Rechargeable Aluminum-Air Cell Using Ionic Liquid Electrolyte
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Solution Overview
Problem
Aluminum-air batteries are currently non-rechargeable due to the aluminum reduction potential being higher than the water decomposition potential in aqueous electrolytes, making it difficult to achieve rechargeability without water decomposition, and existing alternatives like organic solvents and ionic liquids face issues with volatility and viscosity.
Innovation Solution
A secondary aluminum-air electrochemical cell using a non-aqueous electrolyte composed of an ionic liquid and organic solvent, with polymer separation membranes and micro-perforated housing to allow oxygen exchange, and catalytic inks on pyrolytic graphite or carbon fabric electrodes to facilitate reversible reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aqueous electrolyte is used in aluminum-air battery, then the battery can operate with simple composition, but the battery becomes non-rechargeable because aluminum reduction potential is higher than water decomposition potential
Solution Approach 1:
The patent changes the fundamental parameter of the electrolyte from aqueous to non-aqueous (ionic liquid-based), which alters the electrochemical window and enables aluminum deposition during charging without water decomposition. This parameter change resolves the contradiction by making the system rechargeable while maintaining operational simplicity.
Solution Approach 2:
The patent uses a composite electrolyte system combining ionic liquid and organic solvent (carbonate). This composite approach leverages the high electrochemical stability of ionic liquids and the good ionic conductivity of carbonates, achieving both rechargeability and ease of operation.
2Reliability
If organic solvents are used as electrolyte, then rechargeability is achieved, but volatility and corrosion of carbonaceous materials occur
Solution Approach 1:
The patent creates a composite electrolyte where ionic liquid (low volatility, non-corrosive) is combined with organic solvent (high conductivity). The ionic liquid component suppresses volatility and corrosion while the organic solvent maintains good ionic conductivity, resolving the contradiction between rechargeability and material stability.
Solution Approach 2:
The ionic liquid acts as an intermediary between the aluminum anode and the organic solvent, providing a stable interface that prevents direct corrosive interaction while enabling efficient charge transfer. This intermediary role reduces corrosion of carbonaceous materials.
3Reliability
If ionic liquids are used as electrolyte, then rechargeability and low volatility are achieved, but high viscosity at room temperature reduces performance
Solution Approach 1:
The patent changes the temperature parameter by operating at elevated temperatures (above room temperature), which reduces the viscosity of the ionic liquid-based electrolyte and improves ionic conductivity while maintaining rechargeability.
Solution Approach 2:
The composite electrolyte combines ionic liquid (rechargeability, low volatility) with organic carbonate solvent (low viscosity, high conductivity). This composition balances viscosity and conductivity while maintaining the rechargeable nature of the battery.
4Reliability
If polymer separation membranes with small pore size are used, then electrode short circuit is prevented, but mobility of Al3+ ions must be maintained
Solution Approach 1:
The patent uses polymer separation membranes with optimized pore sizes that provide physical separation of electrodes to prevent short circuits while maintaining sufficient porosity for Al3+ ion transport. The porous structure allows ion mobility while ensuring electrode separation.
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 cell achieves over 200 charge cycles with 75% coulombic efficiency and stable potential, maintaining a high initial voltage and preventing electrolyte leakage or corrosion, with materials that are abundant, non-toxic, and easily recyclable.
Implementation Method 1
a non-aqueous electrolyte composed of an ionic liquid and organic solvent... catalytic inks on pyrolytic graphite or carbon fabric electrodes to facilitate reversible reactions... achieves over 200 charge cycles with 75% coulombic efficiency
Implementation Method 2
a micro-perforated housing in order to allow for the entry of oxygen during discharge of the battery and for the exit of oxygen during charge... These micro-perforations are about 1 to 10, preferably between 1 and 5 μm, in order to prevent the exit of the electrolyte or the entry of moisture
Implementation Method 3
polymer separation membranes are used with a pore size that allows for mobility of the Al +3... each separation membrane has a pore size ranging between 60 and 90 pm, which allows for passage of the Al +3 ions
Implementation Method 4
a catalytic ink dispersed on the gas diffusion layer, wherein the catalytic ink comprises: a catalyst that comprises at least one metal oxide selected from ruthenium oxide RuO2, manganese oxide MnO2, iridium oxide IrO2, nickel oxide Ni2O3 and lanthanum oxide La2O3
Data Source
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AI summary
The present invention relates to a secondary aluminum-air electrochemical cell. Therefore, the invention may be framed within the energy storage sector and, in particular, the sector of technologies and industries that require energy accumulators.