Manganese Oxide Positive Electrode for Magnesium Batteries
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Solution Overview
Problem
Magnesium secondary batteries face challenges in achieving high energy capacity due to low energy capacity per unit mass of molybdenum sulfide used as positive electrode active materials, and manganese dioxides have limitations in capacity and require high-temperature, high-pressure synthesis, making them costly.
Innovation Solution
A positive electrode active material is developed by reacting a permanganate with hydrochloric acid to produce a manganese oxide, which is then filtered and heat-treated, resulting in a manganese oxide with high discharge capacity suitable for magnesium batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If molybdenum sulfide is used as positive electrode active material, then magnesium secondary battery can be constructed, but energy capacity per unit mass is low
Solution Approach 1:
The patent changes the chemical composition parameter of the positive electrode active material from molybdenum sulfide to manganese oxide, which has a higher theoretical capacity. This parameter change directly addresses the low energy capacity per unit mass issue while maintaining battery functionality.
Solution Approach 2:
The patent employs manganese oxide, which is abundant and inexpensive compared to molybdenum sulfide. This substitution achieves high energy capacity at lower cost, effectively resolving the contradiction between performance and material value.
2Quantity of substance
If manganese dioxide is used as positive electrode active material, then high capacity is achieved, but high-temperature and high-pressure synthesis is required
Solution Approach 1:
The patent modifies the synthesis parameters from high-temperature and high-pressure conditions to room temperature or mild heating conditions by using a wet chemical synthesis method. This parameter change makes the manufacturing process simpler and more cost-effective while maintaining high discharge capacity.
Solution Approach 2:
The patent replaces the mechanical/physical synthesis method (high-temperature and high-pressure treatment) with a chemical synthesis method using permanganate and hydrochloric acid. This substitution eliminates the need for complex equipment and extreme conditions while achieving the desired material properties.
3Quantity of substance
If conventional manganese oxide synthesis method is used, then material is produced, but production cost is high
Solution Approach 1:
The patent uses inexpensive starting materials (permanganate and hydrochloric acid) to synthesize manganese oxide, replacing expensive conventional synthesis routes. This approach significantly reduces production cost while maintaining material quality suitable for battery applications.
Solution Approach 2:
The synthesis method allows the reaction to proceed under mild conditions that do not require energy-intensive equipment or specialized facilities. The simple filtration and drying steps enable cost-effective production without complex manufacturing infrastructure.
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 manganese oxide exhibits a high discharge capacity, enabling magnesium batteries with improved energy capacity per unit mass and volume, while being cost-effective and safe, thus overcoming the limitations of existing materials.
Implementation Method 1
reacting a permanganate with hydrochloric acid to produce a precipitate
Implementation Method 2
subjecting the precipitate to heat treatment
Data Source
AI summary
The invention provides a high-capacity positive electrode active material capable of sufficiently exploiting the excellent characteristics of magnesium metal or the like as a negative electrode active material, such as high energy capacity; a method for producing the same; and an electrochemical device using the positive electrode active material. A positive electrode 11 includes a positive electrode can 1, a positive pole pellet 2 having a positive electrode active material and the like, and a metal mesh support 3. A negative electrode 12 includes a negative electrode cap 4 and a negative electrode active material 5 such as magnesium metal. The positive electrode pellet 2 and the negative electrode active material 5 are disposed so as to sandwich a separator 6, and an electrolyte 7 is injected into the separator 6. The positive electrode active material, which provides the feature of the invention, is synthesized by a step of reacting a permanganate, such as potassium permanganate, with hydrochloric acid preferably having a concentration of 3 to 4 mol/l to produce a precipitate, and a step of filtering the precipitate, thoroughly washing the filtered precipitate with water, and then subjecting the washed precipitate to heat treatment preferably at a temperature of 300 to 400° C. for not less than 2 hours, thereby giving a manganese oxide.