Patent Application
20250019257
The present disclosure relates to the technical field of lithium-ion batteries, and more particularly, to a precursor of a lithium-containing oxide cathode material, a lithium-containing oxide cathode material, a preparation method and use thereof, and a positive electrode plate and use thereof.
In recent years, new energy vehicles, as a strategic emerging industry to cope with environmental pollution and energy crisis, exhibit a tendency of booming development. Lithium-ion batteries, as new energy carriers with excellent comprehensive performance, are widely used in markets such as electric vehicles, energy storage power stations, communications, digital electronic products, and the like.
In a lithium-ion battery, a cathode serves as a core material and directly determines technical performance level of the battery. Among the commonly used cathode materials for lithium-ion batteries, LiNi1-x-yCoxMnyO2(NCM) and LiNi1-x-yCoxAlyO2(NCA) with layered structure and lithium-rich manganese-based materials (LMR) have attracted much attention and are adequately studied due to their high specific capacity and energy density. However, in order to obtain higher volume energy density and comprehensive electrochemical performance, the cathode material has to be rolled with high pressure during a preparation process of an electrode plate to obtain a high electrode density. The cathode materials with low strength may be fractured or crushed in this process, which may increase contact area and side reactions with the electrolyte, thereby resulting in deterioration in cycle performance and rate performance. In addition, during the use of battery, repeated Li+ deintercalation may cause expansion or contraction of a volume of the layered structure, which may lead to pulverization of the low-strength cathode material, thereby resulting in insufficient contact between particles, continuous formation of new electrolyte layers and increased side reactions, and thereby deterioration and even failure of battery performance.
Therefore, it is of great significance to develop a new preparation method, to adjust microstructure of the cathode materials with the layered structure, and to enhance the compressive strength or particle strength of the cathode materials, for achieving long cycle life, high specific capacity, and high rate performance of batteries.
In a first aspect, the present disclosure provides a lithium-containing oxide cathode material. The cathode material has a compressive index Δλ(P100) satisfying Δλ(P100)≥60%+(y/x)×5%, where y/x is a molar ratio of Mn/Ni in the cathode material.
In a second aspect, the present disclosure provides a precursor of a lithium-containing oxide cathode material. The precursor has a compressive index Δλ′(P50) satisfying Δλ′(P50)≥35%+(v/u)×8%, where v/u is a molar ratio of Mn/Ni in the precursor.
In third aspect, the present disclosure provides a preparation method of a lithium-containing oxide cathode material. The preparation method includes: S1, uniformly mixing a precursor having a chemical formula represented by Formula (1), a lithium source, and an optional additive containing element M2, and performing a first sintering in an atmosphere furnace, to obtain a primary sintered material having a chemical formula represented by Formula (2); and S2: uniformly mixing the primary sintered material with an additive containing element M′, and performing a second sintering on the mixed material in an atmosphere furnace, to obtain a lithium-containing metal oxide having a chemical formula represented by Formula (3),
NiuMnvM1γ(OH)2, Formula (1),
where: u+v+γ=1, 0.2<u<1, 0<v≤0.75, 0≤γ≤0.35, and M1 is selected from at least one element of Al, Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, Na, La, Os, Pr, Re, Ru, Sr, Sm, Ta, and B;
Li[LiaNixMnyMj]O2, Formula (2);
Li[LiaNixMnyMj]O2@M′, Formula (3);
wherein in Formula (2) and Formula (3), a+x+y+j=1, 0≤a≤0.3, 0.2<x<1, 0<y≤0.75, 0<j≤0.35; and M includes element M1 in the precursor and element M2 introduced during the first sintering, M1 and M2 being the same or different and being each selected from at least one element of Al, Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, La, Os, Pr, Re, Ru, Sr, Sm, Ta, and B; and wherein in Formula (3), M′ is oxide, phosphide, sulfide, fluoride, or chloride containing at least one element of Al, Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, La, Os, Pr, Re, Ru, Sr, Sm, Ta, and B, and a molar content of cations in M′is w, w satisfying 0<w/(a+x+y+j)≤0.1.
