Cobalt-free positive electrode material, preparation method thereof and lithium ion battery

Abstract

The invention discloses a cobalt-free positive electrode material, a preparation method thereof and a lithium ion battery. The molecular formula of the cobalt-free positive electrode material is Li1 + nNixMnyMzO2, wherein x + y + z = 1, 0.5 < = x < 1.0, 0 < y < 0.5, 0 < = z < = 0.1,-0.1 < = n < = 0.5; m is one or more of Al, Mg, Sr, Ti, Fe, Sc, V, Y, Zr, Nb and Mo except Co. The preparation method comprises the following steps: mixing raw materials including a nickel source, a manganese source, a lithium source, an M source, a nucleating agent graphene oxide hydrogel, a precipitator and a complexing agent to prepare a mixed solution, and applying a microwave field in the hydrothermal process of the raw material mixed solution; performing hydrothermal reaction in a protective atmosphere to obtain a positive electrode material process sample; and sintering the process sample in an oxygen-containing atmosphere to obtain the cobalt-free positive electrode material. According to the preparation method, the material performance is improved by regulating and controlling the microstructure and optimizing the preparation process, meanwhile, the cost is saved, and the manufacturing process is simplified; the lithium battery prepared from the cobalt-free positive electrode material has excellent chemical stability and electrical performance.

Description

technical field [0001] The invention relates to a positive electrode material, in particular to a cobalt-free positive electrode material and a preparation method thereof and a lithium ion battery, and belongs to the technical field of cobalt-free positive electrode materials for lithium ion batteries. [0002] technical background [0003] As a new type of "green" battery, lithium-ion batteries have been widely used in more and more fields due to their superior performance. With the rapid development of lithium-ion batteries, they also face more challenges. With the continuous development of technology in various fields, the original lithium-ion battery system can no longer meet its needs. Therefore, according to the requirements of different fields, researching lithium-ion batteries with different performance is the key work of future researchers. [0004] The accelerated development and wide application of lithium-ion batteries, coupled with the rising price of raw materi...

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Problems solved by technology

[0005] However, the decobaltization of layered positive electrode materials will lead to the following problems: (1) defects such as poor electronic conductivity and slow lithium ion migration speed seriously affect its capacity and cycle stability; (2) large internal resistance leads to Poor low-temperature electrical properties; (3) The variability of the valence state of manganese ions and the refractory oxidation of divalent nickel ions lead to serious mixed discharge of lithium and nickel; (4) The large difference in normal and high-voltage capacity makes it difficult to apply, etc.

[0006] In the prior art, the commonly used method for synthesizing cobalt-free cathode materials is the solid phase method, through doping, coating and other means, but it increases the cost and cumbersome operation process, and researchers usually only pay attention to the raw materials, while ignoring the microscopic research

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