Preparation method for composite positive electrode material of lithium battery

Abstract

The invention specifically relates to a preparation method for a composite positive electrode material of a lithium battery, belonging to the technical field of preparation of positive electrode materials of lithium batteries. According to the invention, a nitrogen-containing carbon source is added in situ, so the carbon source containing a non-metal element is added during the preparation of a LiFePO4 material; and after heat treatment, a non-metal doped carbon-coated LiFePO4 composite material is formed. Hydrolysis and precipitation of a titanium source provide an alkaline environment for the polymerization of dopamine, avoid the use of a Tris buffer and prevent troubles caused by centrifugal separation after a reaction and product loss during the centrifugation of products. While polymerization of dopamine without Tris is realized, TiO2 nanoparticles are introduced onto the surface of LiFePO4, and the introduction of TiO2 into the system is beneficial for improving the stability ofthe composite material. The preparation method provided by the invention ensures excellent performance of the prepared material and is simple in preparation process, low in cost and free of product loss.

Description

technical field [0001] The invention relates to the technical field of preparation of lithium ion battery electrode materials, in particular to a preparation method of a lithium battery cathode composite material. Background technique [0002] Since the work of Goodenough and colleagues in 1997, olivine-type lithium iron phosphate (LiFePO 4 , LFP) have been extensively and intensively studied as cathode materials for lithium batteries. In addition, LiFePO 4 Due to its low cost of starting materials, high theoretical capacity (170mAh / g), suitable working voltage (3.4V vs. Li + / Li), long cycle stability and non-toxicity and many other attractive advantages, and achieved great commercial success. Despite these advantages, pure LiFePO 4 At low conductivity (~10 -9 S / cm) and Li + Inherent defects such as slow diffusion limit its further application and development. [0003] To overcome these defects, LiFePO can be 4 Combined with highly conductive carbonaceous materials ...

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Problems solved by technology

[0006] Aiming at the problems or deficiencies in the prior art, in order to overcome the complex preparation process of the existing LFP lithium battery positive electrode material and the problem of the inevitable loss of the obtained product, the present invention provides a method for preparing a lithium battery positive electrode composite material. Composite material is TiO 2 LiFePO co-coated with nitrogen-doped carbon 4

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