Coated Cathode Active Material for High-Temperature Stability
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Solution Overview
Problem
Lithium metal oxide-based cathode active materials in lithium secondary batteries suffer from reduced lifespan and operational stability due to side reactions with the atmosphere and electrolyte, leading to the generation of by-products and structural instability.
Innovation Solution
A cathode active material is developed with a lithium-aluminum-titanium oxide coating on the surface of lithium metal oxide particles, formed through a process involving dry-mixing with Al2O3, TiO2, and optionally ZrO2 and H3BO3 under high temperature, enhancing structural stability and mechanical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal oxide is used as cathode active material to achieve high capacity and high output, then energy density and power are improved, but chemical stability and lifespan are deteriorated due to side reactions with atmosphere and electrolyte
Solution Approach 1:
A coating layer comprising aluminum oxide (Al2O3) and lithium aluminum oxide (LiAlO2) is formed on the surface of the lithium metal oxide particles. This coating layer acts as an intermediary barrier between the lithium metal oxide and the external environment (atmosphere and electrolyte), preventing direct contact and side reactions while allowing the underlying high-capacity material to function effectively.
2Quantity of substance
If lithium metal oxide is used to achieve high capacity, then energy storage capability is improved, but structural stability is deteriorated leading to reduced lifespan
Solution Approach 1:
The coating layer of aluminum oxide and lithium aluminum oxide serves as a protective intermediary that maintains structural stability. It prevents structural degradation and collapse of the lithium metal oxide particles during charging and discharging cycles, thereby extending the battery lifespan while preserving high capacity.
Solution Approach 2:
The cathode active material is designed as a composite structure with a lithium metal oxide core and an aluminum oxide/lithium aluminum oxide coating shell. This composite structure combines the high capacity characteristics of lithium metal oxide with the structural stability and protective properties of the oxide coating.
3Ease of operation
If lithium metal oxide contacts with electrolyte to enable electrochemical reactions, then battery operation is enabled, but by-products are generated reducing operational stability
Solution Approach 1:
The coating layer acts as a selective intermediary that allows necessary electrochemical reactions to occur while blocking harmful side reactions. It permits lithium ion transport for normal battery operation but prevents direct contact between lithium metal oxide and electrolyte components that would generate harmful by-products.
Solution Approach 2:
The coating process transforms the potential harm of direct lithium metal oxide-electrolyte contact into a benefit by creating a controlled interface. The coating layer itself becomes a stable, reactive component that enables operation while eliminating the generation of harmful by-products.
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 coated lithium-aluminum-titanium oxide improves the cathode's stability, particularly at high temperatures, extending the battery's lifespan and maintaining its structural integrity by preventing side reactions and penetration.
Implementation Method 1
a lithium-aluminum-titanium oxide coating on the surface of lithium metal oxide particles, formed through a process involving dry-mixing with Al2O3, TiO2, and optionally ZrO2 and H3BO3 under high temperature
Data Source
AI summary
A cathode active material for a lithium secondary battery includes a lithium-aluminum-titanium oxide formed on a surface of a lithium metal oxide particle having a specific formula. The cathode active material may have an improved structural stability even in a high temperature condition.