In a fourth aspect, the present disclosure provides a lithium-containing oxide cathode material prepared by the above-mentioned preparation method of the lithium-containing oxide cathode material.
In a fifth aspect, the present disclosure provides a positive electrode plate. The positive electrode plate includes at least 90 wt % of a lithium-containing oxide cathode material based on a total weight of the positive electrode plate. The lithium-containing oxide cathode material is the lithium-containing oxide cathode material according to the first aspect.
In a sixth aspect, the present disclosure provides a lithium-ion battery. The lithium-ion battery includes the above-mentioned positive electrode plate according to the second aspect, a negative electrode plate, a separator, and an electrolyte.
In the present disclosure, endpoints and any value of the ranges shall not be limited to the exact range or value, and those ranges or values should be understood to include values close to those ranges or values. For numerical ranges, endpoints of respective ranges, an endpoint and individual point value of respective ranges, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be deemed to be specifically disclosed herein.
The conventional lithium-ion batteries using lithium-containing metal oxide material have to withstand high pressure during the preparation process of electrode plates. In addition, during continuous charge and discharge cycles, the material may rupture due to its insufficient compressive strength or unstable structure, thereby increasing side reactions with the electrolyte. Thus, the consumption of the electrolyte and the dissolution of transition metal cations in the cathode material are accelerated, resulting in reduced cycle performance, safety performance, and capacity, and even battery failure.
An object of the present disclosure is to overcome the defects in the prior art that lithium-containing metal oxide materials may rupture during a preparation process of an electrode plate, or secondary particles may rupture during a charge and discharge cycle, resulting in poor rate performance, deterioration of cycle performance, and reduced safety performance. Provided are a precursor of a lithium-containing oxide cathode material, a lithium-containing oxide cathode material, a preparation method and use thereof, and a positive electrode plate and use thereof. The lithium-containing oxide cathode material has high compressive strength and stability, only a small degree of fracture occurs under high pressure during a preparation process of the electrode plate, and it can be continuously subjected to lithium ion deintercalation/deintercalation reactions without serious rupture.
As mentioned above, a first aspect of the present disclosure provides a lithium-containing oxide cathode material. The cathode material has a compressive index Δλ(P100) satisfying Δλ(P100)≥60%+(y/x)×5%, where y/x is a molar ratio of Mn/Ni in the cathode material.
In addition, in the present disclosure:
D50 refers to a value of particle cumulative distribution D5 of the material in a natural state without external mechanical pressure (i.e., P=0 Mpa); D5pn refers to a value of particle cumulative distribution D5 of the material under P=n Mpa; and D5 refers to a particle size value when a cumulative volume distribution of the particles is 5%.
For example, the compressive index Δλ(P100) is calculated based on the following equation:
According to the present disclosure, preferably, the cathode material has a compressive index Δλ(P200) satisfying Δλ(P200)≥45%+(y/x)×5%.
According to the present disclosure, more preferably, the cathode material has a compressive index Δλ(P300) satisfying Δλ(P300)≥35%+(y/x)×5%.
According to the present disclosure, it should be noted that Δλ(P100) represents the compressive index of the material when pressure P=100 Mpa; Δλ(P200) represents the compressive index of the material when pressure P=200 Mpa; and so on. The cathode material according to the present disclosure has excellent compressive
strength and is not prone to rupture. When the cathode material according to the present disclosure is used as a cathode, it has a stable structure, few side reactions, and excellent safety performance and capacity retention rate.
According to the present disclosure, the lithium-containing oxide cathode material has a chemical formula represented by Formula (3):
Li[LiaNixMnyMj]O2@M′, Formula (3), where:
a+x+y+j=1; 0<a≤0.3; 0.2<x<1; 0<y≤0.75; 0<j≤0.35; M is selected from at least one element of Al, Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, La, Os, Pr, Re, Ru, Sr, Sm, Ta, and B; M′ is oxide, phosphide, sulfide, fluoride, or chloride containing at least one element of Al, Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, La, Os, Pr, Re, Ru, Sr, Sm, Ta, and B; and a molar content of cations in M′ is w, w satisfying 0<w/(a+x+y+j)≤0.1.
