Carbon/conducting polymer coated ternary positive electrode material and preparation method thereof

Abstract

The invention discloses a carbon / conductive polymer coated ternary positive electrode material and a preparation method thereof, and belongs to the technical field of lithium ion positive electrode materials. The preparation method comprises the following steps of: putting a ternary positive electrode material into a plasma reaction furnace, performing vacuumizing, performing heating, introducing a carbon source and inert gas, and carrying out plasma treatment to obtain a carbon coated ternary positive electrode material; putting the carbon coated ternary positive electrode material into a mixed solution consisting of ammonia water, hydrogen peroxide and water, performing heating, stirring and dispersing, stopping stirring, continuing to carry out heat preservation reaction, performing washing, filtering and drying to obtain a surface-hydroxylated carbon-coated ternary positive electrode material; and dispersing the surface-hydroxylated carbon-coated ternary positive electrode material into a polar solvent containing a conductive polymer, performing heating, stirring for reaction, performing filtering, washing and drying to obtain the carbon / conductive polymer double-coated ternary positive electrode material. Through double-layer coating, the structural stability of the ternary positive electrode material is improved, the conductivity of the ternary positive electrode material is improved, and the rate and cycle performance are improved.

Description

technical field [0001] The invention relates to the technical field of lithium ion positive electrode materials, in particular to a carbon / conductive polymer-coated ternary positive electrode material and a preparation method thereof. Background technique [0002] The energy crisis and environmental protection issues have become two issues of great concern to people today, so it is advocated to vigorously develop new energy sources to solve the above problems. Lithium-ion batteries, as a kind of new energy and the main power of electric vehicles, have achieved rapid development. At present, higher requirements are put forward for the power density and energy density of lithium-ion batteries. The performance of cathode materials has an important impact on the performance of lithium-ion batteries. The existing ternary cathode materials have the advantages of large specific capacity (>250mAh / g), wide range of charge and discharge voltage, and low price, and are considered to...

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Problems solved by technology

Element doping is mainly metal cation and fluorine anion doping, which can enhance the structural stability of the material to a certain extent, but there is uneven doping, and the doping elements are distributed on the surface and bulk phase of the material particles, which is easy to form impurity phases. Doping cannot solve the oxygen evolution problem of the material under high voltage; the surface coating technology is to coat a protective layer on the surface of the lithium-rich ternary positive electrode material. The protective layer is electrochemically inert and can suppress the high voltage of the material to a certain extent. The structural collapse caused by charge and discharge can alleviate the corrosion of the electrode material by the electrolyte and improve the conductivity of the material. However, in the prior art, there is uneven coating, and the structural stability of the ternary cathode material is not significantly improved. Charging and discharging within the voltage range will lead to serious oxygen evolution of the material, reducing the capacity and structural stability. In addition, there are problems such as complicated process and large amount of toxic industrial wastewater.

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