Electrolytic Manganese Dioxide Composition for High-Load Alkaline Batteries
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Solution Overview
Problem
Existing electrolytic manganese dioxide (EMD) products suffer from poor high-load characteristics, electrode detachment during production, and insufficient content of effective oxidizing agents, leading to suboptimal battery performance.
Innovation Solution
Producing EMD with specific ranges of alkaline potential, manganese content, structural water content, and controlling electrolysis conditions to prevent electrode detachment, ensuring a balanced electrolyte composition that maintains high structural water and manganese content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the concentration of sulfuric acid in the electrolyte solution is increased to improve high-load characteristics, then the high-load characteristics are improved, but the electrolytic manganese dioxide falls off the electrolytic electrode and production stability deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-coating the electrolytic electrode with a specific layer structure before electrolysis begins. The electrode is prepared with a porous layer containing manganese dioxide and conductive material, which is formed in advance to ensure stable adhesion during subsequent high-concentration sulfuric acid electrolysis. This preliminary preparation prevents the falling off problem that would otherwise occur when using high sulfuric acid concentrations for improved high-load characteristics.
Solution Approach 2:
The patent employs composite materials by creating a multi-component electrode structure consisting of manganese dioxide, conductive material (such as acetylene black), and binder material. This composite structure enhances both the adhesion of the electrode to the substrate and the overall performance, allowing the system to achieve good high-load characteristics while maintaining production stability. The composite nature of the electrode prevents detachment during electrolysis.
2Reliability
If the concentration of sulfuric acid is lowered at the beginning of electrolysis to prevent electrode falling off, then production stability is maintained, but the high-load characteristics deteriorate
Solution Approach 1:
The patent resolves this contradiction by performing preliminary action - preparing the electrode with a robust coated layer before electrolysis starts. This pre-formed layer structure ensures that even when high concentrations of sulfuric acid are used from the beginning to achieve good high-load characteristics, the electrode material remains firmly attached and does not fall off, thus maintaining both production stability and high-load performance simultaneously.
3Speed
If the half-width of the (110) plane is reduced to improve discharge characteristics, then the discharge characteristics are improved, but the high-load characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the half-width of the (110) plane to a specific range (1.6 degrees or more and less than 2.2 degrees) rather than minimizing it. This parameter optimization balances the competing requirements: a narrower half-width improves discharge characteristics, but the patent determines that maintaining it within this specific range also preserves high-load characteristics. Additionally, the patent controls the peak intensity ratio of X-ray diffraction peaks (110)/(021) to be 0.70 or more and 1.00 or less, further optimizing the crystal structure to achieve both fast discharge and good high-load performance.
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 produced EMD exhibits improved high-load characteristics and capacity, reducing electrode detachment and maintaining high structural water content, enhancing battery performance.
Implementation Method 1
an electrolytic manganese dioxide produced by controlling electrolysis conditions
Implementation Method 2
electrolytic manganese dioxide electrodeposited during electrolysis
Data Source
AI summary
To provide an electrolytic manganese dioxide with good high-load discharge characteristics and high capacity when used as a positive-electrode material of an alkaline manganese battery and to provide a method for producing the electrolytic manganese dioxide.An electrolytic manganese dioxide with an alkaline potential of 290 mV or more and less than 350 mV, a manganese content of 60.3% by mass or more and 63.0% by mass or less in a dry state, a structural water content of 2.60% by mass or more as defined by mass loss at 110° C. to 240° C. and a total structural water content of 4.10% by mass or more, and a method for producing the electrolytic manganese dioxide.