According to the present disclosure, preferably, 0.02≤a≤0.3; 0.3<x<0.9; 0.05<y≤0.68; 0<j≤0.3; and 0.001<w/(a+x+y+j)≤0.02.
According to the present disclosure, M is selected from at least one element of Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, La, Ta, and B; and M′ is oxide, phosphide, sulfide, or fluoride containing at least one element of Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, La, Ta, and B.
In the present disclosure, the inventors found that: by adopting an appropriate modifier, the compressive strength and stability of material particles can be enhanced, a value of direct current internal resistance and gas production of the material during the cycle can be reduced, and the cycle life of the material can be prolonged.
By doping with elements such as Ti, Sc, Zr, W, Mg, Y, Co, Cr, Ta, and the like, crystal structure of the material can be stabilized, micro-area structure of the material can be improved, and the compressive index, cycle life, and safety performance of the material can be improved. By doping with elements such as Ti, Zr, Nb, La, W, Co, B, and the like, lithium-containing compounds (such as LiNbO3, Li2ZrO3, Li4TisO12, Li3BO3, or LaNiO3, etc.) may be formed on the surface of the material particles or at the interface between the particles, thereby stabilizing the surface structure of the material particles or the interface strength between the particles or the grain boundary structure between the primary crystal grains, and the compressive index and cycle life of the material can be improved. Furthermore, transmission of lithium-ions between the particles and between the interfaces can be accelerated, and rate performance of the material can be improved. The cathode material according to the present disclosure also has other characteristics.
According to the present disclosure, the cathode material has a tap density of ≥1.7 g/cm3, preferably ≥2 g/cm3, and more preferably ≥2.4 g/cm3.
According to the present disclosure, the cathode material has a pellet density of ≥2.8 g/cm3, preferably ≥3 g/cm3, and more preferably ≥3.2 g/cm3.
According to the present disclosure, a content of surface soluble alkali of the cathode material satisfies the following conditions: Li2CO3≤1 wt %, LiOH≤0.5 wt %; preferably, Li2CO3≤0.5 wt %, LiOH≤0.4 wt %; further preferably, Li2CO3≤0.3 wt %, LiOH≤0.3 wt %; and more preferably, Li2CO3≤0.2 wt %, LiOH≤0.2 wt %.
According to the present disclosure, a full width at half maximum FWHM(003) of (003) crystal plane and a full width at half maximum FWHM(104) of (104) crystal plane of the cathode material obtained by X-Ray Diffraction (XRD) satisfy the following conditions: 0.10≤FWHM(003)≤0.25, and preferably, 0.13≤FWHM(003)≤0.22; and 0.20≤FWHM(104)≤0.50, and preferably, 0.22≤FWHM(104)≤0.42.
According to the present disclosure, a peak area S(003) of the (003) crystal plane and a peak area S(104) of the (104) crystal plane of the cathode material obtained by XRD satisfy the following conditions: 1.1≤S(003)/S(104)≤1.8, and preferably, 1.2≤S(003)/S(104)≤1.6.
In addition to using suitable additives, the present disclosure also achieves high crystallinity and compactness of the precursor by controlling the morphology and microstructure of the precursor, thereby increasing the compressive index of the cathode material.
A second aspect of the present disclosure provides a precursor of a lithium-containing oxide cathode material. The precursor has a compressive index Δλ′(P50) satisfying Δλ′(P50)≥35%+(v/u)×8%, where v/u is a molar ratio of Mn/Ni in the precursor.
According to the present disclosure, preferably, the precursor has a compressive index Δλ′(P100) satisfying Δλ′(P100)≥25%+(v/u)×8%.
According to the present disclosure, it should be noted that Δλ′(P50) represents the compressive index of the precursor material when pressure P=50 MPa; Δλ′(P100) represents the compressive index of the precursor material when pressure P=100 MPa; and so on.
