the mixed powder after ball milling treatment to obtain pressed and molded blocks; specifically, the dried mixed powder is placed in a circular groove die with the diameter of 14mm, and tabletting is carried out under the pressure of 10MPa to obtain a circular block with the diameter of 14 mm;
s03: sintering the block, grinding the sintered product to obtain a high-entropy doped manganese-based layered oxide; specifically, the pressed round block is put into an alumina crucible, the crucible is put into a muffle furnace, the temperature is increased to 950 ℃ at 10 ℃/min, the round block is sintered for 12 hours in an air atmosphere and then cooled along with the furnace, and the sintered block is ground and sieved to obtain the target product NaMn 0.89 (Ni 0.02 Fe 0.02 Cu 0.02 Sb 0.03 Zn 0.02 )O 2 。
As shown in figure 1, XRD test results of the obtained target product show that the target product has characteristic peaks of P2 phase at 15.9 degrees, 32 degrees, 35.7 degrees, 39.4 degrees, 43.5 degrees and 48.9 degrees, the characteristic peaks respectively correspond to (002) (004) (100) (102) (103) (104) crystal planes, the characteristic peaks respectively correspond to (001), (-201) (002) (200) (-111) (-202) (111) crystal planes of O '3 phase at 16.6 degrees, 31.7 degrees, 33.6 degrees, 34.4 degrees, 36.6 degrees, 37.7 degrees and 42.7 degrees, the characteristic peaks respectively correspond to (001), (-201) (002) (200) (-202) (111) crystal plane, the target product comprises characteristic peaks of P2 phase and O'3 phase, and the target product NaMn 0.89 (Ni 0.02 Fe 0.02 Cu 0.02 Sb 0.03 Zn 0.02 )O 2 Is a P2/O'3 biphasic composite structure, wherein (002) (102) corresponds to the peak of P2 phase Jiang Yanshe, and (004) (100) (103) (104) is a weak diffraction peak relatively; (001) (111) corresponds to the strong diffraction peak of the O'3 phase, and (002) (200) (-111) (-202) is a weak diffraction peak relatively speaking. Fig. 2a shows a Scanning Electron Microscope (SEM) photograph of the target product, and the microstructure of the target product is in a micron-sized lamellar particle shape, and as can be seen from the element distribution diagrams of fig. 2 b-h, the uniform distribution of each element Na, mn, ni, fe, cu, sb and Zn in the target product is shown.
The embodiment also provides the application of the obtained P2/O'3 biphase high-entropy doped manganese-based layered oxide as a positive electrode material of a sodium ion battery, namely the positive electrode material of the sodium ion battery and the sodium ion battery. FIG. 3 shows the P2/O'3 biphasic high entropy doped manganese-based layered oxide NaMn obtained as described above 0.89 (Ni 0.02 Fe 0.02 Cu 0.02 Sb 0.03 Zn 0.02 )O 2 As a first charge-discharge curve graph of the sodium ion battery as the positive electrode material, the high-entropy doped manganese-based layered oxide of the invention can be seen to have 188mAhg as the positive electrode material of the sodium ion battery -1 The initial capacity of (2) and the first-turn coulombic efficiency can reach 85%. FIG. 4 shows the results of cycle performance test of sodium-ion battery using the above-obtained P2/O'3 dual-phase high-entropy doped manganese-based layered oxide as positive electrode material, and it can be seen that the initial capacity and NaMnO of the high-entropy doped manganese-based layered oxide of the present invention as positive electrode material of sodium-ion battery 2 And NaMn 0.89 Ni 0.04 Fe 0.04 Sb 0.03 O 2 The positive electrode material is equivalent (> 150 mAhg) -1 ) However, the high entropy doped manganese-based layered oxide of the present invention has little capacity decay after 100 charge-discharge cycles, and remains at about 160mAhg -1 In contrast, in the comparative cell, naMnO 2 And NaMn 0.89 Ni 0.04 Fe 0.04 Sb 0.03 O 2 The capacity of the positive electrode material is obviously attenuated, and only about 120mAhg respectively remains after 100 cycles -1 And 130mAhg -1 Shows that the high entropy doped manganese-based layered oxide of the invention is used as the