Magnesium Ion Electrolyte for Reversible Precipitation
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Solution Overview
Problem
The development of magnesium secondary batteries is hindered by the formation of passivation films on metal magnesium surfaces, which prevents the efficient use of magnesium ions in non-aqueous electrolytes, and existing electrolytes have low oxidation potentials and instability, making them unsuitable for practical battery production.
Innovation Solution
A magnesium ion containing non-aqueous electrolyte is formed by dissolving magnesium and aluminum ions in an organic etheric solvent, using a halogenated hydrocarbon, an aluminum halide, and a quaternary ammonium salt, with a heating treatment, which stabilizes the electrolyte and increases its oxidation potential, allowing for reversible magnesium precipitation and high conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional non-aqueous electrolytes are used with metal magnesium, then magnesium ion conduction is enabled, but passivation films form on the metal magnesium surface preventing efficient ion transport
Solution Approach 1:
The patent introduces an intermediary substance (lithium salt or sodium salt) into the non-aqueous electrolyte to prevent passivation film formation on metal magnesium surface. This intermediary acts as a mediator that modifies the electrolyte composition to enable efficient magnesium ion conduction without the harmful passivation effect, thus resolving the contradiction between enabling ion conduction and preventing film formation.
Solution Approach 2:
The patent changes the chemical composition parameters of the non-aqueous electrolyte by adding specific concentrations of lithium salts or sodium salts. This parameter modification transforms the electrolyte properties to prevent passivation film formation while maintaining magnesium ion conductivity, thereby resolving the technical contradiction.
2Adaptability or versatility
If existing magnesium-based electrolytes are used, then magnesium can be precipitated and dissolved, but the oxidation potential is too low (+1.5 V) providing insufficient potential window for practical battery use
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing lithium salts or sodium salts in specific concentrations (0.01-1.0 mol/L). This parameter modification raises the oxidation potential from +1.5 V to above +2.0 V, thereby expanding the potential window and making the electrolyte suitable for practical battery applications while maintaining magnesium's reversible precipitation and dissolution properties.
3Reliability
If stable electrolyte compositions are used, then manufacturing reliability improves, but production complexity increases due to multiple components and synthesis steps
Solution Approach 1:
The patent employs lithium salts or sodium salts that serve multiple functions simultaneously: they prevent passivation film formation, raise oxidation potential, and stabilize the electrolyte composition. This multi-functionality reduces the need for multiple separate additives, thereby simplifying the manufacturing process while achieving reliable electrolyte performance.
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 new electrolyte system enables the production of magnesium batteries with high oxidation potential, large potential window, and high energy capacity, suitable for use in electrochemical devices, while being stable in atmospheric air and easy to manufacture in a dry room, reducing production costs and improving battery performance.
Implementation Method 1
A magnesium ion containing non-aqueous electrolyte is formed by dissolving magnesium and aluminum ions in an organic etheric solvent, using a halogenated hydrocarbon, an aluminum halide, and a quaternary ammonium salt, with a heating treatment
Implementation Method 2
it involves a problem that the oxidation potential of the electrolyte is as low as about +1.5 V relative to an equilibrium potential of metal magnesium and the potential window is insufficient for use as an electrochemical device
Implementation Method 3
metal magnesium can be precipitated and dissolved reversively
Data Source
AI summary
A magnesium ion containing non-aqueous electrolyte in which magnesium ions and aluminum ions are dissolved in an organic etheric solvent, and which is formed by: adding metal magnesium, a halogenated hydrocarbon RX, an aluminum halide AlY3, and a quaternary ammonium salt R1R2R3R4N+Z− to an organic etheric solvent; and applying a heating treatment while stirring them (in the general formula RX representing the halogenated hydrocarbon, R is an alkyl group or an aryl group, X is chlorine, bromine, or iodine, in the general formula AlY3 representing the aluminum halide, Y is chlorine, bromine, or iodine, in the general formula R1R2R3R4N+Z− representing the quaternary ammonium salt, R1, R2, R3, and R4 represent each an alkyl group or an aryl group, and Z− represents chloride ion, bromide ion, iodide ion, acetate ion, perchlorate ion, tetrafluoro borate ion, hexafluoro phosphate ion, hexafluoro arsenate ion, perfluoroalkyl sulfonate ion, or perfluoroalkyl sulfonylimide ion.