Lithium Ion Cathode Material Segmentation for Cycle Stability
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Solution Overview
Problem
Current lithium ion battery cathode materials face challenges in maintaining cycle performance and stability under high temperature and high voltage conditions due to the destruction of doping layers and agglomeration of primary particles, leading to increased internal resistance and rapid decay.
Innovation Solution
A lithium ion battery cathode material composed of secondary particles agglomerated by 10 or less primary spherical single crystal particles, with an area percentage of greater than 80% for particles agglomerated by 10 or less and less than 20% for particles agglomerated by more than 10, formulated as LiaNixCoyMnzMbO2, where 1.0≤a≤1.2; 0.00≤b≤0.05; 0.30≤x≤0.60; 0.10≤y≤0.40; 0.15≤z≤0.30, and M elements include Mg, Ti, Al, Zr, Y, W, Mn, Ba, and rare earth elements, prepared through a method involving mixing lithium, nickel cobalt manganese precursors, and M sources at specific molar ratios, followed by calcination and crushing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If secondary spherical particles are used as cathode material, then mass production is feasible, but the particles are easily broken during coating and cold pressing, destroying the doping layer and leading to high-temperature storage swelling and poor cycle performance
Solution Approach 1:
The cathode material is segmented into primary particles (5-20 μm) that aggregate into secondary particles (10-30 μm). This segmentation allows the primary particles to maintain structural integrity while the secondary particles enable feasible mass production and coating processes
Solution Approach 2:
The cathode material uses a composite structure where primary particles are doped with elements (Al, Ti, Zr, Y, Ba, or rare earth elements) to form a protective layer, creating a composite material that combines the benefits of mass producibility with enhanced structural stability and resistance to high-temperature storage swelling
2Quantity of substance
If high-temperature sintering is used to prepare cathode material, then density and capacity are improved, but primary particles agglomerate and separate during high-temperature cycling, increasing internal resistance and causing rapid capacity decay
Solution Approach 1:
The doping elements are introduced into the primary particles before the final sintering process. This preliminary doping action creates a protective structure that prevents particle aggregation and maintains structural stability during subsequent high-temperature cycling, avoiding increased internal resistance and rapid capacity decay
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 cathode material exhibits uniform morphology, good structural integrity, and excellent cycling performance, making it suitable for mass-scale production and applications in digital products, electric vehicles, and energy storage systems.
Implementation Method 1
the precursors were pre-calcined at high temperature to obtain nickel-cobalt-manganese oxide
Implementation Method 2
the nickel-cobalt-manganese oxide was sintered and coated to obtain the high voltage single crystal cathode material
Data Source
AI summary
The present invention relates to a lithium ion cathode material and a lithium ion battery. The chemical formula of the cathode material is: LiaNixCoyMnzMbO2, wherein 1.0≤a≤1.2; 0.00≤b≤0.05; 0.30≤x≤0.60; 0.10≤y≤0.40; 0.15≤z≤0.30; x+y+z=1; M is one or two or more selected from the group consisting of Mg, Ti, Al, Zr, Y, W, Mn, Ba and rare earth elements; wherein the scanning electron microscope observation shows that, the cathode material consists of secondary particles agglomerated by 10 or less primary single crystal particles and secondary particles agglomerated by more than 10 primary single crystal particles, and wherein, the area percentage of the secondary particles agglomerated by 10 or less primary single crystal particles is greater than 80%, and the area percentage of the secondary particles agglomerated by more than 10 primary single crystal particles is less than or equal to 20%. The lithium battery prepared by the cathode material of the present invention has good cycling performance, the preparation method thereof is simple, and can be conveniently and massively produced.