positive electrode material of the sodium ion batteryThe material has excellent capacity retention and cycle stability. Comparing the test results (FIG. 5) under different multiplying powers (0.1C-5C), it can be seen that the initial capacity of the high entropy doped manganese-based layered oxide of the invention as a positive electrode material of sodium ion battery can reach up to 195mAhg under 0.1C charge-discharge multiplying power -1 About 170mAhg capacity at 0.2C -1 When the charge-discharge rate was increased to 5C, the battery was maintained at about 123mAhg -1 Comparison of NaMnO 2 And NaMn 0.89 Ni 0.04 Fe 0.04 Sb 0.03 O 2 The positive electrode material is only 80mAhg -1 And 104mAhg -1 It can be seen that the high entropy doped manganese-based layered oxide of the present invention also exhibits excellent rate capability. Excellent rate performance benefits from material characteristics, and the material is prepared from layered oxide NaMnO 2 High entropy doping is introduced, and chemical disorder and distortion of multiple elements will locally disturb the site energy, thereby generating a distribution of site energy. When this distribution is wide enough that the energies of adjacent sites overlap, ion hopping between them will be facilitated. If such a network of sites with similar energy is permeated, macroscopic ion diffusion will be enhanced by disorder. An increase in conductivity is exhibited in terms of material properties. This can be calculated by first principles of linearity and experiments demonstrate that the introduction of chemical disorder into an inorganic solid electrolyte with high entropy can increase ionic conductivity by several orders of magnitude, thereby reducing overall cell resistance to improve performance.
In particular, as can be seen from fig. 5, when the charge-discharge rate is restored to 0.1C, the capacity of the high-entropy doped manganese-based layered oxide of the present invention can be restored to 185mAhg -1 And NaMnO 2 And NaMn 0.89 Ni 0.04 Fe 0.04 Sb 0.03 O 2 The capacity of the positive electrode material is only 140mAhg -1 And 173mAhg -1 And cannot be restored to near the initial capacity. The capacity can be restored after the high-rate charge-discharge process, so that the repeated intercalation and deintercalation of sodium ions in the high-entropy doped manganese-based layered oxide does not damage the material structure, and the high-entropy doping is related to the improvement of the structural stability of the layered oxide material. FIG. 6 shows that after 100 cyclesThe XRD spectrogram of the high-entropy doped manganese-based layered oxide is compared with that of the initial high-entropy doped manganese-based layered oxide, so that the high-entropy doped manganese-based layered oxide positive electrode material still maintains the original crystal form even after 100 charge-discharge cycles, and further proves that the structural stability of the high-entropy doped manganese-based layered oxide positive electrode material is excellent.
During the sintering process, sodium carbonate (Na 2 CO 3 ) Sodium carbonate (Na) 2 CO 3 ) After heating, the mixture and the metal oxide are subjected to solid-phase sintering reaction under the high-temperature condition. In other embodiments, the sodium carbonate in the feed may also be replaced with other sodium salts such as sodium bicarbonate (NaHCO 3 ) Sodium acetate (CH) 3 COONa), sodium oxalate (Na 2 C 2 O 4 ) Sodium citrate (C) 6 H 5 Na 3 O 7 ) Sodium nitrate (NaNO) 3 ) Sodium hydroxide (NaOH). The manganese oxide in the raw materials comprises: mnO, mnO 2 、Mn 2 O 3 、Mn 3 O 4 、Mn 2 O 5 Etc.; the nickel oxide in the raw material comprises NiO and Ni 2 O 3 The iron oxide in the raw material comprises FeO and Fe 2 O 3 Fe 3 O 4 。
Example 2
This example provides a high entropy doped manganese-based layered oxide NaMn 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 And a method for preparing the same. The preparation method comprises the following steps:
