CN115939370A - Sodium ion positive electrode material, preparation method thereof and secondary battery - Google Patents
Sodium ion positive electrode material, preparation method thereof and secondary battery Download PDFInfo
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Abstract
The invention relates to the technical field of material preparation, and discloses a sodium ion positive electrode material, a preparation method thereof and a secondary battery. The chemical formula of the sodium ion anode material is Na α Ni x Fe y M (1‑x‑y) O 2 Wherein alpha is more than 0.60 and less than or equal to 1.00, x is more than 0 and less than or equal to 0.50, Y is more than 0 and less than or equal to 0.50, x + Y is less than 1.00, M is at least one of Zr, al, co, cu, sr, Y, mn, ti, mg, K, ca, li, mo, B, sn, si, nb, zn, W, tc, cd, pd, pb, po, tl, ge, sc, ru and Rh, the crystal structure is a single crystal, the contents of Ni and Fe are gradually increased from the surface to the interior of the single crystal, and the content of M is gradually reduced. The sodium ion anode material has stable structure, and can realize high capacity and long cycle performance。
Description
Technical Field
The invention relates to the technical field of material preparation, in particular to a sodium ion positive electrode material, a preparation method thereof and a secondary battery.
Background
Compared with the lithium ion battery, the sodium ion battery has the advantages of rich raw material reserves, low price, relatively stable chemical properties and good safety, and is expected to replace the lithium ion battery to enter the market. Among positive electrode materials for sodium ion batteries, layered oxides are most spotlighted due to their high specific capacity and structure similar to that of positive electrode materials for lithium ion batteries. In order to make the layered oxide material meet the requirement of the battery cycle life, doping and surface coating in the material body are necessary measures. By element doping surface coating, the cycle reversibility of the material can be improved, the reversible capacity of the material can be increased, the sodium ion diffusion dynamic performance can be improved, the properties of crystal lattices can be changed to a certain degree, and the crystal lattice stability, the electronic conductivity, the sodium ion insertion and extraction dynamic performance and the like can be enhanced. However, in general doping, elements are uniformly distributed in the sodium ion material, so that the surface layer component is the same as the internal component, and the material with higher chemical activity on the surface layer is easy to react with the electrolyte, so that coating needs to be performed, and generally the coating material is an oxide, such as alumina, zirconia, titania, boron oxide, and the like, and the oxide is an inactive material, so that sodium ion conduction is not facilitated, and the risk of falling of the coating layer exists, so that the electrical performance of the battery anode material is influenced.
Although sodium ion cathode materials with unevenly distributed doping elements are synthesized in the industry at present, gradient materials or core-shell materials are generally synthesized at a precursor stage, and after sintering, the sodium ion cathode materials are generally in a polycrystalline structure and have large particle size, so that the performance of the prepared sodium ion cathode materials is poor.
Disclosure of Invention
In order to solve the problems, the invention provides a sodium ion positive electrode material, a preparation method thereof and a secondary battery. The invention carries out full-gradient doping on the sodium ion anode material by a solid phase method to form a layered material with stable structure, thereby realizing high capacity and long cycle performance and leading the prepared secondary battery to be applied to the field of large-scale energy storage as a new generation of energy storage device.
In order to achieve the above object, the first aspect of the present invention provides a sodium ion positive electrode material having the chemical formulaIs Na α Ni x Fe y M (1-x-y) O 2 Wherein alpha is more than 0.60 and less than or equal to 1.00, x is more than 0 and less than or equal to 0.50, Y is more than 0 and less than or equal to 0.50, x + Y is less than or equal to 1.00, M is at least one of Zr, al, co, cu, sr, Y, mn, ti, mg, K, ca, li, mo, B, sn, si, nb, zn, W, tc, cd, pd, pb, po, tl, ge, sc, ru and Rh, the crystal structure is a single crystal, and the contents of Ni and Fe are gradually increased and the content of M is gradually reduced from the surface to the interior of the single crystal.
Compared with the prior art, the sodium ion cathode material has at least the following technical effects.
First, the sodium ion positive electrode material of the present invention contains Ni and Fe. Ni is an active metal element in the electrochemical reaction process and can provide more valence state changes, so that the specific capacity of the sodium ion positive electrode material is improved. Fe is also an active metal element, and the electrode potential is higher, so that higher charge and discharge voltage can be provided, and higher energy density can be realized.
And secondly, the contents of Ni and Fe are gradually increased from the surface to the inside of the single crystal, namely, the active metal elements Ni and Fe are mainly distributed in the single crystal, so that the stability of the structure of the sodium ion cathode material can be maintained.
The concrete expression is as follows:
(1) The contact between active metal elements Ni and Fe and electrolyte in the charge and discharge process can be reduced. Especially high oxidizing Ni at high charging voltage 4+ And Fe 4+ Reacts with the electrolyte, resulting in a destruction of the material structure. In addition, the micro-amount of doped M metal ions in the single crystal structure can better maintain the stability of the internal structure, thereby realizing higher capacity and cycle performance.
(2) The problem of overhigh content of residual sodium on the surface can be solved through the distribution of the elements, and M elements with more surfaces can react with the residual sodium to form a sodium ion anode material with low sodium content so as to improve the processing performance of the material and reduce the electrochemical performance of gas production and the like of the battery.
(3) In the process of charging and discharging, the volume of the crystal can be changed, and through the material with gradient distribution, the stable structure of the surface layer can inhibit the phase change of the internal material to a certain extent, and meanwhile, the surface layer can not crack, thereby being beneficial to improving the electrochemical performance of the material.
Thirdly, the sodium ion anode material of the invention is of a single crystal structure, so the particle size is small, the specific surface area is large, the structural stability is high, and the electrical performance of the material has the advantages of high specific capacity, excellent rate capability, long cycle life and the like.
In some embodiments, M is at least one of Zr, al, co, cu, sr, Y, mn, ti, mg, mo, zn, and W.
In some embodiments, 0.60 < α < 0.90,0.10 < x < 0.50,0.10 < y < 0.50.
In some embodiments, M is Zn and/or Mn, α =0.85, x =0.30, y =0.40.
In some embodiments, the single crystal has an average particle size of 1.5 μm to 3.0 μm.
