Composite Cathode Shell Suppresses Side Reactions
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Solution Overview
Problem
Lithium batteries with nickel-based cathode active materials face issues of diminished lifetime and unsatisfactory thermal stability due to side reactions, leading to decreased performance and energy density.
Innovation Solution
A composite cathode active material is developed, comprising a first and second lithium transition metal oxide core with a carbonaceous material-based shell, where the shell includes a metal oxide represented by Formula MaOb and is used to suppress side reactions, improve ionic and electronic conductivity, and enhance thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nickel-based cathode active materials are used to achieve high capacity, then energy density is improved, but side reactions occur leading to diminished lifetime and unsatisfactory thermal stability
Solution Approach 1:
A shell comprising a metal oxide (Formula MaOb where 0 < a/b ≤ 0.5) is introduced as an intermediary layer between the nickel-based cathode active material and the electrolyte. This shell suppresses side reactions between the high-nickel cathode material and the electrolyte, thereby improving lifetime characteristics while maintaining the high energy density benefits of nickel-based materials.
Solution Approach 2:
The invention creates a composite structure consisting of a core (nickel-based cathode active material) and a shell (metal oxide with specific stoichiometry). This composite cathode active material combines the high capacity advantages of nickel-based materials with the stability benefits of the metal oxide shell, resolving the contradiction between energy density and reliability.
2Use of energy by moving object
If nickel-based cathode active materials are used to achieve high capacity, then energy density is improved, but thermal stability becomes unsatisfactory
Solution Approach 1:
The metal oxide shell acts as a thermal barrier and protective intermediary layer that enhances the thermal stability of the nickel-based cathode active material. The shell with Formula MaOb (0 < a/b ≤ 0.5) provides thermal protection while allowing the underlying high-nickel material to maintain its high energy density characteristics.
Solution Approach 2:
The composite structure of core (nickel-based material) and shell (metal oxide) combines materials with complementary properties - the nickel-based core provides high energy density while the metal oxide shell provides thermal stability, thereby resolving the contradiction between these two parameters.
3Reliability
If a shell is added to suppress side reactions, then lifetime characteristics are improved, but device complexity increases
Solution Approach 1:
A single shell layer comprising a metal oxide with Formula MaOb (0 < a/b ≤ 0.5) is used as the protective intermediary, rather than multiple complex coating layers. This simplified single-shell approach effectively suppresses side reactions and improves lifetime characteristics while minimizing the increase in device complexity.
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 cathode active material effectively reduces side reactions, improves cycle characteristics, and maintains energy density and thermal stability, leading to a longer battery lifespan and consistent performance.
Implementation Method 1
a shell along (e.g., around) a surface of at least one of the first core or the second core, wherein the shell includes a first metal oxide represented by Formula MaOb (0
Data Source
AI summary
A composite cathode active material, a cathode and a lithium battery including the composite cathode active material, and a preparation method of the composite cathode active material are provided. The composite cathode active material includes a first core including a first lithium transition metal oxide; a second core including a second lithium transition metal oxide; and a shell along a surface of at least one of the first core or the second core, wherein the shell includes a first metal oxide represented by Formula MaOb and a carbonaceous material, wherein the first metal oxide is within a carbonaceous metal matrix, the first lithium transition metal oxide and the second lithium transition metal oxide have a different particle size from each other, and the second lithium transition metal oxide includes a primary particle having a particle size of about 1 μm or more.