Positive electrode material and preparation method thereof, positive plate and lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a positive electrode material and a preparation method thereof, a positive plate and a lithium ion battery. The positive electrode material comprises a core and a coating shell coating the core, the core is vanadium-doped lithium cobalt oxide, and the coating shell is vanadium-doped lithium iron phosphate. The method comprises the following steps: step (A), dissolving a first lithium source, a cobalt source and a first vanadium source in deionized water according to a certain mass ratio, adding a chelating agent, adjusting the pH value, evaporating to form gel, and drying and sintering the gel to form vanadium-doped lithium cobalt oxide; step (B) adding the vanadium-doped lithium cobalt oxide, a second lithium source, an iron source, a phosphorus source and a second vanadium source into a reagent according to a certain mass ratio, mixing, adding into a microwave reactor, stirring, carrying out ultrasonic treatment, and heating to obtain a mixture; and step (C), washing the mixture, drying in vacuum, and calcining in vacuum to obtain the positive electrode material with a core-shell structure taking vanadium-doped lithium cobalt oxide as a core and vanadium-doped lithium iron phosphate as a coating shell.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a positive electrode material, a preparation method thereof, a positive electrode sheet and a lithium ion battery. Background technique [0002] As people's demand for electricity is increasing, the requirements for lithium-ion batteries are also increasing. How to achieve the same or higher capacity while reducing the volume of lithium batteries? That is, increasing energy density poses new challenges to lithium battery material developers! The development of high-voltage lithium-ion cathode materials is a promising direction in improving the energy density of lithium batteries, but currently high-voltage cathode materials are facing many limiting factors, such as electrolyte mismatch, material structure instability; The increase of the concentration will intensify the irreversible side reaction between the electrolyte and the positive electrode mater...

AI Technical Summary

Problems solved by technology

How to achieve the same or higher capacity while reducing the volume of lithium batteries? That is, increasing energy density poses new challenges to lithium battery material developers! The development of high-voltage lithium-ion cathode materials is a promising direction in improving the energy density of lithium batteries, but currently high-voltage cathode materials are facing many limiting factors, such as electrolyte mismatch, material structure instability; The increase of the concentration will intensify the irreversible side reaction between the electrolyte and the positive electrode material, resulting in a decrease in the electrolyte content and a change in the structure of the positive electrode material, which will ultimately affect the performance of the battery.

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