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CN-121983556-A - Modified high-nickel NCA positive electrode material and preparation method and application thereof

CN121983556ACN 121983556 ACN121983556 ACN 121983556ACN-121983556-A

Abstract

The invention relates to the technical field of lithium ion battery anode materials, and discloses a modified high-nickel NCA anode material, a preparation method and application thereof. The modified high-nickel NCA positive electrode material comprises a core, a first coating layer and a second coating layer which are sequentially arranged from inside to outside, wherein the core comprises nickel cobalt lithium aluminate doped with hafnium, the first coating layer comprises copper oxide, and the second coating layer comprises a lithium fast ion conductor. In the modified high-nickel NCA positive electrode material provided by the invention, the hafnium doping stabilizes the crystal structure from the bulk phase angle, the double-layer cladding synergistic effect inhibits the occurrence of side reaction from the interface angle, and the two synergistic effects solve the problem of bulk-interface synergistic attenuation of the material, so that the positive electrode material has high capacity, long cycle life and excellent multiplying power performance.

Inventors

  • XU KAIHUA
  • ZHOU XIAOYAN
  • Dong Yuanchu
  • CHEN YUJUN
  • MA YONGSONG
  • YANG XINGYU
  • LI JIE

Assignees

  • 格林美（无锡）能源材料有限公司

Dates

Publication Date
20260505
Application Date
20260228

Claims (10)

