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CN-116565176-B - Transition metal doped high nickel cobalt-free positive electrode material coated by mixed ion/electron conductor interface layer

CN116565176BCN 116565176 BCN116565176 BCN 116565176BCN-116565176-B

Abstract

A transition metal doped mixed ion/electron conductor interface layer coated high nickel cobalt-free positive electrode material has a chemical formula of Li a M b N c O d , wherein M is one of V, fe, ni, co, cu, N is one of Al, zr, sn, si, a is 1 or 2,0< b is less than or equal to 0.5,0.5 is less than or equal to c is less than or equal to 1, and 2 is less than or equal to d is less than or equal to 3. The invention reduces the formation of residual lithium on the surface of the high-nickel cobalt-free material. The problems of structural collapse and rapid capacity decay of the high-nickel cobalt-free positive electrode material in the electrochemical process are solved, and the obtained positive electrode material has good cycling stability and high reversible capacity.

Inventors

  • FAN XINMING
  • GUO XUEYI
  • TIAN QINGHUA

Assignees

  • 中南大学

Dates

Publication Date
20260505
Application Date
20230620

Claims (8)

  1. 1. The transition metal doped mixed ion/electron conductor interface layer coated high nickel cobalt-free positive electrode material is characterized in that the chemical formula of the transition metal doped mixed ion/electron conductor interface layer is Li a M b N c O d , wherein M is one of V, fe, co, cu, N is one of Al, zr, sn, si, a is 1 or 2,0< b is less than or equal to 0.5,0.5 is less than or equal to c is less than 1, and 2 is less than or equal to d is less than or equal to 3; The chemical formula of the high-nickel cobalt-free positive electrode material is LiNi x X 1-x O 2 , wherein X is one or two of Mn and Fe, and the range of X is more than or equal to 0.8 and less than or equal to 0.98, and the mol ratio of the transition metal doped mixed ion/electron conductor interface layer to the high-nickel cobalt-free positive electrode material is 0.01-0.08:1; the preparation method of the transition metal doped high-nickel cobalt-free positive electrode material coated by the mixed ion/electron conductor interface layer comprises the following steps: (1) Reacting a lithium source, an M source and an N source under high temperature and high pressure to obtain a Li a M b N c O d material; The high temperature and high pressure condition is that the temperature is 1200-1800 ℃ and the pressure is 1-2MPa; (2) Spraying the Li a M b N c O d material under the high-temperature and high-pressure condition in the step (1) onto a high-nickel cobalt-free positive electrode material precursor, and uniformly mixing to obtain a compound; the reaction in the step (1) is carried out by adopting a high-temperature high-pressure reaction kettle with a spray outlet at the bottom, and the spray is directly realized through the spray outlet after the reaction is finished; (3) Mixing the compound with a lithium source, sintering, and coating a high-nickel cobalt-free positive electrode material by a transition metal doped mixed ion/electron conductor interface layer; The adopted spray-reaction infiltration technology can introduce composite components to the surfaces of primary particles of the main body material, the modified layer can react with the base material through the reaction infiltration process, and the composite material is strongly compounded through chemical bonds, and the optimal compounding effect is achieved by combining a spray process.
  2. 2. The transition metal doped mixed ion/electron conductor interfacial layer coated high nickel cobalt-free cathode material according to claim 1, wherein in the step (1), the lithium source is one or more of lithium oxide, lithium hydroxide, lithium nitrate and lithium carbonate, the M source is one or more of V, fe, co, cu-containing oxide, nitrate, carbonate and acetate, the N source is one or more of Al, zr, sn, si-containing oxide, nitrate, carbonate and acetate, and the reaction time is 1-5h.
  3. 3. The transition metal doped mixed ionic/electronic conductor interfacial layer coated high nickel cobalt-free positive electrode material according to claim 1 or 2, wherein in step (2), the spray rate is 0.1-0.5L/s.
  4. 4. The transition metal doped mixed ion/electron conductor interfacial layer coated high nickel cobalt-free cathode material according to claim 1 or 2, wherein in step (3), the lithium source is one or more of lithium carbonate, lithium oxide and lithium acetate, the molar ratio of the lithium source to the high nickel cobalt-free cathode material precursor is 1.02-1.06:1, the sintering temperature is 900-1200 ℃, and the sintering time is 10-24h.
  5. 5. The transition metal doped mixed ion/electron conductor interfacial layer coated high nickel cobalt-free positive electrode material according to claim 1 or 2, wherein said high nickel cobalt-free positive electrode material precursor is Ni x X 1-x (OH) 2 .
  6. 6. The transition metal doped mixed ion/electron conductor interfacial layer coated high nickel cobalt-free positive electrode material according to claim 5, wherein said high nickel cobalt-free positive electrode material precursor is prepared by co-precipitation reaction of a metal ion solution containing nickel and X element in an inert atmosphere.
  7. 7. The transition metal doped mixed ion/electron conductor interface layer coated high nickel cobalt-free positive electrode material according to claim 6, wherein in the coprecipitation reaction, the nickel source is one or more of nickel nitrate, nickel sulfate and nickel acetate, the X source is one or more of manganese nitrate, manganese sulfate, manganese acetate, ferrous nitrate, ferrous sulfate and ferrous acetate, the complexing agent is ammonia water, and the precipitant is sodium hydroxide solution.
  8. 8. The transition metal doped mixed ion/electron conductor interface layer coated high nickel cobalt-free cathode material according to claim 7, wherein in the coprecipitation reaction, the concentration of the metal ion solution is 1-3mol/L, the concentration of the complexing agent is 15-25wt%, the concentration of the precipitant is 4-6mol/L, the pH value of the coprecipitation reaction solution is 10-12, and the coprecipitation reaction time is 30-60h.

