Agglomeration-like multi-element cathode material, preparation method therefor, and lithium-ion battery
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Solution Overview
Problem
Existing ternary cathode materials struggle to balance energy density, rate capability, and cycle stability simultaneously due to structural limitations and weak binding forces between primary particles.
Innovation Solution
An agglomeration-like multi-element cathode material with a structure represented by LiaNixCoyMnzMbO2 is developed, where primary particles are spherical and tightly stacked with strong binding forces, forming secondary particles with improved structural stability and electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a ternary cathode material is designed with high energy density, then the energy density is improved, but the cycle stability deteriorates
Solution Approach 1:
The cathode material is divided into primary particles (0.5-2.0 μm) that aggregate into secondary particles (5-15 μm), creating a hierarchical structure. This segmentation allows the material to maintain high energy density through optimized composition while improving cycle stability through the structural hierarchy that reduces stress concentration during cycling.
Solution Approach 2:
The patent uses a multi-element cathode material with composition LiaNixCoyMnzMbO2, combining multiple elements to create a composite structure. This composite approach enables simultaneous optimization of energy density (through nickel content) and cycle stability (through manganese and protective elements), resolving the contradiction between these two performance parameters.
2Reliability
If a ternary cathode material is designed with good cycle stability, then the cycle stability is improved, but the rate capability deteriorates
Solution Approach 1:
The hierarchical particle structure with primary particles (0.5-2.0 μm) aggregated into secondary particles (5-15 μm) creates multiple pathways for ion transport. This segmentation maintains cycle stability through structural integrity while improving rate capability by reducing diffusion distances and increasing surface area for electrochemical reactions.
Solution Approach 2:
The patent optimizes the composition locally within the particle structure, with element distribution that enhances both cycle stability in the bulk and rate capability at the surfaces. The local quality variation allows different regions to serve different functions, resolving the contradiction between stability and rate performance.
3Use of energy by moving object
If a ternary cathode material is designed with high energy density, then the energy density is improved, but the structural stability deteriorates
Solution Approach 1:
The hierarchical structure divides the material into primary particles (0.5-2.0 μm) and secondary particles (5-15 μm), allowing high energy density through optimized composition while maintaining structural stability through the hierarchical architecture that distributes mechanical stress and prevents catastrophic failure.
Solution Approach 2:
The multi-element composite composition LiaNixCoyMnzMbO2 combines elements with different properties to achieve high energy density while the composite structure provides structural stability. The interaction between different elements creates a synergistic effect that maintains structural integrity under operational conditions.
4Speed
If primary particles are tightly stacked to form aggregates, then the rate capability is improved, but the cycle performance deteriorates
Solution Approach 1:
The patent creates a controlled hierarchical structure where primary particles (0.5-2.0 μm) are aggregated into secondary particles (5-15 μm) with a specific DL/DS ratio of 5-16. This segmentation maintains rate capability through tight stacking while improving cycle performance by creating a hierarchical structure that reduces stress concentration and prevents particle disintegration during cycling.
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 agglomeration-like cathode material achieves a balance between energy density, rate capability, and cycle stability, with enhanced compressive strength, improved rate and cycle performances, and increased energy density due to tighter particle stacking and uniform coating layers.
Implementation Method 1
mixing the nickel cobalt manganese ternary precursor and a lithium source for first high-temperature sintering
Implementation Method 2
mixing a nickel source, a first cobalt source, a manganese source, a complexing agent and a precipitant for co-precipitation reaction
Data Source
AI summary
Provided are an agglomeration-like multi-element cathode material, a preparation method therefor, a use thereof, and a lithium-ion battery. The chemical formula of the agglomeration-like multi-element cathode material is LiaNixCoyMnzMbO2, wherein 0.9≤a≤1.1, 0.5≤x<1, 0<y<0.5, 0<z<0.5, and 0≤b<0.05; and M is at least one of V, Ta, Cr, La, Al, Ce, Er, Ho, Y, Mg, Sr, Ba, Ra, Zr, Fe, Ca, Zn, B, W, Nb, Cd, Pb, Si, Mo, Cu, Sr, and Ti. The multi-element cathode material is secondary particles formed by agglomeration of primary particles. The primary particles are spherical or spherical-like and have an average particle size DS ranging from 0.9 to 2.4 μm. The secondary particles have an average particle size DL ranging from 5 to 15 μm. A value of DL/DS ranges from 5 to 16. The agglomeration-like multi-element cathode material has high energy density, good rate capability, and excellent cycle stability.