In some embodiments, the sodium ion positive electrode material has a specific surface area of 0.6m 2 G to 1.2m 2 /g。
The second aspect of the present invention provides a method for preparing a sodium ion positive electrode material, comprising the steps of:
(I) Preparation of sodium nickel ferrite cathode material
Weighing a nickel source, an iron source and a sodium source according to a formula, mixing in water to obtain a mixed solution, grinding to obtain slurry, spray-drying to obtain precursor powder, and performing primary sintering and primary crushing on the precursor powder;
(II) preparing full-gradient doped sodium ion anode material
Mixing M source in water to obtain a mixed solution, grinding to obtain a slurry, adding the sodium nickel ferrite anode material according to the formula amount, mixing, spray-drying, performing secondary sintering and secondary crushing,
and the temperature of the first sintering is lower than that of the second sintering.
The preparation method of the sodium ion cathode material is prepared by spray drying and solid-phase sintering. Firstly preparing a sodium nickel ferrite anode material with smaller particle size, then coating a layer of M source material by spray drying, and under the solid-phase sintering mode, slowly permeating M element into the material by increasing the sintering temperature, and gradually permeating Ni and Fe elements occupied by the M element to the outside of the material, thereby forming the full-gradient doped sodium ion anode material. The preparation method can prepare small single crystal particles, and the particles have uniform size, less micro powder and defects and smooth surface layer. Meanwhile, the preparation material has simple process and low cost and can be industrially produced.
In some embodiments, the nickel source is nickel oxide.
In some embodiments, the iron source is iron oxide.
In some embodiments, the M source is an oxide of M, and M is at least one of Zr, al, co, cu, sr, Y, mn, ti, mg, K, ca, li, mo, B, sn, si, nb, zn, W, tc, cd, pd, pb, po, tl, ge, sc, ru, and Rh.
In some embodiments, the sodium source is NaOH, naNO 3 、Na 2 CO 3 And CH 3 And (4) COONa.
In some embodiments, the molar amount of sodium element in the sodium source is m, the sum of the molar amount of nickel element in the nickel source and the molar amount of iron element in the iron source is n, and m/n is from 1.00 to 1.45.
In some embodiments, the mixed liquor in step (I) preparing the sodium nickel ferrite positive electrode material has a solids content of 20wt.% to 40wt.%.
In some embodiments, the Dv50 of the slurry in step (I) to prepare the sodium nickel ferrite positive electrode material is 0.2 μm to 0.7 μm.
In some embodiments, the air inlet temperature for spray drying in the preparation of the sodium nickel ferrite cathode material in the step (I) is 220 ℃ to 280 ℃, and the air outlet temperature is 80 ℃ to 100 ℃.
In some embodiments, air is introduced during the first sintering.
In some embodiments, the temperature of the first sintering is 600 ℃ to 850 ℃.
In some embodiments, the holding time for the first sintering is from 5h to 12h.
In some embodiments, the ramp rate for the first sintering is from 2 ℃/min to 5 ℃/min.
In some embodiments, the first pulverizing comprises coarse crushing and fine crushing the product after the first sintering by using a rotary wheel mill in sequence.
In some embodiments, the Dv50 of the first comminution to particles is from 2.0 μm to 4.0 μm.
In some embodiments, the mass ratio of sodium nickel ferrite positive electrode material to M source is 1 to 8.
In some embodiments, the mixed liquor in step (II) preparing the full-gradient sodium ion-doped positive electrode material has a solid content of 5wt.% to 15wt.%.
In some embodiments, the Dv50 of the slurry in step (II) preparing the full-gradient doped sodium ion positive electrode material is from 0.1 μm to 0.3 μm.
In some embodiments, the air inlet temperature for spray drying in the step (II) of preparing the full-gradient doped sodium ion cathode material is 220 ℃ to 280 ℃, and the air outlet temperature is 80 ℃ to 100 ℃.
In some embodiments, air is introduced during the second sintering.
In some embodiments, the temperature of the second sintering is from 750 ℃ to 950 ℃.
In some embodiments, the holding time for the second sintering is from 6h to 16h.
In some embodiments, the ramp rate for the second sintering is from 1 deg.C/min to 4 deg.C/min.
In some embodiments, the second crushing comprises coarse crushing and fine crushing the product after the second sintering by using a rotary wheel mill in sequence.
In some embodiments, the Dv50 of the second comminution to particles is from 2.5 μm to 4.5 μm.
The invention provides a secondary battery, which comprises a positive electrode material, a negative electrode material and electrolyte, wherein the positive electrode material comprises the sodium ion positive electrode material or the sodium ion positive electrode material prepared by the preparation method of the sodium ion positive electrode material.
In some embodiments, the anode material comprises a carbonaceous anode material and/or a silicon-based anode material.
Drawings
Fig. 1 is an SEM image of a sodium ion positive electrode material prepared in example 1 of the present invention;
fig. 2 is an XRD pattern of the sodium ion cathode material prepared in example 1 of the present invention.
Detailed Description
The secondary battery of the present invention includes a positive electrode material, a negative electrode material, and an electrolyte. The preparation process of the secondary battery is similar to that of the lithium ion battery, and the preparation process comprises the steps of firstly preparing a positive pole piece containing a positive pole material and a negative pole piece containing a negative pole material, then winding or laminating the positive pole piece, the negative pole piece and a diaphragm to form a battery cell, filling electrolyte into the shell and sealing the shell.
The negative pole piece is obtained by coating negative pole slurry containing a negative pole material, a binder and a conductive agent on a negative pole current collector, drying, cold pressing and die cutting. The mass ratio of the anode material, the binder and the conductive agent can be 75-99 and is between 0.1 and 10. The anode material may be, but is not limited to, a carbon-based material and a silicon-based material. The carbon-based material may be, but is not limited to, a graphite-based material, soft carbon, or hard carbon. The silicon-based material may be, but is not limited to, siO x Or carbon-coated SiO x X is more than or equal to 0 and less than 2. The binder is selected from at least one of polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, styrene-butadiene rubber and acrylated styrene-butadiene rubber. The conductive agent is used to improve the conductivity of the negative electrode, and the conductive agent can be, but not limited to, carbon-containing materials such as carbon black, acetylene black, ketjen black, carbon fiber, or metal powder or metal fiber materials such as copper, nickel, aluminum, silver, or a mixture thereof. The solvent of the negative electrode slurry may be N-methylpyrrolidone or N-vinylpyrrolidone. The negative current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, polymer substrate coated with conductive metal, and the like.
The separator may be a conventional insulating porous polymer film or an inorganic porous film, and specifically, but not limited to, may be: single layer or multiple layers of polypropylene, polyethylene, aramid fiber, polyimide and non-woven fabric membrane, such as polyethylene/polypropylene double-layer membrane, polyethylene/polypropylene/polyethylene three-layer membrane or polypropylene/polyethylene/polypropylene three-layer membrane. The separator may also be provided with an insulating layer that allows ions to pass therethrough but does not allow electrons to pass therethrough to prevent the secondary battery from being short-circuited when thermal shrinkage occurs, and has a thickness of 5 to 50 μm.
