SO2 Electrolyte Salt Chemistry for High-Voltage Rechargeable Cells
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Solution Overview
Problem
SO2-based electrolytes for rechargeable battery cells face issues with oxidative decomposition at high voltages, low solubility of conducting salts, and reactivity with water, leading to stability and safety concerns, particularly in high-energy applications.
Innovation Solution
An SO2-based electrolyte with a specific conducting salt formula, which forms a stable liquid solvate complex with SO2, ensuring high solubility and oxidation stability up to higher voltages, and is inert to cell components, reducing self-discharge and improving operational reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SO2-based electrolyte is used in rechargeable battery cells, then the electrolyte provides high ionic conductivity and forms stable solvate complexes, but the electrolyte undergoes oxidative decomposition at high voltages and reacts with water, leading to stability and safety concerns
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing specific conducting salts with formulas (I) and (II) containing chelating ligands and fluorinated groups. These parameter changes in molecular structure provide oxidation stability up to 5.0 volts and reduced water reactivity while maintaining high ionic conductivity through the SO2 solvate complex formation.
2Quantity of substance
If conventional conducting salts are used in SO2-based electrolyte, then the electrolyte can be formulated, but the conducting salts exhibit low solubility in SO2, limiting ionic conductivity
Solution Approach 1:
The patent modifies the conducting salt parameters by incorporating chelating ligands and fluorinated alkyl or aryl groups in the molecular structure. These parameter changes enhance the salts' solubility in SO2 while maintaining high ionic conductivity through improved solvate complex stability.
3Use of energy by moving object
If the electrolyte is designed for high voltage operation, then energy density is improved, but oxidative decomposition occurs at the positive electrode, reducing service life
Solution Approach 1:
The patent changes the electrochemical parameters of the electrolyte by using conducting salts with oxidation potentials exceeding 5.0 volts. This parameter change enables high voltage operation for improved energy density while the stable solvate complex formation prevents oxidative decomposition, extending service life through enhanced electrochemical stability.
4Adaptability or versatility
If organic solvents are used in lithium-ion cells, then the cells are referred to as organic lithium-ion cells, but the organic solvent is combustible, creating safety risks
Solution Approach 1:
The patent replaces combustible organic solvents with SO2-based electrolyte that forms stable solvate complexes with conducting salts. This creates an inert environment that eliminates combustion risks while maintaining the electrolyte's flexibility and adaptability for various battery applications through the stable complex formation.
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 electrolyte provides a broad electrochemical window, increased service life, improved energy density, and enhanced operational reliability, including under harsh conditions, while minimizing water reactivity and reducing production costs.
Implementation Method 1
An SO2-based electrolyte with a specific conducting salt formula, which forms a stable liquid solvate complex with SO2, ensuring high solubility and oxidation stability up to higher voltages
Implementation Method 2
At least one ion of the conducting salt (anion or cation) can move in the electrolyte such that charge can be transferred between the electrodes, this being essential for the rechargeable battery cell to function, by means of ionic conduction
Implementation Method 3
The electrolyte is oxidatively electrochemically decomposed above a specific upper cell voltage of the rechargeable battery cell. This process often leads to components of the electrolyte being irreversibly decomposed
Implementation Method 4
Reductive processes can also decompose the electrolyte below a specific lower cell voltage
Data Source
AI summary
SO2-based electrolyte and rechargeable battery cell (2, 20, 40) comprising this electrolyte, which electrolyte contains at least a first conducting salt of the following formula (I)wherein M is a metal selected from the group formed of alkali metals, earth alkali metals, metals from Group 12 and aluminum; x is an integer from 1 to 3; R1, R2, R3and R4 are selected, independently of one another, from the group formed of a halogen atom, a hydroxyl group, an —OR5chemical group and a chelating ligand, which is collectively formed by at least two of the substituents R1, R2, R3and R4 and is coordinated to Z; wherein R1, R2, R3and R4 are neither four halogen atoms nor four —OR5chemical groups, in particular alkoxy groups; wherein the substituent R5 is selected from the group formed by C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkenyl, C3-C10 cycloalkyl, C6-C14 aryl and C5-C14 heteroaryl; and wherein Z is aluminum or boron.