Composite Cathode Active Material Surface Protrusion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cathode active material layers in lithium batteries often have poor surface characteristics due to protrusions and cracks, which can lead to reduced battery performance and may require additional processing steps, and batteries with such layers may not be suitable for manufacturing.
Innovation Solution
A composite cathode active material is developed, comprising a lithium transition metal oxide with a low amount of lithium-containing impurities, specifically LiOH and Li2CO3, on its surface, which is prepared by mixing precursors and calcining them in an oxygen atmosphere at 950°C or higher to minimize surface protrusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cathode active material is used, then manufacturing process is simple, but surface state is poor with protrusions and cracks
Solution Approach 1:
The patent applies preliminary action by controlling the calcination conditions (temperature of 950°C or higher, oxygen atmosphere, prolonged time) before the material is used in battery manufacturing. This preliminary treatment ensures that the cathode active material has minimal surface protrusions and cracks before being processed into electrodes, thereby improving surface state without requiring additional post-processing steps.
2Reliability
If cathode active material layer with protrusions is used, then manufacturing process is simple, but battery performance is reduced
Solution Approach 1:
The patent applies parameter changes by modifying the calcination parameters: temperature (950°C or higher), atmosphere (oxygen), and time (prolonged). These parameter changes transform the cathode active material to have reduced surface defects, thereby improving battery performance and cycle characteristics while maintaining ease of manufacture through a single optimized calcination process.
3Manufacturing precision
If additional process is added to remove protrusions, then surface state is improved, but manufacturing complexity increases
Solution Approach 1:
The patent converts the harmful effect of surface protrusions into a benefit by using the calcination process itself to eliminate them. Instead of adding a separate removal process, the harmful protrusions are prevented from forming in the first place through controlled calcination at 950°C or higher in oxygen atmosphere, thereby improving surface state without increasing manufacturing complexity.
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 use of this composite cathode active material results in a lithium battery with improved cycle characteristics and reduced surface protrusions, enhancing the battery's performance and manufacturing feasibility.
Implementation Method 1
calcining the mixture in an oxygen atmosphere at a temperature of about 950° C. or higher to obtain a calcined product
Implementation Method 2
calcining the mixture in an oxygen atmosphere
Data Source
AI summary
A composite cathode active material, a cathode including the composite cathode active material, and a lithium battery including the cathode. The composite cathode active material includes: a lithium transition metal oxide; and a lithium-containing impurity on a surface of the lithium transition metal oxide. The lithium-containing impurity includes free lithium in an amount of about 0.050 wt % or less based on a total weight of the composite cathode active material, and LiOH and Li2CO3 in a mole ratio of LiOH to Li2CO3 of about 0.50 or less.