Similar to lithium ion batteries, liquid electrolytes for sodium ion batteries include a non-aqueous organic solvent, a sodium salt, and an additive. The non-aqueous organic solvent may typically be a chain carbonate, cyclic carbonate, carboxylate ester or lactone. The chain carbonate can be dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate or methyl ethyl carbonate. The cyclic carbonate may be ethylene carbonate, propylene carbonate or butylene carbonate. The carboxylic acid ester may be methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate or ethyl propionate. The lactone may be gamma-butyrolactone, delta-decalactone, gamma-valerolactone or gamma-caprolactone. The sodium salt can be NaPF 6 、NaClO 4 、NaAlCl 4 、NaFeCl 4 、NaSO 3 CF 3 、NaBCl 4 、NaNO 3 、NaPOF 4 、NaSCN、NaCN、NaAsF 6 、NaCF 3 CO 2 、NaSbF 6 、NaC 6 H 5 CO 2 、Na(CH 3 )C 6 H 4 SO 3 、NaHSO 4 And NaB (C) 6 H 5 ) 4 Of sodium salt at a concentration of 0.2M to 2.0M. Additives can also be added into the electrolyte to improve the performance of the battery, and the additives can account for at least 10% of the electrolyte by weight of 0.1%. Including but not limited to one or more of vinyl sulfite (GS), fluoroethylene carbonate (FEC), vinylene Carbonate (VC), vinyl Ethylene Carbonate (VEC), 1, 3-Propane Sultone (PS), vinyl sulfate (DTD), 4-methyl ethylene sulfate, 4-propyl ethylene sulfate, propylene sulfate, 4-methyl propylene sulfate, and 4-propyl propylene sulfate.
The preparation of the positive electrode sheet generally comprises: and coating the positive slurry containing the positive material, the binder and the conductive agent on a positive current collector, drying, cold pressing and die cutting. The mass ratio of the positive electrode material, the binder and the conductive agent can be 80-99. The binder may be, for example, but not limited to, at least one of polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl pyrrolidone, styrene-butadiene rubber, acrylated styrene-butadiene rubber, and epoxy resin. The conductive agent is used to improve the conductivity of the positive electrode, and may be, but is not limited to, carbon-containing materials such as carbon black, acetylene black, ketjen black, carbon fiber, or metal powder or metal fiber materials such as copper, nickel, aluminum, silver, or conductive polymers such as polyphenylene derivatives, or mixtures thereof. The positive current collector may be an aluminum foil. The solvent of the positive electrode slurry may be N-methylpyrrolidone or N-vinylpyrrolidone. The positive electrode material can adopt the sodium ion positive electrode material.
The sodium ion positive electrode material of the present invention has a single crystal structure and an average particle diameter of 1.5 to 3.0 μm, and the average particle diameter of the sodium ion positive electrode material may be, but is not limited to, 1.5 μm, 1.8 μm, 2.0 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2.8 μm, 3.0 μm, as an example. The specific surface area is 0.6m 2 G to 1.2m 2 By way of example, the specific sodium ion positive electrode material surface area may be, but is not limited to, 0.6m 2 /g、0.7m 2 /g、0.8m 2 /g、0.9m 2 /g、1.0m 2 /g、1.1m 2 /g、1.2m 2 /g。
As a technical scheme of the invention, the chemical formula is Na α Ni x Fe y M (1-x-y) O 2 Wherein alpha is more than 0.60 and less than or equal to 1.00, x is more than 0 and less than or equal to 0.50, Y is more than 0 and less than or equal to 0.50, x + Y is less than 1.00, M is at least one of Zr, al, co, cu, sr, Y, mn, ti, mg, K, ca, li, mo, B, sn, si, nb, zn, W, tc, cd, pd, pb, po, tl, ge, sc, ru and Rh, the crystal structure is a single crystal, the contents of Ni and Fe are gradually increased from the surface to the interior of the single crystal, and the content of M is gradually reduced. As an example, α may be, but is not limited to, 0.61, 0.63, 0.65, 0.67, 0.69, 0.71, 0.73, 0.75, 0.77, 079, 0.81, 0.83, 0.85, 0.87, 0.89, 0.91, 0.93, 0.95, 0.97, 0.99, 1.00.x may be, but is not limited to, 0.1, 0.2, 0.3, 0.4, 0.5.y may be, but is not limited to, 0.1, 0.2, 0.3,0.4 and 0.5. And x and y are not 0.5 at the same time. In some embodiments, M is at least one of Zr, al, co, cu, sr, Y, mn, ti, mg, mo, zn, and W. In other embodiments, M is Zn and/or Mn.
The preparation method of the sodium ion positive electrode material comprises the steps of (I) preparing the sodium nickel ferrite positive electrode material and (II) preparing the full-gradient doped sodium ion positive electrode material.
The step (I) of preparing the sodium nickel ferrite anode material comprises the following steps: the preparation method comprises the steps of weighing a nickel source, an iron source and a sodium source according to a formula, mixing the nickel source, the iron source and the sodium source in water to obtain a mixed solution, grinding the mixed solution to obtain slurry, carrying out spray drying to obtain precursor powder, and carrying out primary sintering and primary crushing on the precursor powder.
Wherein the precursor is spherical, and the nickel source is nickel oxide; the iron source is ferric oxide. The M source is an oxide of M, and M is at least one of Zr, al, co, cu, sr, Y, mn, ti, mg, K, ca, li, mo, B, sn, si, nb, zn, W, tc, cd, pd, pb, po, tl, ge, sc, ru and Rh. As an example, the M source may be, but is not limited to being ZrO 2 、Al 2 O 3 、Co 3 O 4 、CuO、Y 2 O 3 、TiO 2 、MgO、B 2 O 3 、SnO 2 、SiO 2 、Nb 2 O 5 And ZnO. The sodium source is NaOH and NaNO 3 、Na 2 CO 3 And CH 3 And (4) COONa. The molar quantity of sodium element in the sodium source is m, the sum of the molar quantity of nickel element in the nickel source and the molar quantity of iron element in the iron source is n, m/n is 1.00-1.45, and the control of the excessive quantity of sodium is beneficial to carrying out secondary sintering. By way of example, m/n can be, but is not limited to, 1.00.