s11: weighing Na with corresponding molar ratio according to chemical formula of high-entropy doped manganese-based layered oxide 2 CO 3 And MnO 2 Performing ball milling treatment on the oxide powder doped with the elements to obtain mixed powder; specifically, the molar ratio is 0.5:0.8:0.05:0.025:0.05:0.015:0.02 respectively weighing Na 2 CO 3 、MnO 2 、NiO、Fe 2 O 3 、CuO、Sb 2 O 3 And ZnO powder, and placing the ZnO powder into an agate tank according to the mass ratio of 10:1 adding agate balls, adding proper amount of ethanol as dispersing agent, and finally addingPlacing the ball milling tank on a ball mill for ball milling for 4 hours, and placing the ball milling tank in a blast oven at 80 ℃ for drying for 10 hours after ball milling is completed to obtain mixed powder after ball milling;
s12: pressing the mixed powder after ball milling treatment to obtain pressed and molded blocks; specifically, the dried mixed powder is placed in a circular groove die with the diameter of 14mm, and tabletting is carried out under the pressure of 10MPa to obtain a circular block with the diameter of 14 mm;
s13: sintering the block, grinding the sintered product to obtain a high-entropy doped manganese-based layered oxide; specifically, the pressed round block is put into an alumina crucible, the crucible is put into a muffle furnace, the temperature is increased to 950 ℃ at 10 ℃/min, the round block is sintered for 12 hours in an air atmosphere and then is cooled along with the furnace, and the sintered block is ground and sieved to obtain the target product P2/O'3 biphasic NaMn 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 。
As shown in the XRD test results of the obtained target product in FIG. 7, it can be seen that the target product has characteristic peaks of P2 phase at 15.8 degrees, 31.9 degrees, 35.8 degrees, 39.2 degrees, 43.4 degrees and 48.7 degrees, corresponding to (002) (004) (100) (102) (103) (104) crystal planes respectively, and has characteristic peaks of O '3 phase at 16.5 degrees, 31.8 degrees, 33.5 degrees, 34.3 degrees, 36.7 degrees, 37.6 degrees and 42.6 degrees, corresponding to (001) and (201) (002) (200) (-111) (-202) (111) crystal planes respectively, so that the target product contains characteristic peaks of P2 phase and O'3 phase respectively, and the target product NaMn 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 Is a P2/O'3 double-phase composite structure; unlike in fig. 1, the diffraction intensities of the crystal planes are different, specifically, the characteristic peak intensity of the O '3 phase crystal plane in fig. 1 is greater than the peak intensity of the P2 Xiang Tezheng phase, the characteristic peak intensity of the P2 phase crystal plane in fig. 7 is greater than the characteristic peak intensity of the O'3 phase crystal plane, which means that the proportion of the O '3 phase of the product obtained in example 1 is greater than the proportion of the P2 phase, and the proportion of the O'3 phase of the product obtained in example 2 is less than the proportion of the P2 phase; FIG. 8a shows a Scanning Electron Microscope (SEM) photograph of the target product, which can be seenThe microstructure of the target product is micron-sized lamellar particles, and the uniform distribution of each element Na, mn, ni, fe, cu, sb and Zn in the target product can be seen from the element distribution diagrams of fig. 8 b-h.
The embodiment also provides the application of the obtained P2/O'3 biphase high-entropy doped manganese-based layered oxide as a positive electrode material of a sodium ion battery, namely the positive electrode material of the sodium ion battery and the sodium ion battery. FIG. 9 shows the first charge-discharge curve of a sodium ion battery using the P2/O'3 dual-phase high-entropy doped manganese-based layered oxide of the present example as a positive electrode material of a sodium ion battery, and it can be seen that the high-entropy doped manganese-based layered oxide of the present invention has 156mAhg as a positive electrode material of a sodium ion battery -1 The initial capacity of (c) can reach 83% of the first-turn coulombic efficiency.
