Layered Cathode Precursor Composition for High-Nickel Battery Stability
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Solution Overview
Problem
Existing positive electrode active materials for lithium secondary batteries face challenges in achieving high capacity, life characteristics, and thermal stability, particularly with high-nickel lithium composite transition metal oxides that suffer from reduced structural stability and degraded long-term performance due to increased nickel content.
Innovation Solution
A positive electrode active material precursor is developed with a novel structure comprising distinct regions of nickel, cobalt, and manganese, prepared through sequential precipitation reactions, allowing controlled distribution of these metals to enhance crystalline size and mobility of lithium ions, thereby improving capacity and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-nickel lithium composite transition metal oxide is used to increase capacity, then large capacity is achieved, but structural stability is reduced and long-term lifetime and thermal stability are degraded
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the central core region contains high-nickel content (0.80≤x1<0.95) for high capacity, while the outer shell layer contains lower-nickel content (0.60≤x2<0.80) for structural stability. This spatial differentiation of composition allows each region to perform its optimal function without compromising the other.
Solution Approach 2:
The patent uses composite materials by combining nickel-rich and nickel-poor phases in a core-shell architecture. The composite structure integrates the high-capacity advantage of nickel-rich materials with the structural stability of nickel-poor materials, achieving both high capacity and improved stability simultaneously.
2Quantity of substance
If high-nickel lithium composite transition metal oxide is used to increase capacity, then large capacity is achieved, but thermal stability is degraded
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the central core region contains high-nickel content (0.80≤x1<0.95) for high capacity, while the outer shell layer contains lower-nickel content (0.60≤x2<0.80) for structural stability. This spatial differentiation of composition allows each region to perform its optimal function without compromising the other.
Solution Approach 2:
The patent applies beforehand cushioning by introducing a protective shell layer around the high-nickel core before the material is subjected to thermal stress. This shell layer acts as a buffer that prevents direct exposure of the unstable high-nickel core to thermal degradation, thereby maintaining thermal stability while preserving high capacity.
3Ease of manufacture
If uniform distribution of nickel, cobalt, and manganese is used in the positive electrode active material, then manufacturing is simplified, but capacity characteristics and life characteristics are not optimized
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the central core region contains high-nickel content (0.80≤x1<0.95) for high capacity, while the outer shell layer contains lower-nickel content (0.60≤x2<0.80) for structural stability. This spatial differentiation of composition allows each region to perform its optimal function without compromising the other.
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 precursor achieves excellent capacity and life characteristics by optimizing the distribution of nickel, cobalt, and manganese in different regions, enhancing lithium ion mobility and thermal stability, resulting in a positive electrode active material with improved performance.
Implementation Method 1
a first step of preparing a first metal solution containing M1 wherein M1 is nickel (Ni), cobalt (Co), or manganese (Mn); a second step of adding the first metal solution to a reaction vessel and performing a precipitation reaction to form a precipitate
Data Source
Figure 1
Figure 2(a)~2(f)
AI summary
The present invention relates to a positive electrode active material precursor, which has a composition represented by Formula 1 or Formula 2 and includes a first region formed in a center of a particle of the positive electrode active material precursor, wherein a molar ratio of M1 metal among total transition metals is 90 mol% or more, a second region formed on the first region, wherein a molar ratio of M2 metal among total transition metals is 90 mol% or more, and a third region formed on the second region, wherein a molar ratio of M3 metal among total transition metals is 90 mol% or more, and a method of preparing the same.