Electrolytic Manganese Dioxide Pore Structure for Battery Energy Density
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Solution Overview
Problem
Electrolytic manganese dioxide with high packing property is needed for lithium-manganese complex oxides to enhance energy density, while maintaining reactivity with lithium compounds and inhibiting impurity incorporation, particularly alkaline earth metals, without additional treatment steps or toxic fluorides.
Innovation Solution
Producing electrolytic manganese dioxide with a BET specific surface area between 20 m²/g and 60 m²/g, and a controlled pore structure, using a suspension electrolysis method with a sulfuric acid-manganese sulfate mixed solution, which inhibits impurity incorporation and improves reactivity and packing density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrolytic manganese dioxide with low BET specific surface area is used to improve packing property, then energy density is improved, but reactivity with lithium compounds deteriorates
Solution Approach 1:
The patent applies local quality by creating a bimodal pore structure where large pores (≥200 nm) provide high packing density for energy density, while small pores (<200 nm) provide high surface area for reactivity. This spatial differentiation of pore sizes allows different regions of the material to serve different functions: large pores for compact packing and small pores for chemical reactivity with lithium compounds.
Solution Approach 2:
The patent utilizes porous materials by carefully controlling the pore size distribution of electrolytic manganese dioxide. By maintaining a specific pore structure with controlled volumes of large and small pores, the material achieves both high packing property (for energy density) and high surface area (for reactivity), resolving the contradiction between these two opposing requirements.
2Ease of manufacture
If industrial electrolyte solution with impurities is used to reduce production cost, then manufacturing cost is improved, but impurity incorporation into electrolytic manganese dioxide worsens
Solution Approach 1:
The patent converts the harmful effect of impurities in industrial electrolyte solutions into a beneficial outcome by optimizing electrolysis conditions. By controlling current density (0.5-2.0 A/dm²) and temperature (20-40°C), the process selectively deposits high-purity electrolytic manganese dioxide while leaving impurities like alkaline earth metals in the electrolyte solution. The impurities become harmless spectators that can be easily separated, transforming a manufacturing challenge into a simple filtration step.
Solution Approach 2:
The patent applies parameter changes by precisely controlling electrolysis parameters (current density, temperature, pH) to achieve selective deposition. By maintaining current density within 0.5-2.0 A/dm² and temperature within 20-40°C, the process optimizes the deposition rate while preventing co-deposition of impurities. This parameter optimization allows the use of low-cost industrial electrolyte solutions without compromising product purity.
3Manufacturing precision
If additional impurity removal treatment steps are added to improve purity, then purity of electrolytic manganese dioxide is improved, but device complexity worsens
Solution Approach 1:
The patent extracts impurities from the electrolyte solution during the electrolysis process itself, rather than requiring separate purification steps. By optimizing deposition conditions, impurities such as alkaline earth metals remain in the electrolyte solution while pure electrolytic manganese dioxide deposits on the electrode. The impurities are then easily removed by simple filtration of the electrolyte solution, eliminating the need for complex additional purification equipment or processes.
4Manufacturing precision
If toxic fluorides are used to remove alkaline earth metals to improve purity, then purity of electrolytic manganese dioxide is improved, but harmful factors worsen
Solution Approach 1:
The patent eliminates the need for toxic fluoride chemicals by converting the impurity removal process into a physical separation process. By optimizing electrolysis parameters, alkaline earth metal impurities are prevented from incorporating into the deposit and remain dissolved in the electrolyte solution. The impurities are then removed by simple filtration, completely eliminating the need for toxic chemical treatments while achieving the same purity goal.
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 electrolytic manganese dioxide with high packing and reactivity, enabling lithium-manganese complex oxides with enhanced energy density and cell performance, while allowing the use of impure electrolyte solutions without additional purification steps.
Implementation Method 1
electrolysis is performed using an electrolyte solution obtained from a starting material such as manganese ore or industrial water
Implementation Method 2
lithium ion secondary battery which has a high rate capability
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
The invention provides electrolytic a manganese dioxide with a BET specific surface area of 20 to 60 m2/g, and a volume of at least 0.023 cm3/g for pores with pore diameters of 2 to 200 nm. Also provided is a method for producing an electrolytic manganese dioxide including a step of suspending a manganese oxide in a sulfuric acid-manganese sulfate mixed solution to obtain the electrolytic manganese dioxide, wherein a manganese oxide particles are continuously mixed with a sulfuric acid-manganese sulfate mixed solution, for a manganese oxide particle concentration of 5 to 200 mg/L in the sulfuric acid-manganese sulfate mixed solution. Still further provided is a method for producing a lithium-manganese complex oxide, including a step of mixing the electrolytic manganese dioxide with a lithium compound and heat treating the mixture to obtain a lithium-manganese complex oxide.