Composite Cathode Shell for Stable High-Nickel Lithium Batteries
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Solution Overview
Problem
Nickel-based cathode active materials in lithium batteries suffer from poor lifetime characteristics and poor thermal stability due to side reactions, necessitating a method to prevent or reduce battery performance deterioration.
Innovation Solution
A composite cathode active material is developed, comprising a core of lithium transition metal oxide coated with a shell of first and second metal oxides and a carbonaceous material, where the first metal oxide is embedded in a carbonaceous matrix, effectively blocking electrolyte contact and reducing side reactions, while maintaining high nickel content for capacity.
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 battery energy density is improved, but lifetime characteristics and thermal stability deteriorate due to side reactions
Solution Approach 1:
A shell layer comprising a first metal oxide and carbonaceous material is introduced as an intermediary between the nickel-based cathode active material and the electrolyte. This shell layer suppresses side reactions between the nickel-based material and the electrolyte, thereby improving lifetime characteristics and thermal stability while maintaining high capacity. The shell acts as a protective barrier that prevents direct contact and harmful interactions.
Solution Approach 2:
The cathode active material is designed as a composite structure consisting of a core (nickel-based cathode active material) and a shell (first metal oxide and carbonaceous material). This composite structure combines the high capacity benefits of nickel-based materials with the protective and stabilizing properties of the shell layer, achieving both high energy density and improved reliability.
2Use of energy by moving object
If nickel-based cathode active materials are used to achieve high capacity, then battery energy density is improved, but thermal stability deteriorates
Solution Approach 1:
The shell layer comprising first metal oxide and carbonaceous material serves as a thermal barrier and protective intermediary. It reduces direct thermal exposure and chemical reactions at elevated temperatures, thereby improving thermal stability while allowing the high-capacity nickel-based core to maintain its energy density advantages.
Solution Approach 2:
The carbonaceous material in the shell layer creates a chemically inert environment around the nickel-based cathode active material, preventing oxidative reactions and other thermally-driven side reactions. This inert barrier enhances thermal stability without compromising the electrochemical performance and energy density of the battery.
3Reliability
If a shell layer comprising first metal oxide and carbonaceous material is formed to suppress side reactions, then lifetime characteristics are improved, but internal resistance increases
Solution Approach 1:
The shell layer is designed with specific local properties: the first metal oxide provides chemical stability and interface protection, while the carbonaceous material provides electrical conductivity. By combining materials with complementary local qualities, the shell suppresses side reactions and improves lifetime characteristics while minimizing the increase in internal resistance through the conductive carbon component.
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 enhances cycle characteristics and thermal stability, providing improved discharge capacity and lifetime performance by suppressing nickel ion reduction and resistance layer formation.
Implementation Method 1
a shell disposed on and conformed to a surface of the core, wherein the shell includes at least one first metal oxide and carbonaceous material... capable of preventing or reducing the deterioration of battery performance by suppressing or reducing the side reactions
Implementation Method 2
The composite cathode active material improves cycle characteristics and high-temperature stability of lithium batteries by reducing internal resistance
Data Source
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AI summary
A composite cathode active material includes: a core including a lithium transition metal oxide; and a shell on and conforming to a surface of the core, wherein the shell includes at least one first metal oxide represented by Formula MaOb (wherein, 0<a≤53, 0<b<4, and when a is 1, 2, or 3, b is not an integer), and a carbonaceous material, the first metal oxide is within a carbonaceous material matrix, M is at least one metal selected from groups 2 to 13, group 15, and group 16 of the periodic table of elements, the lithium transition metal oxide contains nickel, and the content of nickel is about 80 mol% or more based on the total moles of transition metals in the lithium transition metal oxide.