Method for preparing lithium-enriched cathodic material of lithium ion battery

Abstract

The invention provides a method for preparing a lithium-enriched cathodic material Li[LixMnyM(1-x-y)]O2(0 is less than x, y is less than 0.5, M is equal Mn0.5Ni0.5 or Mnx'Niy'Co(1-x'-y'), 0 is less than x', y' is less than 0.5), which comprises the following steps of: preparing a stable precursor by a hydrothermal auxiliary oxalate coprecipitation method, so that divalent manganese (II) can be prevented from being oxidized by air in solution, and obtaining solid solution of which metal elements such as Ni, Co, Mn and the like are distributed uniformly in an atomic level, so that the prepared lithium-enriched cathodic material has the high electrochemical activity; and wrapping a layer of graphene material with high conductivity on the surface of the lithium-enriched material uniformly to improve the magnification performance and circular stable performance of the lithium-enriched material obviously. In the method, the reaction process is not needed to be protected by inert gases, so the reaction is simplified and the cost is saved; the prepared lithium-enriched cathodic material is uniform in granules and high in electrochemical activity, and has the specific capacity of more than 250 mAh / g; the magnification performance and circular stable performance of the product is high; and the preparation is high in process repeatability, and the fluctuation of the physico-chemical performance of materials prepared by different batches is small.

Description

Technical field: [0001] The invention belongs to the fields of preparation of chemical power source materials and cathode materials of lithium ion batteries, and relates to a method for preparing cathode materials of lithium ion batteries. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, long cycle life, light weight, and no pollution. They are a new generation of high-efficiency portable chemical power sources. Now it has been widely used in radio communications, digital cameras, notebook computers and space technology. With the further improvement of the energy density and power density of lithium-ion batteries, they will gradually be used in electric tools, electric bicycles, electric vehicles (EV), hybrid electric vehicles (HEV), and large-scale power storage. [0003] Cathode materials play a decisive role in the electrochemical performance, safety, and cost of lithium-ion power batteries, and their development has receive...

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Problems solved by technology

[0009] In addition, although lithium-rich materials Li[Li x mn y m (1-x-y) ]O 2 (00.5 Ni 0.5 or M=Mn x’ Ni y’ co (1-x’-y’) , 0<x', y'<0.5) have extremely high specific capacity, but domestic and foreign studies have shown that this type of material has the following problems: the inherent electronic conductivity and ionic conductivity of the material are not good, resulting in rate performance, high current Poor discharge performance; regarding the stability of material performance, there are great differences in the reports of different literatures; the components in the material are eroded by the electrolyte, resulting in poor cycle performance; the first charge and discharge efficiency of the material is low

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