Cathode Active Material Coating With Controlled Washing for Longer Cycle Life
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Solution Overview
Problem
There is a need for rechargeable lithium batteries with higher energy density and capacity to meet the demands of battery-powered devices and electric vehicles, particularly in enhancing the lifetime characteristics of positive electrode active materials.
Innovation Solution
A method of preparing a positive electrode active material involving the use of a lithium composite oxide represented by Chemical Formula Li a1 Ni x1 M 1< y1 M 2< z1 O 2-b1 , where the oxide is wet-coated and cleaned with washing water, and optionally includes sodium and sulfur, with a specific mass fraction of sulfur to sodium ranging from 1 to 3, to enhance the material's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the positive electrode active material is cleaned with a large amount of washing water, then the purity of the material is improved, but the lifetime characteristics deteriorate
Solution Approach 1:
The patent changes the parameter of washing water amount from excessive to controlled (at most 15 wt% based on total weight of coated lithium composite oxide). This parameter optimization resolves the contradiction by finding the optimal balance point where sufficient purification occurs without causing surface damage that would reduce lifetime characteristics.
2Manufacturing precision
If the positive electrode active material is cleaned with excessive washing water, then residual impurities are removed, but surface damage occurs reducing material performance
Solution Approach 1:
The patent optimizes the washing water amount parameter to at most 15 wt% of the total weight of coated lithium composite oxide. This controlled parameter change ensures thorough removal of residual impurities while preventing surface damage that would occur with excessive washing, thus maintaining surface integrity.
3Manufacturing precision
If the washing water amount is increased to ensure complete cleaning, then the manufacturing quality is improved, but the production efficiency decreases
Solution Approach 1:
The patent establishes an optimal parameter range for washing water amount (at most 15 wt% based on total weight of coated lithium composite oxide) that achieves complete cleaning effectiveness. This optimized parameter eliminates the need for excessive washing, thereby maintaining high production efficiency while ensuring manufacturing quality.
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 method results in a positive electrode active material with improved lifetime characteristics, suitable for high-capacity and high-density rechargeable lithium batteries.
Implementation Method 1
cleaning the coated lithium composite oxide using a washing water
Data Source
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AI summary
A positive electrode active material includes a lithium composite oxide, and a coating layer on a surface of the lithium composite oxide, and may further include some sodium (Na) and sulfur (S), wherein a mass fraction (S/Na) of the S to the Na is in a range of about 1 to about 3. Also disclosed are methods of preparing the same, a positive electrode including the same, and a rechargeable lithium battery including the positive electrode.