FIG. 10 shows the P2/O'3 biphasic high entropy doped manganese-based layered oxide NaMn obtained as described above 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 As a result of the cycle performance test of the sodium ion battery as the positive electrode material, it can be seen that the high entropy doped manganese-based layered oxide of the present invention has an initial capacity (about 120mAhg -1 ) Slightly higher than the comparison sample NaMn 0.8 Ni 0.2 O 2 And NaMn 0.8 Ni 0.07 Fe 0.07 Sb 0.06 O 2 The positive electrode material is equivalent, but the capacity of the high-entropy doped manganese-based layered oxide of the invention is hardly attenuated after 100 charge-discharge cycles, and is still kept at about 122mAhg -1 In contrast to the cells, naMn 0.8 Ni 0.2 O 2 And NaMn 0.8 Ni 0.07 Fe 0.07 Sb 0.06 O 2 The capacity of the positive electrode material is obviously attenuated, and after 100 cycles, the capacities respectively only remain 74mAhg -1 And 98mAhg -1 The high-entropy doped manganese-based layered oxide provided by the invention has excellent capacity retention capacity and cycle stability as a positive electrode material of a sodium ion battery. From comparison of test results at different rates (0.1C-5C) (FIG. 11), it can also be seen that the high entropy doped manganese-based layered oxide of the present inventionAs a positive electrode material of the sodium ion battery, the initial capacity of the sodium ion battery can reach 156mAhg under the charge-discharge multiplying power of 0.1C -1 About 138mAhg capacity at 0.2C -1 When the charge-discharge rate was increased to 5C, the battery was maintained at about 88mAhg -1 Comparative sample NaMn 0.8 Ni 0.2 O 2 And NaMn 0.8 Ni 0.07 Fe 0.07 Sb 0.06 O 2 The positive electrode materials are respectively only 51mAhg -1 And 63mAhg -1 It can be seen that the high entropy doped manganese-based layered oxide of the present invention exhibits excellent rate capability; in particular, when the charge-discharge multiplying power is restored to 0.1C, the capacity of the high-entropy doped manganese-based layered oxide can be restored to 152mAhg -1 While the control NaMn 0.8 Ni 0.2 O 2 And NaMn 0.8 Ni 0.07 Fe 0.07 Sb 0.06 O 2 The capacity of the positive electrode material can only be respectively restored to 131mAhg -1 And 144mAhg -1 And cannot be restored to near the initial capacity. This is related to the fact that high entropy doping elements can improve the stability of the material. It can be seen that the high entropy doped manganese-based layered oxide and NaMn of the present invention 0.8 Ni 0.2 O 2 And NaMn 0.8 Ni 0.07 Fe 0.07 Sb 0.06 O 2 And compared with the prior art, the high-capacity composite material also has excellent multiplying power performance and cycle stability. From the XRD spectrum of FIG. 12, it can be seen that the high-entropy doped manganese-based layered oxide cathode material still maintains the original crystal form after 100 charge-discharge cycles, and has excellent structural stability.
As can be seen from the electrochemical test results of examples 1 and 2, the high-entropy doped manganese-based layered oxide of the invention is used as a positive electrode material of a sodium ion battery, and the cycling stability and the rate capability of the electrochemical performance of the high-entropy doped manganese-based layered oxide are superior to those of undoped NaMnO 2 Is also superior to a layered oxide doped with a small amount of an element (e.g., naMn) 0.8 Ni 0.2 O 2 、NaMn 0.89 Ni 0.04 Fe 0.04 Sb 0.03 O 2 、NaMn 0.8 Ni 0.07 Fe 0.07 Sb 0.06 O 2 ). This is related to the fact that high entropy doping can increase the structural stability of the material and improve the electrical conductivity.
In another embodiment, after the ZnO in example 2 is replaced with MgO, other conditions are unchanged, and the NaMn is obtained by high-temperature solid-phase sintering 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Mg 0.02 )O 2 。
By doping the manganese-based layered oxide NaMn with high entropy in examples 1 and 2 0.89 (Ni 0.02 Fe 0.02 Cu 0.02 Sb 0.03 Zn 0.02 )O 2 And NaMn 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 As a comparison of electrochemical performance test results of the positive electrode material of sodium ion battery (see FIGS. 4, 5 and 10 and 11), it can also be seen that the high entropy doped manganese-based layered oxide NaMn of example 1 0.89 (Ni 0.02 Fe 0.02 Cu 0.02 Sb 0.03 Zn 0.02 )O 2 Is less doped than NaMn in example 2 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 However, from the viewpoint of specific capacity, cycle performance and rate performance, naMn of example 1 0.89 (Ni 0.02 Fe 0.02 Cu 0.02 Sb 0.03 Zn 0.02 )O 2 Are all superior to NaMn in example 2 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 It can be seen that the doping content is also one of the factors affecting the manganese-based layered oxide, and that the higher the doping content is, the better, and the lower the doping content is, instead, beneficial to the improvement of the electrochemical performance of the high-entropy doped manganese-based layered oxide as a positive electrode material of a sodium ion battery. Thus, expressed by the chemical formula, the high entropy doped manganese-based layered oxygen Na x Mn y (M 1a M 2b M 3c M 4d M 5e M 6f )O 2 Wherein a is more than 0 and less than or equal to 0.05, b is more than 0 and less than or equal to 0.05, c is more than 0 and less than or equal to 0.05, d is more than 0 and less than or equal to 0.05, e is more than 0 and less than or equal to 0.05, and f is more than or equal to 0 and less than or equal to 0.05; further reducing the doping element content, preferably, a is more than 0 and less than or equal to 0.04,0, b is more than or equal to 0.04,0, c is more than or equal to 0.04,0, d is more than or equal to 0.04,0, e is more than or equal to 0.04,0, and f is more than or equal to 0.04; more, thePreferably, 0 < a.ltoreq. 0.03,0 < b.ltoreq. 0.03,0 < c.ltoreq. 0.03,0 < d.ltoreq. 0.03,0 < e.ltoreq. 0.03,0.ltoreq.f.ltoreq.0.03. In a preferred embodiment, 0 < a.ltoreq. 0.02,0 < b.ltoreq. 0.02,0 < c.ltoreq. 0.02,0 < d.ltoreq. 0.02,0 < e.ltoreq. 0.03,0.ltoreq.f.ltoreq.0.02. In another preferred embodiment, at least 4 of the values a to f are < 0.02 and greater than 0.
