Phosphate-Coated Nickel-Rich Cathode for Uniform Lithium-Ion Performance
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Solution Overview
Problem
Existing lithium ion batteries face issues with non-uniform coating, structural instability, and reduced performance due to cationic disorder and excessive residual lithium, leading to poor rate performance and cycling stability in nickel-rich cathode materials.
Innovation Solution
A composite cathode material with a phosphate compound coating layer on the surface of active material, prepared using an atomizing coating process, enhances coating uniformity, improves particle hardness, and reduces impedance, thereby improving thermal stability and cycling stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If liquid phase coating method is used, then coating material can be applied to cathode material surface, but coating uniformity is poor and coating amount is difficult to control
Solution Approach 1:
The patent changes the physical state parameter of the coating process from liquid phase to solid phase. The coating material is prepared as solid particles with controlled size distribution (0.5-5 μm) and applied through dry mixing rather than liquid coating. This parameter change eliminates solvent-related uniformity issues and enables precise control of coating amount through mixing time and particle dosage.
Solution Approach 2:
The coating material is segmented into fine particles with specific size distribution (0.5-5 μm). This segmentation allows the coating material to uniformly distribute on the cathode material surface during dry mixing, improving coating uniformity while maintaining ease of application through simple mechanical mixing processes.
2Manufacturing precision
If solid phase coating is used, then coating uniformity improves, but excessive residual lithium remains affecting processing performance
Solution Approach 1:
The patent modifies the chemical composition parameters of the coating material by selecting metal phosphates without lithium content (such as AlPO4, FePO4, CoPO4) instead of lithium-containing phosphates. This parameter change eliminates excessive residual lithium while maintaining the protective and stabilizing functions of the coating layer.
Solution Approach 2:
The patent uses metal phosphates that form stable, inert coating layers which do not participate in harmful side reactions. These coating materials effectively passivate the surface without creating residual lithium issues, providing a clean and stable coating solution.
3Use of energy by moving object
If nickel-rich cathode material is used, then energy density increases, but particle cracking occurs after long cycle reducing stability
Solution Approach 1:
The patent creates a composite structure by coating nickel-rich cathode material particles with metal phosphate layers. This composite structure combines the high energy density advantage of nickel-rich materials with the structural stability and surface protection provided by the phosphate coating, preventing particle cracking during long-term cycling.
Solution Approach 2:
The metal phosphate coating is applied beforehand to the nickel-rich cathode material surface to provide protective cushioning. This pre-formed coating layer prevents direct exposure of the nickel-rich material to electrolyte and mechanical stress, thereby preventing particle cracking and maintaining structural integrity during cycling.
4Reliability
If coating layer is applied to improve thermal stability, then safety improves, but impedance increases reducing rate performance
Solution Approach 1:
The patent applies coating material with specific local properties - using metal phosphates that form thin, uniform layers with controlled thickness. This local quality approach provides thermal stability where needed while maintaining sufficient ionic conductivity, thus not significantly increasing impedance and preserving rate performance.
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 composite cathode material achieves low impedance, high rate performance, and excellent cycling stability, with improved particle hardness and uniform coating, facilitating better electrochemical performance and reduced production costs.
Implementation Method 1
the cathode material has a low impedance
Implementation Method 2
prepared using an atomizing coating process, enhances coating uniformity
Data Source
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AI summary
The present application relates to field of cathode material, and a cathode material and a method for preparing the same, a lithium ion battery provided, where the cathode material includes an active material having a chemical formula Lia(NixCoyRz)1-bMbO2, where 0.9≤a≤1.10, x+y+z=1, 0.8≤x≤0.99, 0≤y≤0.15, 0≤z≤0.1, 0≤b≤0.1; R includes Al and/or Mn, M includes a metal element; and a coating layer on surface of the active material, where the coating layer includes a phosphate compound; the cathode material has a particle hardness of Cs≥50 Mpa and satisfies the following: Cs10/Cs50≥0.7; where Cs10 is hardness of particles with a particle size D10, and CS50 is hardness of particles with a particle size D50. The cathode material and method for preparing the same, lithium ion battery provided, which improve coating uniformity, precisely control coating amount, improve rate and cycling performance of lithium ion battery, and reduce production costs.