Lithium Complex Oxide Coating for Low-Residual-Lithium Cathodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium complex oxide secondary batteries face issues with residual lithium causing degradation, high temperature stability, and reduced battery lifetime due to unreacted LiOH and Li2CO3 on the surface of positive active materials, which also affect capacity and efficiency.
Innovation Solution
A lithium complex oxide with a specific crystalline structure and surface coating, where interplanar distances decrease from the center to the surface, and a Co-coated layer is applied to improve battery characteristics and reduce residual lithium, achieved through a method involving precursor manufacturing, thermal treatment, washing, and metal doping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LiOH and Li2CO3 are used as lithium compounds in the preparation process, then the manufacturing process is simplified and productivity is improved, but residual lithium remains on the surface causing degradation and high temperature instability
Solution Approach 1:
The patent applies preliminary action by conducting thermal treatment at 400-800°C for 0.5-10 hours before the washing step to pre-react and remove residual lithium compounds from the surface of the positive active material. This preliminary thermal treatment reduces residual lithium content to 100-1000 ppm, preventing subsequent degradation issues while maintaining the benefits of using LiOH and Li2CO3 as lithium sources.
2Reliability
If a washing process is executed to remove residual lithium, then residual lithium content is reduced, but the surface of the positive active material is damaged and characteristics of capacity and efficiency are degraded
Solution Approach 1:
The patent performs preliminary thermal treatment before washing to pre-remove residual lithium compounds through thermal decomposition and reaction. This preliminary action reduces the concentration of residual lithium to 100-1000 ppm, thereby minimizing the need for aggressive washing and protecting the surface integrity of the positive active material while still achieving effective residual lithium reduction.
Solution Approach 2:
The patent converts the potentially harmful thermal treatment process into a beneficial step by controlling the temperature (400-800°C) and duration (0.5-10 hours) to selectively remove residual lithium compounds without damaging the positive active material surface. The thermal treatment transforms residual lithium from a harmful contaminant into removable volatile products, protecting the material structure.
3Quantity of substance
If nickel content is increased to equal to or higher than 65% for cost reduction and capacity improvement, then manufacturing cost decreases and energy density increases, but residual lithium generation is significantly increased causing gelation and high temperature instability
Solution Approach 1:
The patent applies preliminary thermal treatment at 400-800°C for 0.5-10 hours to pre-react and remove residual lithium compounds generated during the synthesis of high-nickel positive active materials. This preliminary action converts residual lithium from LiOH and Li2CO3 into removable forms, reducing residual lithium content to 100-1000 ppm before washing, thereby preventing gelation and high temperature instability even when nickel content is 65% or higher.
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 solution enhances battery capacity, resistance, and lifetime by reducing residual lithium, improving the hexagonal structure and ion pathway efficiency, and maintaining high temperature stability.
Implementation Method 1
baking the mixture
Implementation Method 2
unreacted LiOH and Li2CO3 generate gas
Implementation Method 3
coating different elements on the surface
Data Source
AI summary
A lithium complex oxide and method of manufacturing the same, more particularly, a lithium complex oxide effective in improving the characteristics of capacity, resistance, and lifetime with reduced residual lithium and with different interplanar distances of crystalline structure between a primary particle locating in an internal part of secondary particle and a primary particle locating on the surface part of the secondary particle, and a method of preparing the same.