In the present disclosure,
D′50 refers to a value of particle cumulative distribution D5 of the material in a natural state without external mechanical pressure (i.e. P=0 Mpa); D′5Pn refers to a value of particle cumulative distribution D5 of the material under P=n Mpa.
For example, the compressive index Δλ′(P50) of the precursor is calculated as follows:
According to the present disclosure, the precursor has a chemical formula represented by Formula (1):
NiuMnvMγ(OH)2, Formula (1), where:
In the present disclosure, by doping with elements such as Ti, Al, Zr, W, Co, Nb, La, Na, and Mg, micro-area interior or surface structure of the precursor can be stabilized.
The precursor material according to the present disclosure is also characterized in the following aspects.
According to the present disclosure, more preferably, the precursor has a tap density of ≥1.2 g/cm3, preferably ≥1.6 g/cm3, and further preferably ≥2 g/cm3.
According to the present disclosure, the precursor has a specific surface area BET value satisfying BET≤30 m2/g, and preferably, BET≤25 m2/g.
According to the present disclosure, the precursor has a particle size distribution coefficient K90 satisfying 0.5≤K90≤1.6, where K90=(D90−D10)/D50, and D10, D50, and D90 refer to the particle size values when the cumulative volume distribution of the particles is 10%, 50%, and 90%, respectively.
According to the present disclosure, a full width at half maximum FWHM(001) of (001) crystal plane, a full width at half maximum FWHM(100) of (100) crystal plane, and a full width at half maximum FWHM(101) of (101) crystal plane of the precursor obtained by XRD satisfy the following conditions:
According to the present disclosure, a peak area S(101) of the (001) crystal plane and a peak area S(104) of the (101) crystal plane of the precursor obtained by XRD satisfy the following condition: S(001)/S(101)≥2.0.
According to the present disclosure, an integral area S(101) of the (001) crystal plane and an integral area S(104) of the (101) crystal plane of the precursor obtained by XRD satisfy the following condition: S(001)/S(101)≥2.0.
The present disclosure further provides a preparation method of a precursor of a lithium-containing oxide cathode material. The preparation method includes: (1) mixing, by contacting, a solution or suspension of a nickel salt, a manganese salt, and a compound containing M, to obtain a mixed salt solution; and (2) feeding the parallel flows of the mixed salt solution, a precipitant solution, and a complexing agent solution 1 into a reactor for crystallization reaction, and performing solid-liquid separation, washing, heat treatment, and sieving treatment on the obtained slurry, to obtain the precursor of the lithium-containing oxide cathode material.
In the present disclosure, the inventors found that: for metal hydroxide precursors, during the mixing and sintering process, the precursor may rupture due to its insufficient compressive strength, resulting in reduced compressive strength, reduced tap density, and reduced electrochemical performance of the prepared cathode material. In the present disclosure, by controlling the synthesis process of the precursor, such as a concentration and type of the complexing agent, a concentration of the precipitant, stirring intensity, a reaction temperature, additives, a solid content, and a feed rate, a precursor with high crystallinity and compactness can be synthesized. By adjusting the particle size distribution and specific surface area of the precursor, the crystallinity, tap density, and compressive index of the precursor material can be improved. In addition, by adding suitable additives and adjusting the microstructure and morphology of the precursor, the compressive index of the precursor can be improved.
According to the present disclosure, the nickel salt, the manganese salt, or the additive containing M element are dissolved according to a molar ratio of u:v:γ to form a mixed salt solution with a concentration ranging from 1 mol/L to 3 mol/L. The compound containing M is added into water to prepare an M solution or suspension with a certain concentration. The alkali solution with a concentration ranging from 2 mol/L to 10 mol/L is obtained by dissolving alkali. The complexing agent solution with a concentration ranging from 2 mol/L to 13 mol/L is obtained by dissolving a complexing agent.
According to the present disclosure, the slurry has a solid content ranging from 200 g/L to 1000 g/L, and preferably, from 300 g/L to 800 g/L.
