Mn Polyanion Electrode Carbon Shell Water Control
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Solution Overview
Problem
Conventional non-aqueous electrolyte secondary batteries face reliability issues due to water release, leading to gas generation and performance deterioration over time.
Innovation Solution
An electrode with a core part made of a polyanion structure containing Mn and a carbon shell is developed, reducing water content to 1500 ppm or less, thereby minimizing water reactions and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water content in the positive electrode mixture layer is increased to 3000-10000 ppm, then battery characteristics are improved, but reliability decreases due to water release causing gas generation and performance deterioration
Solution Approach 1:
The invention changes the water content parameter from the conventional 3000-10000 ppm range to a lower range of 100-3000 ppm, and preferably 100-1000 ppm. This parameter change resolves the contradiction by demonstrating that lower water content does not compromise battery characteristics while significantly improving reliability by reducing water release during operation.
2Object-generated harmful factors
If water content in the positive electrode mixture layer is reduced to 100-3000 ppm, then gas generation and performance deterioration are reduced, but battery characteristics may be compromised
Solution Approach 1:
The invention establishes a new parameter range for water content (100-3000 ppm, preferably 100-1000 ppm) that simultaneously achieves both goals: reducing gas generation and maintaining excellent battery characteristics. This parameter optimization resolves the contradiction by identifying a window where harmful effects are minimized while performance is preserved.
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 electrode design results in a safer battery with improved reliability by restraining water-related issues, such as gas generation and performance degradation, during charging and discharging.
Implementation Method 1
the water contained in an electrode can be classified into adsorbed water and bonded water
Implementation Method 2
an amount of water, as measured by Karl Fischer's method when an electrode is held at 250° C. for 40 minutes after adsorbed water is volatilized by heating
Data Source
AI summary
An electrode includes an electrode material, which includes: a core part made of an active substance having a polyanion structure having Mn; and a shell part obtained by covering a surface of the core part with carbon. In addition, an amount of water, as measured by Karl Fischer's method when the electrode is held at 250° C. for 40 minutes after adsorbed water is volatilized by heating, is 1500 ppm or less.