Lithium Complex Oxide Coating for Low-Residual Cathode Surfaces
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 are exacerbated by washing processes that damage the material and increase resistance.
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 the battery's capacity, resistance, and lifetime, reducing residual lithium through a method involving precursor manufacturing, thermal treatment, washing, and metal doping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a washing process is executed to remove unreacted Li, then residual lithium 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 applies a surface coating treatment before the washing process to protect the positive active material surface. The coating layer is formed in advance to prevent surface damage during subsequent washing operations, allowing effective removal of residual lithium while maintaining surface integrity and capacity characteristics.
Solution Approach 2:
The patent introduces a coating layer as an intermediary substance between the positive active material and the washing environment. This coating layer acts as a protective barrier that enables the washing process to remove residual lithium without directly damaging the surface of the positive active material.
2Reliability
If a washing process is executed to remove unreacted Li, then residual lithium is reduced, but resistance in high temperature storage is increased
Solution Approach 1:
The surface coating is applied before washing to preemptively protect against high temperature storage issues. The coating layer is formed in advance to prevent the washing process from creating surface defects that would later lead to increased resistance during high temperature storage.
Solution Approach 2:
The coating layer serves as an intermediary protective barrier that allows residual lithium removal while preventing surface damage that would otherwise increase resistance during high temperature storage. The coating mediates between the washing process and the positive active material surface.
3Quantity of substance
If LiOH and Li2CO3 are used for lithium compound, then lithium content is achieved, but unreacted Li remains on the surface causing gas and swelling effects
Solution Approach 1:
The patent extracts or removes unreacted LiOH and Li2CO3 from the surface through a controlled washing process. The washing process selectively removes the harmful unreacted lithium compounds while preserving the reacted positive active material, preventing gas generation and swelling effects.
Solution Approach 2:
The patent changes the chemical composition parameters of the surface by removing unreacted LiOH and Li2CO3 through washing. This parameter change eliminates the source of gas and swelling effects while maintaining the desired lithium content in the bulk material.
4Quantity of substance
If unreacted LiOH remains on the surface, then lithium content is maintained, but gelation occurs due to high viscosity when mixing slurry
Solution Approach 1:
The washing process extracts unreacted LiOH from the surface of the positive active material. This removal eliminates the high viscosity substance that causes gelation during slurry mixing, improving ease of operation for electrode plate manufacturing while maintaining adequate lithium content.
Solution Approach 2:
The patent changes the surface composition by removing unreacted LiOH, thereby changing the viscosity parameter of the slurry mixture. This parameter change prevents gelation and improves the ease of operation during slurry mixing and electrode plate manufacturing processes.
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 the battery's capacity, efficiency, and lifetime while minimizing residual lithium, improving high temperature storage characteristics and reducing surface damage during the washing process.
Implementation Method 1
a lithium complex oxide with a specific crystalline structure and surface coating, where interplanar distances decrease from the center to the surface
Implementation Method 2
a method involving precursor manufacturing, thermal treatment, washing, and metal doping
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.