According to the present disclosure, the mixed salt solution of Ni and Mn, the alkali solution, the complexing agent solution, and the M solution are respectively added to a reactor having an overflow pipe through respective liquid inlet pipes in parallel flows, the stirring speed is kept constant, and inlet flow rates of the mixed salt solution, the precipitant solution, the complexing agent solution, and the M solution are controlled.
According to the present disclosure, the reaction conditions include: a reaction temperature ranging from 40° C. to 70° C., reaction pH ranging from 10.6 to 12.5, and a reaction duration ranging from 5 hours to 100 hours.
According to the present disclosure, the nickel salt is one or more of nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate.
According to the present disclosure, the manganese salt is one or more of manganese sulfate, manganese chloride, manganese nitrate, and manganese acetate.
According to the present disclosure, the compound containing M is one or more of sulfate, chloride, nitrate, acetate, citrate, carbonate, phosphate, oxalate, and fluoride containing the element M.
According to the present disclosure, the precipitant is an alkaline substance, and the alkali is one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide.
According to the present disclosure, the complexing agent is one or more of salicylic acid, ammonium sulfate, ammonium chloride, ammonium hydroxide, sulfosalicylic acid, and ethylenediaminetetraacetic acid.
According to the present disclosure, the sintering system (including sintering temperature, heating rate, sintering atmosphere, etc.) during the preparation of the lithium-containing metal oxide is also very important and will affect the compressive index of the material.
A third aspect of the present disclosure provides a preparation method of a lithium-containing oxide cathode material. The preparation method includes:
NiuMnvM1γ(OH)2, Formula (1),
where: u+v+γ=1, 0.2<u<1, 0<v≤0.75, 0≤γ≤0.35, and M1 is selected from at least one element of Al, Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, Na, La, Os, Pr, Re, Ru, Sr, Sm, Ta, and B;
Li[LiaNixMnyMj]O2, Formula (2);
Li[LiaNixMnyMj]O2@M′, Formula (3);
wherein in Formula (2) and Formula (3), 0≤a≤0.3, 0.2<x<1, 0<y≤0.75, 0<j≤0.35; and M includes element M1 in the precursor and element M2 introduced during the first sintering, M1 and M2 being the same or different and being each selected from at least one element of Al, Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, La, Os, Pr, Re, Ru, Sr, Sm, Ta, and B; and wherein in Formula (3), M′is oxide, phosphide, sulfide, fluoride, or chloride containing at least one element of Al, Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, La, Os, Pr, Re, Ru, Sr, Sm, Ta, and B, and a molar content of cations in M′ is w, w satisfying 0<w/(a+x+y+j)≤0.1.
According to the present disclosure, the source of the element M in the cathode material includes the element M1 in the precursor and the additive containing the element M2 introduced during the first sintering process.
According to the present disclosure, the lithium source is at least one of lithium hydroxide, lithium carbonate, and lithium nitrate;
According to the present disclosure, the additive containing the element M2 is selected from at least one of oxide, hydroxide, oxyhydroxide, phosphate, fluoride, boride, and carbonate containing the element M2.
According to the present disclosure, the element M1 and the element M2 are the same as or different from the element M, and are each selected from at least one element of Al, Zr, Nb, Ti, Y, Sc, Cr, Co, W, Mg, La, Os, Pr, Re, Ru, Sr, Sm, Ta, and B.
According to the present disclosure, the additive containing the element M′ is selected from at least one of oxide, hydroxide, oxyhydroxide, phosphate, fluoride, boride, nitride, carbonate, and oxalate containing the element M′.
According to the present disclosure, a molar ratio Li/(Ni+Mn+M1+M2) of the lithium source to a sum of the precursor and the additive containing the element M2 ranges from 1 to 1.85, and preferably from 1 to 1.5.
According to the present disclosure, the additive containing the element M2 is added according to M2/(Ni+Mn+M1+M2) ranging from 0.0005 to 0.3, and preferably, from 0.001 to 0.2.