As an embodiment of the present invention, the solid content of the mixed solution is 20wt.% to 40wt.%, and the solid content of the mixed solution may be, but is not limited to, 20wt.%, 21wt.%, 23wt.%, 25wt.%, 27wt.%, 29wt.%, 31wt.%, 33wt.%, 35wt.%, 37wt.%, 39wt.%, 40wt.%, by way of example. The Dv50 of the particles in the slurry is 0.2 μm to 0.7 μm, by way of example, the Dv50 of the particles in the slurry may be, but is not limited to, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm. The air inlet temperature of the spray drying is 220 ℃ to 280 ℃, and the air outlet temperature is 80 ℃ to 100 ℃, and by way of example, the air inlet temperature may be, but is not limited to, 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃, 270 ℃, 280 ℃, and the air outlet temperature may be, but is not limited to, 80 ℃, 82 ℃, 84 ℃, 86 ℃, 88 ℃, 90 ℃, 92 ℃, 94 ℃, 96 ℃, 98 ℃, 100 ℃.
As a technical scheme of the invention, air is introduced in the first sintering process. The temperature of the first sintering is 600 ℃ to 850 ℃, and the heat preservation time is 5h to 12h. As an example, the first sintering temperature may be, but is not limited to, 600 ℃, 640 ℃, 680 ℃, 700 ℃, 730 ℃, 760 ℃, 790 ℃, 820 ℃, 850 ℃, and the holding time for the first sintering may be, but is not limited to, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h. As another technical solution of the present invention, the temperature rising rate of the first sintering is 2 ℃/min to 5 ℃/min, and as an example, the temperature rising rate of the first sintering may be, but is not limited to, 2 ℃/min, 3 ℃/min, 4 ℃/min, 5 ℃/min.
As an embodiment of the present invention, the first pulverization includes coarse pulverization of the product after the first sintering by using a rotary mill and fine pulverization by using a jet mill in sequence until the Dv50 of the particles is 2.0 μm to 4.0 μm, and the Dv50 of the particles after the first pulverization may be, but not limited to, 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, and 4.0 μm, as an example.
The step (II) of preparing the full-gradient doped sodium ion cathode material comprises the following steps: mixing M source in water to obtain a mixed solution, grinding to obtain a slurry, adding a sodium nickel ferrite anode material according to a formula amount, mixing, spray-drying, sintering, and crushing, wherein the temperature of the first sintering is lower than that of the second sintering.
Wherein the mass ratio of the sodium nickel ferrite positive electrode material to the M source is 1-8. As an example, the mass ratio of sodium nickel ferrite positive electrode material to M source can be, but is not limited to, 1, 2.
As an embodiment of the present invention, the solid content of the mixed solution is 5wt.% to 15wt.%, and the solid content of the mixed solution may be, but is not limited to, 5wt.%, 6wt.%, 7wt.%, 8wt.%, 9wt.%, 10wt.%, 11wt.%, 12wt.%, 13wt.%, 14wt.%, 15wt.%, for example. The Dv50 of the particles in the slurry is 0.1 μm to 0.3 μm, by way of example, the Dv50 of the particles in the slurry may be, but is not limited to, 0.1 μm, 0.2 μm, 0.3 μm. The air inlet temperature of the spray drying is 220 ℃ to 280 ℃, and the air outlet temperature is 80 ℃ to 100 ℃, and the air inlet temperature can be, but is not limited to, 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃, 270 ℃, and 280 ℃, and the air outlet temperature can be, but is not limited to, 80 ℃, 82 ℃, 84 ℃, 86 ℃, 88 ℃, 90 ℃, 92 ℃, 94 ℃, 96 ℃, 98 ℃, and 100 ℃.
As a technical scheme of the invention, air is introduced in the secondary sintering process. The temperature of the second sintering is 750 ℃ to 950 ℃, and the heat preservation time is 6h to 16h. By way of example, the second sintering temperature can be, but is not limited to, 750 ℃, 780 ℃, 800 ℃, 820 ℃, 850 ℃, 880 ℃, 900 ℃, 920 ℃ and 950 ℃, and the holding time of the second sintering can be, but is not limited to, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h and 16h. As another technical solution of the present invention, the temperature increase rate of the second sintering is 2 ℃/min to 5 ℃/min, and as an example, the temperature increase rate of the second sintering may be, but is not limited to, 2 ℃/min, 3 ℃/min, 4 ℃/min, 5 ℃/min.
As an embodiment of the present invention, the second pulverization includes coarse pulverization of the product after the second sintering by using a rotary wheel mill and fine pulverization by using a jet mill in sequence until the Dv50 of the particles is 2.5 μm to 4.5 μm, and the Dv50 of the particles after the second pulverization can be, but not limited to, 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, and 4.5 μm as an example.
To better illustrate the objects, technical solutions and advantages of the present invention, the present invention will be further described with reference to specific embodiments. It should be noted that the following implementation of the method is a further explanation of the present invention, and should not be taken as a limitation of the present invention.
Example 1
The chemical formula of the sodium ion cathode material of the embodiment is Na 0.85 Ni 0.30 Fe 0.40 Zn 0.10 Mn 0.20 O 2 The single crystal structure has the structure that the contents of Ni and Fe are gradually increased and the contents of Zn and Mn are gradually reduced from the surface to the interior of the single crystal.
The preparation method of the sodium ion cathode material of the embodiment includes the following steps.
(I) Preparation of sodium nickel ferrite cathode material
NiO and Fe are measured according to the formula 2 O 3 And Na 2 CO 3 (Na 2 CO 3 The molar weight of the sodium and the sum of the molar weights of Ni and Fe is 1.20, 1) is mixed in water to obtain a mixed solution with the solid content of 30%, the mixed solution is added into a sand mill for fine grinding to obtain slurry with the particle Dv50 of 0.5 mu m, and the slurry is subjected to spray drying (the spray air inlet temperature is 220 ℃, the spray air exhaust temperature is 90 ℃) to obtain spherical precursor powder. And (3) introducing air into the precursor powder, heating to 800 ℃ at the heating rate of 2.5 ℃/min, preserving the temperature for 12h, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the sodium nickel ferrite anode material with the particle size Dv50 of 2.5 mu m.