Example 3
This example provides another high entropy doped manganese-based layered oxide NaMn 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Ti 0.03 Zn 0.02 )O 2 And a method of preparing the same, wherein the doping element is selected from the fourth period of the periodic table. The preparation method comprises the following steps:
s21: weighing Na with corresponding molar ratio according to chemical formula of high-entropy doped manganese-based layered oxide 2 CO 3 And MnO 2 Performing ball milling treatment on the oxide powder doped with the elements to obtain mixed powder; specifically, the molar ratio is 0.5:0.8:0.05:0.025:0.05:0.015:0.02 respectively weighing Na 2 CO 3 、MnO 2 、NiO、Fe 2 O 3 、CuO、TiO 2 And ZnO powder, and placing the ZnO powder into an agate tank according to the mass ratio of 10:1, adding agate balls, adding a proper amount of ethanol as a dispersing agent, finally placing a ball milling tank on a ball mill for ball milling for 4 hours, and placing the ball milling tank in a blast oven at 80 ℃ for drying for 10 hours after ball milling is completed to obtain mixed powder after ball milling;
s22: pressing the mixed powder after ball milling treatment to obtain pressed and molded blocks; specifically, the dried mixed powder is placed in a circular groove die with the diameter of 14mm, and tabletting is carried out under the pressure of 10MPa to obtain a circular block with the diameter of 14 mm;
s23: sintering the block, grinding the sintered product to obtain a high-entropy doped manganese-based layered oxide; specifically, the pressed round block is put into an alumina crucible, the crucible is put into a muffle furnace, the temperature is increased to 950 ℃ at 10 ℃/min, the round block is sintered for 12 hours in an air atmosphere and then is cooled along with the furnace, and the sintered block is ground and the round block is sinteredSieving to obtain target product P2/O'3 biphasic NaMn 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Ti 0.03 Zn 0.02 )O 2 。
As shown in figure 13, the XRD test results of the obtained target product show that the target product has characteristic peaks of P2 phase at 16 degrees, 31.8 degrees, 35.9 degrees, 39.1 degrees, 43.3 degrees and 48.8 degrees, the characteristic peaks respectively correspond to (002) (004) (100) (102) (103) (104) crystal planes, the characteristic peaks respectively correspond to (001), (-201) (002) (200) (-111) (-202) (111) crystal planes of O '3 phase at 16.6 degrees, 31.7 degrees, 33.4 degrees, 34.5 degrees, 36.8 degrees, 37.5 degrees and 42.4 degrees, the characteristic peaks respectively correspond to (001), (-201) (002) (200) (-202) (111) crystal plane, the target product comprises characteristic peaks of P2 phase and O'3 phase, and the target product NaMn 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Ti 0.03 Zn 0.02 )O 2 Is a P2/O'3 double-phase composite structure; unlike the diffraction intensities of the crystal planes in fig. 1 and 7, specifically, the characteristic peak intensity of the O '3 phase crystal plane in fig. 1 is greater than the characteristic peak intensity of the P2 Xiang Tezheng phase, the characteristic peak intensity of the P2 phase crystal plane in fig. 7 is greater than the characteristic peak intensity of the O'3 phase crystal plane, and the characteristic peak intensity of the O '3 phase crystal plane and the P2 Xiang Tezheng peak intensity in fig. 13 are not greatly different, which means that the proportion of the O'3 phase and the proportion of the P2 phase of the product obtained in example 3 are similar. Fig. 14 shows a Scanning Electron Microscope (SEM) photograph of the target product, and the microstructure of the target product is shown to be micron-sized lamellar particles.