According to the present disclosure, a molar ratio M′/(Ni+Mn+M1+M2) of the additive containing the element M′ to the primary sintered material ranges from 0 to 0.1, and preferably, from 0.001 to 0.02.
According to the present disclosure, when a molar ratio of Ni/Mn is greater than 1,that is, x/y>1, a relationship between a sintering temperature T1 of the first sintering and a content of Ni satisfies 550×(2−x)° C.≤T1≤400×(3−x)° C., and a sintering duration of the first sintering ranges from 6 hours to 20 hours, and preferably, from 8 hours to 15 hours.
According to the present disclosure, when the molar ratio of Ni/Mn is smaller than or equal to 1, that is, y/x≥1, a relationship between a sintering temperature T2 of the first sintering and a content of Mn satisfies 500×(1+y)≤T2≤650×(1+y)° C., and a sintering duration of the first sintering ranges from 6 hours to 20 hours, and preferably, from 8 hours to 15 hours.
According to the present disclosure, when x<0.5, the first sintering and the second sintering are performed in an air atmosphere; when 0.5≤x<0.6, the first sintering and the second sintering are performed in an air atmosphere or a mixture atmosphere of air and oxygen; and when x≥0.6, the first sintering and the second sintering are performed in an oxygen atmosphere or a mixture atmosphere of oxygen and air.
A fourth aspect of the present disclosure provides a lithium-containing oxide cathode material prepared by the above-mentioned preparation method of the lithium-containing oxide cathode material.
A fifth aspect of the present disclosure provides a positive electrode plate. The positive electrode plate includes at least 90 wt % of a lithium-containing oxide cathode material based on a total weight of the positive electrode plate. The lithium-containing oxide cathode material is the above-mentioned lithium-containing oxide cathode material.
According to the present disclosure, preferably, a mass percentage of the cathode material is not less than 95%.
According to the present disclosure, the positive electrode plate has an electrode density of ≥2.8 g/cm3, preferably ≥3.2 g/cm3, and more preferably ≥3.5 g/cm3.
A sixth aspect of the present disclosure provides use of the above-mentioned lithium-containing oxide cathode material, the above-mentioned precursor of the lithium-containing oxide cathode material, or the above-mentioned positive electrode plate in a lithium-ion battery.
Based on the above-mentioned technical solutions, the present disclosure has the following advantages.
The present disclosure will be described in detail below by way of examples.
In the following examples and comparative examples, all raw materials are commercially available, unless otherwise specified.
In the following examples, the involved performances were obtained by the following ways.
The electrochemical performance of the prepared lithium-containing oxide cathode material was obtained by testing 2025-type button batteries using Xinwei Battery Test System. Specifically:
Preparation of electrode plate: a lithium-containing oxide cathode material, carbon black, and polyvinylidene fluoride according to a certain mass ratio were fully mixed with an appropriate amount of N-methylpyrrolidone to prepare a uniform slurry, and the slurry was coated on an aluminum foil, dried at 120° C., rolled, and punched to form a positive electrode plate with a diameter of 11 mm.
Assembly of battery: a Li metal plate with a diameter of 17 mm and a thickness of 1 mm was used as a negative electrode; a polyethylene porous membrane with a thickness of 25 μm was used as a separator; and a mixture of equal amounts of 1 mol/L LiPF6, ethylene carbonate (EC), and diethyl carbonate (DEC) was used as an electrolyte.
The positive electrode plate, the separator, the negative electrode plate, and the electrolyte were assembled into a 2025-type button battery in an Ar glove box with a water content and an oxygen content of less than 5 ppm, and the battery at this moment was regarded as an unactivated battery.
