Lithium-Ion Cathode Particle Mix to Suppress NCM Micro-Cracks
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Solution Overview
Problem
High nickel content in NCM cathode materials for lithium-ion batteries leads to micro-cracks, reducing structural, thermal, and cycling stability, and compromising the battery's performance.
Innovation Solution
A cathode material comprising multicrystal particles and single or quasi single crystal particles, with specific diameter ratios, is prepared through a controlled sintering process, and coated with a conductive layer to enhance strength and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium nickelate is used as positive electrode material to achieve high output, then battery capacity increases, but material stability deteriorates and safety issues arise
Solution Approach 1:
The patent uses a core-shell composite structure where lithium nickelate (high capacity) forms the core and is coated with a layered oxide material (stable). This composite structure allows the battery to achieve high capacity from the lithium nickelate core while the stable layered oxide shell prevents material degradation and safety issues, resolving the contradiction between capacity and stability.
Solution Approach 2:
The patent applies different material properties to different regions: the inner core region uses lithium nickelate for high capacity, while the outer shell region uses stable layered oxide material for structural stability and safety. This spatial differentiation of material qualities allows simultaneous achievement of high capacity and stability.
2Reliability
If conventional coating methods are used to improve material stability, then safety improves, but coating uniformity deteriorates and aggregation occurs
Solution Approach 1:
The patent changes the coating parameters by controlling the concentration of coating solution (0.5-5 wt%), drying temperature (60-120°C), and drying time (1-10 minutes). These optimized parameters ensure uniform coating distribution without aggregation, achieving both stability and manufacturing precision.
Solution Approach 2:
The patent uses a slurry coating method where the coating material is dissolved in a solvent to create a uniform solution that can be evenly applied to the electrode. This solution-based approach creates a uniform coating layer that prevents aggregation and ensures consistent material distribution.
Data Source
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AI summary
The present disclosure relates to the technical field of secondary battery, and discloses a positive electrode material and a preparation method and use therefor, a lithium-ion battery positive electrode poly piece, and a lithium-ion battery. The positive electrode material comprises multicrystal particles A and single crystal particles or quasi single crystal particles B; the particle diameters D5, D50 and D95 of the cathode material satisfy the relationship shown in Formula I: 1.5≤K95=D95−D5/D50≤2.5 The positive electrode material comprises multicrystal particles A and single crystal particles or quasi single crystal particles B, whereby it can significantly suppress generation of micro-cracks in the cathode material, and enhance particle strength of the positive electrode material, so that the positive electrode material has a high compaction density and a high compressive strength, thereby ensuring that a battery comprising the positive electrode material has a high volumetric energy density and a relatively long cycle life.