The embodiment also provides the application of the obtained P2/O'3 biphase high-entropy doped manganese-based layered oxide as a positive electrode material of a sodium ion battery, namely the positive electrode material of the sodium ion battery and the sodium ion battery. And comparing it with a high entropy doped layered oxide positive electrode material having doping elements of different periods.
FIG. 15 shows the P2/O'3 biphasic high entropy doped manganese-based layered oxide NaMn obtained as described above 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Ti 0.03 Zn 0.02 )O 2 As a result of testing the cycle performance of the sodium-ion battery as the positive electrode material, it can be seen that the high-entropy doped manganese-based layered oxide of the invention is used as the positive electrode of the sodium-ion batteryThe initial capacity of the electrode material at 0.5C (about 113mAhg -1 ) Below NaMn 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 Cathode material (about 120 mAhg) -1 ) And NaMn 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Mg 0.02 )O 2 (about 125 mAhg) -1 ) The anode material, and the residual capacity of the high entropy doped layered oxide of the invention is about 96mAhg after 100 charge-discharge cycles -1 Capacity retention was only 87% compared to NaMn in the comparative cell 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Zn 0.02 )O 2 The positive electrode material has a capacity of about 111mAhg after 100 cycles -1 Capacity retention of 92%, naMn 0.8 (Ni 0.05 Fe 0.05 Cu 0.05 Sb 0.03 Mg 0.02 )O 2 The positive electrode material had a capacity retention of 98% after 100 cycles. By comparison, the doping element can be shown to be matched with the metal element of the fifth period, preferably through the metal element of the third period and/or the fourth period, so that the more stable high-entropy doped manganese-based layered oxide is obtained.
Example 4
A preparation similar to that of example 1 was carried out by modifying the Na content of the starting materials 2 CO 3 And MnO 2 And the proportion of the oxide powder doped with the elements, the applicant also obtains other high-entropy doped manganese-based layered oxides through sintering synthesis, and the following table shows:
Figure BDA0004133481070000141
Figure BDA0004133481070000151
it should be noted that, the preparation method of the high-entropy doped manganese-based layered oxide can be further adjusted, and in some embodiments, in the ball milling method mixing, the ball mass ratio is (5-20): 1, dispersing agent adopts ethanol, acetone, N-methyl pyrrolidone (NMP), isopropyl alcohol (IPA) or water, the ball milling speed is 300-600 r/min, and the ball milling time is 3-24 h; in the pressing step, the pressurizing pressure is 5-30 Mpa; in the sintering step, the sintering temperature is 500-1100 ℃, the heating rate is 3-20 ℃/min, and the sintering time is 1-24 h. Specific experimental conditions can be obtained by carrying out experiments for a limited number of times according to different material types, or more optimized experimental conditions can be obtained by carrying out experiments for a limited number of times.
The high entropy doped manganese-based layered oxide is used as a positive electrode material of a sodium ion battery, and preferably P2/O'3 diphase is adopted. The O'3 phase manganese-based layered oxide anode material has the advantages of large capacity, high cost performance and the like. However, the kinetics of the material during extraction and intercalation of Na ions are slow, the volume changes drastically, resulting in lower rate capability and poor cycling stability. The P2 phase layered oxide anode material has a wider triangular Na ion transport channel and a lower migration energy barrier, is favorable for Na ion transport, and has a higher energy barrier for phase transition, so that the P2 phase layered oxide anode material has high rate performance and a relatively stable structure. However, the low sodium content of the P2 phase layered oxide cathode material is disadvantageous for its application in full cells. By integrating the P2 phase with stable structure into the O '3 phase, abrupt lattice strain can be buffered, na ion diffusion is enhanced, and the P2/O'3 biphasic manganese-based layered oxide positive electrode material with stable structure and high rate performance can be obtained. The preferable P2/O '3 dual-phase high-entropy doped manganese-based layered oxide has the advantages of both P2 phase and O'3, and provides a solution to the technical problem that the theoretical density of the battery is reduced due to the fact that the P2 phase layered oxide positive electrode material belongs to low-sodium type materials and has serious irreversible sodium loss when being applied to sodium batteries.