When a molar ratio of Ni/Mn was greater than 1, i.e., x/y>1, the test conditions of the button battery were as follows. The button battery, after being prepared, was placed for 2 hours. After the open circuit voltage was stabilized, the battery was charged to a cut-off voltage of 4.3V with a current density of 0.1 C at the cathode, next charged at a constant voltage for 30 minutes, and then discharged to a cut-off voltage of 3.0V at a same current density. The same method was repeated once, and the battery at this moment was regarded as an activated battery. Under a voltage ranging from 3.0V to 4.3V and within a charge and discharge range from 3.0V to 4.3V, the activated battery was subjected to charge and discharge tests at 25° C. and at 0.1 C to evaluate the charge and discharge capacity of the material. The activated battery was subjected to charge and discharge tests at 0.1 C, 0.2 C, 0.33 C, 0.5 C, and 1 C, and a ratio of 1 C capacity to 0.1 C capacity was used to evaluate the rate performance of the material. In the range from 3.0V to 4.4V, the cycle performance of the material after 80 cycles at 1 C was evaluated.
When the molar ratio of Ni/Mn is not greater than 1, that is, x/y≤1, the test conditions of the button battery were as follows. The button battery, after being prepared, was placed for 2 hours. After the open circuit voltage was stabilized, the battery was charged to a cut-off voltage of 4.6V with a current density of 0.1 C at the cathode, next charged at a constant voltage for 30 minutes, and then discharged to a cut-off voltage of 2.0V at a same current density. The same method was repeated once, and the battery at this moment was regarded as an activated battery. Under a voltage ranging from 2.0V to 4.6V and within a charge and discharge range from 2.0V to 4.6V, the activated battery was subjected to charge and discharge tests at 25° Cand at 0.1 C to evaluate the charge and discharge capacity of the material. The activated battery was subjected to charge and discharge tests at 0.1 C, 0.2 C, 0.33 C, 0.5 C, and 1 C, and a ratio of 1C capacity to 0.1 C capacity was used to evaluate the rate performance of the material. In the range from 2.0V to 4.6V, the cycle performance of the material after 80 cycles at 0.5 C was evaluated.
Example 1 was intended to illustrate a lithium-containing oxide cathode material prepared according to the present disclosure.
Nickel sulfate and manganese sulfate were dissolved according to a metal molar ratio of 5:3 to obtain a 2 mol/L mixed salt solution. Cobalt sulfate and aluminum sulfate were dissolved according to metal molar ratios of Co/(Ni+Mn+Co+Al)=0.18 and Al/(Ni+Mn+Co+Al)=0.02 to obtain a 2 mol/L mixed salt solution. Sodium hydroxide was dissolved to form an alkaline solution with a concentration of 6 mol/L, and ammonium hydroxide was dissolved to form a complexing agent solution with a concentration of 5 mol/L.
Then, 20 L of mixed salt solution, alkaline solution, and complexing agent solution were added into a reactor in parallel for reaction. The stirring speed was kept constant at 600 rpm during the process. In the meantime, an inlet flow rate of the mixed salt solution was controlled to 300 mL/h, reaction pH was controlled to 11.6, reaction temperature was kept at 50° C., and a concentration of ammonia in the reaction system was controlled to be 9 g/L. The reaction was carried out in N2 gas, and the reaction was stayed for 60 hours. The solid content was 500 g/L. The slurry obtained through crystallization reaction of the precipitate was subjected to solid-liquid separation and washing, and then dried at 105° C. for 10 hours. A spherical Ni0.5Mn0.3Co0.18Al0.02(OH)2 precursor material was obtained after sieving, which was recorded as P-1.
The precursor P-1, lithium carbonate, and additives TiO2 and WO3 were mixed evenly in a high-speed mixer according to Li:(Ni+Mn+Co+Al+Ti+W)=1.03, Ti:(Ni+Mn+Co+Al+Ti+W)=0.003, W:(Ni+Mn+Co+Al+Ti+W)=0.002. In an air atmosphere, the temperature was raised to 920° C., maintained for 10 hours, and naturally cooled, to obtain a primary sintered cathode material Li[Li0Ni0.4975Mn0.2985Co0.1791Al0.0199Ti0.003W0.002]O2, which was recorded as S-1.
