Metal-Air Cell Using Low Temperature Ionic Liquid Electrolyte
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Solution Overview
Problem
Metal-air batteries face significant issues with electrolyte solution evaporation, particularly in rechargeable cells, leading to reduced performance and operational lifespan due to the need for large volumes of electrolyte to compensate for evaporation, which increases weight and size without enhancing performance.
Innovation Solution
The use of a low temperature ionic liquid with a melting point below 150°C, contained between flexible fuel and air electrodes, sealed to prevent electrolyte loss, allowing for compact design and reduced electrolyte volume while maintaining effective ion conductivity for electrochemical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high volume of aqueous electrolyte solution is used to compensate for evaporation, then the cell can maintain operation over time, but the overall size and weight of the cell increase significantly
Solution Approach 1:
The patent changes the chemical composition and physical properties of the electrolyte by using an ionic liquid instead of an aqueous electrolyte solution. This parameter change results in extremely low vapor pressure and negligible evaporation, eliminating the need for excess electrolyte volume to compensate for evaporation losses, thereby reducing cell weight while maintaining operational lifespan
Solution Approach 2:
The patent employs a composite electrolyte system using ionic liquid, which combines the benefits of liquid electrolyte (ion conductivity) with the advantages of non-volatile materials. This composite approach allows the electrolyte to maintain its functional properties without the harmful evaporation characteristic of aqueous solutions, resolving the contradiction between reliability and weight
2Reliability
If a high volume of electrolyte solution is used to compensate for evaporation, then the cell can maintain operation over time, but the volumetric energy density and power-to-volume ratio deteriorate
Solution Approach 1:
By changing the electrolyte from aqueous to ionic liquid, the patent fundamentally alters the evaporation parameter, reducing it to negligible levels. This allows the cell to use minimal electrolyte volume while maintaining long-term operation, thereby improving volumetric energy density and power-to-volume ratio
3Adaptability or versatility
If aqueous electrolyte solution is used in rechargeable cells, then the cell can be recharged repeatedly, but the water solvent is oxidized to evolve oxygen during re-charge, depleting the solution
Solution Approach 1:
The patent changes the chemical stability parameter of the electrolyte by using ionic liquid, which has extremely high electrochemical stability and resistance to oxidation. This allows the electrolyte to withstand repeated charging cycles without being depleted by oxygen evolution, maintaining rechargeability while preventing substance loss
Solution Approach 2:
The patent replaces the consumable aqueous electrolyte (which depletes over time) with a durable ionic liquid that can withstand repeated charging cycles. This substitution transforms the electrolyte from a short-living consumable to a long-living reusable component, enabling sustained rechargeability
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
This solution minimizes electrolyte evaporation, reduces the overall weight and volume of the battery, and enhances power-to-weight ratios by using a minimal amount of ionic liquid, maintaining performance and enabling a compact, efficient metal-air cell design.
Implementation Method 1
an ionically conductive medium comprising a low temperature ionic liquid having a melting point at or below 150°C at 1 atm. (1.01x105 Pa) and contained in a space between the fuel electrode and the air electrode for conducting ions for supporting the electrochemical reactions at the fuel and air electrodes
Implementation Method 2
a fuel electrode for oxidizing a metal fuel
Implementation Method 3
an air electrode for absorbing and reducing gaseous oxygen
Data Source
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AI summary
The present application relates to an electrochemical metal-air cell in which a low temperature ionic liquid is used.