In the preparation method, the meaning of weighing the corresponding molar ratio in the preparation method not only includes the stoichiometric molar ratio of each element in the chemical formula of the high-entropy doped manganese-based layered oxide; by Na 0.6 Mn 0.9 (Ni 0.02 Ti 0.02 Mg 0.02 Nb 0.02 Mo 0.02 )O 2 The stoichiometric molar ratio described in the examples refers to the preparation of Na per mole 0.6 Mn 0.9 (Ni 0.02 Ti 0.02 Mg 0.02 Nb 0.02 Mo 0.02 )O 2 Wherein the molar ratio of each element is Na: mn: ni: ti: mg: nb: mo=0.6: 0.9:0.02:0.02:0.02:0.02:0.02; that is, based on the ratio of the corner mark values of the elements in the chemical formula; the method also comprises the steps of properly increasing or decreasing and adjusting the stoichiometric mole ratio of one or more raw material components, and calculating the corresponding feed mole ratio of the actual feed amount of the raw material components; more specifically, the appropriate incremental-decremental post-adjustment dosing mole ratio is 90% to 110% of the stoichiometric mole ratio; in a specific implementation, both the feed molar ratio and the stoichiometric molar ratio are used within the meaning of the "corresponding molar ratio" according to the invention. In a specific embodiment, na 2 CO 3 The actual feed molar ratio of (2) is 102 to 105% of the stoichiometric molar ratio, and the rest of Mn oxide and M oxide are calculated according to the stoichiometric molar ratio according to the feed molar ratio and the stoichiometric molar ratio, respectively.
It should be noted that the main purpose of ball milling treatment in the embodiment of the invention is to fully and uniformly mix the raw materials, which belongs to one of the methods of mixing treatment; in other embodiments, other mechanical devices that achieve uniform mixing may be used, such as mechanical agitation dispersion.
The foregoing descriptions of specific exemplary embodiments of the present invention are presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application to thereby enable one skilled in the art to make and utilize the invention in various exemplary embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.

Claims (11)

1. A high entropy doped manganese-based layered oxide, wherein the high entropy doped manganese-based layered oxide has a chemical formula represented by: na (Na) x Mn y M z O 2 Wherein Na represents a sodium element, mn represents a manganese element, and M represents a doping element selected from five or more metal elements other than sodium and manganese in the third to fifth periods of the periodic table; x is more than or equal to 0.6 and less than or equal to 1,0.8, y is more than or equal to 1, z is more than or equal to 0 and less than or equal to 0.2, and y+z=1;
preferably, the doping element is selected from more than five elements of iron, nickel, cobalt, copper, titanium, magnesium, zinc, calcium, vanadium, chromium, zirconium, niobium, molybdenum, ruthenium, tin, antimony and aluminum.
2. The high entropy doped manganese-based layered oxide according to claim 1, wherein M comprises: at least 1 to 3 kinds of metal elements selected from the fifth period, and at least 2 to 4 kinds of metal elements selected from the third period and/or the fourth period;
preferably, the metal element of the fifth period is selected from zirconium, niobium, molybdenum, ruthenium, tin, antimony elements; the metal element in the third period is selected from magnesium and aluminum elements; the metal element in the fourth period is selected from calcium, titanium, vanadium, chromium, nickel, iron, cobalt, copper and zinc.
3. The high entropy doped manganese-based layered oxide of claim 1, wherein the high entropy doped manganese-based layered oxide has a chemical formula represented by: na (Na) x Mn y (M 1a M 2b M 3c M 4d M 5e M 6f )O 2 ，M 1 、M 2 、M 3 、M 4 、M 5 、M 6 Representing different doping elements, wherein a is more than 0 and less than or equal to 0.05, b is more than 0 and less than or equal to 0.05, c is more than 0 and less than or equal to 0.05, d is more than 0 and less than or equal to 0.05, e is more than 0 and less than or equal to 0.05, and f is more than or equal to 0 and less than or equal to 0.05;
preferably, a is more than 0 and less than or equal to 0.04,0, b is more than or equal to 0.04,0, c is more than or equal to 0.04,0, d is more than or equal to 0.04,0, e is more than or equal to 0.04,0, and f is more than or equal to 0.04; preferably, a is more than 0 and less than or equal to 0.03,0, b is more than or equal to 0.03,0, c is more than or equal to 0.03,0, d is more than or equal to 0.03,0, e is more than or equal to 0.03,0, and f is more than or equal to 0.03; more preferably, 0 < a.ltoreq. 0.02,0 < b.ltoreq. 0.02,0 < c.ltoreq. 0.02,0 < d.ltoreq. 0.02,0 < e.ltoreq. 0.02,0.ltoreq.f.ltoreq.0.02; and/or, at least 4 of the a, b, c, d, e, f values are 0.02 or less and 0 or more.