The primary sintered material S-1, and additives Nb2O5 and La2O3 were mixed evenly according to Nb:(Ni+Mn+Co+Al+Ti+W)=0.002 and La:(Ni+Mn+Co+Al+Ti+W)=0.002. In an air atmosphere, the temperature was raised to 650° C., maintained for 6 hours, and naturally cooled, to obtain a secondary sintered cathode material Li[Li0Ni0.4975Mn0.2985Co0.1791Al0.0199Ti0.003W0.002]@Nb0.002La0.002, which was recorded as FS-1.
Example 2 to Example 14 were intended to illustrate the lithium-containing oxide cathode material prepared according to the present disclosure.
The lithium-containing oxide cathode material was prepared according to the same method as that of Example 1. Example 2 to Example 14 merely differed from Example 1 in the preparation processes of the precursor, primary sintered cathode material, and secondary sintered cathode material, as shown in Table 1.
In Table 1, unless otherwise specified, all ratios and amounts were molar ratios.
Comparative Example 1 adopted the same synthesis method and conditions as in Example 5. Comparative Example 1 merely differed from Example 5 in that, the first sintering temperature was adjusted to 600° C., and the cathode material obtained was recorded as D-1, as shown in Table 2.
Comparative Example 2 adopted the same synthesis method and conditions as in Example 5. Comparative Example 2 merely differed from Example 5 in that, the first sintering temperature was adjusted to 900° C., and the cathode material obtained was recorded as D-2, as shown in Table 2.
Comparative Example 3 adopted the same synthesis method and conditions as in Example 5. Comparative Example 3 merely differed from Example 5 in that, additives of rhenium oxide and samarium oxide were not added in the preparation process of the primary sintered cathode material, and the cathode material obtained was recorded as D-3, as shown in Table 2.
Comparative Example 4 adopted the same synthesis method and conditions as in Example 5. Comparative Example 4 merely differed from Example 5 in that, additives of tungsten nitride and aluminum fluoride were not added in the preparation process of the secondary sintered cathode material, and the cathode material obtained was recorded as D-4, as shown in Table 2.
Comparative Example 5 adopted the same synthesis method and conditions as in Example 9. Comparative Example 5 merely differed from Example 9 in that, the solid content was adjusted to 150 g/L in the preparation process of the precursor, and the cathode material obtained was recorded as D-5, as shown in Table 2.
Comparative Example 6 adopted the same synthesis method and conditions as in Example 9. Comparative Example 6 merely differed from Example 9 in that, additives of tungsten oxide and aluminum hydroxide oxide were not added in the preparation process of the primary sintered cathode material, and the cathode material obtained was recorded as D-6, as shown in Table 2.
Comparative Example 7 adopted the same synthesis method and conditions as in Example 9. Comparative Example 7 merely differed from Example 9 in that, the preparation process of the secondary sintered cathode material was omitted, and the cathode material obtained was recorded as D-7, as shown in Table 2.
The performances of the precursors of the lithium-containing oxide cathode materials prepared in Example 1 to Example 14 and Comparative Example 1 to Comparative Example 7 were tested, and the results were shown in Table 3. The performances of the lithium-containing oxide cathode materials prepared in Example 1 to Example 14 and Comparative Example 1 to Comparative Example 7 were tested, and the results were shown in Table 4 and Table 5.
The lithium-containing oxide cathode materials prepared in Example 1 to Example 14 and Comparative Example 1 to Comparative Example 7 were used as the positive electrode plate of the lithium-ion battery to prepare the lithium-ion battery. The performances of the lithium-ion batteries were tested, and the results were shown in Table 6.
In addition, in the present disclosure,
The preferred embodiments of the present disclosure are described in detail above. However, the present disclosure is not limited thereto. Within the scope of technical conception of the present disclosure, a variety of simple variations may be made to the technical solutions of the present disclosure, including the combination of various technical features in any other suitable manner. These simple variations and combinations shall be regarded as the contents disclosed by the present disclosure, and all of them fall within the scope of protection of the present disclosure.
This application is a continuation of International Application No. PCT/CN2022/120889, filed on Sep. 23, 2022, the disclosure of which is hereby incorporated by reference in entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2022/120889 | Sep 2022 | WO |
| Child | 18900971 | US |
