Preparation method of high-capacity lithium-rich ternary positive electrode material

Abstract

The invention discloses a preparation method of a high-capacity lithium-rich ternary positive electrode material. The method comprises the following steps of weighing a lithium salt, a manganese salt,a cobalt salt and a nickel salt according to a stoichiometric ratio in a general formula zLi2MnO3.(1-z)LiMO2 and dissolving the weighed salts into deionized water to form a mixed salt solution; dissolving a chelating agent into the deionized water to form a chelating agent solution; slowly dropwise adding the chelating agent solution into the mixed salt solution in a back titration manner and mixing evenly; and adding an alkaline solution to adjust the pH value of the solution, heating the solution into a sol form in water bath, carrying out spray drying and then putting a product into a muffle furnace for sintering according to a certain sintering curve to obtain the high-capacity lithium-rich ternary positive electrode material, wherein z is smaller than 1 and greater than 0, M is MnxNiyCo(1-x-y), x is smaller than 1 and greater than 0 and y is smaller than or equal to 0.6 and greater than 0. The high-capacity lithium-rich ternary positive electrode material is prepared by using a one-step sol method; the preparation method is simple, mild, environment-friendly and efficient; and the synthetic product has relatively high specific capacity and relatively good rate capability.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for preparing a high-capacity lithium-rich ternary positive electrode material. Background technique [0002] Lithium-ion batteries have developed rapidly since their introduction in the 1990s, and currently occupy a dominant position in the secondary battery market. Lithium-ion battery cathode material is the most critical material in lithium-ion batteries, which has an important impact on the energy density, cycle life, and safety of lithium-ion batteries. In 1990, Sony introduced layered LiCoO 2 As a lithium-ion battery cathode material and successfully commercialized. Later, layered lithium nickel oxide, lithium manganese oxide, lithium iron phosphate, and nickel-cobalt lithium manganese oxide (ie, ternary materials) have all become common materials for lithium-ion batteries. Ternary materials are well-applied in new energy vehicles because of their ...

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Problems solved by technology

However, with the expansion of the application field of lithium-ion batteries, the application of pure electric vehicles requires batteries with high specific capacity (about 300Wh / kg), so there is an urgent need for materials with high specific characteristics, especially the positive electrode of lithium-ion batteries with high specific capacity materials, and the specific capacity of the above-mentioned commercial lithium-ion battery materials is lower than or close to 200mAh / g, which is difficult to meet the requirements

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