(II) preparing full-gradient doped sodium ion anode material
Adding ZnO and MnO 2 Mixing in water to obtain mixed solution with solid content of 8wt.%, adding into a sand mill, fine grinding to obtain slurry with particle Dv50 of 0.2 μm, and adding sodium nickel ferrite cathode material (sodium nickel ferrite cathode material and dopant (ZnO and MnO) 2 ) The mass ratio of 1.9) and then spray drying (the spray air inlet temperature is 220 ℃ and the spray air exhaust temperature is 90 ℃). And introducing air, raising the temperature to 900 ℃ at the heating rate of 2.5 ℃/min, preserving the temperature for 10h, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the full-gradient doped sodium ion anode material with the granularity Dv50 of 3.0 mu m.
The obtained sodium ion cathode material was subjected to SEM and XRD tests, respectively, and the results thereof are shown in fig. 1 and 2. From the results of fig. 1, it can be seen that the prepared sodium ion cathode material has a single crystal structure, the contents of Ni and Fe gradually increase from the surface to the inside of the single crystal, the contents of Zn and Mn ions gradually decrease, the average particle size is about 1.7 μm, the surface of the material is very smooth, no micropowder is present, and the residual alkali content is low. The XRD of FIG. 2 shows 16.5 DEG and 41 DEG peaks, indicating that the structure is the characteristic diffraction peaks of (003) and (104) of O3 phase layered oxide, belonging to trigonal system, and the space group is R-3m. And good crystallinity with no diffraction peaks for other crystalline phases, indicating that the doped materials are not stacked together.
Example 2
The chemical formula of the sodium ion cathode material of the embodiment is Na 0.80 Ni 0.50 Fe 0.30 Cu 0.10 Mn 0.10 O 2 Which has a single crystal structure, and from the surface to the inside of the single crystal, the contents of Ni and Fe are gradually increased, and the contents of Cu and Mn are gradually decreased.
The preparation method of the sodium ion cathode material of the embodiment includes the following steps.
(I) Preparation of sodium nickel ferrite cathode material
NiO and Fe are measured according to the formula 2 O 3 And Na 2 CO 3 (Na 2 CO 3 The molar weight of the sodium and the sum of the molar weights of Ni and Fe is 1.00. And (3) introducing air into the precursor powder, heating to 800 ℃ at the heating rate of 2.5 ℃/min, preserving the temperature for 12h, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the sodium nickel ferrite anode material with the particle size Dv50 of 2.5 mu m.
(II) preparing full-gradient doped sodium ion anode material
Mixing CuO and MnO 2 Mixing in water to obtain a mixed solution with a solid content of 10wt.%, adding the mixed solution into a sand mill, finely grinding to obtain a slurry with a particle Dv50 of 0.2 μm, and adding sodium nickel ferrite positive electrode material (the sodium nickel ferrite positive electrode material and dopants (CuO and MnO) 2 ) The mass ratio of (a) to (b) is 5.3) mixing, and then carrying out spray drying (the spray air inlet temperature is 220 ℃, and the spray air exhaust temperature is 90 ℃). And introducing air, heating to 850 ℃ at the heating rate of 2.5 ℃/min, preserving the temperature for 10 hours, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the full-gradient doped sodium ion anode material with the granularity Dv50 of 2.8 microns.
Example 3
The chemical formula of the sodium ion cathode material of the embodiment is Na 0.85 Ni 0.30 Fe 0.40 Zn 0.10 Mn 0.20 O 2 The single crystal structure has the structure that the contents of Ni and Fe are gradually increased and the contents of Zn and Mn are gradually reduced from the surface to the interior of the single crystal.
The preparation method of the sodium ion cathode material of the embodiment includes the following steps.
(I) Preparation of sodium nickel ferrite cathode material
NiO and Fe are measured according to the formula 2 O 3 And CH 3 The molar weight of sodium in COONa and the sum ratio of the molar weights of Ni and Fe is 1.45, 1) is mixed in water to obtain a mixed solution with the solid content of 30%, the mixed solution is added into a sand mill for fine grinding to obtain slurry with the particle Dv50 of 0.5 mu m, and the slurry is subjected to spray drying (the spray air inlet temperature is 220 ℃, the spray air exhaust temperature is 90 ℃) to obtain spherical precursor powder. And (3) introducing air into the precursor powder, heating to 800 ℃ at the heating rate of 2.5 ℃/min, preserving the temperature for 12h, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the sodium nickel ferrite anode material with the particle size Dv50 of 2.6 mu m.
(II) preparing full-gradient doped sodium ion anode material
Mixing ZnO and MnO 2 Mixing in water to obtain mixed solution with solid content of 8wt.%, adding into a sand mill, fine grinding to obtain slurry with particle Dv50 of 0.2 μm, and adding sodium nickel ferrite positive electrode material (sodium nickel ferrite positive electrode material and dopant (ZnO and MnO) 2 ) The mass ratio of 1.8) and then spray drying (the spray air inlet temperature is 220 ℃, and the spray air exhaust temperature isAt 90 ℃ C.). And (3) introducing air, heating to 900 ℃ at a heating rate of 2.5 ℃/min, preserving heat for 10 hours, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the full-gradient doped sodium ion anode material with the granularity Dv50 of 3.5 mu m.
Example 4
The chemical formula of the sodium ion cathode material of the embodiment is Na 0.75 Ni 0.35 Fe 0.35 Zn 0.15 Mn 0.15 O 2 The single crystal structure has the structure that the contents of Ni and Fe are gradually increased and the contents of Zn and Mn are gradually reduced from the surface to the inside of the single crystal.
The preparation method of the sodium ion cathode material of the embodiment includes the following steps.
(I) Preparation of sodium nickel ferrite cathode material
NiO and Fe are measured according to the formula 2 O 3 And Na 2 CO 3 (Na 2 CO 3 The molar weight of the sodium and the sum of the molar weights of Ni and Fe is 1.05. And (3) introducing air into the precursor powder, heating to 800 ℃ at the heating rate of 2.5 ℃/min, preserving the temperature for 12h, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the sodium nickel ferrite anode material with the particle size Dv50 of 2.5 mu m.
(II) preparing full-gradient doped sodium ion anode material
Adding ZnO and MnO 2 Mixing in water to obtain a mixture solution with a solid content of 10wt.%, adding the mixture solution into a sand mill, finely grinding to obtain a slurry with a particle Dv50 of 0.2 μm, and adding sodium nickel ferrite positive electrode material (sodium nickel ferrite positive electrode material and dopants (ZnO and MnO) 2 ) The mass ratio of 3.25) and then spray drying (the spray air inlet temperature is 220 ℃, and the spray air exhaust temperature is 90 ℃). Then introducing air to raise the temperatureRaising the temperature to 900 ℃ at the rate of 2.5 ℃/min, preserving the temperature for 10h, naturally cooling to room temperature to obtain black block materials, and then sequentially carrying out rotary wheel milling and jet milling on the black block materials to obtain the full-gradient doped sodium ion anode material with the granularity Dv50 of 3.0 mu m.