Description

Transition metal doped high nickel cobalt-free positive electrode material coated by mixed ion/electron conductor interface layer Technical Field The invention relates to a high-nickel anode material coated by a mixed ion/electron conductor interface layer, in particular to a transition metal doped high-nickel anode material coated by a mixed ion/electron conductor interface layer. Background In recent years, with rapid development of new energy automobile industry, high energy density lithium ion batteries have become an important point of research on current power batteries, and development of positive electrode materials has been a key point of energy density improvement. The most widely studied positive electrode materials are currently mainly ternary materials. According to different proportions of nickel salt, cobalt salt and manganese (aluminum) salt, the nickel salt, cobalt salt and manganese (aluminum) salt are mainly divided into NCM333, NCM523, NCM622, NCM811, NCA and other models. In the ternary material cost composition, the cobalt material cost is relatively large. To reduce the cost of lithium batteries, positive electrode materials will be developed towards high nickel, low cobalt or no cobalt. Taking the current market product model as an example, the nickel content of the NCM523, the NCM622 to the NCM811 and the 9-series ternary materials under development is continuously improved, the cobalt content is always reduced, the dependence of the ternary materials on cobalt metal is effectively reduced while the energy density of the lithium battery is improved, and the requirements of reducing the cost of the lithium battery and the long endurance mileage of a new energy automobile are met. The high-nickel cobalt-free material has poor structural stability, and the problems of capacity, structure, circulation and the like of the material are solved by the surface modification technology such as cooperative compounding or doping. Disclosure of Invention The invention aims to solve the technical problem of overcoming the defects in the prior art and providing the transition metal doped mixed ion/electron conductor interface layer coated high-nickel cobalt-free anode material with good cycle stability. The technical scheme adopted by the invention for solving the technical problems is that the high-nickel cobalt-free positive electrode material is coated by a transition metal doped mixed ion/electron conductor interface layer, wherein the chemical formula of the transition metal doped mixed ion/electron conductor interface layer is Li aMbNcOd, M is one of V, fe, ni, co, cu, N is one of Al, zr, sn, si, a is 1 or 2,0< b < 0.5,0.5 < c <1,2 < d < 3. By adopting the technical scheme, the coating modified high-nickel cobalt-free anode material is obtained. Preferably, the chemical formula of the high-nickel cobalt-free positive electrode material is LiNi xX1-xO2, wherein X is one or two of Mn and Fe, and the range of X is more than or equal to 0.8 and less than or equal to 0.98. By adopting the technical scheme, the coating modified high-nickel cobalt-free anode material is obtained. Preferably, the mole ratio of the transition metal doped mixed ion/electron conductor interface layer to the high nickel cobalt-free cathode material is 0.01-0.08:1. By adopting the technical scheme, the coating modified high-nickel cobalt-free anode material is obtained. Preferably, the preparation method of the transition metal doped mixed ion/electron conductor interface layer coated high nickel cobalt-free positive electrode material comprises the following steps: (1) Reacting a lithium source, an M source and an N source under high temperature and high pressure to obtain a Li aMbNcOd material; (2) Spraying the Li aMbNcOd material under the high-temperature and high-pressure condition in the step (1) onto a high-nickel cobalt-free positive electrode material precursor, and uniformly mixing to obtain a compound; (3) And mixing the compound with a lithium source, sintering, and coating a high-nickel cobalt-free positive electrode material by a transition metal doped mixed ion/electron conductor interface layer. In order to ensure that the conditions of the Li aMbNcOd material used for spraying in the step (2) are consistent with the reaction conditions in the step (1), a high-temperature and high-pressure reaction kettle with a spraying outlet at the bottom can be adopted to carry out the reaction in the step (1), and after the reaction is finished, the spraying is directly realized through the spraying outlet, and other modes capable of ensuring the environment of the Li aMbNcOd material are also feasible. According to the technical scheme, the spray-reaction infiltration technology is adopted, the composite components can be introduced to the surfaces of primary particles of the main body material, the modified layer can react with the base material through the reaction infiltration process, the strong compounding is ca