Electrolytic Manganese Dioxide Pore Control for Discharge
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Solution Overview
Problem
Conventional electrolytic manganese dioxide used in alkali-manganese dry cells does not support extended middle rate discharge due to limitations in pore structure and alkali potential, leading to reduced discharge time and efficiency.
Innovation Solution
Development of electrolytic manganese dioxide with controlled pore size distribution, specifically optimized pore volumes, and higher alkali potential, combined with a suspension electrolysis method to enhance crystal structure and surface area, resulting in improved middle rate discharge characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional electrolytic manganese dioxide is used, then high rate discharge characteristic is improved, but middle rate discharge time is reduced
Solution Approach 1:
The patent applies porous material principles by precisely controlling the pore structure of electrolytic manganese dioxide. It specifies that the volume of pores with diameter of 0.003 μm to 0.05 μm should be 0.002 cm³/g to 0.04 cm³/g, and pores with diameter of 0.05 μm to 0.2 μm should be 0.008 cm³/g to 0.06 cm³/g. This controlled porosity allows optimal electrolyte penetration and ion transport, enabling both high rate discharge capability and extended middle rate discharge time.
Solution Approach 2:
The patent employs parameter changes by optimizing multiple physical and chemical parameters of electrolytic manganese dioxide simultaneously. Key parameters include: pore volume distribution (0.003-0.05 μm and 0.05-0.2 μm ranges), alkali potential (240 mV to 320 mV), crystallinity (110)/(021) peak intensity ratio of 0.5 to 2.0, and specific surface area (5 m²/g to 50 m²/g). These parameter optimizations work together to achieve both high rate discharge characteristic and extended middle rate discharge duration.
2Duration of action of moving object
If pore volume is increased to enhance middle rate discharge, then discharge time is extended, but packing efficiency deteriorates
Solution Approach 1:
The patent applies porous material principles by precisely controlling the pore structure of electrolytic manganese dioxide. It specifies that the volume of pores with diameter of 0.003 μm to 0.05 μm should be 0.002 cm³/g to 0.04 cm³/g, and pores with diameter of 0.05 μm to 0.2 μm should be 0.008 cm³/g to 0.06 cm³/g. This controlled porosity allows optimal electrolyte penetration and ion transport, enabling both high rate discharge capability and extended middle rate discharge time.
Solution Approach 2:
The patent applies local quality principles by creating different pore volume distributions in different size ranges. It specifies distinct volume ranges for two different pore diameter ranges (0.003-0.05 μm and 0.05-0.2 μm), optimizing each pore size range for specific functions: smaller pores for surface area and ion exchange, larger pores for electrolyte access and discharge time extension.
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 optimized electrolytic manganese dioxide exhibits enhanced middle rate discharge capability, achieving longer discharge times and improved packing efficiency when used as a cathode active material in alkali-manganese cells.
Implementation Method 1
an electrolytic manganese dioxide producing step in which electrolytic manganese dioxide is produced by electrolysis
Data Source
Figure 1(a)~2
AI summary
The object of the present invention is to provide electrolytic manganese dioxide excellent in the middle rate discharge characteristic as compared with conventional electrolytic manganese dioxide, and a method for its production and its application. Electrolytic manganese dioxide characterized in that the potential as measured in a 40 wt% KOH aqueous solution by using a mercury/mercury oxide reference electrode as a standard is higher than 250 mV and less than 310 mV, and the volume of pores having a pore diameter of at least 2 nm and at most 50 nm is at most 0.0055 cm3/g. Of such electrolytic manganese dioxide, the volume of pores having a pore diameter of at least 2 nm and at most 200 nm is preferably at most 0.0555 cm3/g.