Example 5
The chemical formula of the sodium ion cathode material of the embodiment is Na 0.85 Ni 0.30 Fe 0.40 Zn 0.10 Mn 0.20 O 2 The single crystal structure has the structure that the contents of Ni and Fe are gradually increased and the contents of Zn and Mn are gradually reduced from the surface to the interior of the single crystal.
The preparation method of the sodium ion cathode material of the embodiment includes the following steps.
(I) Preparation of sodium nickel ferrite cathode material
NiO and Fe are measured according to the formula 2 O 3 And Na 2 CO 3 (Na 2 CO 3 The molar weight of the sodium and the sum of the molar weights of Ni and Fe is 1.20, 1) is mixed in water to obtain a mixed solution with the solid content of 30%, the mixed solution is added into a sand mill for fine grinding to obtain slurry with the particle Dv50 of 0.6 mu m, and the slurry is subjected to spray drying (the spray air inlet temperature is 250 ℃, the spray air exhaust temperature is 85 ℃) to obtain spherical precursor powder. And (3) introducing air into the precursor powder, heating to 850 ℃ at the heating rate of 3.5 ℃/min, preserving the temperature for 10h, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the sodium nickel ferrite anode material with the particle size Dv50 of 2.0 mu m.
(II) preparing full-gradient doped sodium ion anode material
Adding ZnO and MnO 2 Mixing in water to obtain mixed solution with solid content of 8wt.%, adding into a sand mill, fine grinding to obtain slurry with particle Dv50 of 0.1 μm, and adding sodium nickel ferrite cathode material (sodium nickel ferrite cathode material and dopant (ZnO and MnO) 2 ) The mass ratio of (3.2) to (1), and then spray drying (the spray air inlet temperature is 240 ℃, and the spray air exhaust temperature is 100 ℃). Then introducing air, heating to 950 deg.C at a heating rate of 2.0 deg.C/min and maintainingAnd (3) heating for 8h, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the full-gradient doped sodium ion cathode material with the granularity Dv50 of 2.6 microns.
Comparative example 1
The chemical formula of the sodium ion cathode material of the embodiment is Na 0.85 Ni 0.30 Mn 0.40 Zn 0.10 Fe 0.20 O 2 Which has a single crystal structure, and from the surface to the inside of the single crystal, the contents of Ni and Mn gradually increase, and the contents of Zn and Fe gradually decrease.
The preparation method of the sodium ion cathode material of the embodiment includes the following steps.
(I) Preparation of sodium nickel manganese oxide cathode material
Measuring NiO and MnO according to the formula 2 And Na 2 CO 3 (Na 2 CO 3 The molar weight of the sodium and the sum of the molar weights of Ni and Fe is 1.20, 1) is mixed in water to obtain a mixed solution with the solid content of 30%, the mixed solution is added into a sand mill for fine grinding to obtain slurry with the particle Dv50 of 0.5 mu m, and the slurry is subjected to spray drying (the spray air inlet temperature is 220 ℃, the spray air exhaust temperature is 90 ℃) to obtain spherical precursor powder. And (3) introducing air into the precursor powder, heating to 800 ℃ at the heating rate of 2.5 ℃/min, keeping the temperature for 12h, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the sodium nickel manganese oxide anode material with the granularity Dv50 of 2.5 microns.
(II) preparing full-gradient doped sodium ion anode material
Mixing ZnO and Fe 2 O 3 Mixing in water to obtain mixed solution with solid content of 8wt.%, adding into a sand mill, fine grinding to obtain slurry with particle Dv50 of 0.2 μm, and adding sodium nickel ferrite cathode material (sodium nickel ferrite cathode material and dopant (ZnO and Fe) 2 O 3 ) The mass ratio of (3.15) to (1), and then spray drying (the spray air inlet temperature is 220 ℃, and the spray air exhaust temperature is 90 ℃). Introducing air, heating to 900 deg.C at a heating rate of 2.5 deg.C/min, maintaining for 10 hr, and naturally cooling to room temperatureAnd (3) grinding the black block material by a rotary wheel mill and an air flow mill in sequence to obtain the full-gradient doped sodium ion cathode material with the granularity Dv50 of 3.0 mu m.
Comparative example 2
The chemical formula of the sodium ion cathode material of the embodiment is Na 0.85 Ni 0.3 Fe 0.4 Zn 0.1 Mn 0.2 O 2 Which is a single crystal structure and has a partially uniformly graded doped region and an inner undoped region from the surface to the inside of the single crystal.
The preparation method of the sodium ion cathode material of the embodiment includes the following steps.
(I) Preparation of sodium nickel ferrite cathode material
NiO and Fe are measured according to the formula 2 O 3 And Na 2 CO 3 (Na 2 CO 3 The molar weight of the sodium and the sum of the molar weights of Ni and Fe is 1.20, 1) is mixed in water to obtain a mixed solution with the solid content of 30%, the mixed solution is added into a sand mill for fine grinding to obtain slurry with the particle Dv50 of 0.5 mu m, and the slurry is subjected to spray drying (the spray air inlet temperature is 220 ℃, the spray air exhaust temperature is 90 ℃) to obtain spherical precursor powder. And (3) introducing air into the precursor powder, heating to 950 ℃ at the heating rate of 2.5 ℃/min, preserving the temperature for 12h, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the sodium nickel ferrite anode material with the granularity Dv50 of 4.0 mu m.
(II) preparation of doped sodium ion cathode Material
Adding ZnO and MnO 2 Mixing in water to obtain mixed solution with solid content of 8wt.%, adding into a sand mill, fine grinding to obtain slurry with particle Dv50 of 0.2 μm, and adding sodium nickel ferrite positive electrode material (sodium nickel ferrite positive electrode material and dopant (ZnO and MnO) 2 ) The mass ratio of the components is 3.2), and then the mixture is sprayed and dried (the spraying air inlet temperature is 220 ℃, and the spraying air exhaust temperature is 90 ℃). Introducing air, heating to 900 deg.C at a heating rate of 2.5 deg.C/min, maintaining for 10 hr, naturally cooling to room temperature to obtain black block material, and sequentially feeding the black block materialAnd (3) grinding by a rotary wheel mill and a jet mill to obtain the doped sodium ion cathode material with the granularity Dv50 of 5.0 mu m.
