Aluminum Secondary Battery Electrolyte for Low-Temperature Operation
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Solution Overview
Problem
Existing aluminum secondary batteries require high temperatures (above 50°C) for efficient precipitation-dissolution reactions, limiting their practicality and battery capacity at ambient temperatures.
Innovation Solution
An electrolyte composition with an aluminum salt, an alkyl sulfone, and a solvent having a specific dielectric constant of 20 or less, where the solvent content is between 30-88 mol% and the aluminum salt to alkyl sulfone mol ratio is between 4/5 and 7/3, enhancing the dispersion of aluminum salt and facilitating oxidation-reduction reactions at lower temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional electrolyte compositions are used, then the precipitation-dissolution reaction of aluminum can proceed at high temperatures (≥50°C), but the reaction efficiency is low and the progression temperature cannot be reduced to ambient temperature
Solution Approach 1:
The invention changes the chemical composition parameters of the electrolyte by introducing specific solvents with dielectric constants of 15 or less (such as aromatic hydrocarbons, ethers, esters, halogenated hydrocarbons) in combination with conventional solvents. This parameter change enables the precipitation-dissolution reaction to proceed efficiently at ambient temperatures (15°C or higher) rather than requiring high temperatures (≥50°C), thus resolving the contradiction between lowering temperature and maintaining reaction efficiency
Solution Approach 2:
The invention creates a composite electrolyte system by combining multiple solvent types (conventional solvents like cyclic carbonate, chain carbonate, cyclic ether, chain ether with new solvents having dielectric constant ≤15). This composite approach synergistically enhances the solubility of aluminum salts and facilitates the precipitation-dissolution reaction at lower temperatures while maintaining high reaction efficiency, addressing both temperature reduction and productivity requirements
2Stability of the object's composition
If the solvent content is increased to improve reaction progress, then the dispersion amount of aluminum salt decreases, but the precipitation-dissolution reaction requires high temperatures
Solution Approach 1:
The invention optimizes the solvent content parameter within the range of 60-95 mass% and adjusts the dielectric constant parameter of the solvent mixture to 15 or less. This dual parameter optimization ensures sufficient dispersion of aluminum salt while enabling the reaction to proceed at ambient temperatures, resolving the contradiction between composition stability and temperature requirement
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 configuration allows for stable and efficient electrochemical precipitation and dissolution of aluminum at ambient temperatures, improving battery capacity and reducing corrosion risks, with effective reaction progression at temperatures as low as 15°C or higher.
Implementation Method 1
aluminum has a high ionization tendency, and therefore, the electric charge per unit volume obtained by an oxidation-reduction reaction is high
Implementation Method 2
an aluminum secondary battery utilizing a precipitation-dissolution reaction of aluminum
Implementation Method 3
since the dispersion amount of the aluminum salt with respect to the solvent is increased compared to in a case in which the content of the solvent and the mol ratio do not satisfy the foregoing conditions
Data Source
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AI summary
A secondary battery capable of decreasing progression temperature of a precipitation-dissolution reaction of aluminum is provided. A cathode 11 and an anode 12 are separated from each other by a separator 13. An electrolyte with which the separator 13 is impregnated contains an alkyl sulfone (R1-S(=O)2-R2: each of R1 and R2 represents an alkyl group) and a solvent (having a specific dielectric constant of 20 or less) together with an aluminum salt. A content of the solvent is equal to or larger than 30 mol% and is less than 88 mol%, and a mol ratio (a content of the aluminum salt/a content of the alkyl sulfone) is equal to or larger than 4/5 and is less than 7/3.