4. A high entropy doped manganese-based layered oxide according to any one of claims 1 to 3, wherein the doping element is selected from the group consisting of iron, nickel, copper, titanium, magnesium, zinc, antimony, tin, zirconium, aluminum, niobium elements;
and/or the high entropy doped layered manganese-based oxide is in a P2 and/or O'3 phase.
5. A high entropy doped manganese-based layered oxide according to any one of claims 1 to 3, wherein the XRD diffractogram of the high entropy doped layered manganese-based oxide comprises P2 phase diffraction peaks (002) (004) (100) (102);
and/or, the O'3 phase diffraction peak (001) (002) (200) (-111) (-202) (111).
6. A method for preparing the high entropy manganese-based doped layered oxide according to any one of claims 1 to 5, comprising the steps of:
weighing sodium salt and manganese oxide with corresponding molar ratios and oxide of the doping elements according to the chemical formula of the high-entropy doping manganese-based layered oxide, and carrying out mixing treatment to obtain mixed powder;
pressing the mixed powder to obtain a pressed block;
and sintering the block.
7. The method according to claim 6, wherein the sodium salt is at least one selected from the group consisting of sodium carbonate, sodium bicarbonate, sodium acetate, sodium oxalate, sodium citrate, sodium nitrate, and sodium hydroxide;
and/or the mixing treatment comprises ball milling, wherein the ball material mass ratio is (5-20): 1, the ball milling speed is 300 to 600r/min, and the ball milling time is 3 to 24 hours;
and/or, in the pressing treatment, the steps more specifically include loading the mixed powder into a mold, and pressing and molding; preferably, the pressure of the pressurization is 5 to 30Mpa;
and/or in the sintering treatment, the sintering temperature is between 500 and 1100 ℃, the heating rate is between 3 and 20 ℃/min, and the sintering time is between 1 and 24 hours; preferably, the sintering temperature is between 800 and 1000 ℃.
8. A sodium ion battery positive electrode material, characterized in that the sodium ion battery positive electrode material comprises: the high entropy doped manganese-based layered oxide of any one of claims 1 to 5; or the high entropy doped manganese-based layered oxide obtained by the preparation method according to claim 6 or 7.
9. An electrode sheet comprising the sodium ion battery cathode material of claim 8.
10. A sodium ion battery comprising the sodium ion battery positive electrode material according to claim 8, or the electrode sheet according to claim 9.
11. An electrical device comprising a sodium ion battery as claimed in claim 10.
CN202310267446.XA 2023-03-15 2023-03-15 High-entropy doped manganese-based layered oxide, preparation method thereof, sodium ion battery positive electrode material and battery Pending CN116062807A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116314728A (en) * 2023-05-15 2023-06-23 宁德时代新能源科技股份有限公司 Sodium layered metal oxide, method for producing same, secondary battery, and electricity-using device
CN117383627A (en) * 2023-12-13 2024-01-12 泾河新城陕煤技术研究院新能源材料有限公司 Preparation method of sodium-electricity layered anode material
CN117497741A (en) * 2023-12-29 2024-02-02 深圳华钠新材有限责任公司 Monoclinic phase sodium manganate material and preparation method thereof

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116314728A (en) * 2023-05-15 2023-06-23 宁德时代新能源科技股份有限公司 Sodium layered metal oxide, method for producing same, secondary battery, and electricity-using device
CN116314728B (en) * 2023-05-15 2023-10-27 宁德时代新能源科技股份有限公司 Sodium layered metal oxide, method for producing same, secondary battery, and electricity-using device
CN117383627A (en) * 2023-12-13 2024-01-12 泾河新城陕煤技术研究院新能源材料有限公司 Preparation method of sodium-electricity layered anode material
CN117383627B (en) * 2023-12-13 2024-03-12 泾河新城陕煤技术研究院新能源材料有限公司 Preparation method of sodium-electricity layered anode material
CN117497741A (en) * 2023-12-29 2024-02-02 深圳华钠新材有限责任公司 Monoclinic phase sodium manganate material and preparation method thereof
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