Comparative example 3
The chemical formula of the sodium ion cathode material of the embodiment is Na 0.85 Ni 0.43 Fe 0.57 O 2 @ Zn/Mn (i.e. Zn, mn coated Na) 0.85 Ni 0.43 Fe 0.57 O 2 @ Zn/Mn), which is a single crystal structure, zn and Mn are distributed on the surface of single crystal particles.
The preparation method of the sodium ion cathode material of the embodiment includes the following steps.
(I) Preparation of sodium nickel ferrite cathode material
Measuring NiO and Fe according to the formula 2 O 3 And Na 2 CO 3 (Na 2 CO 3 The molar weight of the sodium and the sum of the molar weights of Ni and Fe is 1.20, 1) is mixed in water to obtain a mixed solution with the solid content of 30%, the mixed solution is added into a sand mill for fine grinding to obtain slurry with the particle Dv50 of 0.5 mu m, and the slurry is subjected to spray drying (the spray air inlet temperature is 220 ℃, the spray air exhaust temperature is 90 ℃) to obtain spherical precursor powder. And (3) introducing air into the precursor powder, heating to 800 ℃ at the heating rate of 2.5 ℃/min, preserving the temperature for 12h, naturally cooling to room temperature to obtain a black block material, and then sequentially carrying out rotary wheel milling and jet milling on the black block material to obtain the sodium nickel ferrite anode material with the particle size Dv50 of 2.5 mu m.
(II) preparation of coated sodium-ion cathode Material
Adding ZnO and MnO 2 Mixing in water to obtain a mixed solution (molar ratio of Zn to Mn is 1, 2), the solid content of the mixed solution is 8wt.%, adding the mixed solution into a sand mill for fine grinding to obtain a slurry with particles having a Dv50 of 0.2 μm, and adding a sodium nickel ferrite positive electrode material (a sodium nickel ferrite positive electrode material and dopants (ZnO and MnO) 2 ) The mass ratio of the components is 3.2), and then the mixture is sprayed and dried (the spraying air inlet temperature is 220 ℃, and the spraying air exhaust temperature is 90 ℃). Introducing air, heating to 500 deg.C at a heating rate of 2.5 deg.C/min, maintaining for 10 hr, naturally cooling to room temperature to obtain black block material, and sequentially grinding with rotary wheel mill and air flowGrinding and crushing to obtain the sodium ion positive electrode material with the granularity Dv50 of 3.0 mu m.
The sodium ion positive electrode materials of examples 1 to 5 and comparative examples 1 to 3 were measured for their average particle diameter using a particle size analyzer and for their specific surface area using a mike specific surface area analyzer 3020, while being subjected to electrochemical performance tests, the results of which are shown in table 1.
And (3) electrochemical performance testing: the sodium ion positive electrode materials prepared in examples 1 to 5 and comparative examples 1 to 3 were used as active materials, respectively, mixed with PVDF as a binder and a conductive agent (Super-P) in a mass ratio of 95.5. Using 1mol/L LiPF with metallic lithium as a counter electrode 6 And mixing three-component mixed solvents according to EC: DMC: EMC =1 (1). The charge and discharge test of the button cell is carried out on a cell test system of blue-electricity electronic corporation, wuhan city, under the condition of 25 ℃, the constant current charge and discharge of 0.1C is carried out to 0.01V, then the constant current discharge of 0.02C is carried out to 0.005V, finally the constant current charge of 0.1C is carried out to 4.0V, the capacity charged to 4.0V is the first discharge specific capacity, the ratio of the discharge capacity to the charge capacity is the first charge and discharge efficiency, the corresponding discharge specific capacity of the 100 th circle is obtained after the circulation is carried out for 100 times, and the charge and discharge efficiency of the 100 th circle is calculated.
TABLE 1 electrochemical and physical Properties of the examples and comparative examples
As can be seen from the results in table 1, compared with comparative examples 1 to 3, the sodium ion positive electrode materials of examples 1 to 5 have small particle size and large specific surface area, and still have higher first discharge specific capacity and first charge-discharge efficiency at a high voltage of 4.0V, which are obviously higher than the specific capacity and efficiency of the sodium ion positive electrode materials of comparative examples 1 to 3, which indicates that more sodium ions participate in the reaction and intercalation during the charge and discharge processes of the sodium ion positive electrode materials of examples 1 to 5, which indicates that the power performance is better, i.e., the rate capability is better. After the material is cycled for 100 circles, the specific capacity and the charge-discharge efficiency of the material are higher, which shows that the material has better cycle performance and less side reactions on the surface of the material. The invention mainly causes the material to gradually increase the contents of Ni and Fe from the surface to the inside of the single crystal and gradually reduce the content of the doping element M through solid phase doping, thereby maintaining the structural stability of the sodium ion anode material and reducing the contact of active metal elements Ni and Fe with electrolyte in the charging and discharging process.
In comparative example 1, zinc and iron were used as doping elements, and iron was mainly concentrated on the surface layer of the single crystal material, which had higher activity and was liable to react with the electrolyte, so that the charge-discharge performance and the cycle performance were not good.
In comparative example 2, when the sodium nickel ferrite cathode material is prepared at 950 ℃, the sintering is complete, and then the solid phase doping is carried out at a slightly lower temperature of 900 ℃, zinc and manganese are difficult to permeate into the single crystal particles and mainly gather on the surfaces of the single crystal particles and inner layers close to the surfaces, namely, a part of uniform gradient doped regions and inner undoped regions exist, so that the particle size is large, and the charge and discharge performance and the cycle performance are not good.
In comparative example 3, sodium nickel ferrite cathode material was prepared at 800 deg.C, while the temperature of solid phase reaction was only 500 deg.C, so ZnO and MnO 2 The coating layer is mainly formed on the surface of the sodium nickel ferrite anode material instead of doping, so that the charge and discharge performance and the cycle performance are poor.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it is not limited to the embodiments, and those skilled in the art should understand that the technical solutions of the present invention can be modified or substituted with equivalents without departing from the spirit and scope of the technical solutions of the present invention.
Claims (10)
1. The sodium ion positive electrode material is characterized in that the chemical formula is Na α Ni x Fe y M (1-x-y) O 2 Wherein alpha is more than 0.60 and less than or equal to 1.00, x is more than 0 and less than or equal to 0.50, Y is more than 0 and less than or equal to 0.50, x + Y is less than 1.00, M is at least one of Zr, al, co, cu, sr, Y, mn, ti, mg, K, ca, li, mo, B, sn, si, nb, zn, W, tc, cd, pd, pb, po, tl, ge, sc, ru and Rh, the crystal structure is a single crystal, and the contents of Ni and Fe are gradually increased and the content of M is gradually reduced from the surface to the interior of the single crystal.
