Coated Lithium Cobalt Oxide Cathodes for High-Voltage Cycle Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face challenges in achieving high volumetric energy density and cycle life due to limitations in cathode active materials, particularly in maintaining stability at high voltages and preventing capacity fade.
Innovation Solution
Development of surface-modified lithium cobalt oxide materials with specific compositions, such as LiαCo1−xMxAlγOδ, where M is a transition metal, and coatings like Al2O3 or AlF3, which enhance the structural stability and prevent capacity fade by maintaining the α-NaFeO2 crystal structure during charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional lithium cobalt oxide materials are used to increase energy density, then volumetric energy density improves, but structural stability deteriorates at high voltages leading to capacity fade
Solution Approach 1:
The patent applies composite materials by combining lithium cobalt oxide with aluminum oxide and aluminum fluoride coatings to create a composite cathode material. The core lithium cobalt oxide provides high energy density while the coating layers provide structural stability and protection at high voltages, resolving the contradiction between energy density and reliability
Solution Approach 2:
The patent changes the chemical composition parameters of the cathode material by incorporating aluminum doping (LiαCo1−xMxAlγOδ) and applying aluminum oxide/fluoride coatings. These parameter changes enhance the material's structural stability and voltage retention, preventing capacity fade while maintaining high energy density
2Use of energy by moving object
If high voltage operation is implemented to increase energy density, then energy capacity improves, but capacity retention deteriorates due to structural degradation
Solution Approach 1:
The patent applies beforehand cushioning by pre-applying protective coatings of aluminum oxide and aluminum fluoride on the lithium cobalt oxide particles before battery assembly. These coatings act as a cushion that prevents structural degradation and capacity fade during high voltage cycling, thereby extending cycle life while maintaining energy capacity
Solution Approach 2:
The composite structure of coated lithium cobalt oxide particles provides both high energy capacity from the core material and extended cycle life through the protective coating layers that prevent structural degradation during repeated charge-discharge cycles at high voltages
Data Source
AI summary
Compounds, powders, and cathode active materials that can be used in lithium ion batteries are described herein. Methods of making such compounds, powders, and cathode active materials are described.