Preparation method of cobalt-free lithium-rich positive electrode material modified by sulfur element

Modified cobalt-free lithium-rich cathode materials were prepared by mixing elemental sulfur with cobalt-free lithium-rich cathode material precursors via a hydrothermal method. This solved the problems of low coulombic efficiency and poor cycle stability of the materials, achieving high-efficiency electrochemical performance and a simple preparation process.

CN115477335BActive Publication Date: 2026-07-21OCEAN UNIV OF CHINA +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
OCEAN UNIV OF CHINA
Filing Date
2022-10-19
Publication Date
2026-07-21

AI Technical Summary

Technical Problem

Existing cobalt-free lithium-rich cathode materials suffer from irreversible electrochemical reactions in the first cycle, resulting in low coulombic efficiency, poor cycle stability, and insufficient rate performance, which cannot meet the requirements for long cycle life and high current discharge.

Method used

A modified cobalt-free lithium-rich cathode material was prepared by mixing elemental sulfur with a cobalt-free lithium-rich cathode material precursor using a hydrothermal method, followed by sulfur doping and sulfate coating, and high-temperature sintering. This improved the material's structural stability and electrochemical performance.

Benefits of technology

It significantly improves the cycle stability and rate performance of lithium-ion batteries, ensuring high discharge specific capacity even at high rates, simplifies the modification process, and reduces costs.

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Abstract

The application provides a preparation method of a cobalt-free lithium-rich positive electrode material modified by elemental sulfur. The main content of the preparation method comprises the following steps: a certain amount of Ni source and Mn source are dissolved in deionized water, and after ultrasonic treatment until the solution is clear and transparent, anhydrous ethanol containing dissolved elemental sulfur is added; a certain amount of carbonate is dissolved in deionized water as a precipitant, the above solution is poured into a hydrothermal reaction kettle, and hydrothermal reaction is carried out; the precursor material obtained after hydrothermal reaction is washed, filtered, and dried in an oven; the dried precursor is mixed with a certain proportion of lithium salt, ground, and then high-temperature sintering is carried out, so that the cobalt-free lithium-rich positive electrode material after doping is obtained. In the application, the addition of elemental sulfur makes a part of sulfur doped into the material crystal lattice, and another part of sulfur is coated on the particle surface in the form of a sulfate, so that the structure of the secondary particles is more compact, the cycle stability and the rate performance of the cobalt-free lithium-rich positive electrode material are significantly improved, and the problem of voltage attenuation is effectively alleviated.
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