Electrolytic Manganese Dioxide XRD Control for High-Rate Discharge
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Solution Overview
Problem
Alkaline manganese dry cells using conventional manganese dioxide as cathode active material face reduced utilization and impaired discharge capacity at high-rate discharge conditions, necessitating a material with improved high-rate discharge characteristics and packing properties.
Innovation Solution
Electrolytic manganese dioxide with specific XRD characteristics, including a half width of the (110) plane between 1.8° and 2.2°, peak intensity ratio of (110)/(021) between 0.70 and 1.00, and JIS-pH between 1.5 and 5.0, along with controlled BET specific surface area, alkali potential, and particle size distribution, is developed to enhance high-rate discharge performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional manganese dioxide is used as cathode active material, then storage stability and cost are excellent, but utilization rate decreases with increase of discharge current and discharge capacity is impaired at high-rate discharge
Solution Approach 1:
The patent applies parameter changes by precisely controlling the half width of the (110) plane between 2.00° and 2.40° and the peak intensity ratio of X-ray diffraction peaks (110)/(021) between 0.50 and 0.80. These specific parameter ranges optimize the crystal structure to enable both high storage stability and excellent high-rate discharge characteristics, resolving the contradiction between reliability and productivity.
2Productivity
If manganese dioxide with half width of (110) plane between 2.00° and 2.40° and peak intensity ratio (110)/(021) between 0.50 and 0.80 is used, then high-rate discharge characteristics are improved, but the utilization rate still cannot be fully maintained under high discharge current conditions
Solution Approach 1:
The patent further refines the parameters by specifying the half width of the (110) plane within 2.00° to 2.40° and peak intensity ratio (110)/(021) between 0.50 and 0.80. These optimized parameters enhance the crystal structure's ability to facilitate ion transport and electron transfer, thereby improving both high-rate discharge characteristics and the utilization rate of manganese dioxide under high discharge current conditions.
3Power
If alkaline manganese dry cell is designed for high-rate discharge, then large current can be taken out in short time, but manganese dioxide is not fully utilized and useful time becomes short
Solution Approach 1:
The patent resolves this contradiction by optimizing the crystal structure parameters of manganese dioxide, specifically controlling the half width of the (110) plane between 2.00° and 2.40° and the peak intensity ratio (110)/(021) between 0.50 and 0.80. These parameter optimizations enable the material to support high power output while maintaining high utilization efficiency, thereby extending the useful time of the battery even under high-rate discharge conditions.
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 electrolytic manganese dioxide exhibits excellent packing properties and high-rate discharge characteristics, enabling longer discharge times and increased discharge capacity when used in alkaline manganese dry cells.
Implementation Method 1
a sulfuric acid-manganese sulfate mixed solution is used whereby the sulfuric acid concentration in the electrolyte at the termination of electrolysis is higher than the sulfuric acid concentration in the electrolyte at the initiation of electrolysis
Implementation Method 2
the half width of the (110) plane in XRD measurement using CuKα line as the radiation source is at least 1.8° and less than 2.2°, the peak intensity ratio of X-ray diffraction peaks (110)/(021) is at least 0.70 and at most 1.00
Data Source
AI summary
To provide electrolytic manganese dioxide excellent in packing property and high-rate discharge characteristics when used as a cathode material for alkaline dry cells. Electrolytic manganese dioxide in which the half-value width of the (110) plane in XRD measurement using CuKα line as the radiation source is at least 1.8° and less than 2.2°, the peak intensity ratio of X-ray diffraction peaks (110)/(021) is at least 0.70 and at most 1.00, and the JIS-pH (JIS K1467) is at least 1.5 and less than 5.0; a method for producing the electrolytic manganese dioxide; and its application.