Preparation method of LiNixCoyMnl-x-yO2 cathode material for lithium ion battery

Abstract

The invention discloses a preparation method of a LiNixCoyMnl-x-yO2 cathode material for a lithium ion battery. A NixCoyMnl-x-yCO3 precursor is prepared by adopting a solvent/hydrothermal method, wherein urea is utilized as a complexing agent, so as to avoid a phenomenon of segregation of transition metal ions, and ensure uniform precipitation of the transition metal ions, then by thoroughly mixing with a lithium source, LiNixCoyMnl-x-yO2 is prepared by utilizing a high-temperature solid phase method, and then the conductivity is improved by adding carbon fiber, thereby improving the rate performance of the LiNixCoyMnl-x-yO2 cathode material. The LiNixCoyMnl-x-yO2 cathode material obtained by the preparation method disclosed by the invention has relatively high specific capacity, good large rate performance and excellent cycle performance, and can be applied to various fields such as portable electronic devices, electric vehicles and energy storage equipment.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery LiNi x co y mn l-x-y o 2 Preparation method of cathode material. Background technique [0002] Since my country is a country with a large population and energy shortage, the per capita resource is small, the energy situation is very severe, and the energy problem is facing serious challenges. And when fossil fuels are burned, they will release a lot of harmful gases and dust, which has become one of the sources of environmental pollution in our country. All of these require people to improve the utilization of resources and develop clean and renewable new energy sources, among which lithium-ion batteries are one of the effective ways to achieve this goal, thus promoting the commercial application of lithium-ion batteries. With the continuous improvement of the performance of lithium-ion batteries, it has been applied in 3C electronic produ...

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Problems solved by technology

where due to Mn(OH) 2 It is easily oxidized to trivalent MnOOH in aqueous solution, and even oxidized to tetravalent MnO 2 , resulting in uneven components of the precursor, leading to the formation of impurity phases in the obtained material after the heat treatment process, affecting the electrochemical performance of the synthesized material

When the precursor is prepared by the carbonate co-precipitation method, all the metal ions in the precursor exist in the form of stable carbonate, but the solubility product constants of the three metal ions carbonates of Ni, Mn and Co are quite different. , will inevitably lead to the precipitation of metal ions with small solubility products first, resulting in component segregation

[0004] Since the energy density of the battery is limited by the inherent properties of the active material, it is also affected by external factors, such as the low lithium ion conductivity due to poor wettability of the electrolyte. If the thickness of the positive electrode sheet is large, it will cause The conduction of electrons from the current collector (bottom) to the positive electrode sheet (top layer) is slow, which will affect the rate performance of the material. Therefore, in order to improve the rate performance of the material, researchers have added single-layer carbon nanotubes and graphene, etc., but these will affect the rate performance of the material. Seriously increase production costs

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