  1. 1. The modified high-nickel NCA anode material is characterized by comprising an inner core, a first coating layer and a second coating layer which are sequentially arranged from inside to outside; the core comprises nickel cobalt lithium aluminate doped with hafnium element; The first cladding layer comprises copper oxide; the second cladding layer includes a lithium fast ion conductor.
  2. 2. The modified high nickel NCA positive electrode material according to claim 1, wherein at least one of the following conditions is satisfied: (1) The mass of the first coating layer is 0.1-0.5 wt% of the mass of the inner core; (2) The mass of the second coating layer is 0.5-2 wt% of the sum of the mass of the first coating layer and the mass of the core; (3) The mole amount of hafnium in the hafnium-doped nickel cobalt lithium aluminate is 0.2% -1% of the total mole amount of hafnium, nickel, cobalt and aluminum in the hafnium-doped nickel cobalt lithium aluminate, the mole amount of nickel is 80% -95% of the total mole amount of hafnium, nickel, cobalt and aluminum in the hafnium-doped nickel cobalt lithium aluminate, the mole amount of cobalt is 2% -15% of the total mole amount of hafnium, nickel, cobalt and aluminum in the hafnium-doped nickel cobalt lithium aluminate, and the mole amount of aluminum is 1% -5% of the total mole amount of hafnium, nickel, cobalt and aluminum in the hafnium-doped nickel cobalt lithium aluminate; (4) The lithium fast ion conductor comprises one or more of LiAlO 2 、Li 2 ZrO 3 、Li 2 TiO 3 、Li 3 PO 4 , lithium lanthanum zirconium oxide and lanthanum lithium titanate.
  3. 3. A method for preparing the modified high nickel NCA positive electrode material according to claim 1 or 2, comprising the steps of: S1, preparing a mixed solution of soluble salts of nickel, cobalt, aluminum and hafnium according to stoichiometric ratio, reacting the mixed solution with a precipitator and a complexing agent, and controlling pH to be 10.5-11.5 to obtain a hafnium doped precursor; S2, mixing a hafnium doped precursor with a lithium source, pre-sintering, and calcining to obtain hafnium doped nickel cobalt lithium aluminate; S3, dispersing hafnium-doped nickel cobalt lithium aluminate in a copper-containing salt solution, and performing first heat treatment after spray drying to obtain hafnium-doped nickel cobalt lithium aluminate coated by a first coating layer; s4, mixing the hafnium-doped nickel cobalt lithium aluminate coated by the first coating layer obtained in the S3 with an M source, and performing second heat treatment to obtain the modified high-nickel NCA anode material containing the second coating layer; The M element in the M source comprises one or more of Al, zr, ti, P, la.
  4. 4. The method for preparing a modified high nickel NCA positive electrode material according to claim 3, wherein said precipitant in S1 comprises one or more of NaOH, KOH, na 2 CO 3 、NH 4 HCO 3 , preferably at least one of NaOH, na 2 CO 3 ; and/or the complexing agent in the S1 comprises one or more of NH 3 ·H 2 O, citric acid, ethylenediamine tetraacetic acid and tartaric acid, preferably NH 3 ·H 2 O.
  5. 5. The method for producing a modified high nickel NCA positive electrode material according to claim 3 or 4, wherein the reaction temperature in S1 is 50 to 70 ℃ and the reaction time is 20 to 50 hours.
  6. 6. The method for producing a modified high-nickel NCA positive electrode material according to claim 3 or 4, wherein said S1 satisfies at least one of the following conditions: (1) The soluble salts of nickel include one or more of NiSO 4 、Ni(NO 3 ) 2 、NiCl 2 ; (2) The soluble salts of cobalt include one or more of CoSO 4 、Co(NO 3 ) 2 、CoCl 2 ; (3) The soluble salts of aluminum include one or more of Al 2 (SO 4 ) 3 、Al(NO 3 ) 3 、AlCl 3 ; (4) The soluble salt of hafnium includes at least one of Hf (NO 3 ) 4 、HfOCl 2 ; (5) The chemical general formula of the hafnium-doped precursor in S1 is Ni x Co y Al z Hf w (OH) 2 , wherein x is more than or equal to 0.8 and less than or equal to 0.95,0.02 and y is more than or equal to 0.15, z is more than or equal to 0.01 and less than or equal to 0.05,0.002 and w is more than or equal to 0.01, and x+y+z+w=1.
  7. 7. The method for producing a modified high-nickel NCA positive electrode material according to claim 3, wherein said S2 satisfies at least one of the following conditions: (1) The ratio of the molar quantity of lithium element in the lithium source in the S2 to the total molar quantity of metal element in the hafnium doping precursor is (1.03-1.08): 1; (2) The presintering temperature in the step S2 is 400-600 ℃, and the presintering time is 3-5h; (3) The calcination temperature in the step S2 is 750-850 ℃ and the calcination time is 15-20h.
  8. 8. The method for preparing a modified high nickel NCA positive electrode material according to claim 3 or 7, wherein the copper salt in the copper-containing salt solution in S3 comprises one or more of CuSO 4 、Cu(NO 3 ) 2 、CuCl 2 , preferably CuSO 4 ; And/or the temperature of the first heat treatment in the step S3 is 350-550 ℃, and the time of the first heat treatment is 3-6h.
  9. 9. The method for producing a modified high-nickel NCA positive electrode material according to claim 3 or 7, wherein said S4 satisfies at least one of the following conditions: (1) The M source in the S4 comprises one or more of Al(NO 3 ) 3 、Al 2 (SO 4 ) 3 、AlCl 3 、Al(C 3 H 7 O) 3 、ZrOCl 2 、Zr(NO 3 ) 4 、 tetrabutyl titanate 、TiCl 4 、(NH 4 ) 2 HPO 4 、H 3 PO 4 、La(NO 3 ) 3 、LaCl 3 、La(CH 3 COO) 3 、La 2 (SO 4 ) 3 ; (2) The molar ratio of the M element in the M source in the S4 to the residual LiOH on the surface of the nickel cobalt lithium aluminate doped with the hafnium element is (2-2.4): 1; (3) The temperature of the second heat treatment in the step S4 is 450-600 ℃, and the time of the second heat treatment is 4-8h.
  10. 10. A lithium ion battery employing the modified high nickel NCA positive electrode material according to claim 1 or 2 or the modified high nickel NCA positive electrode material produced according to the production method of any one of claims 3 to 9.

