Nickel-Rich Composite Oxide Cathode With Dual Particle Sintering Strategy
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Solution Overview
Problem
The existing methods for manufacturing lithium metal composite oxides with a mixture of large and small secondary particles result in excessive or incomplete sintering, leading to reduced performance and increased costs due to multiple heat treatment processes, complicating the preparation of positive electrodes for lithium secondary batteries.
Innovation Solution
A method involving the concurrent heat-treatment of large-particle and small-particle nickel-based lithium metal composite oxide precursors with a lithium precursor, controlling particle sizes and nickel contents within specific ranges to achieve improved structural stability and energy density, thereby simplifying the manufacturing process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If large secondary particles and small secondary particles are heat-treated at the same time, then the heat treatment process is simplified, but the particles are excessively sintered or incompletely sintered, deteriorating performance
Solution Approach 1:
The heat treatment process is segmented into two distinct stages: first heat-treating large secondary particles separately, then heat-treating small secondary particles separately. This segmentation allows each particle size to receive optimized heat treatment conditions, preventing excessive or incomplete sintering while maintaining manageable process complexity through systematic separation of operations.
2Manufacturing precision
If large secondary particles and small secondary particles are separately heat-treated, then sintering quality is improved, but the preparation process becomes complicated and costs increase
Solution Approach 1:
The separately heat-treated large secondary particles and small secondary particles are merged into a mixed secondary particles composition. This merging combines the benefits of separate heat treatment (optimized sintering quality for each particle size) with the advantage of a unified final product, eliminating the need for separate handling in subsequent processes while maintaining high manufacturing precision.
3Manufacturing precision
If multiple heat treatment processes are performed, then particle sintering quality is improved, but preparation costs and process time increase
Solution Approach 1:
Large secondary particles are heat-treated in advance as a preliminary action before being mixed with small secondary particles. This preliminary heat treatment ensures that large particles achieve optimal sintering quality beforehand, so that when mixed with small particles, no additional heat treatment is needed for the large particles, thereby reducing total process time while maintaining high sintering quality.
4Quantity of substance
If nickel content in large secondary particles is increased, then energy density is improved, but structural stability may be compromised
Solution Approach 1:
Different nickel contents are applied locally to different particle sizes: large secondary particles have high nickel content (55-65 mol%) to maximize energy density, while small secondary particles have lower nickel content (45-55 mol%) to maintain structural stability. This local quality differentiation allows each particle size to optimize its properties for its specific function, achieving both high energy density and structural stability in the composite material.
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
This approach results in nickel-based lithium metal composite oxides with enhanced structural stability and energy density, leading to improved efficiency and lifetime of lithium secondary batteries.
Implementation Method 1
heat-treating the precursor mixture to obtain the aforementioned nickel-based lithium metal composite oxide
Implementation Method 2
large secondary particles or small secondary particles are excessively sintered or incompletely sintered when they are heat-treated at the same time
Data Source
AI summary
Disclosed herein are a nickel-based lithium metal composite oxide, a method of preparing the same, and a lithium secondary battery including a positive electrode including the same. The nickel-based lithium metal composite oxide includes secondary particles including aggregates of primary particles, wherein a content of nickel in the nickel-based lithium metal composite oxide is 50 mol % or more, based on the total content of transition metals in the nickel-based lithium metal composite oxide, the secondary particles include large secondary particles having a particle size of 10 μm or more and small secondary particles having a particle size of 5 μm or less, and the content of nickel in the large secondary particles is larger than the content of nickel in the small secondary particles.