Composite Positive Electrode Material Shell for Thermal Stability
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Solution Overview
Problem
Existing high-capacity composite positive active materials face issues with side reactions with electrolyte solutions and thermal stability, which are critical for achieving high energy density in lithium batteries.
Innovation Solution
A composite positive electrode active material is designed with a first lithium transition metal oxide core, a second lithium transition metal oxide core, and a shell composed of a first metal oxide in a carbon-based material matrix, featuring different particle diameters and crystal structures to enhance conductivity and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacity composite positive active materials are used to increase energy density, then the capacity and energy density are improved, but side reactions with electrolyte solution and thermal stability deteriorate
Solution Approach 1:
The patent applies composite materials by combining lithium transition metal oxide particles (providing high capacity) with metal oxide particles (providing thermal stability) in a carbon-based conductive matrix. This composite structure enables the positive electrode active material to simultaneously achieve high capacity and excellent thermal stability, resolving the contradiction between capacity improvement and thermal stability deterioration.
2Quantity of substance
If high-capacity composite positive active materials are used to increase energy density, then the capacity and energy density are improved, but side reactions with electrolyte solution worsen
Solution Approach 1:
The patent uses a carbon-based conductive material matrix as an intermediary between the lithium transition metal oxide particles and the electrolyte solution. This intermediary layer reduces direct contact and harmful side reactions between the high-capacity active material and the electrolyte, while maintaining electrical conductivity and enabling lithium ion transport.
3Reliability
If shell structure with metal oxide and carbon-based material is added to reduce side reactions, then thermal stability and conductivity are improved, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into a single integrated shell structure that simultaneously provides thermal stability (through metal oxide), electrical conductivity (through carbon-based material), and protection against side reactions. This unified approach achieves multiple benefits while minimizing structural complexity compared to separate layered coatings.
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 composite material reduces side reactions with electrolytes, improves conductivity, and enhances thermal stability, leading to improved cycle characteristics and energy density in lithium batteries.
Implementation Method 1
a shell (30) including a first metal oxide (31) in a first carbon-based material matrix (32)
Implementation Method 2
a composite positive electrode active material includes: a first core (10) including a first lithium transition metal oxide
Data Source
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AI summary
Provided are a composite positive electrode active material, a positive electrode including the same, and a lithium battery, the composite positive electrode active material including: a first core (1st core) including a first lithium transition metal oxide; a second core (2nd core) including a second lithium transition metal oxide; and a shell arranged over a surface of at least one of the first core and the second core, the shell including: at least one type of first metal oxide; and a first carbon-based material, wherein the at least one type of first metal oxide is arranged in a matrix of the first carbon-based material, the at least one type of first metal oxide is represented by a formula of MaOb (0<a≤3, 0<b<4, and b is not an integer when a is 1, 2, or 3), wherein M is at least one metal selected from Groups 2 to 13, 15, and 16 of the periodic table of the elements, the first lithium transition metal oxide and the second lithium transition metal oxide have different particle diameters, the first lithium transition metal oxide has a layered crystal structure and a nickel (Ni) content of 60 mol% or more, and the second lithium transition metal oxide has an olivine-based crystal structure.