Composite Oxide Cathode Surface Chemistry for High-Rate Li-Ion Output
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Solution Overview
Problem
Current methods for improving lithium secondary battery output characteristics have limitations and require further enhancement to achieve higher capacity and better performance.
Innovation Solution
A lithium-containing transition metal composite oxide is developed, represented by Formula Li[Lix(Ni(1−y−z−w)CoyMnzMw]O2, with specific conditions for secondary particle structure and composition, including X-ray photoelectron spectroscopy ratios, BET surface area, crystallite size, and particle size distribution, to enhance battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional methods for improving lithium secondary battery output characteristics are used, then some performance improvement is achieved, but the output characteristics and capacity cannot be sufficiently enhanced
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the surface region of secondary particles has a different composition and properties from the interior. Specifically, the surface has a higher Li content and different transition metal composition compared to the core, which optimizes surface reactivity for high output characteristics while maintaining a stable core for high capacity and cycle stability
Solution Approach 2:
The patent uses composite materials by combining multiple transition metals (Ni, Co, Mn) with lithium to create a composite oxide structure. The material Li[Lix(Ni(1-y-z-w)CoyMnzMw)1-x]O2 integrates different metallic elements with complementary properties: Ni for capacity, Co for conductivity and stability, and Mn for structural stability, achieving both high output characteristics and high capacity
2Power
If the surface composition of secondary particles is modified to improve output characteristics, then power performance increases, but manufacturing precision and control become more difficult
Solution Approach 1:
The patent applies preliminary action by pre-forming the core structure with appropriate transition metal composition before introducing lithium. The core structure Li[Lix(Ni(1-y-z-w)CoyMnzMw)1-x]O2 is prepared with controlled composition ratios, and then lithium is doped into the surface region through controlled heat treatment, achieving the desired surface composition without requiring complex multi-step manufacturing processes
Solution Approach 2:
The patent uses parameter changes by controlling the lithium content parameter x and transition metal ratios (y, z, w) within specific ranges to achieve the desired surface composition. By adjusting these compositional parameters and the heat treatment temperature, the surface Li content can be precisely controlled to optimize output characteristics while maintaining manufacturability
3Quantity of substance
If higher capacity is pursued to expand battery applications, then energy storage increases, but output characteristics and discharge rate performance deteriorate
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the surface region of secondary particles has a different composition and properties from the interior. Specifically, the surface has a higher Li content and different transition metal composition compared to the core, which optimizes surface reactivity for high output characteristics while maintaining a stable core for high capacity
Solution Approach 2:
The patent uses composite materials by combining multiple transition metals (Ni, Co, Mn) with lithium to create a composite oxide structure. The material Li[Lix(Ni(1-y-z-w)CoyMnzMw)1-x]O2 integrates different metallic elements with complementary properties: Ni for capacity, Co for conductivity and stability, and Mn for structural stability, achieving both high output characteristics and high capacity
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 solution provides a lithium secondary battery with improved output characteristics, high cycle stability, and efficient lithium insertion and desorption, leading to better discharge rate performance.
Implementation Method 1
secondary particles that are aggregate of primary particles into or from which lithium ions are dopable or dedopable
Implementation Method 2
when an area value of a peak appearing at 53.8 eV in a lithium 1s spectrum and an area value of a peak appearing at 529.0 eV in an oxygen 1s spectrum when X-ray photoelectron spectroscopy is performed
Data Source
AI summary
This lithium-containing transition metal composite oxide includes secondary particles that are aggregates of primary particles into or from which lithium ions are dopable or dedopable, and satisfies the following conditions:(1) the lithium-containing transition metal composite oxide is represented by Formula (I),Li[Lix(Ni(1−y−z−w)CoyMnzMw)1−x]O2 (I)(2) from X-ray photoelectron spectroscopy, a specific γ is calculated for each of the surface of the secondary particle and the inside of the secondary particle, and when the γ value of the surface of the secondary particle is referred to as γ1 and the γ value of the inside of the secondary particle is referred to as γ2, γ1 and γ2 satisfy the condition of Formula (II).0.3≤γ1/γ2≤1.0 (II).