Ternary Cathode Surface Coating for Residual Lithium and Micro Powder
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Solution Overview
Problem
The preparation process of ternary cathode materials for lithium ion batteries results in high micro powder content and surface defects, leading to uneven coating and reduced battery capacity, which affects the safety and endurance of electric vehicles.
Innovation Solution
A nano-scale coating agent is uniformly dispersed in a solvent to react with niobium, boron, or titanium compounds, depositing micro powder into crystal defect positions and consuming residual lithium to form lithium niobate, lithium borate, or lithium titanate, thereby reducing micro powder and surface defects, improving the material's cycle and rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional preparation process is used, then production efficiency is maintained, but micro powder content and surface defects increase significantly
Solution Approach 1:
The patent applies preliminary action by performing a coating treatment on the ternary cathode material surface before the material is fully processed. The coating agent is applied to the surface of the calcined material to prevent micro powder formation and surface defects during subsequent crushing and processing operations, thereby improving surface quality without significantly reducing production efficiency
Solution Approach 2:
The patent changes the surface parameters of the cathode material by introducing a coating layer with specific chemical composition (containing Al, Si, P, S, or B elements). This coating layer modifies the surface properties to reduce micro powder generation and improve surface quality while maintaining the bulk material properties and production efficiency
2Manufacturing precision
If crushing process is intensified to improve particle size distribution, then D50 and K90 values improve, but micro powder content increases significantly
Solution Approach 1:
The patent converts the harmful effect of crushing (which generates micro powder) into a beneficial process by using the crushing operation to distribute and embed micro powder into crystal defect positions on the material surface. The coating layer prevents this micro powder from becoming loose contaminants, thereby improving particle size distribution while controlling micro powder content
3Stability of the object's composition
If residual lithium is not removed, then material composition is maintained, but slurry mixing and electrode coating become difficult
Solution Approach 1:
The patent extracts excess residual lithium from the cathode material surface by reacting it with the coating agent. The coating layer selectively removes surface lithium that would otherwise cause slurry gelation and coating defects, while maintaining the bulk material composition and enabling smooth slurry mixing and electrode coating processes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method significantly reduces micro powder and residual lithium content, facilitating easier electrode preparation and enhancing the cycle and rate performance of the ternary cathode material, leading to improved battery performance and safety.
Implementation Method 1
a reaction of a niobium compound, a boron compound and a titanium compound with the residual lithium on the surface of the ternary material is introduced by calcinating
Implementation Method 2
a nano-scale coating agent is uniformly dispersed in a solvent by stirring so as to contact with the surface of a ternary material evenly
Implementation Method 3
micro powder of the ternary material deposits into the crystal defect position on the surface of the ternary material
Data Source
AI summary
Disclosed are a ternary cathode material and a preparation method and application thereof. The ternary cathode material has a chemical formula of LiNix CoyMn(1-x-y)MO2, wherein 0.5≤x≤1, y≥0, M is at least one selected from the group of niobium, boron and titanium. In the present disclosure, through the reaction between the niobium compound, the boron compound or the titanium compound with the residual lithium on the surface of the calcinated materials, the micro powder deposits in the defect position of the lithium crystal lattice on the surface of the calcinated material, so that the content of the micro powder can be greatly reduced. Meanwhile part of the surface residual lithium is consumed by the reaction to generate lithium niobate, lithium borate or lithium titanate which is uniformly coated on the surface of the material, thereby obtaining the ternary cathode material with excellent cycle and rate performance.