Description

Modified high-nickel NCA positive electrode material and preparation method and application thereof Technical Field The invention relates to the technical field of lithium ion battery anode materials, in particular to a modified high-nickel NCA anode material, a preparation method and application thereof. Background The high-nickel NCA material (such as LiNi 0.88Co0.09Al0.03O2) is regarded as a core positive electrode material of the next-generation lithium ion battery due to high energy density (theoretical specific capacity can reach 274 mAh/g), and has wide application prospect in the fields of electric automobiles, energy storage systems and the like. However, the high nickel content also brings a series of technical challenges, namely firstly, high-activity Ni 4+ and electrolyte are easy to generate side reaction, so that surface residual lithium compounds (LiOH and Li 2CO3) are increased, gas generation and capacity attenuation are caused, secondly, H2-H3 phase transformation causes lattice contraction in the direction of the c axis in the charge and discharge process, microcracks are generated, the structure degradation is accelerated, and in addition, the cycle life and the safety are limited by cation mixing and interface instability. At present, in the modification strategy of the high-nickel NCA positive electrode material, the surface coating technology is widely used for isolating the electrolyte from direct contact with the surface of the material, so that the interface side reaction is inhibited, the residual lithium compound is reduced, and the structural stability is enhanced. However, although the conventional single component coating layer has a certain physical isolation effect and chemical stability, it is usually an electronic insulator or semiconductor, which hinders interfacial charge transfer, resulting in degradation of the rate performance of the battery. While some conductive polymers or carbon materials can improve electron conductivity, they lack promotion of lithium ion migration, and have poor structural stability and thermal expansion coefficient matching with high nickel matrix, which affects long cycle life of the battery. In addition, the element doping can enhance the stability of the crystal structure, but the problems can not be effectively solved, and the capacity and the multiplying power performance of the battery are still not improved enough when the battery is singly used. Therefore, developing a comprehensive modification scheme capable of improving the capacity, long cycle life and rate capability of high-nickel NCA materials is an urgent need for current research. Disclosure of Invention The invention provides a modified high-nickel NCA positive electrode material, a preparation method and application thereof, and has the characteristics of high capacity, long cycle life and excellent multiplying power performance. In a first aspect, the invention provides a modified high-nickel NCA positive electrode material, which comprises a core, a first coating layer and a second coating layer which are sequentially arranged from inside to outside; the core comprises nickel cobalt lithium aluminate doped with hafnium element; The first cladding layer comprises copper oxide; the second cladding layer includes a lithium fast ion conductor. In an alternative embodiment, the modified high nickel NCA positive electrode material satisfies at least one of the following conditions: (1) The mass of the first coating layer is 0.1-0.5 wt% of the mass of the inner core; (2) The mass of the second coating layer is 0.5-2 wt% of the sum of the mass of the first coating layer and the mass of the core; (3) The mole amount of hafnium in the hafnium-doped nickel cobalt lithium aluminate is 0.2% -1% of the total mole amount of hafnium, nickel, cobalt and aluminum in the hafnium-doped nickel cobalt lithium aluminate, the mole amount of nickel is 80% -95% of the total mole amount of hafnium, nickel, cobalt and aluminum in the hafnium-doped nickel cobalt lithium aluminate, the mole amount of cobalt is 2% -15% of the total mole amount of hafnium, nickel, cobalt and aluminum in the hafnium-doped nickel cobalt lithium aluminate, and the mole amount of aluminum is 1% -5% of the total mole amount of hafnium, nickel, cobalt and aluminum in the hafnium-doped nickel cobalt lithium aluminate; (4) The lithium fast ion conductor comprises one or more of LiAlO 2、Li2ZrO3、Li2TiO3、Li3PO4, lithium Lanthanum Zirconium Oxide (LLZO) and Lithium Lanthanum Titanate (LLTO). In a second aspect, the invention provides a preparation method of the modified high nickel NCA positive electrode material, which comprises the following steps: S1, preparing a mixed solution of soluble salts of nickel, cobalt, aluminum and hafnium according to stoichiometric ratio, reacting the mixed solution with a precipitator and a complexing agent, and controlling pH to be 10.5-11.5 to obtain a hafnium doped precursor; S2, mixing a hafnium