Composite Cathode Shell Coating for Stable High-Nickel 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 solution to prevent battery performance deterioration.
Innovation Solution
A composite cathode active material is developed, comprising a lithium transition metal oxide core coated with a shell of metal oxides and carbonaceous material, where the metal oxides are embedded in a carbonaceous matrix, forming a uniform and conductive layer that suppresses side reactions and enhances thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-based cathode active materials are used to achieve high capacity, then battery capacity is improved, but lifetime characteristics and thermal stability deteriorate due to side reactions
Solution Approach 1:
A shell comprising a first metal oxide and a carbonaceous material is introduced as an intermediary layer between the nickel-based cathode active material and the electrolyte. This shell prevents direct contact and side reactions while allowing lithium ion transport, thereby maintaining high capacity while improving lifetime characteristics and thermal stability
Solution Approach 2:
The cathode active material is constructed as a composite structure with a core-shell configuration, where the core contains the nickel-based cathode active material and the shell contains a first metal oxide embedded in a carbonaceous material matrix. This composite structure combines the high capacity of nickel-based materials with the protective and conductive properties of the shell
2Quantity of substance
If nickel-based cathode active materials are used to achieve high capacity, then battery capacity is improved, but thermal stability deteriorates due to side reactions
Solution Approach 1:
The shell acts as a thermal barrier and protective intermediary between the nickel-based cathode active material and the electrolyte, preventing side reactions that generate heat and improve thermal stability while maintaining high capacity
Solution Approach 2:
The carbonaceous material in the shell creates an inert environment around the nickel-based cathode active material, preventing oxidative side reactions and improving thermal stability while preserving the high capacity characteristics
3Reliability
If a shell is formed to suppress side reactions, then lifetime characteristics are improved, but internal resistance increases due to additional coating layers
Solution Approach 1:
A thin shell layer is formed on the surface of the cathode active material particles. The shell is thin enough to minimize resistance to lithium ion diffusion while being sufficiently continuous to suppress side reactions and improve lifetime characteristics
Solution Approach 2:
The shell comprises a carbonaceous material component that provides electrical conductivity, counteracting the insulating effect of oxide materials. This parameter optimization ensures the shell protects against side reactions while minimizing increases in internal resistance
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 improves the high-temperature and high-voltage cycle characteristics of lithium batteries by reducing resistance and preventing the deterioration of the lithium transition metal oxide core, thereby enhancing battery performance.
Implementation Method 1
the first metal oxide is embedded in a carbonaceous material matrix
Implementation Method 2
mechanically milling the lithium transition metal oxide and the composite
Data Source
Figure 1
AI summary
A composite cathode active material includes: a core including a lithium transition metal oxide; and a shell disposed on and conformal to a surface of the core, wherein the shell includes at least one first metal oxide represented by Formula MaOb (0<a≤3, 0<b<4, when a is 1, 2, or 3, b is not an integer), and a carbonaceous material, the first metal oxide is disposed within a matrix of the carbonaceous material, and M is at least one metal selected from Groups 2 to 13, Group 15, and Group 16 of the Periodic Table of Elements. A cathode may include the composite cathode active material, and a lithium battery may include the cathode. Further provided is a method of preparing the composite cathode active material.