2. The sodium ion positive electrode material according to claim 1, wherein M is at least one of Zr, al, co, cu, sr, Y, mn, ti, mg, mo, zn, and W.
3. The sodium ion positive electrode material according to claim 1, wherein α is 0.60 < α.ltoreq.0.90, x is 0.10. Ltoreq.x < 0.50, and y is 0.10. Ltoreq.y < 0.50.
4. The sodium ion positive electrode material according to claim 1, wherein M is Zn and/or Mn, and α =0.85, x =0.30, y =0.40.
5. The sodium ion positive electrode material according to claim 1, wherein the single crystal has an average particle size of 1.5 μm to 3.0 μm.
6. The sodium ion positive electrode material according to claim 1, wherein the specific surface area of the sodium ion positive electrode material is 0.6m 2 G to 1.2m 2 /g。
7. The preparation method of the sodium ion cathode material is characterized by comprising the following steps:
(I) Preparation of sodium nickel ferrite cathode material
Weighing a nickel source, an iron source and a sodium source according to a formula, mixing in water to obtain a mixed solution, grinding to obtain slurry, spray-drying to obtain precursor powder, and performing primary sintering and primary crushing on the precursor powder;
(II) preparing full-gradient doped sodium ion anode material
Mixing M source in water to obtain a mixed solution, grinding to obtain a slurry, adding the sodium nickel ferrite anode material according to the formula amount, mixing, spray-drying, sintering for the second time, crushing for the second time,
and the temperature of the first sintering is lower than that of the second sintering.
8. The method for producing a sodium ion positive electrode material according to claim 7, characterized by comprising at least one of the following features (1) to (24):
(1) The nickel source is nickel oxide;
(2) The iron source is ferric oxide;
(3) The M source is an oxide of M, and M is at least one of Zr, al, co, cu, sr, Y, mn, ti, mg, K, ca, li, mo, B, sn, si, nb, zn, W, tc, cd, pd, pb, po, tl, ge, sc, ru and Rh;
(4) The sodium source is NaOH and NaNO 3 、Na 2 CO 3 And CH 3 At least one of COONa;
(5) The molar weight of sodium element in the sodium source is m, the sum of the molar weight of nickel element in the nickel source and the molar weight of iron element in the iron source is n, and m/n is 1.00-1.45;
(6) The solid content of the mixed solution in the step (I) of preparing the sodium nickel ferrite cathode material is 20-40 wt.%;
(7) The Dv50 of the slurry in the sodium nickel ferrite positive electrode material prepared in the step (I) is 0.2-0.7 μm;
(8) The air inlet temperature of the spray drying in the preparation of the sodium nickel ferrite anode material is 220-280 ℃, and the air outlet temperature is 80-100 ℃;
(9) Introducing air in the first sintering process;
(10) The temperature of the first sintering is 600 ℃ to 850 ℃;
(11) The heat preservation time of the first sintering is 5 to 12 hours;
(12) The heating rate of the first sintering is 2 ℃/min to 5 ℃/min;
(13) The first crushing comprises the steps of carrying out coarse crushing and fine crushing on the product after the first sintering by adopting a rotary wheel mill in sequence;
(14) The first pulverizing to particles having a Dv50 of 2.0 μm to 4.0 μm;
(15) The mass ratio of the sodium nickel ferrite positive electrode material to the M source is 1-8;
(16) The solid content of the mixed solution in the step (II) of preparing the full-gradient sodium ion-doped positive electrode material is 5-15 wt.%;
(17) The Dv50 of the slurry in the step (II) of preparing the full-gradient sodium ion-doped anode material is 0.1-0.3 μm;
(18) The air inlet temperature of the spray drying in the step (II) of preparing the full-gradient sodium ion-doped anode material is 220-280 ℃, and the air outlet temperature is 80-100 ℃;
(19) Introducing air in the process of the second sintering;
(20) The temperature of the second sintering is 750-950 ℃;
(21) The heat preservation time of the second sintering is 6-16 h;
(22) The temperature rise rate of the second sintering is 1-4 ℃/min;
(23) The second crushing comprises the steps of performing coarse crushing and fine crushing on the product obtained after the second sintering by adopting a rotary wheel mill in sequence;
(24) The Dv50 of the second crushed particles is from 2.5 μm to 4.5 μm.
9. A secondary battery comprising a positive electrode material, a negative electrode material and an electrolyte, wherein the positive electrode material comprises the sodium ion positive electrode material according to any one of claims 1 to 6 or the sodium ion positive electrode material prepared by the method of preparing the sodium ion positive electrode material according to any one of claims 7 to 8.
10. The secondary battery of claim 9, wherein the negative electrode material comprises a carbonaceous negative electrode material and/or a silicon-based negative electrode material.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116354417A (en) * | 2023-04-19 | 2023-06-30 | 荆门市格林美新材料有限公司 | Sodium ion precursor material and preparation method and application thereof |
| CN117038995A (en) * | 2023-10-09 | 2023-11-10 | 宁波容百新能源科技股份有限公司 | Positive electrode active material, preparation method thereof, positive electrode plate, battery and electricity utilization device |
| CN117457895A (en) * | 2023-12-25 | 2024-01-26 | 宁波容百新能源科技股份有限公司 | Positive electrode material, preparation method thereof and sodium ion battery |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116354417A (en) * | 2023-04-19 | 2023-06-30 | 荆门市格林美新材料有限公司 | Sodium ion precursor material and preparation method and application thereof |
| CN117038995A (en) * | 2023-10-09 | 2023-11-10 | 宁波容百新能源科技股份有限公司 | Positive electrode active material, preparation method thereof, positive electrode plate, battery and electricity utilization device |
| CN117038995B (en) * | 2023-10-09 | 2024-03-19 | 宁波容百新能源科技股份有限公司 | Positive electrode active material, preparation method thereof, positive electrode plate, battery and electricity utilization device |
| CN117457895A (en) * | 2023-12-25 | 2024-01-26 | 宁波容百新能源科技股份有限公司 | Positive electrode material, preparation method thereof and sodium ion battery |
| CN117457895B (en) * | 2023-12-25 | 2024-04-12 | 宁波容百新能源科技股份有限公司 | Positive electrode material, preparation method thereof and sodium ion battery |
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