High-Voltage Battery Cell Electrolyte for Stable SO2 Solvation
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Solution Overview
Problem
Rechargeable lithium-ion cells with organic electrolytes face issues such as instability, safety risks due to flammability, and reduced energy density, while SO2-based electrolytes suffer from poor solubility of conducting salts and reactivity with water, leading to limited operational reliability and cycle life.
Innovation Solution
A rechargeable battery cell design featuring a high-voltage electrode and an SO2-based electrolyte with a conducting salt that forms a liquid solvate complex with SO2, ensuring high solubility and oxidation stability, allowing for increased cell voltage and improved cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic electrolytes are used in lithium-ion cells, then ease of manufacture and initial performance are improved, but stability, safety, and energy density deteriorate due to flammability and decomposition
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by using SO2 as the solvent instead of organic solvents, and by employing specific conducting salts (LiAlCl4, LiGaCl4, LiInCl4) with defined concentrations. This parameter change transforms the electrolyte from flammable organic-based to non-flammable SO2-based, resolving the contradiction between ease of manufacture and stability.
Solution Approach 2:
The patent creates a composite electrolyte system combining SO2 solvent with specific conducting salts (LiAlCl4, LiGaCl4, or LiInCl4) in defined ratios. This composite material approach achieves both manufacturability and enhanced stability, as the specific combination of SO2 with these salts provides chemical stability while maintaining ionic conductivity.
2Use of energy by moving object
If cell voltage is increased to improve energy density, then energy density improves, but electrolyte decomposition occurs leading to cell failure
Solution Approach 1:
The patent changes the electrochemical stability window parameter by using SO2-based electrolyte with conducting salts, which maintains stability at high voltages up to 4.0V or higher. This allows the battery to operate at increased cell voltages for higher energy density without the decomposition issues that plague organic electrolytes.
3Reliability
If SO2-based electrolytes are used to improve stability and safety, then stability and safety improve, but solubility of conducting salts deteriorates
Solution Approach 1:
The patent optimizes the concentration parameter of conducting salts in the SO2 electrolyte. By using specific concentrations of LiAlCl4, LiGaCl4, or LiInCl4 (typically 0.5-2.0 M), the patent achieves sufficient ionic conductivity while maintaining the stability advantages of SO2. The specific choice of salt and concentration resolves the solubility issue.
Solution Approach 2:
The patent uses SO2 as an intermediary solvent that mediates between the conducting salt and the electrode interfaces. SO2 provides a unique solvation environment that maintains salt solubility and ionic mobility while preventing decomposition reactions, thus resolving the contradiction between stability and solubility.
4Object-affected harmful factors
If SO2-based electrolytes are used to improve safety, then safety improves, but reactivity with water deteriorates operational reliability
Solution Approach 1:
The patent changes the chemical composition to use SO2 with specific conducting salts that form stable complexes. This composition change reduces the reactivity with trace water compared to pure SO2, thereby maintaining both safety advantages and operational reliability over extended cycle life.
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 design achieves enhanced energy density, stability against water, and extended cycle life with reduced self-discharge and improved safety, enabling high-voltage operation without electrolyte decomposition, thus addressing the limitations of both organic and SO2-based electrolytes.
Implementation Method 1
The electrolyte is based on SO2 and comprises at least one first conducting salt. Said first conducting salt has the formula (I)... which forms a liquid solvate complex with SO2, ensuring high solubility and oxidation stability
Implementation Method 2
At least one ion of the conducting salt (anion or cation) is sufficiently mobile in the electrolyte such that a charge transport between the electrodes, required for the functioning of the rechargeable battery cell, can take place through ionic conduction
Implementation Method 3
These electrochemical processes lead directly or indirectly to the release of electrons into the external circuit or to the absorption of electrons from the external circuit
Data Source
AI summary
This disclosure relates to a rechargeable battery cell comprising an active metal, at least one positive electrode, at least one negative electrode, a housing and an electrolyte, the positive electrode being designed as a high-voltage electrode and the electrolyte being based on SO2 and at least one first conducting salt having the formula (I),M being a metal selected from the group formed by alkali metals, alkaline earth metals, metals of group 12 of the periodic table of the elements, and aluminum; x being an integer from 1 to 3; the substituents R1, R2, R3 and R4 being selected independently of one another from the group formed by C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 cycloalkyl, C6-C14 aryl and C5-C14 heteroaryl; and Z being aluminum or boron.