Magnesium-Bismuth Electrode for High Capacity Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current rechargeable batteries, such as lithium-ion batteries, face limitations in achieving high capacity density due to the lack of effective cathode or anode active materials that can fully utilize the high capacity density potential of magnesium ions, which carry two electrical charges.
Innovation Solution
The development of magnesium batteries utilizing a negative electrode with an active material comprising bismuth and an inter-metallic compound of magnesium and bismuth, such as Mg3Bi2, along with a magnesium compound-based electrolyte, to enhance capacity density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional electrode materials are used in magnesium batteries, then the battery structure is simple and easy to manufacture, but the capacity density is limited and cannot fully utilize the high capacity density potential of magnesium ions
Solution Approach 1:
The patent employs composite electrode materials consisting of bismuth and inter-metallic magnesium-bismuth compounds (such as Mg3Bi2) to achieve high capacity density. This composite material approach allows the battery to fully utilize the two-electron transfer capability of magnesium ions, resulting in capacity densities exceeding 380 milliamp-hours/gram, while maintaining a manageable device structure through the use of well-defined inter-metallic phases.
2Quantity of substance
If bismuth and inter-metallic magnesium-bismuth active materials are used, then the capacity density exceeds 380 milliamp-hours/gram with 100% Coulombic efficiency, but the material composition and electrode structure become more complex
Solution Approach 1:
The patent utilizes controlled changes in compositional parameters (ratios of bismuth to magnesium) and processing parameters (temperature, pressure, and atmosphere during synthesis) to produce inter-metallic compounds with specific stoichiometries such as Mg3Bi2. These parameter changes enable the formation of well-defined phases that deliver high capacity density while maintaining manufacturability through established metallurgical techniques.
Solution Approach 2:
The invention exploits phase transitions during battery operation, where the active material transforms between bismuth metal phase in the charged state and inter-metallic compound phase in the discharged state. This reversible phase transition mechanism enables 100% Coulombic efficiency and high capacity density, as the structural transformation is fully reversible and utilizes the complete two-electron transfer capability of magnesium ions.
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 use of bismuth and inter-metallic magnesium-bismuth active materials in magnesium batteries achieves a high energy capacity density, exceeding that of lithium-ion batteries with over 380 milliamp-hours/gram and 100% Coulombic efficiency, demonstrating significant potential for improved battery performance.
Implementation Method 1
the active material has a phase corresponding to bismuth metal in a charged state of the active material and wherein the active material has a phase corresponding to an inter-metallic compound of magnesium and bismuth in a discharged state of the active material
Implementation Method 2
An electrolyte is disposed between the negative electrode and the positive electrode. The electrolyte includes a magnesium compound.
Data Source
AI summary
A magnesium battery includes a first electrode including an active material and a second electrode. An electrolyte is disposed between the first electrode and the second electrode. The electrolyte includes a magnesium compound. The active material includes an inter-metallic compound of magnesium and bismuth.